Quaestiones
entomologicae
A periodical record of entomological investigations,
published at the Department of Entomology, Uni-
versity of Alberta, Edmonton, Canada
VOLUME IV
1968
CONTENTS
Editorial - The trumpet shall sound . 1
Awram - Effects of crowding on wing morphogenesis in Myzus persicae
Sulz.(Aphididae; Hemiptera) 3
Craig - The clarification of a discrepancy in descriptions of maxillary
musculature in larval Simuliidae 31
Editorial - Man and whose world? 33
McDonald - The life history of Cosmopepla bimaculata (Thomas)
(Heteroptera : Pentatomidae) in Alberta 35
Klassen - Dispersal of mosquitoes 39
Sehgal - Descriptions of new species of flies of the family Agromyzidae
from Alberta, Canada (Diptera) 57
Book review 89
Tawfik - Feeding mechanisms and the forces involved in some
blood-sucking insects 92
Abdelnur - The biology of some black flies (Diptera : Simuliidae)
of Alberta 113
Editorial - On the life and death of information 175
Krishnan - Lipid metabolism in Blattella germanica L.: composition during
embryonic and post embryonic development 177
Matthews - A paleoenvironmental analysis of three late Pleistocene
coleopterous assemblages from Fairbanks, Alaska 202
Tawfik - Effects of the size and frequency of blood meals on Cimex lectularius L 225
11
Abdelnur, O.M., 113
Acheta mitrnra, 179
Acridium peregrinum, 178
Acylophorus, 210
Adams, P.C.G., 48, 51
Aedes, 39
aegypti, 40, 50, 92
head, 95
mouthparts, 94
albopictus* 49
aldrichi , 44
albimanus, 92
cantator, 50
cataphylla, 42
communus, 49
dorsalis, 49
fitchii , 40
flavescens, 50
leucocelaenus, 49
nigromaculis , 50
punctor, 42
spencerii, 50
sollicitans, 39
tarsalis , 42
taeniorhynchus, 39, 49
Aeshna ,117
Agonum quinquepunctatum, 210, 219
Agrion ,117
Agromyza albertensis (n.sp.), 57, 77
ambigua , 58
barberi, 59
isolata, 60
masculina (n.sp.), 57, 59, 78
niveipennis, 58
spiraeae, 60
Agromyzidae (from Alberta), 57
Alaska, 202
biota, 204
paleoenvironment, 202
physical environment, 204
Albrecht, G., 193, 197
Allais, J.P., 178, 197
Amara alpina, 203, 210
Anderson, G.B., 3, 29
Anderson, J.R., 117, 166
Annelida, 1 17
INDEX
Anopheles albimanus, 48
aldrichi , 49
atroparvus, 48
cantator, 49
culcifacies , 40
flavirostris, 48
freeborni , 40
funestus, 48
gambiae, 42, 48
labranchiae , 48
maculipennis , 39, 48
melas, 45
minimus, 48
pharoensis 39, 48
quadrimaculatus , 40, 92
saccharovi , 39
sollicitans , 48
sundaicus 39, 48
wgws , 48
Ansell, G.B., 196, 197
Aphididae, 3
aphids, alate, 3
apterous, 3
Aphodius, 21 1, 219
aquatic organisms, 1 1 7
Arnason, A.P., 113, 166
Arthropoda, 117
Athabasca River, 1 18
Athripsodes, 118
Awram, W.J., 3, 8, 29
Babcock, K.L., 177, 198
Bacot, A.W.,225,256
Bailey, S.F., 40,51
Ball, G.E., 75, 208, 223
Barlow, C.A., 249,256
Barlow, J.S., 180, 198
Barnley, G.R., 159, 166
Barreda, E.A., 159, 166
Barreda, E.A., 159, 166
Basrur, V.R., 113, 166
Bartlett, G.R., 182, 198
Beckel,W.E., 227,256
bed bugs, 92
beetles (ground), 89
behavior (mosquito), 40
Bell, W., 225,256
Ill
Bembidion , 209
(Peryphus), 209
grapei , 209
(Plataphodes), 209
arcticum , 209
Bennet-Clark, H.C., 101, 109
Bennett, G.F., 148, 166
Bidlingmayer, W.L., 40, 51
Bieber, L.L., 196, 198
Bison priscus, 214
black flies, 1 1 3
Blackith, R.E., 178, 198
Blatchley, W.S., 35,37
Blattella germanica ,177
vaga, 192
blood meals, 225
size effect, 227
Boell, E.J., 178, 198
Bonnemaison, L., 3, 29
Bonnet, D.D., 49, 52
Bowland, J.P., 197
Brachycentrus occidentalis , 117
Brachycera, 120
Brevicoryne brassicae, 3
Britton, M.E., 204, 223
Brown, A.W.A., 113, 167
Brown, W.J., 223
Buerger, G., 96, 109
Bugher, J.C., 50, 52
Burton, A.C., 108, 109
Burton, G.J., 50, 52
Busnell, R.G., 192, 198
Busvine, J.R.,92, 109
Buxton, P.A., 92, 109
Byrrhidae, 21 1
Byssodon, 121
Caenocara ,211
Camelops ,214
Cameron, A.E., 133, 167
Campbell, F.N., 192,200
Canada, 33, fossils, 202
carabid, 202
Carabus chamissonis ,203
truncaticollis , 209
Carausius (Dixippus) morosus, 178
Carlsson, G., 140, 167
Carrol, K.K., 181, 198
Causey, O.R., 44, 52
Ceratopogonidae, 120
Cerodontha dorsalis, 65
occidentalism, sp.), 57,64,82
Chew, R.M., 45,53
Chironomidae, 118
Chisholm Creek, 120
Chojnacki, T., 196, 198
Cholodkowsky, N., 92, 109
Chordata, 1 18
Choristoneura fumiferans, 47
Christophers, S.R., 92, 109
Chrysolina, 21 1
Chrysomelidae, 211
Chubb, H.S., 51 , 53
cibarial dilators, 103
pump, 101
Cimex lectularius, 92, 225
blood meals, 225
eggs, 238, 249
fecundity, 237, 245
head, 94
instars, 25 1
longevity, 241
moulting, 244
mouthparts, 93
nymphs, 227, 241
preoviposition period, 237, 245
weight, 245
Clarke, J.L., 40, 52
Clements, A.N., 39, 52, 92, 109
Clifford, H.F., 166
Cnephia-, 123
emergens , 125, 153
mutata, 113, 125, 151
saileri , 125
saskatchewana, 125
Coleoptera, 45, 118
fossils, 202
Colinvaux, P.A., 222, 223
Collins, D.L., 117, 170
Colymbetes, 210
Coope, G.R., 202, 223
Cook, E.F., 31
copulation (in Cosmopepla ), 35
Corixidae, 118
corpus allatum, 241
Cosmopepla bimaculata (of Alberta), 35
life history, 35
Cragg, F.W., 225, 256
Craig, D.A., 31
IV
Cross Lake Creek, 1 1 9
Crosskey, R.W., 166
crowding (effects of), 3
adults, 22
larvae, 24
parents, 24
temporary, 17
throughout reproductive period, 5
Crustacea, 117
Cryobius, 208
Cryptophagidae, 21 1
Cryptophagus, 21 1
Culex pipiens berbericus, 39
fatigans, 50
quinquefasciatus, 50
salinarius , 50
tarsalis, 39, 50
Curculionidae, 21 1
Curimopsis, 21 1 , 222
Cutkomp, L.K., 180, 199
Cymindis, 210, 219
Dalmat, H.T., 145, 167
Dame, D.A., 40, 52
Daphnia, 117
Das, G.M.,31
Davies, D.M., 147, 167
Davies, L., 120, 168
Davis, G.C., 51 , 52
Davis, N.T., 225,256
DeCoursey, R.M., 36, 37
Decticus, 105
development (of Cosmopepla ), 35
Defant, F., 45, 52
DeFoliart, G.R., 139, 171
DeMeillon, B., 42, 52, 225, 258
Deonier, C.C., 159, 169
Dethier, V.G., 129, 168
Diacheila polita, 209
Dianous, 210
Dicke, R.J., 117, 166
Dickerson, G., 92, 109
Dicrostonyx , 214
Dindymus versicolor, 97
Diploptera dytiscoides, 192
Diptera,47,57, 113, 118
dispersal (of mosquitoes), 39
& behavior, 40
& topographical features, 44
& wind, 41
Drosophila, 1 1
Dryptini, 89
Dubois, R., 177, 198
Dunbar, R.W., 113, 168
Durdan, A., 181, 200
Dyschirius , 209
nigricornis, 209
Dytiscidae, 1 18, 210
Eabry, H.S., 117, 170
Ectemnia, 121
Edwards, F.W., 120, 168
egg laying (in Cosmepepla ), 35
eggs (of Cosmopepla ), 36
(of Simuliidae), 133
Ejercito, A., 48, 52
Elaphrus ,219
pallipes , 209
riparius , 209
Elateridae, 211
Elmore, C.M., 48, 52
embryogenesis, 177, 192
Enderlein, G., 92, 109
England climates, 202
environment, postnatal, 7
prenatal, 7
Ephemerida, 117
Ephemeroptera, 1 17
Equus, 214
Esox lucius, 1 1 8
Esselbaugh, C.O., 36, 37
Eusimulium, 121
Eva Creek, 202, 205
Evans, A.M., 92, 110
Evans, W.G., 29,36, 197
Expo 67, 33
Eyles, D.E., 39, 52
Fairbanks, Alaska, 202
frozen silts of, 204
Fairchild, G.B., 159, 168
Fallis, A.M., 148, 168
Fast, P.G., 177, 198
fatty acids, 187
Fawzi, M.H., 179, 198
fecundity, 6
feeding apparatus, 93
mechanisms, 92
rate & forces, 98
Felt, E.P., 39,52
Fernando, W., 92, 109
V
Fink, D.F., 192, 198
Finkel, A.J., 192, 198
Finney, D J., 230, 256
Flatbush (Andy’s) Creek, 1 19
flies (new species), 57
Flint, W.P., 92, 110
Florence, L., 92, 109
Folch, J.M., 180, 189
food (of Cosmopepla), 35
food canal, 96
fossils (Coleoptera), 202
ecological classification, 214
identification notes, 208
fossils (mammalian), 214
fossils (pollen), 214
Fredeen, F.J.H., 113, 168
French Creek, 1 1 9
Frey, D.G., 202, 224
Frick, K.E.,57,75
Friend, W.G., 225,256
Fulleborn, F., 92, 109
Galun, R., 50, 55
Gammarus, 1 17
Garnham, P.A., 159, 169
Garrett-Jones, C., 48, 52
Gartrell, 40, 46
Gastropoda, 1 17
Geyh, M.A., 207
Giglioli, M.E.C., 45, 52
Gilbert, L.I., 177, 198
Gilby, A.R., 177, 199
Gillies, M.T.,45,52
Gilmour, D., 177, 199
Giral, F., 180, 199
Giral, J., 180, 199
Giral, M.L., 180, 199
Gjullin, C.M., 159, 169
Glick, P.A.,47,52
Gnus, 121
Goiny, H.H., 159, 169
Golberg, L., 225, 258
Gooding, R.H., 92, 1 10, 197, 240, 256
Gordon, R.M., 92, 109
Gottlieb, M.I., 179,200
Goulden, C.H., 5,29
Goulding, R.L., 159, 169
Greenbank, D.D., 47, 53
Greenslade, P.J.M., 202, 224
Grenier, P., 120, 169
Griffiths, G.C.D., 58,75
Gunstream, S.E., 45, 53
Guthrie, R.D., 205, 224
Gymnopais, 121, 123
Gyorkos, H., 122, 174
habits (of Cosmopepla), 35
Habu, Akinobu, 89
Hadjijev, D., 197
Haeger, J.S., 40, 53
Hagenomyia, 121
Handlirsch, A., 120, 169
Happold, D.C.D., 113, 169
Harden, F.W., 4 0, 53
Harrison, L., 92, 1 10
Hase, A., 225,257
Hasset, C.C., 45, 53
hatching (of Cosmopepla), 36
Haufe, W.O., 47,53
Hays, R.O., 40, 54
Hilditch , T.P., 177, 199
Hill, D.L., 178, 199
Hinton, H.E.,31
Hirudinea, 1 17
Hitchen, C.S., 159, 169
Headlee, T.J., 53, 54
Hearle, E., 44, 53
Helicopsyche borealis, 1 17
Helobdella stagnalis, 1 17
Helodon, 121
Hemimetabola, 234
Hemiptera, 92, 118
Heptagenia, 1 17
Heteroptera, 35
Hocking, B., 2, 29 ,34, 36, 39, 40, 42, 53, 75, 108,
113, 166, 169
Holmes, J., 166
Homoptera, 3
Hopkins, D.M., 212
Horsfall, 44, 53
Horhammer, L., 182, 201
Hoskins, C.H., 223
Howden, G.F., 178, 198
Hughes, Col., 166
Hughes, N., 166
Hyalophora cecropia, 192
hydrocarbon content, 186
Hydrophilidae, 118
Hydropsyche, 1 17
recurvata, 117
VI
hypsotaxis, 44
Imms, A.D., 92, 110
incubation period (of Cosmopepla), 36
insect fats, 177
insect fossils, 202
insects (and man), 33
(as trumpeters), 1
blood-sucking, 92
intraspecific interaction, 9
Irish Creek, 119
Ivanova, L.V., 45, 53
Jamnback, H.A., 113, 172
Janisch, E., 225,257
Jeffery, G.M.,92, 110
Jenkins, D.W., 45, 53
Jobbins-Pomeroy, A.W., 133, 177
Johansson, A.S., 240, 257
Johnson, B., 3, 29
Johnson, C.G., 225, 257
Jones, R.M., 225, 257
Kalmus, H., 44, 53
Kassianoff, L., 225, 257
Kemper, H., 92, 1 10, 225, 257
Kennedy, J.S.,41,53
key to Simuliidae, 122, 125
Kilby, B.A., 177, 199
Kindler, J.B., 159, 170
Kinsella, J.E., 177, 199
Kirkpatrick, T.W., 39, 53
Klassen, Waldemar, 39, 40
klinokinesis, 45
Knowlton, G.F., 113, 172
Krishnamurthi, 197
Krishnan, Y.S., 177
Kumm, H.W., 44, 52
laboratory rearing (roaches), 180
(Simuliids), 145
Lafon, M., 178, 199
Landau, R., 112, 170
Larson, D.J., 91
larviposition, 6
Lathrobium, 210
Lea, A.O., 159, 170
Lebia , 90
bifenestrata, 90
Leech, R., 166
Lees, A.D., 3, 29
Lees, M., 180, 198
Lemurimyza pallida (n.sp.), 57, 72, 87
LePrince, J. A .A., 48, 54
Leptocella, 118
Lepyrus gemellus , 21 1
Leucophaea maderae, 179
life history (of Cosmopepla ), 35
Limnephilus canadensis, 1 17
Lindquist, A. W., 40, 54
Lindroth, C.H., 45, 54, 203, 224
lipid metabolism, 177
lipids (extraction), 181
purification), 181
Liriomyza assimilis , 67
conspicua (n. sp.), 57, 66, 83
cordilleranc^ n.sp.), 57, 69, 72, 85
eupatori , 68
flaveola , 7 1
flavonigra, 61
graminicola , 68
montana (n.sp.), 57 ,67 , 84
pedestris , 68, 70
richteri , 68
septentrionalis( n.sp.), 57, 70, 86
Livingston, D.A., 222, 224
Locke, M., 225, 257
Locus ta migratoria ,178
pardalina ,179
Lofgren, C.S., 180, 199
Low, N., 48, 54
Lowry, O.H., 251, 257
LT50, 230, 235
Ludwig, D., 192, 199
Lumsden, W.H.R., 92, 109
Lupinus sericeus, 75
McCarthy, R.D., 181,200
McCay, C.M., 179, 199
MacCreary, D., 45, 54
McCrae, A.W.R., 166
McDonald, F.J.D., 35
MacDonald, W.W., 47, 54
McDuffie, W.C., 113, 169
McGee assemblage, 220
MacGillivray, M.E., 3, 29
McMahon, J.P., 159, 169
Mackerras, I.M., 145, 170
Mackerras, M.J., 145, 170
Macrosiphum solanifolii, 3
Maddock, D.R., 159, 170
Madge, R., 89
Mammuthus, 214
man, 33
Mangold, G.K., 181, 199
Mason, W.R.M., 204, 224
Matsuda, R., 31
Matthee, J.J., 179, 199
Matthews, J.V., 202
maxillary musculature (Simuliidae), 31
Maynard, L.A., 179, 200
Melanagromyza, 62
Mellampy, R.M., 179, 200
Mellanby, K., 225, 257
Melanoplus atlanis , 1 80
differential is ,178
sanguinipes, 180
Merriam’s lifezones, 204
Metcalf, C.L., 92, 110, 141, 170
Mickel, C.E., 113, 171
Micralymma, 210, 221
Micro t us gregalis, 214
Miles, P.W., 97, 110
Mitchell, P.H.,98, 110
Mollusca, 117
Moorebdella ferrida, 1 1 7
Morland, H.B., 40, 54
morphology (of Simuliidae), 31
Morychus, 211
mosquitoes (dispersal), 39
(passive transport), 47
movement, along lines, 45
toward illumination, 45
with strata of vegetation, 45
Moxostoma, 1 18
Muirhead-Thomson, R.C., 159, 170
Munson, S.C., 179, 200
myristic acid, 187
Myzus persicae, 3
Nebria nivalis , 203
Needham, J., 177,200
nematodes, 162
Nemoura, 117
Nicholson, H.P., 113, 170
Nielsen, E.T., 40, 54
Niemierko, W., 177, 200
Nimmo, A., 166
Noble, L.W., 47,52
Notiophilus, 209
borealis , 209
semistriatus, 209, 219
Nuttall, G.H.F., 92, 110
Odacanthini, 89
Odonata, 1 17
offspring (of aphids), 3
survival rate, 24
O’Kane, W.C., 133, 171
oleic acid, 187
Olophrum, 210
Omaliinae, 210
Omori, N., 225, 258
Oncopeltus, 97
Ophiomyia monticola (n.sp.), 57, 60,62,79
nasuta , 61
pulicarioides{ n.sp.), 57, 61 , 62, 80
punctohalterata, 62
Orgain, H., 40, 52
Osborn, H., 147, 171
Osborne, P.J., 202, 224
Ovibos moschatus, 2 1 4
Ovis nivicola ,214
Paederinae, 210
Paige, R.A., 204, 224
paleoenvironment (of Alaska), 202
Parasimulium ,121,123
parasites (of Cosmopepla ), 36
Pasternak, J., 113, 171
Patton, S., 181, 200
Patton, W.S., 92, 110
Pausch, R.D., 40, 54
Pawlowsky, E., 92, 110
Peacock, A.D., 92, 1 10
Pearincott, J.V., 196, 200
Pearson, R., 202, 224
Peck, O., 36
Pediculus humanus, 92
head of, 96
Pembina River, 1 1 8
Pentatomidae, 35
Periplaneta americana, 178
Peterson, B.V., 166
Peterson, D.G., 113, 171
Petrishcheva, P.A., 159, 171
Pewe, T.L., 204, 224
Phelps, R.J., 139, 171
Phillipson, J., 140, 171
phospholipids, 178, 187
Phytobia amelanckieris, 63
flavohumeralisf n.sp.), 57, 62, 81
(Phytobia) setosa , 63
waltoni , 63
viii
Phytomyza agromyzina, 75
angelicella , 74
aquilegiana, 74
lupini (n.sp.), 57, 73, 88
lupinivora (n.sp.), 57, 74, 88
Pickard, E., 45,55
Pickering, L.R., 141, 169
Piechowska, M .J., 196, 198
Pimephales promelas, 1 1 8
Pisces, 1 1 8
Plecoptera, 1 17
Pleistocene assemblages, 202
Poisson, R., 35, 37
pollen analysis, 220
Poly centro pus, 1 18
Popillia japonica, 192
population densities (effects), 5
on fecundity, 27
on longevity, 27
on offspring, 27
(on Simuliids), 138
postembryonic development
(of Cosmopepla ), 36
Prevost, G., 113, 171
Prosimulium , 121, 123
decemarticulatum , 125
fontanum, 113
frohnei, 1 1 3
formosum ,113
fulvum, 113, 125
fuscum, 1 1 3
hirtipes, 1 1 3
mixtum, 1 1 3
onychodactylum , 113, 125
pleurale ,125
travisi , 1 13, 125, 151
protein content, 251
Provost, M.W., 39, 54
Psilozia, 121
Psorphora, 5 1
Pterostichus , 208
( Cryobius) , 209
anriga, 209
brevicornis, 210, 221
caribou, 210
chipewyan, 209
gerstlensis, 209
kotzebuei , 209
mandibularoides, 210, 221
Pterostichus ( Cryobius)
nivalis , 210, 221
ochoticus, 209, 221
parasimilis, 209, 221
pinguedineus , 209, 221
similis, 209, 221
soperi, 209
tareumiut, 209, 221
ventricosus, 210, 221
Pterostichus (Sterocerus) haematopus ,210,221
Pulmonata, 1 17
Puri, I.M., 31
Quarterman, K.D., 51,54
Radzivilovskaya,A., 120, 172
Rageau, J., 120, 169
Rainey, R.C., 192, 100
Ramazzotto, L.J., 192, 199
Rangifertarandus , 214
Raphanus sativus, 4
Rhodnius prolixus , 101 , 227
Rhopalosiphum prunifolia, 3
Ribbands, C.R., 44, 54
Richards, W.R., 113, 169
Rickard, E.R., 48, 54
Robinson, G.G., 92, 110
Roeder, K.D., 108, 110
Rosentiel, R.G., 40, 55
Ross, H.H., 192,200
Ross, R., 40, 55
Roth, L.M., 192,200
Rothfels, K.H., 113, 172
Rothstein, F., 192, 200
Roy, D.N., 249,258
Rubtzov, I.A., 120, 172
Rudolfs, W., 192,200
Russell, P.F., 40, 55
Rutschky, C.W., 177, 198
Sacharov, N.L., 179, 200
Saf’yanova, V.M., 159, 171
Sanderson, M, 223
Sane, P.V., 197
Santiago, D., 48, 55
Sato, S., 44, 55
Sautet, J., 40, 55
Scarabaeidae, 211
Schaefer, C.W.,225,25 6
Schiemenz, H., 92, 110
Schneidermann, H.A., 192, 198
Schoof, H.F.,40, 51
IX
Schweet, R.S., 179, 200
Scoggin, J.K., 177, 200
Scott, J., 109
Scydemaenidae, 21 1
Sehgal, Vinod K., 57
sense organs, 96
(of Cimex), 97
Sharplin, J., 166
Shemanchuk, J.A., 50, 55, 113,169
Shewell, G.E., 120,172
Shotton, F.E., 202, 224
Siakotos, A.N., 179, 200
Sikora, H., 92, 110
Silpha sagax ,211
trituberculatus, 21 1
Silphidae, 21 1
Simpolcaria, 211
Simuliidae, 1 13
adults, 148
control, 159
larvae, 31 , 134
larval migration, 142
life history, 151
maxillary musculature, 31
pupae, 147
Simulium , 123
arcticum, 125, 153
aureum , 113, 125, 154
bivittatum, 125
corbis ,125
decorum, 124, 155
griseum, 125
hunteri , 124
latipes, 113, 125, 155
luggeri , 124, 156
malyshevi, 124
meridionale, 124
pictipes, 125
piperi, 125
puge tense ,125
rugglesi ,125
transiens, 125
tuberosum, 113, 124, 156
venustum, 113, 124, 157
verecundum, 124, 157
vittatum, 113, 125, 158
Slifer, E.H., 178,200
Sloane-Stanley, G.H., 180, 198
Smart, J., 120, 172
Smith, G.F., 47,55
Smith, C.N., 109
Smyth, T., 178, 199
Snodgrass, R.E., 92, 110
Snow, W.E., 45, 55
Sommerman, K.M., 113, 172
Rees, D.M., 44, 54
Reeves, W.C., 50,54
Regan, F.R., 159, 170
Reger, R., 223
Rempel, J.G., 49, 54
respiration rate, 253
Spector, W.S., 25 1,258
Spencer, K.A., 57
Sphenarium purpuras ce ns , 180
Stachys palustris, 35
Stage, H.H., 44,55
Stains, G.S., 113, 172
Staphylinidae, 210
starving (effects), 3, 27
Stearns, L.A., 49, 54
Stegoconops spegassinii, 5 1
Stegopterna, 121
Steiner, G., 41, 55
Stenus, 210
sterol content, 186
Stojanovich, C.J., 92, 111
Stone, A., 113, 173
Strickland, E.H., 113, 173
stroking, 1 1
(effects), adults, 12
larvae, 16
Syme, P.D., 147, 167
Swellengrebel, N.H., 48, 55
Tachinus, 210
Tachyporinae, 2 1 0
Taeniopoda auricornis, 180
Tauber, O.E., 177, 200
Tawfik, M.S., 92, 225
Taylor, J., 50, 52
taxonomic relationships (Coleoptera), 219
Tettigonia, 105
Theromyzon occidentalis , 1 17
Tichimirov, A., 192, 201
Timon-David, J., 177, 201
Titschack, E., 225, 258
transport, passive, 47
Travis, B.V., 159, 173
Trichocellus porsildi, 210
X
Trichoptera, 1 1 7
Twinn, C.R., 113, 169
Twinnia, 121 , 123
Umbreit, W.W., 251,258
Urbino, C.M., 48, 52
Usinger, R.L., 109,225,258
VanBreeman, M.L., 48, 55
Vargas, L., 159, 173
Veraphis , 2 1 1
Vlasov, N.A., 159, 172
virginopara, apterous, 4
vitellogenesis, 240
Vogel, R., 92, 1 1 1
VonGernet, G., 96, 109
Wada, Y., 40,55
Wadley, F.M., 3, 29
Wagner, H., 182,201
Wanson, M.L., 159, 173
Weber, H., 92, 111
Wellington, W.G., 47, 55
Wenyon, C.M., 48, 55
West, A.S., 113, 171
Westwood, J.O., 120, 173
Wiegers, J.E., 223
Wigglesworth, V.B., 105, 111,227,258
Williams, C.B., 148, 173
Wilton, D.P., 159, 173
wing morphogenesis, 3
Wisconsin age, 202
Wolfe, A.S., 113, 171
Wolff, P., 182,201
Wolfinsohn, M., 50,55
Wood, D.M., 122, 167
Worcester, D.J., 49, 52
Wright, S., 98,111
Wu, Y.F., 120, 174
Yakuba, V.N., 142, 174
Zahar, A.R., 120, 174
Zoller, H.S., 170,200
Quaestiones
entomologicae
A periodical record of entomological investigations,
published at the Department of Entomology, Uni-
versity of Alberta, Edmonton, Canada.
VOLUME IV
NUMBER 1
JANUARY 1968
QUAESTIONES ENTOMOLOGICAE
A periodical record of entomological investigations published at
the Department of Entomology, University of Alberta, Edmonton, Alberta.
Volume 4 Number 1 3 January 1968
CONTENTS
Editorial 1
Awram - Effects of crowding on wing morphogenesis in
Myzus persicae Sul z. (Aphididae; Hemiptera) 3
Craig - The clarification of a discrepancy in descriptions of
maxillary musculature in larval Simuliidae 31
Editorial - The Trumpet shall Sound
Strictly speaking, insects have no need of a trumpeter, for though
they lack both the blow and the lips to perform on this imposing instru-
ment nevertheless some of them seem to produce a similarly regal sound
in a related manner. Neither are insects in need of anybody to beat the
drum for them, for many are accomplished performers on percussion
instruments. But since neither human ears nor hearing aids of any kind
are yet attuned to all of the messages thus broadcast, a word of comment
may be appropriate.
It is believed that when a queen bee produces the piping sound one
so often hears of but so rarely hears, she does so by forcing air out
through the thoracic spiracles. These, supposedly, are appropriately
tuned or tensioned. By contrast the death's head hawk moth produces a
sound sufficiently similar to gain her some, at least, of the privileges
of .the queen bee by forcing air out through the mouthparts. This is a
skill which any trumpeter might covet. It is perhaps no accident that in
many places human percussion instruments started from hollow logs,
since many insect percussors, from termites to beetles, perform on
these instruments. Human ideas in many fields have originated from
insect activities, and Pope's advice still applies:
Go, from the creatures thy instructions take:
Thy arts of building from the bee receive;
Learn of the mole to plough, the worm to weave;
Many years ago my duties as an entomologist in Calcutta con-
verged strangely with those of an exorciser of ghosts. I was called in
rather early one morning to advise on the possible source of a fine speci-
men of the cerambycid Stromatium barbatum Fabr. When I arrived the beetle
was nonchalantly waving its antennae from the mantelshelf at a somewhat
less than enthusiastic member of the household of a petty rajah. Across
the corner of the room was a recently acquired grand piano. I commented
on this and occasioned embarrassment; tactles s persistance revealed that
the house was haunted and the ghost a pianist - of sorts. Grovelling under
under the piano I came upon a tidy pile of rather coarse wood strands
2
and, dropping a negative plumb line upwards, a rounded rectangular hole
in the frame of the piano. Solicitous enquiries of the household in the
days that followed confirmed my suspicions that this hole marked the
exit of both the beetle and the ghost. The lusty chewing of the larvae,
supplemented perhaps by the stridulation of the adult evidently invoked
a minor resonance in the strings of the instrument. I put a plug in the
hole.
Insects contribute so much that is of interest in life that we should
all of us be prepared to put in a plug for them when opportunity offers,
for though they need neither trumpeter nor drummer among their own
kind, we who are of coarser fibre are too often insensitive to them.
They, for their part, too often leave their holes open.
Brian Hocking
3
EFFECTS OF CROWDING ON WING MORPHOGENESIS
IN MYZUS PERSICAE SULZ. (APHIDIDAE; HOMOPTERA)
W. J. AWRAM
Rothamsted Experimental Station Quaestiones entomologicae
Harpenden, Herts., England 4 : 3 - 29 1968
Adult apterous aphids, Myzus persicae Sulz., were raised on discs of radish and cabbage
leaves to determine the effect of different population densities on the proportion of alate off-
spring produced. Parents in the higher density treatments produced a greater proportion of alate
offspring. It is thought that this was a result of the crowding of the young instars as well as the
crowding of the parents. Parents fed on cabbage produced a greater proportion of alate offspring
than did those on radish. The fecundity of the adults and the survival of the offspring were re-
duced when fed on cabbage.
An effect of crowding was imitated by stroking the dorsal surfaces of the head, thorax, fore
and hind abdomen, sides of the abdomen, antennae, and legs of adult apterae. These procedures
caused no increase in the proportion of alatae among the offspring. A slight response of question-
able significance was obtained to stroking over the general dorsal surface. A few first and second
instar larvae were also stroked; none became alate.
Temporarily starving and crowding young adult apterae did not cause them to produce more
than a normal number of alate offspring. First instar larvae were crowded. If their parents had
not been crowded, most developed into apterae. If their parents had been crowded, most became
alatae. In the clone studied larvae remained indeterminate as regards wing development at least
until the first moult and possibly until the second.
An association between conditions of crowding and the develop-
ment of winged forms in aphids has been reported (Wadley 1923 in
Rhopalosiphum prunifolia Fitch, Bonnemaison. 1951 in Myzus persicae Sulz. and
Brevicoryne brassicae L. ). Lees (1959) suppressed alate production by raising
Megoura viciae Buckton individually . In 1961 Lees reported that individually
raised apterae which were producing only apterous offspring, produced
alate offspring if they were crowded together in a testtube for 24 hours.
Johnson (1965) presented substantial evidence that contact between two
adults of Aphis craccivora Koch caused them to produce winged offspring.
He concluded that mechanical rather than visual or olfactory contact
effected the response. The dorsal rather than the ventral surface of
the parent aphid was affected by the stimulus. Aphids kept together for
periods of time as short as 1 minute produced alate larvae. Most of the
parents which responded did so completely, that is, their offspring were
all alate. Johnson attempted to effect an artificial mechanical stimulus
by stroking adult aptera for 2 minutes with a brush. Aphids so treated
produced a percentage of alate offspring intermediate between that of
singly reared parents and parents which had been in physical contact
with other adults. MacGillivray and Anderson (1958) reported that the
development of wings in Macrosiphum solanifolii Ashm. was not a response
to crowding. Myzus persicae Sulz. raised concurrently under the same con-
ditions did not develop winged forms.
My original objective was to produce alate offspring by mechani-
cally stimulating (stroking) their apterous parents. The purpose was to
4
Awram
determine whether the essential, functional component of the "effet de
groupe" (Bonnemaison 1951) was physical contact among the crowded
adult aphids. Concurrent with efforts to induce the production of alatae
mechanically, adult apterae were raised under different degrees of crow-
ding to insure that the particular clone studied responded to crowding by
producing alate offspring. The results of the first few experiments forced
a broadening of the basis of the general objective, which then became an
investigation of the effects of intraspecific interaction on the development
of wings in the aphid Myzus persicae Sulz.
METHODS AND MATERIALS - GENERAL
A clone of Myzus persicae was begun in early December 1964 with a
single apterous virginopara taken from a radish plant in a greenhouse.
The descendants of this individual were raised in a plywood cabinet, in
a constant temperature room at 60 F. From March 1965 a Sherer Gro
Lab growth chamber was used (500 foot candles at the leaf surface).
The aphids were reared on discs of radish leaf cut with an 18 mm
cork borer. The discs were placed, dorsal surface down, on a column
of wet cotton wool in a short glass tube. The aphids were contained on
the ventral surface of the disc by means of a small cylindrical glass
tube. An elastic band secured the cage and also pressed the disc of
radish into the cotton wool and ensured contact between the disc and the
water in the cotton. The glass tubes were placed in distilled water, in
an aluminum tray. Each cage was 12 mm in diameter inside and 9 mm
high, enclosing an area on the leaf of 113 mm^; the glass tube which
supported the cotton wool was 35 mm in diameter and 32 mm high. Cir-
cles, cut from a nylon fabric (27 strands per mm), were glued with
LePage's Pliobond to the tops of the glass cages (fig. 1). Each cage
was identified by a number in wax pencil on the glass tube. At the end
of each experiment, both cages and tubes were washed and the tubes
were refilled with fresh cotton wool. The discs were cut from radish
( Raphanus sativus L. ) plants, variety Forcing Scarlet Globe, grown under
natural lighting conditions during the summer. In the fall and winter
supplemental artificial light was added to bring the photoperiod to 14
hours. Only vigorous, growing leaves were used. The photoperiod in
the growth chamber was set at a constant 16 hours light per 24 hours for
all the experiments. The temperature was set at 72 F for 16 hours and
55 F for the remaining 8 hours. The 1& hours at 72 F began 1 hour after
the lights were switched on. The growth chamber malfunctioned twice
during the series of experiments. Both times conditions were restored
to normal within a few hours.
The leaf discs remained in suitable condition for 4-7 days, de-
pending on the density of aphids feeding on them. Both adults and larvae
were handled with a moist camel hair brush. The brush was inserted
between the front legs from in front and the aphid was moved. Care was
taken to avoid touching the dorsal surface.
Wing Morphogenesis
5
32 mm
35 mm
Fig. 1. Rearing cage.
EXPERIMENTS
Twenty five experiments were conducted; 4 on the effect of con-
tinuous crowding; 10 on the effect of stroking, 6 with adults and 4 with
larvae; 11 on the effects of temporary crowding, 5 of adults from crow-
ded parents, 3 of adults from parents raised singly and 3 of larvae from
parents variously raised.
The data from all experiments were analyzed by means of an
IBM 7 040 computer, program number BMD02V, an analysis of variance
for factorial design. The death of individual aphids resulted in some
missing values. Where there was one missing value in an experiment,
an empirical value was substituted, calculated by the missing plots method
of Goulden (I960). The experiments in which these calculations were
made are noted below.
Crowding throughout Reproductive Period
Objective and methods
Adult aphids were subjected to different degrees of crowding dur-
ing the entire reproductive period in an attempt to confirm that crowded
parents produced more alate offspring than parents which were not crow-
ded. Such treatment would also provide information on the relationships,
if any, between the age of the parent and the degree of alate production,
on the effects of crowding on the fecundity of the parents and on the sur-
vival rate of parents and offspring.
Aphids were reared under different population densities for the
entire reproductive period. The aphids chosen as parents were selected
in the fourth instar from leaf discs on which there were fewer than 10
6
Awram
individuals. When larviposition began, the parents were moved to new
discs whenever the number of offspring exceeded 7. An attempt was
made to limit the greatest number of offspring per disc to 15. As a re-
sult, parents in the greater densities were moved more often than those
under less dense conditions. The parents in the lesser densities were
picked up and put down whenno moving was necessary in order to equal-
ize, across all densities, the number of times parents were disturbed.
The offspring were raised to maturity and the form of each, alate or ap-
terous, was noted. A few intermediate forms were born. These were
classed as alate.
Four experiments in which parents were crowded during the entire
reproductive period were performed. The aphids for the third experi-
ment were selected from among the last offspring of the second experi-
ment and were kept within the density and replication of the parents. In
the fourth experiment cabbage as well as radish ^yas used as a host plant.
Results and Discussion
The results of the first experiment (table 1) confirmed the find-
ings of Bonnemaison (1951). The increased proportion of alatae was a
result of both an increase in the number of alatae born and a decrease
in the number of aptera in the higher densities. The increase in alate
offspring did not manifest itself statistically until after the first third of
the reproductive period, although the tendency appeared earlier. The
length of the reproductive period was much the same at all densities,
averaging 21 days. The fecundity of the parents was unaffected by the
increased population density, according to the statistical analysis (F< 1).
However, the number 3 replicate of the solitary group was not a normal
individual and perhaps should not have been included in the analysis. It
produced 21 offspring, the average of the solitary aphids was 61.2. A-
side from this value, there was no overlap between densities. The total
offspring per parent per day did not show a statistical difference between
densities, but a trend toward decreasing numbers of offspring with in-
creasing parent population density was apparent.
In the first experiment, it seemed that a population density of 4
parents was sufficient to produce the desired effect, therefore, in the
next experiment the 8 parent density was eliminated and a 2 parent den-
sity begun. The same trend in the proportion of the total offspring which
were winged, was observed. In the intermediate density the proportion
of alatae was closer to the control than to the highest density (table 2).
Unlike the 1,4, 8 experiment the increase of alatae was greatest in the
first third of the reproductive period. The mean total number of off-
spring (56) was close to that of the 1, 4, 8 experiment (54). However,
in the 1, 2, 4 experiment the single parents were the least fecund.
The additional data collected on the mean number of offspring
per cage provided two interesting observations. First, although the
number born per parent was highly variable (range 41-90), the percent
survival was high (grand mean 87%). The second observation was the
highly significant difference between treatments in the mean number of
offspring per cage for the first third of the reproductive period and for
the total period. In both these parameters the higher density parent
Wing Morphogenesis
7
treatments had more offspring per cage (table 2). The third experiment
used the second generation from the second experiment at the same den-
sities (1, 2, 4). Two of the solitary parents died soon after the experi-
ment was begun. Analyses of variance were done using a desk calcul-
ator. In response to the observation made in the fir st generation experi-
ment on the mean number of offspring per cage, great care was taken
to keep the size of the offspring groups fairly small; otherwise conditions
were similar. The results of the second generation 1, 2, 4 experiment
are given in table 3. The total number born per parent was even more
variable than in experiment 2 (range 12-86); the average was 52. The
per cent survival was high (88) and showed little variation (range 82-95%),
as in the first generation. However, the per cent alatae differed from
both earlier experiments and did not increase with increased parent pop-
ulation density. There was no statistical difference at P = 0. 5 between
the single parent treatment (10%) and the 4 parent treatment (12%) . Very
few more alate offspring were born to the crowded parents than to the
parents raised singly. Two explanations of the contradiction in the re-
sults of the proportions of alatae are possible. The results of the second
generation 1, 2, 4 experiment might be due to a "generation" effect. It
is possible that the environment experienced by the grandparent (parents
in experiment 2) affected the progeny of experiment 3. The phenomenon
which makes such a situation possible is the telescoping of generations
characteristic of aphids. Very often, the more mature embryos in a
parent have within themselves developing embryos. Lees (1959) has
shown that such a "generation" effect is possible in the production of
sexuals. However, I do not think this is a satisfactory explanation here.
If the stimulus which diverts an embryo toward becoming apterous also
diverts embryos which itcontains, thena first generation of aptera would
have to be followed by a second generation of aptera. This is not so.
Also, although the conditions under which the grandparents were kept
as adults differed, the parents were raised to maturity under very sim-
ilar conditions, i. e. between 5 and 10 individuals per radish disc.
A better explanation is the one suggested earlier from the results
of the first 1, 2, 4 experiment. The size of the offspring group might
have an effect on the number of larvae within that offspring group which
developed wings. Very few of the offspring groups in experiment 3 ex-
ceeded 15. AX2test (Goulden I960) was performed testing the indepen-
dence of size class of offspring groups (< 10, 10-15, > 15), and the num-
ber of alatae and apterae in these groups. In experiment 2 there was a
marked association between a large offspring group and alatae, and a
corresponding association between a small offspring group and apterae
X2= 123.9** There were no such associations in experiment 3 ( X2 =
2.46).
If the association between a high proportion of alatae and a high
larval population density is valid, then perhaps the initial premise that
high parent population density is the principal cause of alate production
is incorrect. That is, the postnatal environment rather than the prenatal
environment with respect to crowding may be more or at least equally
important. The lack of association between a high percentage of alates
and a high larval population density in the second generation 1, 2, 4 ex-
8
Awram
periment could be interpreted as a threshold response. It may take more
than 10-15 larvae to make a crowd.
TABLE 1. First crowding experiment. Mean numbers of alate and ap-
terous offspring born to apterous parents raised singly or in groups of
4 or 8.
* = P < . 05; ** = P < . 01
Bonnemaison reported that Myzus persicae raised on radish produced
more alatae than M. persicae raised on cabbage. If the hypothesis that
alatae are a result of mechanical stimulation is correct, then there is
an implication that aphids raised on radish are more restless than aphids
raised on cabbage, i. e. that on cabbage there is les s intraspecific inter-
action. Another implication is that singly raised aphids, whether on
radish or cabbage, should give birth to few alate offspring. A fourth
experiment was performed with these considerations in mind. The re-
sults (Awram 1966, table 5) were quite variable; however these obser-
vations could be made. On radish the pattern of results was similar to
the first two experiments. The greater the population density of the
parents, the greater was the proportion of winged offspring (22% for
singly kept parents, 30% for parents kept in pairs, 43% for parents kept
in groups of 4). Again the increased proportion of alatae was a result
Wing Morphogenesis
9
of both an increase in alatae and a decrease in apterae in the high den-
sities. On cabbage results were similar except that the mean proportion
of alatae in the intermediate density exceeded that in the high density
(34% alatae for singly kept parents, 58% for paired parents, 49% for
parents kept in groups of 4).
TABLE 2. Second crowding experiment. Mean numbers of offspring
born to apterous parents raised singly or in groups of 2 or 4.
* = P < . 05; ** = P < .01
Bonnemai son's observations with respect to host plant were not
confirmed; in fact, the opposite result was obtained. Both the 2 and 4
parent densities on cabbage (58%, 49%, respectively) had a greater pro-
portion of alatae than the corresponding radish densities (3 0%, 43% res-
pectively). The hypothesis that intraspecific interaction maintains alate
10
Awram
production is, however, not disproved. The effects of radish and cab-
bage are just reversed. That cabbage was a less desirable host plant
could not be doubted. The per cent survival on radish was characteris-
tically high at 91. 2 as compared to 71.7 on cabbage. The fecundity of
the parents was also affected. The number born was less on cabbage
than on radish. Cabbage would presumably result in restless aphids,
there would be greater intraspecific interaction and thus a greater per-
centage of winged individuals.
X test for independence onthe data of the fourth experiment again
indicated an association between a high proportion of alatae and a high
larval population density (X2 = 71. 36##).
TABLE 3. Third crowding experiment. Mean numbers of offspring born
to apterous parents raised singly or in groups of 2 or 4.
Wing Morphogenesis
11
Strokin g
Objective and methods
One of the more obvious effects of crowding is increased physical
contact among the individuals crowded. The mechanical stimulation re-
sulting from this increased contact might influence wing morphogenesis.
If mechanical stimulation is the principal factor eliciting the production
of alatae, then stroking the adults or the early instar larvae or both should
produce more winged forms. Aphids were stroked at various frequen-
cies, over the entire dorsum and over particular parts of the dorsum,
to determine if alate production could be so induced (or more properly
if apterae production could be reduced) and to find out if a particular
area was especially sensitive.
Adults - Fourth instar larvae were removed from offspring groups
of 10 or fewer individuals and confined alone in separate cages on radish
discs. Stroking began after they had moulted into the adult but before
they had offspring, or on the first day that offspring were born. They
were stroked at different frequencies with either the leg of an adult ap-
terous aphid, a Drosophila leg, or a human hair. The direction of stroking
was more or less caudad, with the tarsal claws of the legs raked over
the area being stroked. The aphid and Drosophila legs and the hair were
manipulated with fine forceps under X 12 power of a stereo binocular
microscope. Some treatments consisted of timed contact with a live
adult aphid which had been mounted with paraffin on a pin. The parent
aphids were moved when their offspring numbered more than 7, usually
every second day. In the first experiment only, parents were moved
almost daily.
There were 3 treatments and a control and 4 replicates in each
experiment. Missing values calculations were made for 1 replicate each
in the third, fourth, and fifth experiments. In the first experiment 100
strokes were applied daily with a hair, a Drosophila leg, and the leg of an
adult aphid respectively to the entire dorsal surface. In the second ex-
periment one batch spent 2 minutes daily in contact with a live adult
aphid, the other two received 300 strokes daily with the leg of an adult
aphid, and with a hair respectively, again on the entire dorsal surface.
In the third experiment 500 strokes daily were applied with the leg of an
adult aphid to the head, the thorax, and the abdomen respectively. In
the fourth experiment 400 strokes were applied daily with the leg of an
adult aphid to the hind half of the abdomen, the front half of the abdomen,
and to the legs respectively. In the fifth experiment 500 strokes were
applied daily with the leg of an adult aphid to the antennae and to the
sides of the abdomen, and with a hair to the entire dorsal surface. In
the final experiment one batch had 1000 strokes applied daily to the entire
dorsal surface with the leg of an adult aphid, one had 5 minutes daily
contact with a live adult aphid, and the last had a twice daily smearing
with cornicle secretion.
Larvae - The association revealed in all crowding experiments
except the third between a high proportion of alate offspring and a large
offspring group, provided a basis for suspecting that in M. persicae, the
postnatal environment may be of greater consequence than prenatal con-
ditions. Four experiments were done to test this suspicion. First and
12
Awram
second instar larvae were stroked at different frequencies with a de-
tached aphid leg. Larvae so treated were of 2 types, either from un-
crowded (first 2 experiments) or from crowded (last 2 experiments) par-
ents. They were removed from the parent within 8 hours of birth and
raised to maturity alone. The first two experiments were the same:
from 3 to 5 aphids were in each batch. One batch was stroked 500 times
in the first instar , one batch 500 times in first and secondinstars, a third
batch served as an un- stroked control. The last two experiments de-
pended on the results of the first two and are described belowunder that
heading.
Results and discussion
Adults - In the first adult stroking experiment (table 4), parents
receiving 100 strokes daily with an aphid leg gave birth to a proportion
of alate offspring much greater than others. The higher percentage of
alataewas a result more of increased alate births than of decreased ap-
terous births. In the first third of the reproductive period the number
of alate offspring was about the same as in the other treatments; by the
last third, the increased incidence of alate offspring was of statistical
significance. The length of the reproductive period was about the same
for all treatments, averaging 12.8 days. The total offspring reaching
maturity during the experiment averaged 47.7 per parent but varied from
6 to 78.
TABLE 4. First adult stroking experiment. Mean numbers of offspring
born to apterous parents stroked 100 times daily with a hair, a Drosophila
leg, or an aphid leg.
* = P < . 05; ** = P < . 01
Wing Morphogenesis
13
For the second experiment (table 5) the Drosophila leg was dropped
as a stroking device because of its poor utility as such an instrument and
because it seemed no more effective than the hair. The difference be-
tween treatments, with respect to proportion of alatae, narrowly missed
statistical significance at P< 0. 05. The percentage of alatae was great-
est from parents which had contact with a live aphid, next from those
stroked with an aphid leg, then those stroked with a hair, and least from
the un- stroked control. This supports the hypothesis that alatae are de-
termined by intraspecific interaction. The argument is further suppor-
ted by the numbers of alatae and apterae in each treatment during each
third of the reproductive period. The mean size of the offspring groups
was greatest from adults stroked with a hair, however these gave the
second lowest proportion of alate offspring. The rate of survival was
characteristically high with a grand mean of 89%.
TABLE 5. Second adult stroking experiment. Numbers of offspring
born to apterous parents stroked daily with an aphid leg or a hair or kept
in contact with a live aphid for 2 minutes.
* = P < . 05; ** = P < . 01
The frequency of stroking in this second experiment was 3 times
that in the first, yet there was not a corresponding increase in the effect
which the stroking was presumed to induce. However, I viewed the re-
sults optimistically and reasoned as follows. If mechanical stimulation
was the cause of alatae production, then perhaps there was some special
area of the body most receptive to such stimulation. The next 3 exper-
iments were designed to explore this. Concentration of stroking in a
small area would also have the effect of increasing the intensity of the
treatment. I hoped that the dorsal abdominal area would be a sensitive
one because the often observed phenomenon of alatae giving birth only
to apterae might then be explained; receptors on the abdomen would be
14
Awram
covered by the wings and could not therefore be stimulated.
The results (tables 6, 7 and 8) were disappointing. In the first
2 experiments the controls had the highest proportion of alatae. In the
last experiment the controls had the second highest, being slightly ex-
ceeded by those given 500 strokes to the antennae. In none of these 3
experiments was there any statistical difference of consequence in alate
production. The per cent alatae increased through the 3 experiments.
There was a corresponding increase in the average size of the offspring
groupand in the percent survival. AX2test was performed to determine
if there was an association between the type of progeny and the size of
the offspring groups. TheX2values were respectively 2.66, 10.01**,
51. 08**.
TABLE 6. Third adult stroking experiment. Numbers of offspring born
to apterous parents stroked on head, thorax, or abdomen.
The results of the 3 experiments on regional stroking caused me
to doubt my original success with the first 2 stroking experiments. A
final experiment was done to confirm or refute this success. The cor-
nicle secretion treatment was introduced to round off the experiment to
4 treatments. Since it is possible that the intraspecific interaction is
of a chemical as well as, or rather than, a mechanical nature, I thought
it worth trying this most obvious secretion. Cornicle exudate from
roughly handled aphids was brushed against the aphids and solidified al-
most immediately; by the end of the experiment, these parents were
coated with the hardened secretion.
The differences (table 9) in the per cent alatae were not statis-
tically significant, but the treatments rank in much the same order as
in the first experiments so far as these are comparable. Again the num-
ber of alatae and apterae corresponded to what would reasonably be ex-
pected. The live aphid and stroking treatments had more alate offspring
Wing Morphogenesis
15
and less apterous offspring than the control. The control had the least
alate and the most apterous offspring. Statistical significance was reached
in the differences in apterous offspring in the second and third batches
of offspring. The cornicle secretion treatment was ineffective.
TABLE 7. Fourth adult stroking experiment. Numbers of offspring born
to apterous parents stroked daily.
TABLE 8. Fifth adult stroking experiment. Numbers of offspring born
to apterous parents stroked 500 times daily.
* = P < . 05
16
Awram
TABLE 9. Sixth adult stroking experiment. Numbers of offspring born
to apterous parents variously treated daily.
Reasons for the conflicting results obtained in the stroking ex-
periments were not obvious to me. There appeared to be a response to
general stroking over the entire dorsal surface. I can offer no explan-
ation why a stroking frequency of only 100 strokes per day was much
more effective than 300 or 1000 strokes per day. The lack of response
when stroking was restricted to particular areas implies that the sen-
sitive area, if such an area exists, was missed. This seems unlikely
because the areas chosen covered most of the dorsal surface.
Larvae - I have followed a general tendency to think in terms of
establishing conditions that result in the production of alatae. As Johnson
and Birks (I960) have stressed, one should think in terms of conditions
that result in the production of apterae. The embryo probably begins its
development toward analate form. Along its developmental path, it en-
counters conditions which may keep it on the path to becoming alate or
"switch" it into an apterous pathway. Such a switch may be irreversible.
This means that conditions designed to maintain an embryo or larva on
the alate pathmay be imposed in vain if that embryo or larva has already
been switched to the apterous path. The first two larval stroking exper-
iments may have suffered from this oversight since they were done with
the progeny of a single parent which had been raised under uncrowded
conditions. None became alate.
Two further experiments were therefore done for which the par-
ents were under very crowded conditions (17 per 50 mm^) for 4 days
before the experiments began. The offspring of 3 of these parents were
used for 3 aphid leg stroking treatments and a control in the first ex-
periment and 4 treatments and a control in the second. In the first 200
strokes 3 times in the first instar, in the second instar, and in both of
these instars were applied. In the second 300 strokes once in the first
Wing Morphogenesis
17
instar, 300 strokes twice in the first instar, 300 strokes once in the first
and in the second instar, and 300 strokes once in the first and twice in
the second instar were applied. None developed into alatae. The off-
spring, all apterae, were kept and the first 2 batches of their offspring
were collected and raised to maturity. No third generation effects could
be observed with respect to the proportion of alatae born (Awram 1966,
tables 17 and 18).
Temporary Crowding
Objective and methods
The results which Lees (1961, M.viciae) and Johnson (1965,
A. craccivora ) reported on the effect of temporary crowding were unequiv-
ocal. In M. viciae, individuals which had been producing essentially all
apterous offspring switched completely to the production of essentially all
alate offspring after they had been crowded for 24 hours. In A. craccivora ,
Johnson found that a similar change could occur after as little as 1 or
2 minutes contact between as few as 2 aphids. I tried similar temporary
crowding experiments to clarify the confusing results which I obtained
in the rearing and stroking experiments.
Adult aphids were crowded at different densities, for different
periods of time away from the host plant in an attempt to induce the pro-
duction of alate forms. It was hoped to learn the smallest amount of
"togetherness" which evoked a response. First and second instar lar-
vae were also crowded for short periods to determine whether or not
high postnatal population densities could maintain the larvae on the path
to the alate condition.
Adults - Adult aphids were crowded in the standard sized cage
previously described, and also in a small cage 8 mm in diameter (inside
measurement) and 9 mm high, enclosing an area on the leaf of 50 mm^,
and in microtubes 4 mm in diameter and 7 mm long (inside measure-
ments). They were maintained in these containers on moist cotton. No
leaf discs were available to them during the period of their confinement.
After a set period of time, they were placed on fresh leaf discs and kept
individually. Their first 2 batches of offspring were raised to maturity
and the form they had taken was noted. All other conditions were similar
to those described above under methods and materials - general. The
periods of crowding which lasted less than 16 hours were imposed dur-
ing the day. The 16 hour periods included 8 hours of night. Because of
the lack of time and space, not all 16 of the aphids crowded 16 together
could be used; 4 were selected to represent that treatment. A detailed
description of the temporary crowding experiments follows.
There were 4 replicates in each treatment in each of the five ex-
periments with adults from crowded parents. One estimate for a missing
value was calculated in each of the 4 and 16 hour treatments in the second
experiment. In the first temporary crowding experiment single aphids
were kept in the microtube overnight (about 12 hours), and groups of 4
aphids were kept in the microtube 1 hour, and overnight (about 12 hours)
(table 10). In the other four experiments all aphids were crowded and
held in the standard sized cage (see materials methods - general). In
the second temporary crowding experiment 1 aphid was kept alone away
from the host plant for 1 hour, for 2 hours, for 4 hours, and for 16 hours
18
Awram
(table 11). The third (table 12), fourth (table 13), and fifth (table 14)
experiments on temporary crowding were the same except 2, 4, and 16
aphids respectively were crowded away from the host plant for the same
time periods.
TABLE 10. First experiment on temporary crowding of adults from
crowded parents. Numbers of offspring born to apterous parents kept
alone or 4 together in microtubes.
Treatment Description
* = P < . 05
TABLE 11. Second experiment on temporary crowding of adults from
crowded parents - control, uncrowded. Numbers of offspring born to
apterous parents starved alone for 1, 2, 4, or 16 hours.
Wing Morphogenesis
19
TABLE 12. Third experiment on temporary crowding of adults from
crowded parents. Numbers of offspring born to apterous adults crowded
2 together for 1, 2, 4, or 16 hours.
* = P < . 05; ** = P < . 01
Three experiments were done on the effect of temporary crowding
of adults from parents raised singly. Only a control and the most in-
tense crowding were used. First instar larvae from uncrowded parents
were raised to maturity individually. In the first experiment 8 were
then maintained separately as controls, 16 were crowded together for
16 hours (16 per 113 mm^), after which they were again kept separately.
The first several batches of offspring were collected and raised to mat-
urity. The second experiment was the same except that only 4 controls
were used and of the 16 crowded together, 8 were selected as progen-
itors. The 16 aphids were crowded in the small cage (50 mm^). The
use of the small cage increased the effective population density by a fac-
tor of 2.25 (table 15). The third experiment was identical except that
the aphids were crowded in their fourth instar, rather than as newly e-
merged adults (table 16).
Larvae - In 3 experiments first instar larvae less than 12 to 24
hours old were crowded in the small cage for 12, 16 or 24 hours at den-
sities of 16, 32 or 48 per 50 mm^ (table 17).
TABLE 13. Fourth experiment on temporary crowding of adults from
crowded parents. Numbers of offspring born to apterous parents crowded
4 together for 1, 2, 4, or 16 hours.
TABLE 14. Fifth experiment on temporary crowding of adults from
crowded parents. Numbers of offspring born to apterous parents crowded
16 together for 1, 2, 4, or 16 hours.
* = P < . 05; ** = P < . 01
TABLE 15. First and second experiments on temporary crowding of
adults from parents raised singly. Numbers of offspring born to apter-
ous parents kept individually or crowded 16 together.
TABLE 16. Third experiment on temporary crowding of adults from
parents raised singly. Numbers of offspring born to apterous parents
crowded 16 together for 4 hours in their fourth instars.
* = P < . 05
22
Awram
TABLE 17. X2 for independence between crowded and uncrowded larvae,
and development into the apterous or alate state. Results of temporary
crowding of larvae from uncrowded parents (above) and from crowded
parents (below).
* = P < .05
Results and discussion
Adults - In the first temporary crowding experiment (table 10) no
difference in the proportion of alate offspring among the treatments could
be observed. The per cent alatae was almost identical in the aphids
kept individually and in those crowded together in a microtube. Four
crowded for 1 hour had the greatest proportion of alatae but the differ-
ence was not significant. The significantly high F values obtained for
the first batch apterous, total offspring, and total apterous were, I think,
a result of the unusually small per cent survival of those kept singly
(74%).
From the second experiment (table 11) with single aphids off the
host for different times, many results were missing so that this could
not be analyzed by the IBM program. Only the means are given. This
was essentially a test of the effect of different periods of temporary star-
vation on the production of offspring. No pattern could be observed in
any of the measurements taken. The number of alate offspring, the num-
ber of apterous offspring, the total number of offspring, the proportion
of offspring which were alate, the total offspring born and the per cent
survival were not noticeably affected by 1, 2, 4, or 16 hours of star-
vation.
The results of the third experiment (table 12) were similar to
those of the second temporary crowding experiment. There appeared tq
be no association between the proportion of alatae produced and the length
of time that 2 parent aphids were in the same cage with oneanother. The
exception to this general observation was the number of alate offspring
in the first batch. Significantly more alate (8. 2) were born to individuals
caged together for 16 hours than to those caged for 1 and 2 hours. An
intermediate number (4. 8) was born to the individuals in the intermediate
treatment (4 hours). The significant F values for the second batch of
Wing Morphogenesis
23
apterae was probably a result of the zero values for replicates 1 and 2
in this treatment. These would probably be best viewed as missing val-
ues. The significant F value for the size of the offspring group of the
second batch also reflected the zero of replicate 2 in this treatment.
The large number of offspring per cage from those crowded for 16 hours
might be suspected as the cause of the high per cent alatae of this treat-
ment. However, the second batch here was almost all apterous.
A number of the parameters in the experiment with groups of 4
off the host (table 13) displayed statistically significant differences among
the treatments. Most important of these was the total per cent alatae.
The proportion of winged offspring was greatest after 16 hours crowding.
The percentage after 1 hour crowding was considerably less and that
after 2 hours crowding was intermediate. However the pattern was bro-
ken by the 4 hours crowding which gave the lowest per cent alatae. The
situation was the same for alate offspring in the first batch, the 4 hour
treatment falling outside the pattern. The difference between treatments
shown by the number of apterous offspring in the second batch was a
manifestation of the unusually high fecundity of the individuals crowded
for 16 hours, which gave a much higher average number of offspring per
cage in the second batch than the other treatments. The large size of
the offspring group was not associated with a corresponding increase in
alatae.
The experiment with groups of 16 (table 14) completed the sym-
metry of the experimental design of the crowding experiments. There
was no difference between treatments in the number of alatae or apterae
produced or in the per cent alatae. The significance attained with respect
to total offspring, average, and second day size of offspring group and the
total born was caused by the partial sterility and low survival rate of the
individuals crowded for 4 hours.
The data obtained from the latter four experiments on temporary
crowding of adults from crowded parents differed from some of the re-
sults obtained by Lees and Johnson. Several explanations are possible.
Both these workers had raised the parent aphids used in their experi-
ments separately. Mine were taken from groups of 10 or fewer indivi-
duals. The results I obtained may have been confounded by this previous
association. Another possible explanation is that the density of parents
was not great enough. It is possible that the 16 aphids would not encounter
one another often enough to produce a response. A third explanation
might be that the 4 individuals selected to represent the 16 of the high
density treatments had never been walked upon, i. e. had themselves been
the most active. Still another possible explanation is that I did not use
enough replicates. The last three experiments were performed to cor-
rect these possible defects. Because there were only 2 treatments in
each of these experiments, t rather than F values were calculated.
In the first experiment one of the control parents and 2 of the
treated parents did not survive long enough to produce offspring. There
was little difference (table 15) between the 2 treatments in any of the
measurements taken in either of the first two experiments. Both con-
trol groups had the higher proportion of alatae, 38% against 3 0% in the
first and 45% to 24% in the second experiment. As in the first experi-
24
Awram
ment with adults from parents raised singly, none of the measurements
taken showed a significant difference between the controls and the treated
individuals (table 15). Again, the controls had a greater per cent alatae
than the treated aphids.
The results of the last experiment, in which aphids were crowded
in their fourth instar, rather than as newly emerged adults are given in
table 16. There is a significant difference in the proportion of alatae
between the controls and the treatment parents, the treated having a
greater per cent alatae. The greater proportion of alatae was a con-
sequence of both more alatae in the treated and more apterae in the un-
treated group. The other significant factor was the size of the offspring
group in the second batch. It was larger for the treated group and there-
fore postnatal effects could not be ruled out as a cause for the increased
alate production.
Larvae - Crowding first instar larvae of comparatively uncrowded
parents (raised in groups numbering less than 10) at a density of 16 per
50 mm^ did not result in proportionately more becoming alate than among
the uncrowded control individuals (X2 = 0.61). Where the parents were
raised individually for most of their lives, the difference in the propor-
tion of alatae between crowded and uncrowded larvae appeared to be more
definite, perhaps because the crowding was twice as severe as in the first
experiment (X2 = 3.34). The more intensive crowding still of the treated
individuals in the last experiment resulted in a still larger proportion be-
coming alate (X2 = 6. 19*)- The effects of heavy parental crowding were
apparently reversed in the control individuals.
GENERAL DISCUSSION
A few observations that transcended the 3 general types of ex-
periments were made and are discussed here.
Fig. 2 is a plot of the percent alate of control treatments against
time. The variation was considerable and there was no discernible long
term trend. Bonnemaison (1951) found that over a 6 month period dur-
ing which he experimented with M. persicae , there was a general tendency
for increased alate production with increased age of the clone. This was
not so in my experiments over the period June through December 1965.
No matter how careful I was to keep a parent isolated from other
adults during both its infancy and adulthood, I was never able to prevent
completely the occurrence of some alatae among its offspring. Fig. 2
illustrates the point. Never were the offspring of control parents entire-
ly apterous. This implies that the production of a small proportion of
alatae may be obligatory in the clone studied.
The rate of survival of offspring was high (average 88. 1 percent)
in all of the experiments. An exception was the larvae which were stroked
during their fir st and second instars, many of which died before reaching
maturity. The survival rate of the parents was also high. Only 14 of
421 died before leaving 7 or more offspring.
The results I have obtained differ from Bonnemaison's , Johnson's,
and Lees* on several points. Rearing aphids under crowded conditions
Wing Morphogenesis
25
temporary crowding of apterous parents resulted in an increased pro-
portion of alate offspring. Mechanical stimulation of apterous parents
by stroking did not result in a predictable increase in alate offspring.
When a parent aphid seemingly responded to a treatment by producing
alate offspring, it did not necessarily continue to produce alate offspring.
A few examples, fig. 3, have been selected to illustrate this character-
istic.
Fig. 3. Numbers and the ratio of alate to apterous offspring in consecu-
tive batches born to individual parents of M.persicae; □ alate, IS apterous.
26
Awram
All of these contradictory results can be resolved if it is assumed
that in the clone studied, the postnatal effects of population density were
at least as important as the prenatal effects. The data obtained gave
much support to this hypothesis . In almost all cases wherea significant
difference in per cent alatae between treatments was obtained, there
was a corresponding association between a large offspring group size
anda high proportion of alatae. Under the conditions of the experiments,
about 15 larvae constituted a large enough population to produce a res-
ponse.
If the hypothesis that postnatal crowding is at least as important
as prenatal crowding is correct, then the ontogeny of an individual would
follow one of the following pathways (Johnson and Birks I960): if the
parent is under crowded conditions, the embryo remains on the path to-
ward becoming alate. After its birth, the larva may encounter crowded
or uncrowded conditions; if crowded, it continues development toward
becoming alate; if uncrowded, it is sidetracked and becomes apterous.
If the parent is not crowded, then the embryo is sidetracked and irrever-
sibly set on a developmental path leading to the apterous state, and is
insensitive to conditions it encounters in its early instars. Alate off-
spring are obtained when parents and offspring (first and second instars)
are subjected to crowding or conditions simulating crowding. The re-
sults of all experiments can be fitted into one or other of these hypo-
thetical pathways. Table 18 illustrates the interaction of parent and off-
spring crowding and the type of offspring which would be formed if the
pathways hypothesized exist. All the treatments are listed according to
the parent offspring regime each encountered. An asterisk indicates a
statistical significance between the treatment marked and the corres-
ponding control treatment in respect of per cent alatae. All but one of
the controls fall into the parent uncrowded- offspring uncrowded quad-
rant. All but one of the treatments which showed a significantly high
proportion of alatae fall into the parent crowded- offspring crowded quad-
rant. Reasons for regarding this one exception (100 strokes daily with
aphid leg) as anomalous have already been given. The data fit the hypo-
thetical pathways.
The data and the hypothesis can be examined in the light of the
characteristics of the life history of M. persicae. M. persicae is a diecious
aphid, that is, it has primary and secondary host plants between which
it must travel to successfully complete its life history. Wings, twice a
year, are necessary. It has the widest range of secondary plant hosts
of any aphid. Therefore, winged forms of M. persicae are more likely than
those of any other aphid to alight on suitable host plants. The percentage
of seemingly obligate alatae which I observed, might thus be explained.
Aphis craccivora and Megoura viciae the species used by Johnson and by Lees,
are monecious and much more host specific than M. persicae.
There are adaptive advantages to maintaining the option of becom-
ing alate or apterous until the first or second instars. A first or second
instar larva that is still on the path toward the alate state, might, after
a heavy rainstorm, find itself in uncrowded conditions. It would be to
its reproductive advantage to be switched to the apterous state. Or an
adult aptera might walk away from a crowded condition and deposit her
Wing Morphogenesis
27
presumptive alate offspring in uncrowded circumstances. These could
take advantage of such circumstances by being shunted to the path leading
to the apterous state. This last instance is supported by one of the char-
acteristics of M. persicae . Bonnemaison (1951) found it to be a relatively
"antisocial" aphid. M. persicae individuals tended to space themselves
over the available surface of leaf, whereas Brevicoryne brassicae L. , a more
sociable type, remained in family groups.
CONCLUSION
The higher the population density of the parents , the greater was
the proportion of alate offspring born to apterous Myzus persicae Sulz. But
this general tendency can be overcome by preventing the size of the
offspring groups from becoming too great. Apterae raised on cabbage pro-
duced a greater proportion of alate offspring than apterae raised on ra-
dish. The percent survival of offspring reared on radish was high, near
90; on cabbage was lower, near 7 0. The fecundity of parents fed on cab-
bage was less than that of parents fed on radish. The fecundity and lon-
gevity of singly reared parents did not differ from that of parents reared
in groups. No association between the physiological age of the parents
and the tendency to produce alatae was observed.
An attempt was made to imitate physical contact among aphids
by stroking individuals. Stroking adult, apterous aphids on the dorsal
surface with a Drosophila leg or a human hair, at intensities of 100 or 3 00
strokes per day was ineffective in causing the aphids to produce alate
offspring. Stroking particular parts of the body, with an aphid leg, at
intensities of 400 or 500 strokes per day was also ineffective. Areas
stroked included the head, thorax, fore and hind parts of the abdomen,
the sides of the abdomen, the antennae, and the legs. Stroking applied
generally to the entire dorsal surface at 300 or 1000 strokes per day
may have caused a slight increase in alate production. One hundred
strokes daily applied generally over the dorsal surface elicited a highly
significant increase in the number of alate offspring. Two or 5 minutes
daily contact of adult apterae with other adults mounted live on a pin,
caused a slight increase in the proportion of alate offspring born to them.
There was an association, across the treatments of the stroking experi-
ments, between a large number of offspring per cage and a large pro-
portion of alate offspring.
Stroking first and second instar larvae at intensities of 200, 3 00
or 500 strokes once or twice per instar did not cause these larvae to
develop into alatae. Offspring of these larvae were not disproportionately
alate.
Starving young, adult apterae for short periods (1, 2, 4 or 16
hours), did not affect the number of alate offspring produced. Crowding
young, adult apterae at population densities of 1, 2, 4 or 16 per 50 mm2
for 1, 2, 4 or 16 hours did not result in an increased number of alate
offspring. Crowding first instar larvae whose parents had been crowded,
resulted in an increased number of them becoming alate.
In the clone studied, it was necessary for the first instar larvae
28
Awram
as well as their parents to be crowded before there was an increase in
the number of alate individuals produced. The capacity to be channelled
into the developmental pathway leading to the apterous state was retained
beyond the embryo stage and well into the first and possibly second in-
stars.
TABLE 18. A summary of the results, sorted into parents crowded or
uncrowded and offspring crowded or uncrowded categories.
Wing Morphogenesis
29
ACKNOWLEDGMENT
I am grateful to Drs. W. G. Evans and B. Hocking for help given
me in the execution of this work.
REFERENCES
Awram, W. J. 1966. Wing morphogenesis in Myzus persicae . M.Sc. the-
sis. University of Alberta. 70 pp.
Bonnemaison, L. 1951. Contribution a 1‘etude des facteurs provoquant
1‘apparition des formes ailees et sexuees chez les Aphidinae.
These Fac. Sci. Univ. de Paris. 380 pp.
Goulden, C.H. I960. Methods of statistical analysis. John Wiley and
Sons, Inc. New York. 467 pp.
Johnson, B. 1965. Wing polymorphism in aphids. II. Interaction be-
tween aphids. Ent. exp. appl. 8 : 49-64.
Johnson, B. , and P. R. Birks. I960. Studies on wing polymorphism in
aphids. I. The developmental process involved in the production
of the different forms. Ent. exp. appl. 3 : 327-339.
Lees, A.D. 1959. The role of photoperiod and temperature in the de-
termination of parthenogenetic and sexual forms in the aphid
Megoura viciae Buckton. I. The influence of these factors on apter-
ous virgnioparae and their progeny. J. Insect Physiol. 3 : 92-
117.
Lees, A.D. 1961. Clonal polymorphism in aphids , pp. 68-79. In J.S.
Kennedy, (ed.), Insect polymorphism. R. ent. Soc. Lond. ,
Symp. No. 1.
Lees, A.D. 1965. The day length clock in the aphid Megoura viciae Buck-
ton. (Abstr.) Proc. R. ent. Soc. Lond. C, 30 : 19.
MacGillivray, M. E. , and G.B. Anderson. 1958. Production of apterous
and alate progeny by apterous and alate viviparae of Macrosiphum
solanifolii Ashm. (Homoptera : Aphididae) . Can. Ent. 90 : 241-
245.
Wadley, F.M. 1923. Factors affecting the proportion of alate and ap-
terous forms of aphids. Ann. ent. Soc. Amer. 16 : 279-303.
30
Note:
Copies of all back issues of Quaestiones entomologicae are still
available at the regular subscription price. New subscribers may ob-
tain the entire series by writing to the Subscription Manager at the De-
partment of Entomology, University of Alberta, Edmonton, Canada .
Complete runs of the abstract edition on either 3" x 5" plain cards or
5" x 8" punched cards are also still available.
31
THE CLARIFICATION OF A DISCREPANCY IN DESCRIPTIONS
OF MAXILLARY MUSCULATURE IN LARVAL SIMULIIDAE
DOUGLAS A. CRAIG Quaestiones entomologicae
Department of Entomology 4:31 - 32 1968
University of Alberta
The fir st definitive account of the morphology of larval Simuliidae
was provided by Puri (1925) . In his description of maxillary musculature
he states that the maxillary palp is provided with a pair of small adductor
and abductor muscles . Cook’s (1949) description of the maxillary mus-
culature of larval simuliids agrees with that given by Puri, with the ex-
ception that Cook makes no mention of palpal muscles.
To resolve this discrepancy the maxillary musculature of simuliid
larvae was re-examined.
Large, recently moulted larvae were examined to provide a clear
view of maxillary structures. These were fixed in Bouin's fixative and
the head capsule stained in Mayer's carmalum. The maxillae and as-
sociated muscles, as well as the adjacent regions of the head capsule,
were dissected from the head and differentiated in acid alcohol. The
maxillae were then mounted in Canada Balsam and examined and photo-
graphed with a Leitz Orthomat.
Examination showed no palpal muscles. However, there is a
prominent nerve running to the palp witha ganglion at the palp base (fig.
1). It is unlikely that Puri would mistake the palpal nerve for muscle.
What then did he observe?
During the investigation a number of mature larvae were fixed,
stained, and examined. In these specimens the pharate maxillae of the
next instar stained with the same intensity as muscle (fig. 2). Examin-
ation under phase-contrast was necessary here to distinguish muscles
from other tissue but again no palpal muscles were detected.
Exactly what Puri observed is not known but this investigation
indicates that he interpreted a pharate maxillary palp as muscle.
These observations as well as those of Cook (1949) agree with
Das (1937), Hinton (1958), and Matsuda (1965), who state that dipterous
larvae never have palpal muscles.
Cook, E. F. 1949. The evolution of the head in the larvae of Diptera.
Microentomology 14(1) : 1-57.
Das, G. M. 1937. The musculature of mouthparts of insects. Q. Jl.
microsc. Sci. 80 : 39-80.
Hinton, H.E. 1958. The phytogeny of the Panorpoid orders. A. Rev.
Ent. 3 : 181-206.
Matsuda, R. 1965. Morphology and evolution of the insect head. Mem.
Amer. Ent. Inst. 4 : 1-334.
Puri, I.M. 1925. On the life-history and structure of the early stages
of Simuliidae (Diptera, Nematocera). Parti. Parasitology 17 :
295-334.
Fig. 1. Aboral view of maxilla from recently moulted larva; Abd. =
abductor muscle, Add. = adductor muscle, Mx. n. = maxillary nerve,
Mx. p. = maxillary palp, Ph. mx. p. = pharate maxillary palp.
Fig. 2. Aboral view of maxilla from mature larva.
Quaestiones
entomologicae
A periodical record of entomological investigations,
published at the Department of Entomology, Uni-
versity of Alberta, Edmonton, Canada.
VOLUME IV
NUMBER 2
APRIL 1968
QUAESTIONES ENTOMOLOGICAE
A periodical record of entomological investigations published at the
Department of Entomology, University of Alberta, Edmonton, Alberta.
Volume 4 Number 2 11 April 1968
CONTENTS
Editorial 33
McDonald - The life history of Cosmopepla bimaculata (Thomas)
(Heteroptera : Pentatomidae) in Alberta 35
Klassen - Dispersal of mosquitoes . , 39
Sehgal - Descriptions of new species of flies of the family
Agromyzidae from Alberta, Canada (Diptera) 57
Editorial - Man and Whose World?
Now that the tumult of a centennial year for Canada is over, it is
perhaps no longer picayune or churlish to ask this question in public.
Last year man, sponsored by Canadians, raised his standard on a tiny
island wrested from the swirling waters and swarming caddis flies of
the St. Lawrence River and declared that the world was his. Nobody
challenged him; or if they did he never heard. The title "Man and his
World" is bad enough; but when this is interpreted as it was: "Man and
His own World" when, in other words, man looks upon the world as be-
longing to him and upon nature as producing /or him, the voices of bio-
logists must be raised in protest.
Admittedly, I am criticizing from ignorance for I never went to
Expo 67. I was sufficiently nauseated by such literature and publicity
relating to it as reached me.
If this is man's world, man's own world, then man has a lot to ans-
wer for, for ownership carries with it responsibility for control. Man
then, must accept the blame for hurricanes and earthquakes, floods and
tornadoes, as well as the credit (if any) for atomic bombs and spacecraft,
for the Empire State Building and the Pyramids of Giza. Millions of
dollars worth of mutual admiration will not help him in this task.
I was told that insects were to find a place among the exhibits in this
centennial celebration, but it transpired that all that was meant was in-
secticides, and valiant efforts were made to ensure that the otherwise
ubiquitous caddis flies did not show their genae at the party. They might
have reminded man that in his world the waters of the St. Lawrence still
swirled; that beneath them the case makers would continue to make a
case for themselves as owners of at least this stony substrate.
A centennial, naturally, looks back a hundred years and surely it
might at least try to look forward a hundred years too, rather than a
mere twenty as on this occasion. Its twenty year vision had its blind
spots. Perhaps in another ninety-nine years there will be an opportunity
34
to focus on some of these, to draw attention to a few of man's mistakes
and his many unsolved problems . A second centennial celebration draw-
ing attention to the fact that though God maybe in his heaven everything
is not all right with man's world would be more accurate, more interes-
ting, and in the long runmore profitable. I hope my greatgrandchildren
will visit it. I hope the caddis flies will visit it; even if they have to be
trapped on arrival and served as caddisburgers to my great grandchildren
and others. Better to build the flesh of men, than give a bellyache to
fish.
This is no more man's world than an orange belongs to the coccid
whose stylets probe its peel more deeply than man's machines probe the
earth's crust. Man and whose world then? It is surprising that in a coun-
try so rich in religion as Canada, God's spokesmen raised no finger on
His behalf; perhaps there was a conflict of interests between Gods. And
what about the money men? Was there no banker or billionaire whose
claim could rival that of the rest of the human race? Where was the voice
of women? And where that of the little green men whose flying objects
remain, like so many caddis flies, unidentified?
Brian Hocking
35
f.j. d. McDonald
Department of Agricultural Botany
The University of Sydney
Sydney, New South Wales, Australia
Quaestiones entomologicae
4 : 35-38 1968
The habits and food plant of Cosmopepla bimaculata (Thomas) are recorded. A study of the
duration of the nymphal instars was made both under fluctuating and constant laboratory condi-
tions. The external genitalia of the fifth nymphal instar are described.
Cosmopepla bimaculata (Thomas) is a small black and orange pentatomid
commonly found on hedge nettle Stachys palustris L. in Alberta. It is not
considered a serious pest of crops in this province. The species is
widespread throughout North America and Mexico.
Habits and Food
The adults were observed feeding on Stachys in Edmonton towards
the end of June and were freely copulating by the first week in July.
Eggs were observed on 13 July and by 22 July first instar nymphs were
abundant. The life cycle was completed by early August, but mating
continued right through July and first instar nymphs were observed in
August. It appears that this insect overwinters in the adult stage, but
it is probable that a few overwinter as fourth or fifth instar nymphs.
Cosmopepla was observed and bred on Stachys palustris for this series of
observations. Blatchley (1926) records many host plants for this species.
The insect in all stages feeds on the seed of Stachys both unripe seed on
the plant and mature seed on the ground. Very little sap sucking occurs
and the adults and nymphs can be kept on seed and water alone.
Copulationis the same as described for other pentatomids (Poisson
1951). The pair of bugs remain attached on the average one day (S.D.
0. 37 days; n = 18).
The first batch of eggs was laid on the undersurface of a leaf ap-
proximately twelve hours after copulation, second and third batches
were laid almost immediately afterwards, but occasionally the female
would hold her eggs for 24 hours or more between each laying. This is
reflected in the wide variation in incubation time for the eggs.
Each female lays from 1-3 batches of eggs (mean 1. 9, n = 8) con-
taining 11. 5 ± 1. 0 eggs (n = 47).
Development and Life History
Eight egg masses were reared through to the adult stage in a labor-
atory where the temperature was recorded. The average of the maximum
and minimum temperatures for the period of development was 23. 5 C.
Copulation
Egg Laying
36
McDonald
Another series of eight egg masses was transferred on hatching to a
growth chamber and reared at a constant temperature and light regime
(23 C, day length 14 hours). The intensity of illumination was 2400 foot
candles at 30 cm from the light bank. The duration of each instar was
recorded when 50% of individuals in each hatch had moulted to the next
instar. The two sets of results are given in table 1. Although the mean
development times were less for the first three instars at fluctuating
temperatures, and for the last two at a constant temperature, the dif-
ferences in the results are not significant at the 5% level.
Eggs
The eggs (fig. 1) are oval, 0. 75 mm long (± 0. 04; n = 30) and 0. 60
mm in diameter (± 0. 04; n = 30) and when laid are pale green. The up-
per margin of the egg bears 15-23 chorionic processes (mean 18. 9 ± 2. 0;
n = 100) at regular intervals in a circle (fig. 4).
Incubation Period and Hatching
The eggs take from 3-6 days to hatch after laying (mean 4. 7 ±1.0
day; n = 23). The shorter incubation period was due in all cases to the
fact that these females retained the fertilized eggs for a longer period
before laying them. The vertex of the embryonic head bears an elongate
triangular sclerotized egg burster (figs. 3 and 4).
Postembryonic Development
The nymphal instars have been figured and described by DeCoursey
and Esselbaugh (1962). The colour of first instar nymphs on hatching is
pale yellow-green, the eyes are bright red. This instar is gregarious,
clustering around the eggs after hatching. At 23 C the duration of each
instar was: 1st 3. 2 days, 2nd 4. 7 days, 3rd 4. 2 days, 4th 2. 9 days and
the 5th 6.4 days (table 1).
The external female genitalia can readily be distinguished in the 5th
instar. Abdominal sternum VIII has a median longitudinal suture (fig.
6) and, apically, two small sclerites, the first gonapophyses (fig. 5, 1
Gp. ), one on either side of the suture forming a V.
Abdominal sternum IX has, basally and medianly, a pair of small
triangular sclerites; these are probably rudiments of the second gona-
pophyses (fig. 5, 2 Gp. ).
Parasites
Some egg masses collected in the field were found to be parasitised
by a small wasp Telenomus sp. (Scelionidae) .
ACKNOWLEDGEMENTS
I should like to thank Dr. O. Peck of the Entomology Research Ins-
titute, Ottawa, for identifying the hymenopterous parasite of the eggs,
and Dr. Brian Hocking and Dr. W. G. Evans, Entomology Department,
University of Alberta, for reading and editing this manuscript.
Life History-
37
TABLE 1. Developmental periods for all instars of Cosmopepla bimaculata at
constant and fluctuating temperatures.
At 23 C and 14 hours daylight -
At fluctuating temperatures (mean over 27 days, 23.5 C) -
REFERENCES
Blatchley, W. S. 1926. Heteroptera or true bugs of eastern North Am-
erica. Nature Publishing Company, Indianapolis. 1116 pp.
DeCoursey, R. M. and C. O. Esselbaugh. 1962. Descriptions of the
nymphal stages of some North American Pentatomidae. (Hemip-
tera : Heteroptera). Ann. ent. Soc. Amer. 55 : 323-342.
Poisson, R. 1951. Ordre de heteropteres , pp. 1730-1731. In P. Grasse,
Traite de zoologie 10. Masson et C^e, Paris.
38
McDonald
Cosmopepla bimaculata . Fig. 1. Egg. Fig. 2. Egg burster, lateral view.
Fig. 3. Egg burster, dorsal view. Fig. 4. Longitudinal section through
chorionic process. Fig. 5. Instar V; external female genitalia. Fig.
6. Instar V; abdominal sterna 8-10. A^q, abdominal segment 10; An.,
anus; C. p. , chorionic process; 1 Gp. , first gonopophysis; 2 Gp. ,
second gonopophysis; 1 Gx. , first gonocoxa; Sg, abdominal sternum 8;
S9, abdominal sternum 9.
39
DISPERSAL OF MOSQUITOES
W ALDEMAR KLASSEN
Metabolism and Radiation Research Laboratory
State University Quaestiones entomologicae
Fargo, North Dakota 58102 4 : 39-55 1968
This review of the literature shows that mosquitoes may undergo displacement of many miles
from the site of eclosion. The dispersal of mosquitoes may be influenced by wind, topographical
features, vegetation, and by an illuminated sector of sky. Wind, more than any other environmental
factor, influences dispersal. The optomotor responses of mosquitoes flying in a wind are useful in
predicting the pattern of dispersal.
Vigorous dispersalis vital to the survival of mosquito species. Al-
though it is frequently wasteful (mosquitoes may perish that venture into
deserts, over oceans, or to other inhospitable regions), dispersal pre-
vents extinction of the species because of a fluctuating climate, a fluc-
tuating sparsity or distribution of host species, or the vagaries of human
activity. Populations may be totally destroyed in parts of the range, but
as soon as these areas again become tolerable, the vigorously dispersing
emigrants repopulate them, and the reclaimed area may serve as a re-
fuge when other parts of the range become intolerable. Also, vigorous
dispersal causes such rapid gene flow between local populations that the
genotypes may be repatterned rapidly to meet the new conditions, i. e. ,
changing climate, vegetation, human settlements, or insecticides.
Some Aedes species can fly as far as 30 air miles or remain airborne
about 12 hours without feeding (Hocking 1953), and Culex pipiens berbericus
Roubaud can fly no less than 5 km by using reserves carried over from
the pupal stage (Clements 1963). However, the extent to which mos-
quitoes in nature make use of this ability to travel depends on the species,
the vicissitudes of weather, the terrain, and on yet unknown factors.
The tendency to disperse varies greatly between species. Some
show a marked tendency to disperse great distances shortly after ec-
losion and before seeking the first blood meal. The best examples are
Aedes sollicitans (Walker) (Felt 1904), Aedes taeniorhynchus (Wied. ) (Provost
1957) , Anopheles sundaicus (Rodenwaldt) , Anopheles saccharovi (F avr . ) , and
Anopheles maculipennis Meigen (see Eyles 1944), andperhaps Anopheles pharoensis
Theobald (Kirkpatrick 1925) which regularly disperse in large numbers
in excess of 10 miles and sometimes in excess of 100 miles from the site
of eclosion. Yet, another species such as Culex tarsalis Coquillett show
40
Klassen
no marked migratory phase between eclosionand the search for the first
blood meal; yet this species may spread 25 miles per generation (Bailey
et al. 1965), and it and others such as Anopheles quadrimaculatus Say (Gartrell
and Orgain 1946), Anopheles freeborni Aitken (Rosentiel 1948) and Anopheles
maculipennis (see Eyles 1944) may show a prehibernation migratory phase
that takes a portion of the population miles from the site of eclosion.
Still other mosquitoes such as the domesticated populations of Aedes aegypti
(L. ) (Morland and Hays 1958), Anopheles culici facies Giles (Russell et al. 1944)
and Culex pipiens fatigans (Lindquist et al. 1965) do not fly far from the site
of eclosion; nevertheless, the first flight of some individuals of C. pipiens
fatigans is believed to be truly migrational. Almost nothing is known of
dispersal of adults that have overwintered.
Populations appear to be heterogeneous with regard to the drive to
disperse. Even in the highly migratory Aedes taeniorhynchus , a significant
number do not disperse beyond a few hundred meters of the site of ec-
losion (Bidlingmayer and Schoof 1957). Perhaps these stragglers emerge
too late to profit from the stimuli of twilight (see Provost 1957, Pausch
and Provost 1965). However, the tendency to disperse also depends on
the genotype of the individual: the motility of one laboratory strain of
Anopheles quadrimaculatus was found to have been selected away through pro-
longed colonization (Dame et al. 1964). Nevertheless, we lack evidence
that selection by insecticides has affected the drive to disperse (Sautet
1957), and Wada (1965) believed that crowding during the larval stadia
may increase the drive.
With anophelines, males do not always disperse as widely as females
(Eyles 1944), and similar observations have been made for Aedes
taeniorhynchus (Provost 1957) in which mating may occur before the mig-
ratory flight (Haeger I960). However, Klassen and Hocking (1964) did
not find any apparent difference between the sexes of Aedes cataphylla Dyar;
they mated after the initial long-distance flight. Clarke (1943) calculated
the average flights of male and female Culex pipiens fatigans and Aedes vexans
(Meigen) to be 9.8, 10.3, 9.4, and 9.1 miles, respectively.
Behavior and Dispersal
Ross (1905) distinguished between two types of flight: relatively
long flights from one "breeding ground" to another and "flitters" or
trivial flights near the habitat. The long flight is believed to be an ex-
ample of nonappetential flight (Provost 1952) (nonpurposive spontaneous
flight; Nielsen 1958). It starts shortly after sundown in Aedes vexans
(Clarke 1943), Aedes taeniorhynchus (Provost 1957 ; Bidlingmayer and Schoof
1957; Nielsen 1958) , Aedes cataphylla (Klassen and Hocking 1964), and
Culex tarsalis (Bailey et al. 1965). The drive to disperse is so pronounced
in newly emerged Aedes fitchii (Felt and Young) mosquitoes that they will
take flight in a wind of 12-14 mph that inhibits the flight of mosquitoes
several days old (Klassen and Hocking 1964). In Aedes taeniorhynchus , the
nonappetential drive to disperse does not persist past the first day of
adult life (Provost 1957), but host- seeking females and females searching
for resting and oviposition sites do make short appetential (purposive)
flights that, though they are markedly influenced by host density, micro-
climate, and terrain, may add substantially to the ultimate dispersal of
Life History-
41
a species (Provost 1957).
Wind and Dispersal
Wind has been shown to be of overriding importance in determining
the pattern of dispersal by releases and recaptures of marked mosquitoes
and by direct observations of migratory flights (table 1, p. 49). Valuable
insights into dispersal may be obtained by a thorough study of the manner
in which a mosquito navigates in a wind.
Kennedy (1940, 1951) showed that insects flying in a wind navigate
by making compensatory responses to visual stimuli from the relative
movement of the ground below them. His optomotor hypothesis of navi-
gation postulates that an insect flying in certain windspeeds and at certain
heights above the ground will orient into the wind; at other heights and
windspeeds, it will orient downwind. Observations in the field by Steiner
(1953), Haeger (I960), Klassen and Hocking (1964), and Bailey et al.
(1965) support Kennedyrs hypothesis.
The manner in which a flying insect controls its track is somewhat
similar to the manner in which one controls the path of an automobile.
On a straight road with ideal conditions, one prefers to drive so the images
pass across the visual field from front to back at, say, 60 mph. If the
automobile skids, the movement of the images across the visual field
has a transverse component, and the driver immediately reduces this
component to zero by reorienting the automobile. On a slippery hill,
the automobile may cease to make headway and may slide backwards, a
movement detected by the back to front movement of the images; it is
prevented either by accelerating or by braking.
The dispersing mosquito has similar reactions; however, its navi-
gation is more complex and can be described mathematically (Klassen
and Hocking 1964).
Since the velocity of the images varies as
V = w(Z - X) (1)
and the windspeed increases as
W = u log _Z
K Zo (2)
upwind flight is described as
W(Z - A ) = V - u log _Z
K Zo (3)
and downwind flight as
V + u log Z = w(Z - A)
K Zo (4)
when z is the height of the mosquito above ground
A is the height of the vegetation providing the visual pattern
Z is the height of the mosquito above the visual pattern
V is the airspeed of the mosquito
w is the preferred angular rate of apparent movement of the ground
from front to back
W is the windspeed at height Z above the ground
u is the friction or the velocity
K is Karmanls constant
Zo is the roughness length.
42
Klassen
Thus the velocity of the images varies inversely with increasing height
above the background (1) andbecause windspeedincreases logarithmically
with the height above the ground (2). In addition, the mosquito prefers
a certain airspeed (cruising speed) (Hocking 1953). Thus, the dispersing
mosquito compensates for undesirable visual effects by changing its air-
speed within certain limits, by constantly correcting its orientation along
the direction of the wind so no side slippage occurs, by turning from
upwind to downwind or vice-versa, or by settling.
In a gentle wind, the mosquito takes off against the wind, climbs to
an altitude at which the images pass by at a preferred rate, and flies
near its preferred airspeed. Upwind flight is described by equation 3.
If thewindspeed at the altitude of flight exceeds the preferred airspeed,
the insect can lower its altitude or even settle. Also, the mosquito may
turn downwind (fig. la). Then the windspeed added to the airspeed will
greatly increase movement relative to the background, and the mosquito
must gain altitude so the movement of images will be at the preferred
rate. Downwind flight is described by equation 4. Figure lb shows the
permissible heights of flight of Aedes punctor (Kirby) in relation to wind-
speed measured at 500 cm above ground. The lines in this figure were
calculated from equations 3 and 4 and represent the values at which stim-
uli calling for change start to be received. Actually, because these
stimuli must reach a minimum threshold, the permissible heights of
flight are zones whose width is small when the background is well-per-
ceived and when the altitude is low. Figure lc shows the relationship
between windspeed and maximum rate of displacements of Aedes punctor and
Aedes aegypti in upwind and downwind flight. Theoretically, the weak flier,
Aedes aegypti , should be able to disperse upwind and downwind at the same
rate when the windspeed at 500 cm above ground is about 120 cm/ sec
(2.6 mph). At greater windspeeds, downwind displacement increasingly
predominates. Also, theoretically, the moderately strong flier, Aedes
punctor , should be able to disperse upwind and downwind at the same rate
when the windspeed at 500 cm is 160 cm/sec (3. 5 mph). However, ex-
perience (table 1) indicates that in these cases, downwind dispersal would
predominate, probably because at the start of migratory flight, mos-
quitoes climb to fairly high altitudes at which, according to equation 4,
only downwind flight is possible.
Clarke (1943) observed with regard to Aedes vexans that "during the
period of emergence . . . vexans rises from the marsh singly and contin-
uously at dusk for a period of approximately one hour. They are observed
to rise to a height of 40 feet and fly with the wind. " Similarly, Aedes
taeniorhynchus climbs at an angle of 30-60° to above the mangroves (Nielsen
1958, Haeger I960, Provost 1957). Also, Bailey et al. (1965) observed
that "when swarms of Culex tarsalis emerged from the rice fields in the
early evening they would spiral upward in an irregular manner to heights
of 12 to 15 feet, according to the temperatures of the atmospheric layers,
and then would level off in the wind current. " These authors found that
C. tarsalis usually flies at altitudes between 1.5 and 15 meters (5 and 50
feet). Aedes cataphylla rises to 4 to 8 meters, depending on the speed of
the wind (Klassen and Hocking 1964). Somewhat similar behavior was
observed for Culex pipiens fatigans (Lindquist et al. 1965) and for Anopheles
gambiae Giles (DeMeillon 1937).
IM
Fig. 1 a, Paths of Aedes cataphy lla take-off into a wind W, on a plain, b,
The permissible heights of flight of. Aecfes punctor in relation to windspeed
at 5 m above ground, c, The relationship between windspeed and themax.
displacement rate of A. punctor ( ) and Aedes aegypti- ( ) in upwind and
downwind flight. Redrawn from Klassen & Hocking (1964) with permission.
44
Klassen
The observations of Bailey et al. (1965) on the effect of wind on the
dispersal of Culex tarsalis agree precisely with the effect predicted by the
optomotor hypothesis. They found that:
"1. At low wind velocities, up to 2 mph (94 cm/sec, W.K. ), dis-
persal takes place in all directions. The greatest distance of
recapture was 2. 75 ... against a wind of 0 to 2. 9 mph (136
cm/ sec, W. K. ).
2, At least 10 percentof the mosquitoes from any particular re-
lease may disperse laterally, i. e. , across the direction of
the wind.
3. Above a limiting wind velocity of about 4 mph (188 cm/sec,
W. K. ) the general direction dispersal is downwind. There is
only very limited movement against or across a wind as high
as 4 mph. No recaptures were made upwind when velocities
were 5. 4 mph or higher . . . ",
Moonlight allows the phenomenon of twilight flight to continue (Rees
1945, Ribbands 1945, Provost 1958, Bidlingmayer 1964) because the in-
tensity of the light at full moon approaches that at twilight. The eyes of
mosquitoes are adapted forvisionin dim light (Sato et al. 1957), and their
wide visual solid angle is especially suitable for maintaining a track even
in dim light. Also, mosquitoes respond to the plane of polarized light
(Kalmus 1958), and since polarization of skylight is maximum one hour
after sundown, mosquitoes may use it as a navigational aid.
Dispersal and Topographical Features
Topographical features may affect dispersal by their influence on
micrometerological conditions, i. e. , they may influence the prevailing
wind and the creation of local winds, and by presenting visual stimuli to
dispersing mosquitoes.
Evidence exists that, in the absence of wind, mosquitoes with a pro-
nounced drive to disperse tend to orient toward the low point of the hori-
zon; this response, then, contributes to the movement of mosquitoes
into andalong valleys (Klassen and Hocking 1964). Are dispersingmos-
quitoes attracted to prominent sections (skototaxis) or are they attracted
to low points (hypsotaxis) of the landscape? Movement of mosquitoes up
the side of mountains has been recorded (Hearle 1926); however, this
may have been caused by upwind orientation to the sloping wind.
Also, the assembly of mosquitoes in wooded areas may be directed
not only by a taxis but by wind-borne moisture that causes an upwind
orientation (see Klassen and Hocking 1964).
On clear evenings, plains radiate their heat and cool the air im-
mediately above them. This cool air sinks into ravines and flows down
river channels at ca. 5 mph (measured at Edmonton, Canada; Klassen
1962), and these local winds are not usually affected by the prevailing
wind. Perhaps river channels thus accumulate dispersing mosquitoes
and then channel their movements up or down a valley (Klassen and
Hocking 1964). During dry seasons in the Transvaal, dispersal is res-
tricted to wooded river valleys (DeMeillon 1933 as cited by Horsfall
1965). Similarly, dispersal of Aedes vexans and Aedes aldrichi occurred
mainly along the Columbia River Valley and its tributaries and not on
the plain (Stage et al. 1937). Causey and Kumm (1948) recaptured most
Life History
45
tagged mosquitoes within a river valley.
In deep valleys (fig. 2), winds blow up their sides and up-valley by
day and reverse direction by night (Defant 1951). By flying against the
down-valley wind during a single night, female Anopheles maculipennis may
disperse into human settlements no less than 5 km from the site of ec-
losion (Ivanova 1962). Moreover, female mosquitoes locate their hosts
by flying against the scent-bearing downslope wind (Ivanova 1962).
Near bodies of water, a wind may blow from water to land by day
and reverse at night. These winds, too, affect dispersal patterns (Iv-
anova 1962). Regularly, an early evening wind from the Pacific is chan-
nelled along the Sacramento River and affects the up-valley dispersal of
Culex tarsalis (Bailey et al. 1965).
Movement along Lines or Borders
Mosquitoes have been observed to orient and move along lines or
borders, irrespective of the wind (Jenkins and Hasset 1951, Snow and
Pickard 1957). Recently, Giglioli (1965) observed that Anopheles melas
(Theobald) traveled 1 to 2 miles from the site of eclosion to a village by
followingthe interface between bushes and cleared land. The mosquitoes
formed streams about 20 to 60 feet wide, flew below an altitude of 5
feet, and did not align with the direction of the wind.
Movement with Strata of Vegetation
Horsfall (1955) reported that the movements of mosquitoes may be
restricted to the undergrowth. "Females were moving eastward in the
undergrowth of a forest area during a sultry afternoon whenno wind was
blowing. The females flitted from one low plant to another, but always
in the same general easterly direction." Such creeping migration seems
to occur in Utahalso; Rees (1945), too, noted that females followed paths
above a low canopy of vegetation and that a flight moved 8 km in 2 to 5
days in this case.
Movement toward Illuminated Sector of the Sky
Horsfall (1955) reported that a mass flight of Aedes vexans took place
toward "the flowing skyline caused by suburban glowing lights. " Sim-
ilarly, Gunstreamand Chew (1964) observed that this species mayorient
to the strongly illuminated western sky rather than to the wind. Orien-
tation of Coleoptera to a lighted section of the horizon has been demon-
strated by Lindroth (1948) and deserves investigation.
MacCreary (1939) operated 5 light traps in Newark, Delaware, and
found that the catch in each varied. He felt that the mosquitoes were ob-
served to fly toward areas that had the highest population (Tensity of man
and cited the opinion of Headlee (1936) that "Both Aedes vexans (Meig. ) and
Culex pipiens L. tend to migrate in the direction of great populations regard-
less of the wind direction. " Similarly, Gillies (1961) found the disper-
sion of Anopheles gambiae was related primarily to the distribution of human
settlements. Perhaps the lights of human settlements are attractive, or
perhaps the mosquitoes simply accumulate near the blood source by
klinokinesis. Ivanova (1962) believed that mosquitoes several kilometer s
distant from a human settlement responded to human odors carried on
katabatic winds.
SUNRISE
FORENOON
MIDNIGHT
AFTERNOON
EARLY NIGHT
BEFORE SUNRISE
Fig. 2. Air currents within a large valley at various times of day.
Based on Defant's (1951) model of the valley-slope wind system.
Life History
47
Passive Transport of Mosquitoes
Movements of mosquitoes other than those near the surface of the
earth have been reported. Smith et al. (1956) demonstrated with marked
mosquitoes that whena cool air mass moved across a semitropical area
in California, vast numbers of mosquitoes were picked up and deposited
30 to 60 miles distant from the site of eclosion. Smith (personal com-
munication) explained this transport as follows: "I do not have any air
temperature data of the moving air but would assume it would not be much
below 10° lower than the valley air ... I do not believe this mass could
be considered as passing over in the nature of a frontal movement. Met-
eorological information indicated that it was a local movement drawn in
from the coast over about 60 miles of low hot hills to fill a local baro-
metric low and dissipated once it entered the valley. My belief is that
the mosquitoes were not carried on this cool air or any local surface
movement it set up, but were stimulated by cool air and carried by ther-
mal currents at higher altitudes . . . ".
A mass transport of Aedes vexans in a cold front was described by
Horsfall (1954). Perhaps storm cells of the advancing air mass picked
up the mosquitoes and carried them high into the air as is apparently also
the case with the spruce budworm moth, Choristoneura fumiferans (Clemens)
(Greenbank 1956). Some species of mosquitoes were caught by Glick
(1939) at 3000 feetand 5000 feet over the central United States, and adult
Culex tarsalis were taken at 500, 1000, and 2000 feet over Texas (Glick and
Noble 1961). Also, Bailey et al. (1965) trapped this species at the top of
a 1540-foot television tower in California.
Changes in pressure associated with the passage of cold fronts "ex-
cite" some Diptera (Wellington 1945, 1946), and Haufe (1954, 1963) de-
monstrated that Aedes aegypti exhibits increas ed activity with such changes .
Moreover, Kennedy (1940) and Kalmus and Hocking (I960) showed that
mosquitoes take flight when windspeeds are decreasing. Conceivably,
mosquitoes, particularly newly-emerged ones, could be picked up by
frontal systems as a result of their flight activity.
Armstrong (1963) felt that observations are needed to determine
whether the low-level jet streams that develop above temperature inver-
sions on the Great Plains could transport mosquitoes . The chances seem
small that significant numbers of mosquitoes would be entrained into
these jets that occur at a height greater than 800 feet above the plain.
Also, mechanical dispersal of eggs or larvae of Aedes aegypti in water
containers moved along commercial routes has expanded the range of
this species (MacDonald 1956).
48
Klassen
TABLE 1. Reports on the influence of wind on mosquito dispersal.
Species Maximum distance
Remarks
Sources
minimus
flavirostris
vagus var, limosus
sollicitans
40
Rough terrain, windspeed
and direction variable,
max. distance 1.25 miles,
flew in all directions.
Experiments of Smith.
Flew up to 4 miles, per-
haps upwind.
(1925)
Ejercito &
Urbino
(1951)
Felt (1904)
Elmore &
Schoof (1963)
Life History-
49
TABLE 1. (cont. )
Species Maximum distance
flown (miles)
Remarks
Sources
Anopheles:
Upwind Downwind
sollicitans
cantator
(Coquillett)
aldrichi
(Dyar & Knab)
= sticticus (Meigen)
vexans
Aedes:
ca. 10 Regularly flies across
Delaware Bay,
MacCreary &
Stearns (1937)
40 Experiments of Smith
ca. 10 Regularly flies across
Delaware Bay.
Felt (1904)
MacCreary &
Stearns (1937)
several
several
several
14
90-230
Flew along Fraser River
valley, Hearle (1926)
Flew up and down Columbia Stage et al.
River valley & tributaries. (1937)
Rempel (1953)
Flew along Fraser River
valley
Flight mostly restricted
to Columbia River valley
& tributaries.
Flight of newly emerged
adults has strong down-
wind tendency, windspeed
< 34 mph.
Cold front following hot
weather.
Hearle (1926)
Stage et al.
(1937)
Clarke (1943)
Horsfall
(1954)
leucocelaenus
Dyar & Shannon
communis (DeGeer)
taeniorhynchus
< 20
25
Slow movement, level Rees
plain. (1935)
Bonnet &:
Worcester
(1946)
Flight has downwind bias.
Flew in all directions <
5000 ft, wind variable in
speed and direction.
Downwind bias, terrain
may affect orientation.
All downwind 4 days after
eclosion.
Causey &
Kumm (1948)
Jenkins &
Hassett (1951)
Provost
(1952)
Provost
(1957)
50
Klassen
TABLE 1. (cont. )
Life History-
51
TABLE 1. (cont.)
Species Maximum distance Remarks
flown (miles)
Upwind Downwind
Sources
Other genera:
Unknown
Stegoconops spegazzinii
(Brethes)
Psorophora sp.
22
< 6
Several genera; "slow
steady breezes brought
large numbers over
desert".
Flight has downwind bias
Strong tendency to move
downwind.
Davis (1901)
Causey &
Kumm (1948)
Quarterman
etal. (1955)
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57
DESCRIPTIONS OF NEW SPECIES OF FLIES OF
THE FAMILY AGROMYZIDAE FROM ALBERTA, CANADA (DIPTERA)
VINOD K. SEHGAL
Department of Entomology
University of Alberta Quaestiones entomologicae
Edmonton, Alberta, Canada 4 : 57-88 1968
Thirteen new species of flies of the family Agromyzidae (Dipt era) described in this paper are:
Agromyza albertensis, A. masculina, Ophiomyia monticola, 0. pulicarioides, Phytobia flavohumer-
alis, Cerodontha occidentalis, Liriomyza conspicua, L. montana, L. cordillerana, L. septentrion-
alis, Lemurimyza pallida, Phytomyza lupini and P. lupinivora. Necessary amendments to existing
keys are given to include the above species.
The description of new species in this paper is a partial report on
the survey of Agromyzid flies of Alberta, conducted during the years
1966 and 1967. The holotype and allotype of all new species will be de-
posited in the Canadian National Collection, Ottawa, Canada.
Since the publication of Frick's (1959) keys for the North American
Agromyzid flies, many changes have taken place. Nowakowski (1962)
suggested a new grouping of the genera based on genitalic structures.
While I agree with Nowakowski's classification, the generic arrange-
ments of Frick's keys have not been changed. The new species have
been included in the existing framework of keys by giving the necessary
amendments. Mr. K. A. Spencer intends to publish shortly a synopsis
of the Canadian Agromyzidae and these new species will be included in
his new keys.
As will be evident from the discussion of various species, the char-
acters of the male genitalia have been extremely important in distinguish-
ing between closely related species.
Agromyza albertensis new species
Description
Head (fig. 1). Frons slightly narrower than the width of an eye (1 :
0. 9), almost equal in length to its width at level of front ocellus. In
profile orbits and frons projecting in front of eye margin particularly
above antenna. Lunule lower than a semicircle. Two strong Ors directed
58
Sehgal
upwards, two strong Ori directed inwards; orbital setulae few, about
four, reclinate; lower ocellar bristle reaching the base of lower Ors .
Eyes bare; ocellar triangle small. Gena about one fourth of the eye
height midway between vibris sal and posterior margins, not extending in
front of eye in profile. Vibrissal hair short and bent inwards. Antennal
bases approximate; third antennal segment rounded anteroventrally,
covered with uniform pubescence; arista 1.75 times the total lengthof
antenna, pubescent.
Mesonotum . Two small presutural and four postsutural dc increasing
in length posteriorly; acr in about 5-6 irregular rows.
Leg. Mid-tibia without a bristle medially.
Wing (fig. 2). Length about 2. 0 mm in cl* and 2. 6 mm in ?; costa ex-
tending to vein R445; costal segments 2-4 in ratio of 1 : 0. 36 : 0.31;
last segment of M344 0.9 times the punultimate segment; r-m crossvein
slightly beyond the middle of the discal cell; wing tip between R445 and
■M-1+2 •
Male Genitalia (fig. 3). Hypandrium with pregonites large and flattened;
disti phallus elongate and well sclerotized, with a sharp characteristic
bend at its base; basiphallus consisting of a pair of broad bent sclero-
tized strips, relatively short in relation to the long distiphallus . Phallo-
phore weakly sclerotized; postgonites with a small apical lobe as in
other members of the nigripes-ambigua group (Griffiths 1963). Ejaculatory
apodeme broad and fan shaped, bulb small.
Colour. Frons matt black; ocellar triangle weakly shining; max-
illary palpi black; mesonotum and scutellum shining black; wing veins
dark brown; calypter with margin and fringe yellow; halteres yellow;
abdomen black; legs black.
Material Examined
Holotype cf (with genitalia preparation) Canada, Alberta, Banff, 28.
vi. 1966. Allotype $ same data. Paratypes, 1 ? Alberta, Blairmore,
26. vi. 1966; 1 cf- and 1 ? Alberta, Banff, 28. vi. 1966 (K.A. Spencer) and
1 cf Alberta, Blairmore, 26. vi. 1966 (K.A. Spencer).
Derivation of the Specific Name
The specific name albertensis has been derived from the name of the
province of Alberta, Canada.
Comparisons
Agromyza albertensis belongs to the ambigua group and is very close to
A. ambigua Fallen. In Frick's (1959) key to the North American species
of Agromyza Fallen, A. ambigua Fallen and A. niveipennis Zetterstedt both key
out at couplet 18. Spencer (1965a) synonymized niveipennis Zett. with
ambigua Fallen after examination of Zetterstedt* s type series in Lund.
Theaedeagus of A. ambigua Fallen has been illustrated by Spencer (1965a).
A. albertensis may be included in Frick* s (1959) key to Agromyza species by
amending couplets 17 and 18 as below:
17 Gena in height midway between vibrissal and posterior angles about
one fourth the eye height 18
Gena in height midway between vibrissal and posterior angles about
New Agromyzidae
59
one seventh the eye height barberi
18 Wings shining milk white (Hendel 1936), aedeagus as figured by
Spencer (1965a) ambigua
Wings normal. Distiphallus with a characteristic bend at its base,
relatively longer and narrower albertensis
Biology
Not confirmed, but as far as known all species of this group are
grass feeders in the larval stage (Griffiths 1963).
Agromyza masculina new species
Description
Head (fig. 4). Frons 1.2 times longer than broad, slightly narrower
than the width of the eye (1 : 0. 8) at the level of front ocellus, not pro-
jecting above the eye in profile. Lunule lower than a semicircle, slightly
sunken below the frons. Two strong Ors directed upwards; two Ori di-
rected inwards and upwards; orbital setulae 6-8, reclinate. Eyes bare;
ocellar triangle small. Gena narrow, one eighth of the eye height in its
middle, not projecting in front of the eye margin in profile. Vibrissal hair
short and bent inwards. Antennal bases approximate; third antennal
segment broad with slightly longer pubescence in front; arista longabout
twice the total length of the antenna.
Mesonotum . Dor socentrals 3+1, strongly developed; acr in about six
irregular rows.
Leg . Mid-tibia without a bristle medially.
Wing (fig. 5 ). Length about 2. 5 mm; costa extending to vein M^2
costal segments 2-4 in the ratio of 1 : 0. 2 : 0.2; last segment of
0. 79 times the penultimate segment; r-m slightly before the middle of
the discal cell; wing tip between R4+5 and M142*
Male Genitalia (fig. 6). Hypandrium V-shaped, with small pregonitesat
the anterior end, basal half of the side arm flattened. Distiphallus elon-
gate and well sclerotized; mesophallus with two sclerotized bars, of
which the right continues as a narrow strip to join the basiphallus; basi-
phallus with weakly sclerotized broad strip on one side and a membranous
fold on the other. Ejaculatory apodeme fan shaped, bulb small.
Colour . F rons dull greyish black; ocellar triangle weakly shining
black; antennae black; maxillary palpi brownish black; mesonotum,
scutellum and abdomen weakly shining black; wing veins dark brown;
calypter margin and fringe yellowish brown; halteres yellow; legs with
femora brownish black, tibiae and tarsi yellowish brown.
Material Examined
Holotype cf (with genitalia preparation) Canada, Alberta, Blairmore,
26. vi. 1966. Allotype $ same locality, 27. vi. 1966. Paratypes, 1 $,
Alberta, Okotoks, 10. vi. 1966 (K.A. Spencer).
Derivation of the Specific Name
Agromyza masculina belongs to the spiraeae group. The species in this
60
Sehgal
group are poorly differentiated in external characters but examination
of the male genitalia reveals conspicuous differences among the included
species. The name masculina was suggested by K.A. Spencer in view of
the distinctly larger and sclerotized aedeagus when compared to that of
spiraeae Kaltenbach.
Comparisons
Agromyza masculina can be included in Frick!s (1959) key to North Am-
erican Agromyza species by amending and extending the couplets 19 and
20 as follows:
19 Calypter with margin and fringe brown or yellowish brown 20
Calypter with margin and fringe white or yellow 21
20 Mid-tibia medially with two posterolateral setae isolata
Mid-tibia without posterolateral setae 20a
20a Calypter with margin and fringe brown; distiphallus widely separ-
ated from basiphallus by a completely membranous section
spiraeae
Calypter with fringe yellowish brown; mesophallus with a pair of
sclerites distally; hypandrium with broader arms masculina
Ophiomyia monticola new species
Description
Head (fig. 7). Frons slightly narrower than the width of the eye
(1 : 0.9) at the level of the front ocellus, projecting conspicuously in
front of the eye margin in profile. Two equal, strong Ors directed up-
wards; two Ori , weaker than Ors, directed inwards and upwards; orbital
setulae few, 5-6, reclinate. Eyes 1.3 times longer than broad, bare;
ocellar triangle small. Gena about one third of the eye height midway
between the vibrissal and posterior margins, projecting in front of the
eye margin in profile. Vibrissal hair normal. Facial keel broad and
distinctly bulbous below the antennal bases. Antennal bases separate;
third antennal segment rounded; arista about one and a half times the
total length of the antenna; pubescent.
Mesonotum . Two distinct postsutural dc ; acr numerous, in about ten
irregular rows.
Leg . Midtibia without a bristle medially.
Wing (fig. 8). Length about 2. 1 mm in cf and 2.3 mm in $; costa
reaching the vein ^4^.5, costal segments 2-4 in the ratio of 1 : 0. 35 :
0. 25; last segment of M344 about three quarters the penultimate; r-m
cross vein beyond the middle of the discal cell.
Male Genitalia ( fig. 9). Hypandrium with a distinct hypandrial apodeme;
aedeagus with a complex distiphallus; basiphallus with two broad scler-
otized strips, of which the right is longer and bent at base; phallophore
broad and strongly sclerotized; ejaculatory apodeme long, fan shaped
with a small gland at the base.
Colour. Completely black species; frons matt black; ocellar triangle
weakly shining; mesonotum and scutellum matt black; abdomen weakly
shining; wing veins dark brown; calypter with margin and fringe dark
New Agromyzidae
61
brown; halteres black.
Material Examined
Holotype - d* (with genitalia preparation) CANADA, Alberta, Banff,
28. vi. 1966. Allotype - 9 same data. Paratypes - 2 99 Alberta, Jasper,
16. vi. 1966; 2 same locality, 18- 19. vi. 1966; 1 $ Alberta, Cypress
Hills, Elkwater, 24. vi. 1966.
Mr. K.A. Spencer has reported the following further specimens
which are referable to this species:
CANADA, Alberta, Jasper - 1 cff 19. vi. 1966 (K.A. Spencer); Banff,
2^, 2 9$, 28. vi. 1966 (K.A. Spencer), 1 cf 1 9, 8-29. vi. 1922 (C.B.D.
Garrett); British Columbia, Atlin - 1 9, 14.vii. 1955 (H. J. Huckel), 1
cT, 13. vi. 1955 (B.A. Gibfarl); 32 miles SW of Terrace - 19, 11. vi. I960
(G.E. Shewell); Manitoba - Mile 505, Hudson Bay Railway -19, 29. vi.
1952 (J. D. Chillcott); Yukon Territory- FirthRiver, British Mountains -
1 cT, 19, 25. vii. 1956 (R.E. Leech). ALASKA - Big Delta - 1 dj 10. vi.
1951 (J.R. McGillis), 19, 27. v. 1951 (W. R. Mason).
Derivation of the Specific Name
The name monticola signifies that the species is mountain inhabiting.
Comparisons
Ophiomyia monticola is very close to 0. nasuta (Melander) ( -Tylomyza nasuta
(Melander) sensu Frick 1959) innot havinga distinct vibrissal hornin the
male, but differs in having only two dorsocentrals and distinct genitalia.
Ophiomyia monticola may beincludedin Frick's (1959) key to North American
Ophiomyia species as given in the extension of couplet 1 at the end of the
description below of Ophiomyia pulicarioides .
Ophiomyia pulicarioides new species
Description
Head (fig. 10). Frons narrower than the width of an eye (1 : 0.87)
at the level of front ocellus, not projecting in front of the eye margin in
profile. Lunule lower than a semicircle. Two strong Ors directed up-
wards; two Ori , weaker than Ors, directed inwards and upwards; or-
bital setulaeabout 12-15, reclinate. Eyes 1.2 times longer than broad,
bare; ocellar triangle small. Gena about one fifth of the eye height mid-
way between vibrissal and posterior margins, not extending in front of
the eye in profile. Vibrissal hair normal. Facial keel narrow. Anten-
nal bases approximate; third antennal segment rounded; arista about
twice the total length of the antenna, pubescent.
Mesonotum . Two distinct postsutural dc ; acr numerous, in about ten
irregular rows.
Leg . Midtibia without a bristle medially.
Wing (fig. 11). Length about 2. 0 mm in cf and 2. 25 mm in 9; costa
extending to vein M^2> costal segments 2-4 in the ratio of 1 : 0. 26 :
0.24; last segment of M344 about 0.77 times the penultimate;
cross vein beyond the middle of the discal cell.
r-m
62
Sehgal
Male Genitalia { fig. 12). Hypandrium typical V- shaped; aedeagus with
a complex distiphallus; basiphallus with two broad sclerotized strips, of
which the right is larger than the left; phallophore broad and strongly
sclerotized.
Colour . Completely black; frons matt black; ocellar triangle weakly
shining; mesonotum, scutellum and abdomen shining black; wing veins
dark brown; calypter with margin and fringe dark brown; halteres black.
Material Examined
Holotype - cT (with genitalia preparation) CANADA, Alberta, Cypress
Hills, Elkwater, 24. vi. 1966; Allotype - ? same data.
Derivation of the Specific Name
The name 0. pulicarioides indicates that this species belongs to the
pulicaria group.
Comparisons
Ophiomyia pulicarioides resembles 0. pulicaria (Meigen) in having no vi-
brissal horn in the male and no distinct facial keel (both sexes); but the
male genitalia are distinct. Like 0. pulicaria , 0. pulicarioides can easily be
confused with the genus Melanagromyza Hendel on the basis of external
characters alone, but both possess an aedeagus typical of the genus
Ophiomyia Bras chniko v .
Ophiomyia pulicarioides and 0. monticola described above maybe included
in Frick's (1959) key to the North American species of Ophiomyia by ex-
tending couplet 1 as below:
1 Haltere black la
Haltere with a white spot on the knob punctohalterata
la Distinct facial keel separating antennae ... lb
Distinct facial keel lacking; male without a vibrissal horn
pulicarioides
lb Male with a distinct vibrissal horn 2
Male without a distinct vibrissal horn; two strong postsutural dc ;
aedeagus as in fig. 9 monticola
Phytobia flavohumeralis new species
Description
Head (fig. 13). Frons almost equal to the width of the eye at the
level of the front ocellus, slightly projecting in front of the eye margin
in profile. Lunule low, reaching slightly above the base of Iqwer Ori .
Two strong Ors directed upwards; two strong Ori directed inwards and
upwards; orbital setulae about 8-10, reclinate. Eyes about 1.25 times
higher than broad; ocellar triangle small. Gena about one eighth of the
eye height midway between vibris sal and posterior margins , not extending
in front of the eye margin in profile. Vibrissal hair normal. Antennal
bases approximate; facial keel narrow; arista long and pubescent.
Mesonotum. Dor socentrals 3+1; acr numerous , in about 10 irregular
rows .
Leg . Midtibia with a couple of conspicuous setae medially.
New Agromyzidae
63
Wing (fig. 14). Length in males 2. 8-3. 1 mm; costa extending to vein
■^■1+2’ cos^al segments 2-4 in the ratio of 1.0 : 0.30 : 0.24; last segment
of M3+4 about 0. 9 times the penultimate; r-m cross vein approximately
at the centre of the discal cell.
Male Genitalia (fig. 15). Hypandrium U-shaped with darkly sclerotized
broad arms; aedeagus tubular and lightly sclerotized structure, the
distiphallus complex has a swollen bulb at the base, basiphallus con-
sists of a long tube with a distinct curvature; phallophore darkly sclero-
tized section at the base; ejaculatory apodeme broad and lightly sclero-
tized, ejaculatory bulb large.
Colour . Frons, orbits and lunule greyish black; gena slightly yel-
lowish; antennae black; maxillary palpi black; mesonotum dull greyish
black; humeral areas with a characteristic yellow ring; pleural region
dull black; mesepisternum with a narrow yellow band along the upper
margin; legs black with a slight yellow at the tip of the femora; wings
normal; calypter with margin and fringe dark brown; halteres yellow;
abdomen dull greyish black.
Material Examined
Holotype - (with genitalia preparation) CANADA, Alberta, George
Lake, from the Malaise trap collection of Peter Graham of the University
of Alberta, Edmonton, 18. v. 1967; Paratypes - 10 ctf (all with genitalia
preparations), same data, 18-23. v. 1967; 7 c£f same data, 11. v. 1966;
5 same data, 19-20. v. 1966. Mr. Spencer has examined the following;
CANADA, British Columbia, Robson- 1 cf, 14. v. 1947 (H.R. Foxlee);
Saskatchewan, Saskatoon - 2 9. v. 1949 (A.R. Brooks); Ontario, Ot-
tawa - 1 14. v. 1925 (C. H. Curran); Bell's Corner - 2 c£f} 25. v. 1949
and 21. v. 1950 (G. E. Shewell).
Derivation of the Specific Name
The name flavohumeralis indicates that the species possesses a char-
acteristic yellow on humeral areas.
Comparisons
Phytobia flavohumeralis is very close to Phytobia (Phytobia) sefosa (Loew); but
differs from it in having a black third antennal segment and a character-
istic yellow ring around the humeral areas . It may be included in Frick's
(1959) key to the subgenus Phytobia Lioy by amending and extending the
couplets 6 and 7 as follows;
6 Cross vein m-m about its own length from r-m 7
Cross vein m-m not more than six-tenths of its length from r-m. .
wait on i
Head with one upper-orbital reclinate; dorsal margin of lunule semi-
circular (figs. 57 &: 58, Frick 1959); mid-tibia with three postero-
lateral setae
amelanchieris
Head with both upper-orbitals reclinate; dorsal margin of lunule
flattened; mid- tibia with one or two posterolateral setae 7a
7a Mesonotum black; third antennal segment reddish
Mesonotum with a characteristic yellow ring around humeral areas;
third antennal segment black; aedeagus as fig. 15 flavohumeralis
This species belongs to the genus Phytobia Lioy in the restricted sense
proposed by Nowakowski (1962). This group was given subgeneric rank
( Phytobia , subgenus Phytobia ) in Frick's (1959) classification.
64
Sehgal
Cerodontha occidentalis new species
Description
Head (fig. 16). Frons broad, about 1. 1 times the width of the eye
at the level of front ocellus; conspicuously projecting in front of the eye
margin in profile, less so at the rear. Lunule higher than a semicircle.
Two strong Ors directed upwards; one Ori directed inwards with a small
proclinate hair in front; orbital setulae 2-4, the lower two usually pro-
clinate or bent inwards the upper reclinate. Eyes oval about 1. 1 times
higher than broad; ocellar triangle small. Lower ocellar bristle long
extending below the base of the Ori . Gena about one- third of the eye
height midway between vibris sal and posterior margins. Vibrissal hair
strong. Third antennal segment elongate and produced into a sharp spine
at the upper angle; arista long and pubescent.
Mesonotum . 3+1 strong dor socentrals; first two dors ©centrals of al-
most equal length and strength, third and fourth increase in size poster-
iorly; acr absent.
Leg . Midtibia without a bristle medially.
Wing (fig. 17). Length 2. 2-2. 5 mm in <& and 2. 7-2. 9 mm in ?$; costa
extending to vein costal segments 2-4 in the ratio of 1 : 0. 2 : 0.2;
last segment of M344 about 0. 9 times the penultimate; r-m cross vein
slightly before the middle of the discal cell; at the wing tip.
Male Genitalia (fig. 18a, b) . Hypandrium typical U-shaped; aedeagus
conspicuously elongate structure; distiphallus with a pair of long sigmoid
tubes with a distinct sclerotized bulb at its tip; the apical bulb at the
most twice as long as broad; mesophallus is an elongate tubular struc-
ture swollen at the base, it has a small recurved process at the distal
and a distinct sclerotized section at its base; hypophallus consists
of a pair of recurved processes; basiphallus is a distinct, broad, bent
and sclerotized part, its narrow basal end is connected to the distal end
of the broad circular and sclerotized phallophore; ejaculatory duct is
visible inside the phallophore and basiphallus; ejaculatory bulb broad
and has a sclerotized lower wall; ejaculatory apodeme broad, fan shaped
and well sclerotized.
Colour . Frons, lunule, facial keel, gena, first and second antennal
segments yellow; second antennal segment of antenna sometimes brown-
ish; orbits usually yellow but sometimes slightly darkened along the eye
margin in front, in the region of orbital bristles; maxillary palpi and
proboscis yellow; mesonotum matt black, humeral callus yellow, with
a black spot anteriorly; notopleural areas yellow; scutellum usually
matt black sometimes with a light brown central area; mesepisternum
and mesepimeron varies from dark brown to black, but always with a
yellow band along the upper margins; legs with coxae and femora yel-
low, tibiae and tarsi brownish yellow to dark brown; wings normal; cal-
ypter margin and fringe dark brown; halteres yellow; abdominal terga
matt black with a narrow yellow posterior margin.
Material Examined
Holotype - d* (with genitalia preparation) CANADA, Alberta, Canmore
nr. Banff, 28. vi. 1966, swept on open grass. Paratypes - 20 <& (all with
New Agromyzidae
65
genitalia preparations) and 4 $?, same data; 7 c& and 2 ?$, same data in
K.A. Spencer’s collection; 1 c? Alberta, Blairmore, 27. vi. 1966.
Mr. K.A. Spencer has kindly compared the following further speci-
mens referable to this species:
1 $ - CANADA, Yukon Territory, Rampart House, 17. vi. 1951 (J.E.
H. Martin), lcf- ALASKA, Big Delta, 24. vi. 1951 (J. R. McGillis), 1
$ - Anchorage, 27. vi. 1951 (R.S. Bigelow).
Derivation of the Specific Name
The name occidentalis indicates that the species is described from
western Canada.
Comparison
Cerodontha occidentalis is very close in its external characters to the
only other Nearctic species, C. dorsalis (Loew), which has been widely
reported from United States and Canada (Frick 1959). This new species
like C. dorsalis (Loew) shows some colour variation. This colour var-
iation however does not affect the uniformity in the structure of the male
genitalia. A detailed examination of a long series of specimens collected
mainly at Canmore near Banff, Alberta, shows conspicuous differences
from those of typical C. dorsalis (Loew). The aedeagus of a typical C. dorsalis
from the United States (Indiana, Lafayette) collected by J. M. Aldrich is
illustrated (fig. 18c) for comparison with that of C. occidentalis (figs. 18a,
b). The aedeagus in C. occidentalis is about one and a half times as long as
in C. dorsalis . The main distinguishing features are the broader hypo-
phallus, the incurved process at the distal end of the mesophallus, the
longer tubes of the distiphallus and comparatively shorter bulb at the tip
of the distiphallus.
Other specimens of C. dorsalis examined are: Manitoba, Aweme - 1
cT 27.viii. 1917 (N. Criddle); Alberta, Banff - 1 cf 3.ix. 1966; Blair-
more - 2 ff, 4. ix. 1966; Crowsnest - 1 5. ix. 1966; Medicine Hat -
1 $, 16. vi. 1928 (F. S. Carr) det. C.H. Curran; British Columbia, Crows-
nest - 1 c( 26.vii. 1926 (A. A. Dennys); Shuswap Lake - 1 cf 22.vii.
1926 (J.M. Dunnough); Chilliwack - 1 cf, 14.x. 1938 (J. K. Jacob).
Cerodontha occidentalis may be separated from the only other species
Cerodontha dorsalis (Loew) known in the Nearctic region, by the following
key:
1 S cut ellum adjoining mesonotum usually with a variable yellow spot;
the sigmoid tubes of the distiphallus comparatively short with an
elongate apical bulb; the latter at least three times as long as broad
(fig. 18c) dorsalis
Scute Hum and adjoining mesonotum usually with a uniform matt
black; the sigmoid tubes of the distiphallus long with a short bulb
at the tip; the apical bulb of the distiphallus at the most twice as
long as broad (fig. 18 a, b) occidentalis
Nowakowski (1962) has proposed an enlarged concept of the genus
Cerodontha Rondani, including a number of subgenera which were trans-
ferred from Phytobia Lioy. The above new species Cerodontha occidentalis
like C. dorsalis (Loew) belongs to the genus Cerodontha in the restricted sense
(subgenus Cerodontha in Nowakowski’s classification).
66
Sehgal
Liriomyza conspicua new species
Description
Head (fig. 19). Frons narrower than the width of the eye at the level
of front ocellus, projecting conspicuously in front of the eye margin in
profile. Lunule reaching up to the base of second Ori . Two strong Ors
directed upwards; three Ori in male, the two females referable to this
species have four Ori on one side, all directed inwards and upwards; or-
bital setulae about 13-18, reclinate. Eyes oval, 1. 3 times higher than
broad in profile; ocellar triangle small. Gena high about one fourth the
eye height midway between vibrissal and posterior margins, not exten-
ding in front of eye margin in profile. Vibrissal hair normal. Facial
keelnarrow. Antennal bases approximate; third antennal segment broad;
pubescent.
Mesonotum (fig. 21). Dorsocentrals 3+1; acr in about 5 irregular
rows.
Leg . Midtibia without a bristle medially.
Wing (fig. 20). Length 2.5 mm in cf and 3.0-3.25 mm in ?; costa
extending to vein M-j^.;?, costal segments 2-4 in the ratio of 1 : 0. 3 : 0. 2;
last segment of M3^ about 1. 5 times the penultimate; r-m cross vein
approximately at the centre of the discal cell.
Male Genitalia (fig. 22). Hypandrium typical U-shaped with broad pre-
gonites. Aedeagus complex; disti phallus consisting of two long narrow
processes joined at the base by a thin membrane; mesophallus a long
darkly sclerotized spindle shaped structure; hypophallus complex, par-
tly fused with the basiphallus; the two arms of basiphallus are fused at
the base, a short sclerotized segment is connected to one side of basi-
phallus by a thin membrane. Phallophore well sclerotized and continuous
with the basiphallus. Aedeagalrod broad at its anterior end. Ejaculatory
apodeme broad and fan shaped; ejaculatory bulb large with thin walls.
Colour . Frons, orbits and antennae yellow; ocellar triangle dark
brown; gena yellow; black of occiput touching upper posterior margin
of the eye; vte and vti on the margin of dark brown and yellow grounds;
maxillary palpi yellow; mesonotum (fig. 21) brownish black with a char-
acteristic yellow before the scutellum; humeral and notopleural areas
yellow; humeral areas with a small brown spot anteriorly; scutellum
yellow with very small brown areas near its basal corners; mesepister-
num dark brown with upper one third yellow; mesepimeron black with a
yellow upper margin; legs with coxae distally yellow; femora yellow;
tibiae and tarsi brown; wings normal; calypter with margin and fringe
dark brown; halteres yellow; abdominal tergites dark brown with a yel-
low line along posterior margins.
Material Examined
Holotype - cf (with genitalia preparation) CANADA, Manitoba, 5 miles
S. W. Shilo, Floodplain community nr. Tamarack Bog, open grassy
marsh, 2.viii.l958, coll. J. G. Chillcott. Paratypes - 1$, Saskatchewan,
Butland, 19.vii.1940, coll. A.R. Brooks; 1 $- Alberta, Jasper, 16. vi.
1966.
Mr. K. A. Spencer has kindly compared the following further speci-
New Agromyzidae
67
mens also referable to this species:
Manitoba, Minnedosa - 1 cf 7. vi. 1926 (R„ M. White); 9 miles N of
Forrest - Id* and 3 $$, 29. vi. and 19.vii. 1958 (R.B. Madge and R. L.
Hurley), 5 miles SW of Shilo, 2 $?, 5. vi. and 16. vi. 1958 (R. L. Hurley).
Ontario, Ottawa -1?, 3.vi. 1958. Saskatchewan, Saskatoon -2^3
?$, 9. v. 1949 (A. R. Brooks), 1$, 28.vii.1923 (N. L. Atkinson), 1 ?, 28.
vi, 1941 (Arnason); Indian Head - 1 c? 3.viii. 1939 (C.R. Douglas); As -
siniboia- 1$, 27. vi. 1955 (J. R. Vockeroth).
Derivation of the Specific Name
The name conspicua indicates that this species is very conspicuous
in having very bright colouration and characteristic genitalia.
Comparisons
Liriomyza conspicua belongs to the group of species having a character-
istic prescutellar yellow. It can be included in Frick’s (1959) key to
North American Liriomyza species by amending and extending the couplet
15 as below:
15 Acrostichal setae in 4-5 rows; prescutellar yellow area subrectan-
gular 15a
Acrostichals five or six in number, in two rows; yellow area tri-
angular assimilis
15a Acrostichals about 13 in number, in four rows; all four dorsocen-
tral setae on yellow ground (Frick 1959) flavonigra
Acrostichals many in about five irregular rows (fig. 21); all four
dorsocentral setae on dark brown ground; aedeagus as illustrated
(fig. 22) conspicua
Liriomyza montana new species
Description
Head (fig. 23). Frons slightly wider than the width of the eye at the
level of front ocellus, slightly projecting in front of the eye margin in
profile. Lunule low, reaching to the base of the lower Ori. Two Qrs
directed upwards; two to three Ori directed inwards and upwards; or-
bital setulae 4-6, reclinate. Eyes about 1.3 times higher than broad;
ocellar triangle small. Gena about one fifth of the eye height midway be-
tween vibrissal and posterior margins, not extending in front of the eye
margin in profile. Vibrissal* hair normal. Facial keel narrow; antennal
bases approximate; third antennal segment rounded; arista long; weakly
pubescent.
Mesonotum . Dor socentrals 3+1; acr numerous in about 4 irregular
rows; humeral callus with 4-5 hairs.
Leg . Midtibia without a bristle medially.
Wing (fig. 24). Length 1. 9-2. 0 mm in cb* and 2. 0-2. 25 mm in $9;
costa extending strongly to the vein M^;?; costal segments 2-4 in the
ratio of 1 : 0. 3 : 0. 24; last segment of Mg^ about twice as long as the
penultimate; r-m crossvein almost at the centre of the discal cell, some-
times slightly before it; vein M^2 ending at the wing tip.
68
Sehgal
Male Genitalia (fig. 25). Hypandrium typical U-shaped; pregonites
broad; distiphallus elongate with a characteristic bend and sclerotization
at its base and has a distinctive small bulb at its tip; basiphallus consis-
ting of two long and narrow sclerites enclosing characteristic sclerotized
and swollen ejaculatory duct; hypophallus almost membranous fold;
phallophore long and well sclerotized; ejaculatory apodeme fan shaped
with a sclerotized bulb at its base.
Colour . Frons, lunule, orbits and gena entirely yellow; third anten-
nal segment yellow, arista brown; black of occiput touching the upper
posterior margin of the eye; vte. usually on dark brown ground; vti on
the margin of dark brown and yellow ground; mesonotum shining black
with yellow humeral and notopleural areas; humeral area with a small
dark spot, humeral seta on yellow ground; scutellum with very small
dark area on the basal corners; mesepisternum with upper two thirds
yellow and lower one third dark brown; mesepimeron dark brown with
a dorsal band of yellow; legs with coxae yellow but have slight brown
bases; femora primarily yellow; tibiae and tarsi brown; wings normal;
calypter margin and fringe brown; halteres yellow; abdomen shining
black.
Material Examined
Holotype - cf (with genitalia preparation) CANADA, Alberta, Jasper
17. vi. 1966. Allotype - ?, same data. Paratypes - 14 and 5 ?$, same
locality, 17-19. vi. 1966; 3 Alberta, Banff, 28. vi. 1966. All speci-
mens swept on open grass.
Derivation of the Specific Name
The name montana indicates that the species is mountain inhabiting.
Comparison
Liriomyza montana belongs to the flaveola group of species on the basis
of the male genitalic structures and is very close to European species
L. pedestris Hendel, but has very distinct genitalia. It is also very close
to L. graminicola de Meij. in external characters but the male genitalia is
very distinct in the shape of the distiphallus.
L. montana resembles L. richteri Hering in the general shape of male
genitalia, but differs in having yellow femora.
L. montana resembles L. eupatori (Kaltenbach) in having yellow femora
and four rows of acrostichals but has male genitalia typical of the
flaveola group. L. montana can be included in Frick's (1959) key to the
Liriomyza species by extending the couplet 29 as below:
29 Crossveinm-m notmore than its length from r-m; ultimate section
Ms^4 about three times as long as the penultimate 30
Crossvein m-m more than its own length from r-m; ultimate sec-
tion of M344 about two times as long as the penultimate 29a
29a Crossvein m-m 1. 5 to two times its length from r-m; humeral callus
with 4-9 hairs (Hendel 1936) eupatori
Crossveinm-m slightly less than 1.5 times its length from r-m;
humeral callus with 4-5 hairs; male genitalia as illustrated (fig.
?5\ montana
New Agromyzidae
69
Liriomyza cordillerana new species
Description
Head (fig. 26). Frons almost equal to the width of the eye at the
level of front ocellus, slightly projecting in front of the eye margin in
profile. Lunule low, reaching to the base of lower Or/. Two strong
Ors directed upwards; usually two Or/, of which(but one female has
lower Or/ missing on one side) the lower one slightly weaker than the
upper; both Or/ directed upwards and inwards; orbital setulae about
5-6, reclinate. Eyes about 1.3 times higher than broad; ocellar triangle
small. Gena about one fifth of the eye height midway between vibrissal
and posterior margins, not extending in front of the eye margin in pro-
file. Vibrissal hair normal. Facial keel narrow. Antennal bases ap-
proximate; third antennal segment slightly elongate; arista long and
weakly pubescent.
Mesonotum . Dorsocentrals 3+1; acr numerous in about 4-5 irregular
rows.
Leg . Midtibia without a bristle medially.
Wing (fig. 27). Length 2. 4-2. 8 mm in d* and 2. 5-3. 0 mm in ?; costa
extending to vein costal segments 2-4 in the ratio of 1 : 0. 2 : 0.2;
last segment of M344 about twice as long as the penultimate; r-m cross-
vein approximately at the centre of the discal cell.
Male Genitalia (fig. 28). Hypandrium typical U-shaped with broad pre-
gonites; postgonites characteristically elongate; distiphallus with a
characteristic bend at its base and a darkly sclerotized bulb at its apex,
within which two strongly sclerotized ducts can be seen; basiphallus con-
sisting of two long narrow sclerites enclosing the sclerotized ejaculatory
duct which does not form a swollen bulb before entering the distiphallus;
hypophallus consisting of long narrow and bent sclerites; phallophore
broad and strongly sclerotized. Ejaculatory apodeme fan shaped with a
strongly sclerotized bulb at its base; ejaculatory duct also sclerotized
for a short distance.
Colour . Frons usually yellow but sometimes orange or brownish
yellow; ocellar triangle shining black; antennae yellow, with the third
segment usually darkened distally; black of occiput touching the upper
posterior margin of the eye; vte on black ground; vti usually on the mar-
gin of black and yellow; orbits usually darkened along the eye margin;
maxillary palpi yellow; mesonotum shining black with yellow humeral
and notopleural areas; both humeral and notopleural areas with a black
spot; scutellum yellow with dark areas near its basal corners; pleural
areas mainly black; mesepisternum with anarrow yellowupper margin;
legs with coxae black; femora black with a yellow distal tip; tibiae and
tarsi black; wings normal; halteres yellow.
Material Examined
Holotype - cf (with genitalia preparation) CANADA, Alberta, Banff,
3.ix. 1966. Allotype - $, same data. Paratypes -9c tf and 7 9$, same
data; 3 c£f Alberta, Jasper, l.ix. 1966; 1 cf Alberta, Jasper, Sunwapta
Falls, 2.ix. 1966; 2 ctf and 2 $$, Alberta, Blairmore, 26-27. vi. 1966; 2
same locality, 4.ix. 1966; 1 cf Alberta, Crowsnest, 5.ix. 1966; 13
70
Sehgal
cfcf and 5 ?$, Alberta, Waterton Park, 6-7. ix. 1966.
Derivation of the Specific Name
The name cordillerana indicates that the species is mainly distributed
in the Rockies.
Comparisons
Liriomyza cordillerana belongs to the flaveola group of species and is very
close to Liriomyza pedestris Hendel and L. richteri Hering in external appear-
ance but has very distinct genitalia. The male genitalia of L. richteri
Hering was illustrated by Griffiths (1964), and of L. pedestris Hd. by Spen-
cer (1965b).
Liriomyza cordillerana is also very close to L. septentrionalis , the new spe-
cies described below, and can be reliably separated only by detailed ex-
amination of the characteristics of its male genitalia. L. cordillerana can
be included in Frick's (1959) key to North American Liriomyza species as
shown below at the end of the description of L. septentrionalis .
Liriomyza septentrionalis new species
Description
Head (fig. 29). Frons narrower than the width of an eye (1 : 0. 8) at
the level of front ocellus, not projecting in front of the eye margin in pro-
file. Lunule low, reaching to the base of lower Ori. Two strong Ors ,
directed upwards; two slightly weaker Ori (three in one specimen) , dir-
ected inwards and upwards; orbital setulae about 5-8, reclinate. Eyes
about 1. 2 times longer than broad; ocellar triangle small. Gena about
one fifth of the eye height midway between vibrissal and posterior mar-
gins, not extending in front of the eye margin in profile. Vibrissal hair
normal. Facial keel narrow. Antennal bases approximate; third an-
tennal segment oval; arista long and weakly pubescent.
Mesonotum . Dor socentrals 3+1; acr in about 5 irregular rows.
Leg . Midtibia without a bristle medially.
Wing (fig. 30). Length about 2.5 mm in cf and 2.7 mm in ?; costa
extending to vein M 442, costal segments 2-4 in the ratio of 1 : 0.24:0.20;
last segment of M34.4 about 1.7 times the penultimate; r-m crossveinat
the middle of the discal cell.
Male Genitalia (fig. 31). Hypandrium typical U-shaped; pregonites
broad; postgonites characteristically elongate; distiphallus with a char-
acteristic bend at the base and weakly sclerotized bulbat its apex, within
which a long narrow and weakly sclerotized duct can be seen; basiphallus
consisting of two long narrow sclerites enclosing the strongly sclerotized
ejaculatory duct which forms a characteristic swollen bulb towards the
apex of basiphallus; hypophallus consisting of a pair of short bent scler-
ites. Ejaculatory apodeme fan shaped; ejaculatory bulb large with stron-
gly sclerotized walls.
Colour . Frons yellow; ocellar triangle dull black; antennae yellow,
sometimes third antennal segment slightly orange or brownish; orbits
yellow, but may be very slightly darkened; black of occiput touching the
New Agromyzidae
71
upper posterior margin of the eye; vte on black and vti on the margin of
black and yellow; maxillary palpi brownish yellow; me s on o turn shining
black with yellow humeral and notopleural areas; both humeral and noto-
pleural areas with a black spot; scutellum yellow, with a black margin
near the upper scutellars; pleural areas mainly black; mesepisternum
with anarrow yellowupper margin; legs with coxae black; femora black
but with a distal yellow; tibiae and tarsi black; wings normal; calypter
margin and fringe black; halteres yellow; abdomen black.
Material Examined
Holotype - cf (with genitalia preparation) CANADA, Alberta, Banff,
28. vi. 1966. Allotype - $ same data. Paratypes - 1 $, same data; 1 cf
and 1?, Alberta, Jasper, 17- 18. vi. 1966; 2 Alberta, Blairmore,
26. vi. 1966; 3 cfcf Alberta, Waterton National Park; 6-7. ix. 1966.
Mr. K.A. Spencer has kindly examined the following specimens re-
ferable to this species:
CANADA, Alberta, Frank - 1 ?, 13. vii. 1966 ex mine in grass leg.
26. vi. 1966 (K.A. Spencer); Jasper - 1 25. vii. 1926 (J. McDunnough);
Banff - 1 $, 7. vii. 1955 (J.R. Cogles); Elkwater -1?, 2.vi. 1955 (J. R.
Vockeroth); British Columbia, Cultus Lake - 2 ^ 4- 10. vii. 1948 (H. R.
Foxlee); Brilliant -1$, viii. 1947 (H. R. Foxlee).
Derivation of the Specific Name
The name septentrionalis indicates that the species is northern in its
distribution.
Comparisons
Liriomyza septentrionalis belongs to the flaveola group and is very close to
L. flaveola (Fallen) but has a darker mesepisternum and a distinct aede-
agus. It is also very close to European species L. pedestris Hendel exter-
nally, but has a distinct genitalia. The genitalia of L. flaveola (Fallen) and
L. pedestris Hendel have been illustrated by Spencer (1965a, 1965b).
Liriomyza septentrionalis is also very close to L. cordillerana , the species
described above, from which it can be reliably differentiated only by a
close examination of aedeagus, which has characteristically swollen
ejaculatory duct between basiphallus and distiphallus , and a paler disti-
phallus. It also differs in having usually yellow orbits and third antennal
segment.
Liriomyza septentrionalis and L. cordillerana can be included in Frick‘s (1959)
key to North American Liriomyza species by amending and extending the
couplet 23 as below:
23 Femora primarily yellow, usually marked with brown or black
streaks or spots 24
Femora black, distal one third yellow 23a
23a Mesepisternum with at least dorsal one third yellow 23b
Mesepisternum approximately with upper half yellow (Frick 1959);
aedeagus as illustrated by Spencer (1965a) flaveola
23b Orbits usually yellow; aedeagus with ejaculatory duct characteris-
tically swollen between basiphallus and distiphallus (fig. 31) disti-
phallus lightly sclerotizedand as illustrated (fig. 31) .... septentrionalis
72
Sehgal
Orbits usually darkened; ejaculatory duct between basiphallus and
distiphallus not swollen, distiphallus darkly sclerotized and as il-
lustrated (fig. 28) cordillerana
Lemurijnyza pallida new species
Description
Head (fig. 32). Frons almost equal to the width of the eye; slightly
projecting in front of the eye margin in profile, particularly so at the
base of the antenna. Two strong Ors directed upwards; one 0ri directed
inwards; orbital setulae about 8-9. Eyes oval, 1.2 times higher than
broad; ocellar triangle small. Gena about one third (1 : 0.3) of the eye
height midway between vibris sal and posterior margins, notextending in
front of the eye in profile. Antennal bases approximate; third antennal
segment elongate; arista long and covered with uniform pubescence.
Mesonotum . Dor socentrals 3+1; acr in two rows.
Wing (fig. 33). Length in cf 2. 1 mm; costa extending to vein M^+2;
costal segments 2-4 in the ratio of 1 : 0. 26 : 0. 21; last section of M3_j.4
about twice as long as the penultimate; r-m crossvein almost at the
centre of the discal cell; wing tip at
Male Genitalia (fig. 34). Hypandrium typically U - shaped with narrow
side arms and broad fused pregonites. Distiphallus with the character-
istic paired tubules bent outwards; mesophallus long and cylindrical,
darkly sclerotized; hypophallus consists of sclerotized narrow ventral
appendages at the base of mesophallus. Surstyli with sclerotized teeth
on their ventral surface. Ejaculatory apodeme broad and fan shaped;
ejaculatory bulb large and membranous.
Colour . Frons, orbits, genae and antennae entirely yellow; arista
brownish; ocellar triangle brown. Mesonotum matt black; humeral and
notopleural areas yellow with a small black spot on both. Legs with fe-
mora and tibiae yellow; tarsi brownish. Wings normal; calypter margin
and fringe brown; halteres yellow.
Material Examined
Holotype - cf (with genitalia preparation) CANADA, Alberta, Banff,
28. vi. 1966.
Derivation of the Specific Name
The name pallida indicates that the species is mostly yellow in colour .
Comparisons
The genus Lemurimyza was described by Spencer (1965) and includes
four world species. Lemurimyza pallida represents the first record of the
genus in the Nearctic region. This species is characteristic in having
a yellow third antennal segment and characteristic male genitalia.
New Agromyzidae
73
Phytomyza lupini new species
Description
Head (fig. 35). Frons almost equal to the width of the eye at the
level of the front ocellus, conspicuously projecting in front of the eye
margin in profile. One Ors directed upwards; two Ori directed inwards;
orbital setulae many, proclinate. Eyes almost circular; ocellar tri-
angle small. Orbits prominantly projecting in front and below the eye
margin. Gena about one third (1:0. 33) of the eye height midway between
the vibrissal and posterior margins, becoming higher posteriorly. An-
tennal bases approximate; third antennal segment elongate; arista long
and swollen at the base, weakly pubescent.
Mesonotum . Dorsocentrals 3+1; acr in 2-3 irregular rows.
Wing (fig. 36). Length 2. 6 mm in 2. 8 mm in $?, costa extending
strongly to vein R4+5; costal segments 2-4 in the ratio of 1 : 0. 24 : 0.4;
wing tip at the vein
Male Genitalia (fig. 37). Hypandrium V-shaped with broad side arms
and flattened pregonites; aedeagus complex; distiphallus with a char-
acteristic bent section which has a sclerotized tip; basiphallus consisting
of twobroad sclerotized arms joinedat the base which are produced into
broad sclerotized plates distally; phallophore broad and continuous with
the basiphallus; aedeagual apodeme very broad; ejaculatory apodeme
fan shaped with a slightly sclerotized bulb.
Colour. Frons dominantly yellow or slightly brownish at the base;
orbits yellow; black of the occiput touching the posterodor sal margin of
the eye; vte on black ground and vti on the margin of yellow and black
ground; ocellar triangle weakly shining black; third antennal segment
shining black; first and second segments yellowish black. Mesonotum
and scutellum matt black; pleura matt black. Legs: femora with a distal
ring of yellow; tibiae and tarsi black. Wings normal; calypter margin
and fringe yellowish brown; halteres yellow. Abdomen black.
Material Examined
Holotype - cf (with genitalia preparation) CANADA, Alberta, Blair-
more, ex stem mines on Lupinus sericeus Pursh (Leguminosae) collected
6.ix. 1966, emerged ll.iii. 1967; puparium chilled at 45 F for 12 weeks;
Allotype - ?, same data, emerged 20. iii. 1967; Paratypes - 1 cfand 3 ?? ,
same data.
Mr. K.A. Spencer has kindly examined the following specimens
which are referable to this species:
CANADA, British Columbia, Albion - 2 7.viii.l952, ex " crown
of Lupinus sp. " (Y. Ayre).
Derivation of the Specific Name
Phytomyza lupini is named after its larval food plant Lupinus sericeus Pursh
(Leguminosae) .
Comparisons
Phytomyza lupini may be included in Frick's (1957) key to the genus
Phytomyzq Fallen by amending and extending the couplet 17 as below:
74
Sehgal
17 Genovertical plates darkened angelicella
Genovertical plates yellow 17a
17a Acrostichals in 4-5 rows (Frick 1957); intraalar row with 10-12
setulae anterior to and 13-15 posterior to the transverse suture . .
. aquilegiana
Acrostichals in 2-3 irregular rows; intraalar row withabout 3 set-
ulae anterior to and 2-3 posterior to the transverse suture; male
genitalia as illustrated (fig. 37) lupini
Biology
The larvae bore inside the stems of Lupinus sericeus Pursh (Legumin-
osae). Pupation takes place inside the stem. The puparia are charac-
teristic in having a distinct horn on the posterior spiracles.
Phytomyza lupinivora new species
Description
Head (fig. 38). Frons narrower than the width of the eye (1 : 0.84)
at the level of the front ocellus, not projecting in front of the eye margin
in profile. Two strong Ors directed upwards; two slightly weaker On
directed inwards; orbital setulae few, about4, proclinate. Eyes rounded;
ocellar triangle small. Gena about two fifths (1 : 0.4) of the eye height
midway between the vibrissal and posterior margins, not extending in
front of the eye in profile. Antennal bases approximate; third antennal
segment rounded; arista small and thickened at the base; weaklypubes-
cent.
Mesonotum . Dorsocentrals 3+1; two small act present between first
and second pair of dorsocentrals.
Wing (fig. 39). Length in $ 1. 75 mm; costa extending strongly to vein
I3-4+5’ costal segments 2-4 in the ratio of 1 : 0.24 : 0.75; wing tip at
■^•1+2- The wing of the? holotype is abnormal in having an additional
vein near the tip of R-2+3.
Colour . Completely black species; frons dullblack; ocellar triangle
weakly shining; gena, orbits and antennae matt black; mesonotum and
scutellum matt black; pleura weakly shining black; legs black; wing
veins dark brown; calypter margin and fringe dark brown; halter es yel-
low; abdomen matt black.
Material Examined
Holotype - 9 CANADA, Alberta, Blairmore, ex leaf mines on Lupinus
sericeus Pursh (Leguminosae), collected 6.ix. 1966, emerged 20. ii. 1967;
puparium chilled at 45 F for 8 weeks.
Derivation of the Specific Name
Phytomyza lupinivora is named after its larval food plant, Lupinus sericeus
Pursh (Leguminosae).
Comparisons
Phytomyza lupinivora is veryunusual in havinga very short second costal
New Agromyzidae
75
segment and a rather long fourth segment. It can be included in Frick's
(1957) key to North American species of the genus . Phytomyza Failed by
extending the couplet 30 as below:
30 Antenna darkbrown or black; tarsi and tibiae black, brown or dark
reddish brown 30a
Antenna with first, second, and basal portion of third reddish yellow;
tarsi and distal portion of tibiae yellow agromyzina
30a Acrostichals in 2-8 rows 31
Acrostichals very few (about two); wings with costal segments 2-4
in the ratio of 1 : 0. 24 : 0. 75 lupinivora
Biology
Larvae feed inside the linear mines in the leaflets of Lupinus sericeus
Pursh (Leguminosae) . Mines are for the most part upper surface, ir-
regular and partly lower surface. The pupation takes place outside the
mine.
ACKNOWLEDGEMENTS
I am grateful to Dr. B. Hocking, Chairman, Department of Ento-
mology, University of Alberta, for providing the opportunity and neces-
sary support to carry out this project in Canada.
I am also grateful to Mr. K. A. Spencer (19 Redington Rd. , Hamp-
stead, London, NW3) and Mr. G.C. D. Griffiths (Department of Entom-
ology, University of Alberta) for their many useful discussions and val-
uable suggestions during the present study. I am also indebted to Dr.
Hocking and Dr. G.E. Ball (Department of Entomology, University of
Alberta) for their encouragement and helpful criticism of the manuscript.
REFERENCES
Frick, K.E. 1959. A synopsis of the species of agromyzid leaf miners
described from North America (Diptera). Proc. U.S. nat. Mus.
108 : 347-465. 170 figs.
Griffiths, G.C.D. 1963. A revision of the Palaearctic species of the
nigripes group of the genus Agromyza Failed (Diptera: Agromyzidae).
Tijdschr . Ent. 106(2) : 113-168.
Griffiths, G.C.D. 1964. The agromyzid fauna of Iceland and the Faroes ,
with appendices on the Phytomyza mi lii and robustella groups (Diptera,
Agromyzidae). Ent. Medd. 32 : 393-450.
Hendel, F. 1936. Agromyzidae. In Lindner: Die Fliegen der Palaeark -
tischen Region. Bd. 6(2). 570 pp.
Nowakowski, J. T. 1962. Introduction to a systematic revision of the
Family Agromyzidae (Diptera) with remarks on host plant selection
by these flies. Ann. Zool. Warszawa 20 : 67-183.
Spencer, K.A. 196,5a. A clarification of Fallen's type Specimens of Ag-
romyzidae (Diptera) in Stockholm and Lund. Ent. Tidskr. 86(3-4) :
76
Sehgal
249-259.
Spencer, K.A. 1965b. Some Agromyzidae (Diptera) from Sicily. Ento-
mologist's mon. Mag. 101 : 172-177.
ABBREVIATIONS
acr, acrostichal hair; Adap, aedeagal apodeme; Adh, aedeagal hood;
Ar, arista; As3, third antennal segment; Bsph, basiphallus; C, costa;
dc, dorsocentral bristles; DC, discal cell; Dph, distiphallus; Ejap,
ejaculatory apodeme; Ejb, ejaculatory bulb; Ejd, ejaculatory duct; Epph,
epiphallus; Hph, hypophallus; Hypa, hypandrium; m-m, medial cross
vein; an(l -^-3+4 median veins; Mph, mesophallus; oc, ocellar bris-
tles; Ori, lower orbital bristles; Ors, upper orbital bristles; os, orbital
setulae; Pgo, postgonites; Phph, phallophore; Prgo, pregonites; Pvt,*
postvertical bristle; Ri, R2+3 & R4+5, radial veins; r-m, radiomedial
cross vein; Sc, subcostal vein; Vi, vibrissal hair; Vte, outer vertical
bristle; Vti, inner vertical bristle.
New Agromyzidae
77
Figs. 1-3. Agromyza albert ensis new species: 1 - head, lateral view; 2 -
wing; 3a - aedeagus, lateral view; 3b - aedeagus, ventral view; 3c -
hypandrium, ventral view; 3d - ejaculatory apodeme.
78
Sehgal
Figs. 4-6. Agromyza masculina new species: 4 - head, lateral view; 5 -
wing; 6a - aedeagus, lateral view; 6b - hypandrium, ventral view; 6c -
ejaculatory apodeme.
New Agromyzidae
79
/ Vt'
7
Figs. 7-9. Ophimomyia monticola new species: 7 - head, lateral view; 8 -
wing; 9a - aedeagus, lateral view; 9b - aedeagus, ventral view; 9c -
hypandrium, ventral view; 9d - ejaculatory apodeme .
80
Sehgal
Figs. 10-12. Ophiomyia pulicarioides new species: 10 - head, lateral view;
11 - wing; 12a - aedeagus, lateral view; 12b - aedeagus, ventral view;
12c - hypandrium, ventral view.
New Agromyzidae
81
Figs. 13-15. Phytobia flavohumeralis new species: 13 - head, lateral view;
14 - wing; 15a -aedeagus, lateral view; 15b - hypandrium, ventral view;
15c - ejaculatory apodeme.
0 -25mm
82
Sehgal
Figs. 16-18. Cerodontha occidentalis new species: 16 - head, lateral view;
17 - wing; 18a - aedeagus, lateral view; 18b - ejaculatory apodeme;
18c - Cerodontha dorsalis (Loew) - aedeagus, lateral view.
New Agromyzidae 83
Figs. 19-22. Liriomyza conspicua new species: 19 - head, lateral view; 20 -
wing; 21 - mesonotum, dorsal view; 22a - aedeagus, lateral view; 22b -
aedeagus, ventral view; 22c - ejaculatory apodeme.
0-25 mm
S4
Sehgal
Figs. 23-25. Liriomyza montana new species: 23 - head, lateral view; 24 -
wing; 25a - aedeagus, lateral view; 26b — distiphallus, ventral view;
25c - hypandrium, ventral view; 25d - ejaculatory apodeme.
New Agromyzidae
85
Figs. 26-28. Liriomyza cordillerana new species: 26 - head, lateral view;
27 - wing; 28a - aedeagus, lateral view; 28b - distiphallus, ventral view;
28c - hypandrium, ventral view; 28d - ejaculatory apodeme, front view;
28e - ejaculatory apodeme, side view.
86
Sehgal
0.1 mm
31a-d
Figs. 29-31. Liriomyza septentrionalis new species: 29 - head, lateral view;
30 - wing; 31a -aedeagus, lateral view; 31b - distiphallus, ventral view;
31c - ejaculatory apodeme, front view; 3 Id - ejaculatory apodeme, side
view.
New Agromyzidae
87
33
Figs. 32-34. Lemurimyza pallida new species: 32 - head, lateral view; 33
wing; 34a - sur stylus, ventral view; 34b - distiphallus , ventral view
34c - ejaculatory apodeme.
88
Sehgal
Figs. 35-37. Phytomyza lupini new species: 35 - head, lateral view; 36 -
wing; 37a - aedeagus, lateral view; 37b - ejaculatory apodeme. Figs.
38-39. Phytomyza lupiniv ora new species: 38- head, lateral view; 39 - wing.
Quaestiones
entomologicae
A periodical record of entomological investigations,
published at the Department of Entomology, Uni-
versity of Alberta, Edmonton, Canada.
VOLUME IV
NUMBER 3
JULY 1968
QUAESTIONES ENTOMOLOGICAE
A periodical record of entomological investigations published at
the Department of Entomology, University of Alberta, Edmonton, Alberta.
Volume 4 Number 3 July 1968
CONTENTS
Book review 89
Tawfik - Feeding mechanisms and the forces involved in some
blood-sucking insects 92
Abdelnur - The biology of some black flies (Diptera: Simuliidae)
of Alberta 113
Book Review
HABU, AKINOBU. 1967. Fauna Japonica. Carabidae, Truncatipennes
Group (Insecta:Coleoptera) . Tokyo Electrical Engineering College Press,
Hakushin-Sha Printing Co. , Ltd. , Tokyo, Japan. 338 pp. + xiv, 527
figs. , XXVII plates, some in color. Cloth bound. $20. 00 USA.
This work deals with the heterogeneous assemblage of ground beetles
with truncated elytra. In Japan this includes 109 species arranged in 43
genera of the tribes Odacanthini, Hexagoniini, Pentagonicini, Masoreini,
Lebiini, Zuphiini, Dryptini, and the subfamily Brachininae.
For each species, Habu gives the common Japanese name, an exten-
sive synonymy, a synoptic description and a statement on geographical
distribution. Following the generic descriptions, notes are provided on
biology and references to larval descriptions are given.
The text is in English, however, in many places it is confusing and
some errors exist. This work seems to have suffered much in trans-
lation perhaps because of poor editing. For example, on page 2 the
first sentence after the introduction states "The head is generally wider
than thepronotum, but in the Odacanthini and the Dryptini it is narrower
than this". In fact, the opposite is true. Lesser mistakes which are
certainly the result of mistranslation occur throughout the text.
The illustrations are excellent and are certainly one of the outstan-
ding features of the book. Almost all characters of taxonomic importance
have been illustrated with fine line drawings by the author. The colored
plates by Mr. T. Sekigvchi and the black and white plates by the author
have been superbly drawn and reproduced. The only criticism I have of
the illustrations deals with the figures of the male genitalia. The struc-
ture of the internal sac of the aedeagus is shown in only its inverted pos-
ition. In species that lack well-defined sclerotized fields on the internal
sac, this is completely satisfactory. However, many species possess
characteristic arrangements of spines and sclerites that are often very
useful for identification and classification. Madge (Quaest. ent. 1967
90
(3) : 139-242) made gooduse of this character in his revision of the North
American species of the genus Lebia . Habu indicates, through the use
of stippling, that such structures are present in the internal sacs of
many of the Japanese Truncatipennes . However, as the relative posi-
tions of the fields in the internal sac vary with slight differences in in-
version, the most satisfactory method of studying this structure in a
uniform manner is to completely evert it. In this way the fields are
readily observable and their relative sizes and positions can be easily
determined.
Keys are provided as an aid to identification and as a summary of
characters used in erecting classifications. The keys to the species of
the various genera appear to be straightforward; each couplet consists
of a pair of rather distinct alternatives. However, the keys to the high-
er taxa, especially the supra-generic groups, are much more difficult
because the alternatives presented are less distinct. These keys, which
are apparently a summary of the classification, are to some extent based
on variable characters and for this reason present difficulties in defining
some higher taxa. An example of this is shown by the classification pro-
vided for the subtribes of the Lebiini. Here the principal characters
that Habu has used are the structure of the legs and mandibles. The
structure of the leg is related to the habitat of the insect. For example,
most arboreal carabids possess dilated legs and tarsi, an adaptation that
increases the area of contact between the insect and the surface it is
climbing and, hence, providing better traction; physical considerations
indicate that a slender, longer leg is more suitable for a cursorial ani-
mal. Within the Lebiini, the various subtribes tend to be adapted to a
particular habitat. For example, the Callidina is primarily an arboreal
group and shows adaptations for an arboreal existence in the structure
of the legs. On the other hand, the ter restrial genus Anomotarus Chaudoir
possesses all the characteristics of the more typical members of the
Callidina except that its tarsi are slender and lack dense ventral setose
pads. Because of this, Habu chooses to separate this genus from the
Callidina and places it in a new subtribe. Hubu's Callidina maybe homo-
geneous as regards the structure of the legs and mandibles, but the fe-
male genitalia, mouthparts -- especially the ligula andmentum, and gen-
eral habitus suggest that the subtribe Callidina is a heterogeneous as-
semblage and should be redefined, perhaps by placing Anomotarus Chaudoir
and those callidine genera that possess styli with setose apices in the
Callidina s. str. and by removing those genera which possess other forms
of female ovipositor to one or perhaps two groups of subtribal rank.
This proposed rearrangement provides more homogeneous groups, and
I think each of these groups is likely to be monophyletic, and thus natur-
al in a phylogenetic sense.
Species whose members are varied in their color pattern have been
illustrated but aside from this, little account has been taken of variation.
Subspecies have been recognized in several instances and while criteria
for recognizing subspecies have not been given, the author appears to
follow currently recognized practice. What is surprising, however, is
his formal recognition of "forms". Hehas described Lebia bifenestrata form
ogurai new form in addition to recognizing the "typical form" and the
91
"form lucescens" . All of these "forms" appear to be sympatric and are
included in the normal intraspecific variation found in this species. This
is a regrettable regression to typological thinking.
This work forms one of the most thorough treatments accorded a
group of ground beetles. The morphology of the insects dealt with ap-
pears to have been studied in a most careful and painstaking manner.
The female ovipositor, a structure that has frequently been overlooked
by previous worker s , has received detailed study by Habu, who adequately
demonstrates the potential of this organ in further taxonomic work. It
is unfortunate that Habu himself has not used the possibilities of the data
he presents. Few statements are devoted to a discussion of relationships
existing among the higher taxa. The classification is traditional even
though certain of Habu's data suggest that a modification is necessary
of certain groups such as the subtribes of the Lebiini.
Habu has certainly provided an excellent manual for the identification
of the species of the Truncatipennes group of Carabidae of Japan. Un-
fortunately this work narrowly mis ses being one of the major contributions
to the understanding of the higher taxa of this large and very complex
group of insects.
David J. Larson
Research Station
Canada Department of Agriculture
Lethbridge, Alberta
92
FEEDING MECHANISMS AND THE FORCES
INVOLVED IN SOME BLOOD-SUCKING INSECTS
M. S. TAWFIK
Department of Entomology
Faculty of Science
Cairo University Quaestiones entomologicae
Giza, Egypt, U.A.R. 4 : 92 - 111 1968
In the stages of Cimex lectularius L. and Pediculus humanus L. and in adult female
Aedes aegyptifLJ the weight of the blood meal was greater than the body weight. In C.
lectularius L. and P. humanus L. the negative pressure required to draw the blood to the
cibarial pump decreased from the first to the second instar and then increases to a maximum
in the adult. This pressure may be as high as 5.6 x left dyne/cn? . In A. aegypti female it
is smaller than any instar of C. lectularius or P. humanus. The muscular tension of the cib-
3 9
arial pump dilators in the species studied ranged from 5.7 to 18.4 x 10 g/cmf and the power
output ranged from 2.75 to 13.3 x 10 ^ £ cm/sec/ g ot muscle. Sensilla were found in the cib-
arium of C. lectularius but not of P. humanus.
Blood-sucking insects can ingest enormous meals in a short time.
In view of thenarrowness of the feeding canal and viscosity of vertebrate
blood, the rate of feeding, the negative pressure producedin the cibarial
pump, and the power required from the cibarial pump dilators are of
interest. All the nymphal instars and the adult males and females of
Cimex lectularius L. and Pediculus humanus L. , as well as adult females of
Aedes aegypti (L. ) were studied.
The structure and many details in the mechanism of sucking apparatus
in Hemiptera have been studied by Weber (1928, 1928a, 1929), Dickerson
and Lavoipierre (1959), and Lavoipierre et al. (1959). Kemper (1932)
and Snodgrass (1935, 1944) described in detail the feeding apparatus in
the bedbug C. lectularius .
The anatomy of the mouth parts of some mosquitoes has been des-
cribed in detail by Vogel (1921), Robinson (1939), Gordon and Lumsden
(1939), Christophers (I960), Schiemenz (1957), and Clements (1963).
The weight of the blood ingested by the females of different species of
mosquitoes and the rates of the ingestion have been reported in many
publications. Fulleborn (1908) reported the blood taken by gorged
A. aegypti averaged 0. 75 mg with a minimum and maximum of 0.20 and
0. 84 mg respectively. He also found that 53 out of 137 took a blood meal
much greater than their own weight. Jeffery (1956) recorded that Anopheles
quadrimaculatus and Anopheles albimanus ingest about 3.46 and 2. 58 mg of blood
respectively. Christophers (I960) reported that the feeding canal in
Aedes aegypti is about 2 mm long and has a diameter of 0. 03 mm. He added
Q
that from 2 to 1 mm of blood pass through this channel in 2 minutes and
that the linear rate of flow is from 2 to 4 cm/ sec.
The morphology of the piercing organs in Siphunculata has been dealt
with by Cholodkowsky (1904) , Enderlein (1905, 1905a), Pawlowsky (1906) ,
Harrison (1914), Sikora (1916), Peacock (1918), Florence (1921), Vogel
(1921), Fernando (1933), Snodgrass (1944) and Stojanovich (1945). Sum-
marized accounts are also given by Patton and Evans (1929), Metcalf
and Flint (1962), and Imms (I960). The relationships between food sup-
ply and the biology of Pediculus'humanus have been described by Nuttall (1917) .
Buxton (1947), Busvine (1948) and Gooding (1963).
Blood-Sucking Insects
93
Feeding Apparatus and Feeding Mechanisms
Whole mounts of the head and mouthparts were prepared. The in-
sects were soaked overnightin 5% potassium hydroxide solution, washed
thoroughly in water, stained with acid fuchsin if necessary, dehydrated
in ethanol, cleared in xylol and mounted in Canada balsam. Serial cross
sections of the mouthparts and the head, and serial horizontal sections
of the head were necessary. Mallory's triple stain was used. Measure-
ments were made with an ocular micrometer.
The mouthparts of the bedbug C. lectularius (fig. 1) consist of a labium
considerably longer than the head and when not in use turned backwards
at its base with its distal part between the forelegs. The labium is four-
segmented with the first one mostly concealed by the labrum and the
maxillary lobes. The labium is grooved on the lower surface and the
sides diverge near the tip of the last segment to leave a small aperture.
The maxillae and the mandibles are stylet-like and are held together
within the groove of the labium. Between the maxillary stylets is a min-
ute salivary duct and a relatively large food canal. The length of the
food canal and its radius vary from one instar to the next (table 2). At
the base of the labium the maxillae turn backwards into the head pouches
and diverge against the base of the hypopharynx where the food canal
opens into the anterior surface of the hypopharyngeal lobe that leads back
into the cibarial pump. The hypopharynx is a small lobe and its dorsal
surface is continued back into a large and deeply concave sitophore with
strong lateral margins, which is the floor of the cibarial pump (fig. 2).
The dorsal wall of the cibarial pump is in the form of a diaphragm (d. )
which is attached by a rubbery margin (r.m.) along either edge of the
sitophore (sit.). The diaphragm when not in action is completely col-
lapsed into the cavity of the sitophore. The measurements of the various
parts of the cibarial pump in the different instars are shown in tables 3
and 4. The dilator muscles (m. ) consist of two lateral bundles of fibers,
arising on nearly the whole clypeus. Measurements of these muscles
are shown in tables 3 and 4. The cibarial pump discharges directly into
the tubular oesophagus as there is no differentiated pharynx.
0-2 MM
I 1
Fig. 1. Head and mouthparts of female C. lectularius (ventral view).
94
Tawfik
Fig. 2.
Cross section through the head of female C. lectularius . (d) dia-
phragm; (rm) rubbery margin; (m) cibarial pump dilators.
When the bedbug feeds the stylets are forced into the skin of the
host. The labium helps in lowering the head of the insect near the skin
of the host by a backward bending of the third and fourth segments. The
mandibular stylets are the effective piercing organs while the two max-
illary stylets closely adhere to act as a sucking needle. Contraction of
the cibarial pump dilators moves the diaphragm upwards during the fil-
ling stroke. Emptying is achieved by the return of the diaphragm under
the elastic force of the rubbery margins.
The mouthparts of female aegypti , like those of C. lectularius , are
modified for piercing and most of the mouthparts are extended into long
and slender stylets. The labium is relatively stout and contains a dorsal
groove in which the stylets lie closely beside each other in a fascicle.
The labium ends with a pair of labella. The labrum is a broad pointed
stylet in the labial groove. It is curved so that its edges meet and thus
forms thefood canal. Towards the baseof the labrum the edges separate
and the hypopharynx forms the floor of the food canal. The average
length and the radius of the food canal are shown in table 2. The hypo-
pharynx is a very slender stylet with a median rib containing the salivary
canal. The mandibles are also stylets which come to a simple point with-
out teeth at the tip. The maxillae, which are the principal piercing or-
gans, each consist of a long flattened stylet with a curved end. The ci-
barial pump (cb.), fig. 3, is located under the clypeus (cl. ) and is trough-
shaped. The lower wall of the trough is well- sclerotized and is continuous
with the upper surface of the hypopharynx. The upper wall is thinner and
is continuous with the inner surface of the labrum. The upper wall is
elastic and when the cibarial pump is not in action it lies close to the
lower wall. Attached to the upper wall of the cibarial pump are two bun-
dles of muscles, the dilators of the cibarial pump (m. ), which have their
Blood-Sucking Insects
95
origin from the clypeus. Measurements of the cibarial pump and its di-
lators are shown in tables 3 and 4. For a short distance behind the ci-
barial pump the cuticle is thin and forms a valve. The cibarial pump is
connected to the pharyngeal pump by a narrow canal.
Fig. 3. Cross section through the head of female A. aegypti . (cb) cibarial
pump; (cl) clypeus; (m) cibarial pump dilators.
The head of P. humanus is produced anteriorly into a very small snout-
like proboscis probably formed from the lab rum and in which is a term-
inal opening or prestomum. This snout-like proboscis is armed inter-
nally with small teeth used to grip the host during feeding. The pres-
tomum opens to a preoral cavity within the head, the upper part of it is
continuous with the cibarial pump; the lower part extends to a long sac
which contains the stylets and nearly reaches the posterior end of the
head. The three stylets lie one above the other, the dorsal and ventral
ones forked at their bases. The dorsal stylet is made of two united
halves with the edges curved upwards and rolled over each other to form
the food canal. The ventral stylet is the effective piercing organ and its
apex is armed with teeth. The median stylet is pierced throughout its
length by the salivary duct. The homology of these stylets with the
mouthparts of biting insects has been a subject of dispute for many years.
Scholzel (1937) reinvestigated the development of these mouthparts. He
claimed that the ventral stylet is the labium, and he said that the max-
illae and mandibles are reduced and merged into the lateral walls of the
preoral cavity and that the dorsal and median stylets are both derived
from the embryonic hypopharynx. This interpretation was accepted by
Snodgrass (1944). During feeding the blood passes through the food can-
al of the dorsal stylet into a trough that fits into the proximal end of the
food canal. This trough, which is closed dorsally by the inner clypeal
wall, is connected with the cibarial pump. Fig. 4 shows the action of
the cibarial pump during the filling and emptying strokes. The mea-
96
T awf ik
surements of the feeding canal and the various parts of the cibarial pump
are shown in tables 3 and 4.
Fig. 4. Cross section through the head of the female P. humanus . A. Dur-
ing filling stroke. B. During emptying stroke, (cb) cibarial
pump; (m) cibarial pump dilators.
Sense Organs in the Food Canal
Von Gernet and Buerger (1966) studied the labral and cibarial sense
organs in some mosquitoes . They suggested that food is detected by the
apical labral sense organs and the pumping action is initiated by impulses
received by the cibarial muscles from the labral sense organs via the
frontal ganglion. They also suggested that the cibarial sense organs
control the openings of the stomach and diverticula, thus setting the
food-directing mechanism in action.
Similarly, I studied C. lectularius and P. humanus . No sense organs
Blood-Sucking Insects
97
could be located on the maxillae of C. lectulariusi. On the other hand, two
types of sensilla were found in the cibarium. A dorsal group consists
of six sensilla at the anterior end, three on each side of the cibarium
(fig. 5A). These are formed from minute hollow spines and innervated
by fine dendrites originating from the adjoining sensory cells. These
sensory cells seem to be innervated by a branch from the frontal nerve.
The second group consists of two campaniform sensilla, one on each
side of the sitophore (fig. 4B). Miles (1958) found that Oncopeltus and
Dindymus versicolor , could dis criminate between liquids sucked up the feeding
canal while any contact receptors were masked.
Fig. 5. Sense organs in the cibarium of female C. lectularius . A. Dorsal
sense organs. B. Sitophore sense organs.
98
T awf ik
No sensor/organs could be located in the food pathway of P. humanus.
Rate of Feeding and the Forces Involved
Methods
Feeding was observed under a binocular microscope and the feeding
period was timed with a stop watch. The weight of the blood meal was
determined by weighing the insects on a tor sion balance before and after
feeding. In all the experiments the insects were fed naturally on human
blood.
Calculation of the pressure difference required to force a liquid along
a tube at known rate can be made from Poiseuille's formula:
8 Q 1 n
▲ P = 7T r4 t
where A P = pressure difference in dynes/cm^
Q = volume moved in cm3, ri - viscosity of the liquid in poises, 1 =
length of the tube in cm, r = radius of the tube in cm, t = time in sec-
onds .
Poiseuille's formula was applied for the determination of the neg-
ative pressure required to draw the blood to the cibarial pump in these
insects, on the assumption that the blood behaves like a simple fluid and
the flow is laminar, because no more precise procedure has been dev-
eloped. These assumptions are questionable.
The volume of the blood (Q cm3) ingested during feeding for t sec-
onds was determined from the weight, taking the density of human blood
as 1.056 g/cm3 (Spector 1956, p. 51). The viscosity of human blood is
approximately 0. 025 poises at 38 C (Mitchell 1948, p. 407). The neg-
ative pressure in the cibarium was obtained by subtracting from the
pressure difference the capillary blood pressure which is 12 mm Hg or
1. 6 x 104 dynes/ cm^ (Wright 1952). The muscular force required to
provide this negative pressure was calculated by multiplying the corrected
pressure difference by the area of the diaphragm.
The force obtained from these calculations was doubled for the esti-
mation of the tension of the cibarial pump dilators on the as sumption that
half of the time is spent in the filling stroke. The muscular tension per
unit cross sectional area of muscles was obtained by dividing the cor-
rected force by the mean cross sectional area of the cibarial pump di-
lators. The mean cross sectional area was determined from cross sec-
tions of the cibarial pump dilators cut at 6 microns.
The power required of the cibarial pump dilators expressed as ergs/
sec/ g of muscle was found by multiplying the force by the total working
travel of the diaphragm in a second and dividing by the weight of the ci-
barial pump dilators. The total working travel was determined by mul-
tiplying the width of the rubbery margin (length in section, fig. 2) by the
number of pump cycles per second. The geometry of the cibarium, flat
and expanded, suggests that the diaphragm moves a distance approxi-
mately equal to the width of the rubbery margin in each stroke. For
determining the weight of these muscles the volume was obtained by mul-
tiplying the mean cross sectional area by the length of muscles and as-
suming the specific gravity of insect muscle to be one.
Blood-Sucking Insects
99
The rates of feeding observed are shown in table 1.
TABLE 1. Feeding period, weight of blood meal, and rate of feeding in
C. lectularius , P- humanus , and A. aegypti females.
Time to en- Wt Pump Blood tak-
Species gorgement Weight of meal Blood taken cycles/ en/pump
& stage in seconds meal (mg) body per sec (pg) second cycles (pg)
C. lectularius
Adult cf 286. 9±14. 6
(20)
195 - 410
6. 23±0. 41 2.8 21.7 0±0. 46 2. 4±0. 02
(15) (15) (30)
3.90 - 11.4 20.86 - 27.91 2.3 - 2.5
8. 89
100
Tawfik
TABLE 1 (cont. ).
Time to en- Wt Pump Blood tak-
* Mean ± SE
(number of insects used)
Range
>:«>;< Third nymphal instar of P. humanus was not studied because of some
difficulties in maintaining the culture.
Rate of Feeding
The feeding period of C. lectularius and A aegypti females was taken as
the time required for the insect to feed till engorged and of P. humanus
as the time required for the insect to feed till the blood started to exude
from the anus.
The feeding period of C lectularius is a minimum in the first nymphal
instar, increases to a maximum in the fifth instar and then decreases in
the adult. The feeding period of the adult female is shorter than that of
the male.
In P. humanus the feeding period of the first instar is slightly longer
than that of the second instar and shorter than that of the adult. The
feeding period of the female is shorter than that of the male. The feed-
ing period in P. humanus is much longer than in C. lectularius and in A. aegypti
female, that to engorgement would be longer still. The duration of the
Blood-Sucking Insects
101
feeding period can be correlated with the behaviour of these insects and
their access to their hosts. The longer feeding period in P. humanus may
be related to their living on the host while both C lectularius and A. aegypti
leave their host after feeding.
The feeding period of the female A. aegypti is longer than that of each
one of the first four instars and shorter than that of the fifth instar and
the adult of C. lectularius.
When the insects feed till engorgement the weight of the blood meal
varies from one instar to the next. In G lectularius and P. humanus the min-
imum value is found in the first nymphal instar and the maximum in the
adult stage. The weight of the female's blood meal was greater than the
male's in both C. lectularius and P. humanus. The weight of the blood meal in
C lectularius is greater than that in P. humanus. The weight of the blood meal
in A aegypti is greater than that of any instar in P. humanus and that of the
first three instars ofC lectularius , but smaller than that of the other in-
stars in the latter species.
In all three species the weight of the blood meal is greater than the
body weight. The ratio of weight of the blood meal to body weight is great-
er in C. lectularius than in the other two species . In C. lectularius and P. humanus
the ratio is higher in the nymphal instars than in either the female or
the male because of the flexibility of the integument which becomes more
sclerotized in the adult stage. In C lectularius the number of pump cycles
per second decreases gradually from the first instar to the adult stage.
In P. humanus the number of pump cycles per second increases from the
first to the second instar and then decreases slightly in the adult stage.
The rate of feeding in C. lectularius and P. humanus, expressed as mi-
crograms of blood taken per second or as micrograms of blood taken
per pump cycle, increases gradually from the first instar to the adult.
The rate of feeding is greater in the adult female than in the male in
both species. In the first nymphal instar of C lectularius the rate of feed-
ing is much greater than in any instar of P. humanus. The weight of blood
taken per second by A aegypti females is greater than that taken by the first
three nymphal instars of C. lectularius and smaller than that taken by each
of the other instars. On the other hand, the weight of blood taken per
pump cycle in aegypti is greater than in the first and second instars of
C lectularius and smaller than in the other instars.
Negative Pressure in the Cibarial Pump
Table 2 shows the negative pressure required to draw the blood to
the cibarial pump at the observed rates in these insects. In C. lectularius
the pressure difference decreases from the first to the second nymphal
instar and increases from the second to the adult stage. The pressure
difference in female A. aegypti is smaller than in any instar of C. lectularius
and than in the first instar and the adult stage of P. humanus. In the last
species it decreases from the first to the second nymphal instar with a
maximum value in the adult. Table 2 also shows the results obtained by
Bennet-Clark (1963) for the fifth nymphal in star of Rhodnius prolixus (Stahl).
He claimed that 1. 96 x 106 dynes / cm2 or about 2 atmospheres, can be
taken as the likely minimum, but he ignored the proximal 5 mm of the
feeding canal and assumed that the viscosity of the blood is equal to that
102
Tawfik
of water*. He added that if he took these into consideration the pressure
required for Rhodnius to feed could be as high as 9 atmospheres, i.e.
9. 12 x 106 dynes/ cm2.
TABLE 2. Negative pressure (relative to atmospheric) in the cibarial
pump in c lectularius , female A aegypti, P. humanus and R prolixus
▲ P** cor-
Blood-Sucking Insects
103
TABLE 2 (cont. )
A P** cor-
(number of insects used)
Range
blood pressure.
*** Data from Bennet-Clark (1963.
p. 223).
The Muscular Tension and the Power Output of the Cibarial Dilators
In C. lectularius the mean tension required of the cibarial pump dilators
decreases from the first to the second nymphal instar and then increases
to a maximum in the adult (tables 3 and 4). The value for the cibarial
pump dilators of the male was larger than for those of the female. In
the female A aegypti the muscular tension required per unit sectional
area of the cibarial pump dilators is larger than in the first three nym-
phal instars and smaller than in the other instars of C. lectularius. In
P. humanus the mean muscular tension of the cibarial pump dilators de-
creases from the first to the second nymphal instar and reaches a max-
imum in the adult with a higher value in the female than in the male.
From the data published by Bennet-Clark (1963) the mean muscular
tension required per cm2 sectional area of the cibarial pump dilators of
the fifth nymphal instar of R prolixus was calculated to be in the range be-
tween 1.2 to 5.7 kg/cm^.
104
T awfik
TABLE 3. The mean force and muscular tension of the cibarial pump
dilators in C. lectularius , female A aegypti } p. humanus , and
R. prolixus .
Area of diaphragm*
Species cm^
Mean***
Mean** muscular
force tension
dynes dynes
Cross sectional* Muscular
area of muscles tension
cm'
dyne/ cm 2
C. lectularius
First 8.6xl0"5
(5) R
7. 6x10"5-9.4x10“5
Second 1. OxlO-4
(7)
9. 6x10“5-1.4x10-4
12.0 24.0 4.2x10-4 5.7xl04
(5)
3. 7x10-4-4. 8x10-4
11.0 22.0 5.1xl0”4 4. 3xl04
(5)
4. 7x10-4-5. 6x10-4
Third 1. 6xl0"4
(5)
1. 0x10-4-2. 1x10-4
Fourth 2. 5x10-4
(5)
2. 2x10-4-2. 9x10-4
Fifth 3. 2xl0“4
(5)
2. 9x10-4-3. 7x10-4
$ 5.7x10-4
(8)
4. 9x10-4-5. 9x10-4
cf 4. 1x10-4
(5)
3. 8x10-4-4. 5x10-4
22.4 44.8
77.5 155.0
140.8 281.6
239.4 478.8
221.4 442.8
8.2x10-4 5. 5xl04
(6)
7.9x10-4-8.4x10-4
1.2x10-3 1.3xl05
(6)
1. OxlO”3- 1. 5xl0-3
1.3x10-3 2. 2xl05
(5)
1. 0x10-3-1. 8x10-3
2.1x10-3 2.3xl05
(7) ,
1. 9x10” -2. 5x10-3
1.5x10-3 2.9xl05
(8)
1. 2x10-3-1. 9x10-3
A aegypti
? 1.9x10-4
(10)
1.4x10-4-2. 3x10-4
5.7 11.4
1. 8x10-4
(10)
1. 3x10-4-2. 3x10-4
6. 3xl04
P. humanus
First 2.4xl0-5
(6)
1. 9xl0-5-2. 7xl0-5
1.1 2.2
6.8x10-5
(5)
6. 1x10-5-7. 6x10-5
3. 2xl04
Blood-Sucking Insects
105
TABLE 3 (cont. ).
Area of the diaphragm* force
Species cm^ dynes
Second 4. 5xl0"3 1. 0
(5)
3. 9x10"5-5. 2x10-5
Mean***
Mean** muscular Cross sectional* Muscular
tension area of muscles tension
8. lx 10” 5
(8)
7. 3x10“5-9. 2x10" 5
6. 4x10" 5
(8)
5. 8xl0-5-7. 4xl0-5
15.4
8. 3
dynes
2. 0
30. 8
16.6
dyne/ cm2
1. lxlO”4
(5)
9. 4x10-5-1. 7xl0"4
1. 9xl0"4
(8) ,
1. 4xl0“-2. 5x10
-4
2. 0x1 0"4
(8)
1. 3xl0-4-2. 2xl0-4
1. 8x10
1. 6xl05
8.3x104
R. prolixus
Fifth 9. 8xl0"3
(2) (2)
9. 6xl0"3-l. OxlO"2 8. 9x1 04 17. 8xl04 2. 8x10” 2-3. 5xl0"2 5.6xl06
1. 9x104+ 3. 8x104+35 2x10”2
1. 2x106+
**>
+
Average
(number of measurements)
Range
Mean force = ▲ P x area of the diaphragm
Mean muscular tension during working stroke = mean force x 2
The two values correspond to the two different values of ▲ P of
Bennet-Clark (see table 2).
The muscular tension of the cibarial pump dilators most probably
reaches a peak value of twice the estimated mean in table 3. Wiggles -
worth (1965) reported the maximum load a muscle can raise per square
centimeter of cross section in some species and he found that there is
no great difference between insects and vertebrates as the value for man
is 6-10 kg, for the frog 3 kg, for the mandibular muscles of insects 3. 6
-6.9 kg, for the hind leg of Tettigonia 4.7 kg and for the flexor tibia of
Decticus 5. 9 kg.
The power output of the cibarial pump dilators expressed as erg/
sec/ g of muscle and as g cm/ sec/ g of muscle are shown in table 4. In
C lectularius the power developed by these muscles, like the muscular ten-
sion, decreases from the first to the second nymphal instar and then in-
creases to a maximum in the adult stage. In the female A. aegypti the
power output/ g of muscle was higher than that of the first three nymphal
instars and lower than that of the fifth instar and the adult of C. lectularius.
TABLE 4. The power output of the cibarial pump dilators in C. lectularius , female A aegypti , P. humanus , and
R prolixus .
106
T awf ik
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CM
O M
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+-> .—l
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Blood-Sucking Insects
107
CO
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3
*
O
a £
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<0 u
2 p §
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<!
Power output = mean force x travel of the diaphragm in a second.
lectularius , female A aegypti ,
Travel of* Pump Travel of Power** Length of* Weight of
Species diaphragm cycles/ diaphragm output muscles muscles Power output
h stage cm second cm/sec erg/sec cm g in erg/sec/g
Fourth 4
: 10-3 - 2.7 x lO-3
: 10-3 3.8 9.9x 10-3 0.11
: lO-3 _ g.g x io-3
lO-3 3.3 1.2xl0-2 0.27
2 x 10-3 - 3. 9 x 10-3
5 x lO"3
(5)
1 x lO"3 . 4. 9 x l0-3
2 x 10-3
(5)
8 x 10-3 . 6.6 x 10-3
3.3 1.5x10-2 1.20
1. 9 x 10'* 2.70
2.4 1.8x10-2 4.30
lO'” 1. 9 x 10*
8.7 xlO'6 1.3xl04
3. 1 x 10-5 3. 9 x lo4
3.6x10-5 7.5x10*
x 10-3 . 7.8 x 10-3
0x 10-3 - 3.9 x 10-3 2.8 3.0x 10-3 0. 003 3
(6) 4 3
5 x 10-4 - 1.4 x 10-3 3
5 x 10-3 5.3 8.0 x 10-3 o. 008 5
(5)
3 x lO"3 . 1.7 x lO"3 4
0x10-3 4,6 1.4x10“3 0.216 9
(7)
7x10-3-3.4x10-3 8
0x10-3 4.2 1.3x10-2 o. 108
(5)
5 x 10-3 - 3.4 x lO"3
. 048 912
5 x 10-3 2.4 x 10"
<6> -
h-7
104
5.7 x 10-
1 - 5.5 x lO-3
1 1.7 xlO-6 1. 3 x 10'
x 10-° 6.3x10’
3 x lO-0 - 9.0 x •
* Average
(number of insects)
I x 103
** Power output = mean force x travel of the diaphragm in a second.
108
T awfik
It is also higher than that of the first two instars and lower than that of
the adult P. humanus.
Roeder (1953) reported the power of the flight muscles in some in-
sects. The minimum was 205 g cm/sec/g of muscle for Vanessa atalanta
L. and the maximum was 558 g cm/sec/g of muscle for Aeschna mixta Latr.
The cibarial pump dilators in C. lectulanus , A aegypti } and P. humanus are not
required to operate at specific power outputs as great as these. The
dilators of the cibarial pump of the fifth nymphal instar of R. prolixus , on
the other hand, would, on the basis of Bennet-Clark' s data, be required
to work at a greater specific power output than the flight muscles of these
insects .
Discussion
The actual laws of blood flow, at least in the range of physiological
rates of flow, approximate sufficiently the simple laws (e.g. Poiseuille's
law) for these to be applied with caution, using the appropriate value for
the effective viscosity rather than the value obtained in viscometers of
a large bore. Burton (1965) stated "As long as the diameter of the cap-
illary tube used in the viscometer is more than 1 or 2 mm, the relative
viscosity of the blood is the same, whatever the size of the tube used.
When, however, tubes of narrower diameter are used, the value for rel-
ative viscosity found is less. This is because the absolute viscosity of
water is the same however small the diameter of the tube; but that of
the blood decreased to less than half the value found when large tubes
are used". This has long been known as the Fahraeus- Lindquist effect.
From this the viscosity value and consequently the values of A P obtained
in my calculations could be in error by a factor of 2. Burton (1965)
also discusses the effect of temperature on viscosity of the blood. I
should not expect significant variation in the viscosity of the blood through
changes in temperature in the quick pumping process of sucking in these
insects.
The ability to feed at a relatively high rate through a minute feeding
canal is very important for blood-sucking insects. For this purpose
they are equipped with very efficient feeding apparatus with a sucking
pump which is capable of exerting a high tension on the blood upon which
they feed. Differences in the rate of feeding in the different blood-suck-
ing insects can be due to many factors. One of these factors is the
negative pressure that can be produced in the cibarial pump. This in
turn is dependent upon the tension which can be developed in the cibarial
pump dilators, the length of the feeding canal and its diameter as well
as the viscosity of the blood and thecapillary blood pres sure of the host.
These experiments suggest that blood viscosity and the capillary blood
pressure of the host might be of importance in the evolution of host sel-
ection in blood- sucking insects.
ACKNOWLEDGEMENTS
I wish to express my profound gratitude to Professor B. Hocking,
Department of Entomology, University of Alberta, for his valuable guid-
Blood-Sucking Insects
109
ance, unfailing encouragement and helpful criticism. I am grateful to
my external examiner, Dr. R. L. Usinger, Department of Entomology,
University of California, Berkeley. I thank Mr. J. Scott for his help in
photography. I wish to offer my sincere appreciation to Dr. Carroll N.
Smith for providing the lice. I also wish to acknowledge the financial
assistance of the U.S. Army Grant No. 63-G83 (Hocking Trust) which
made this study possible.
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Dickerson, G. , and M. M. J. Lavoipierre. 1959. Studies on the methods
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Enderlein, G. 1905a. Zur Morphologie Lausekopfes. Zool. Anz. 28 :
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Fernando, W. 1933. The development of homologies of the mouthparts
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Gordon, R.M. and W. H. R. Lumsden. 1939. A study of the behavior of
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110
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Gooding, R. H. 1963. Studies on the effect of frequency of feeding upon
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Philadelphia and London, 584 pp.
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76, 120 pp.
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Tiere 14 : 59-165.
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don, New York, Toronto.
THE BIOLOGY OF SOME BLACK
FLIES (DIPTERA : SIMULIIDAE) OF ALBERTA
0. M. ABDELNUR
Medical Entomologist
Medical Research Laboratory
Khontanm, Sudan
Quaestiones entomologicae
4 : 113 -174 1968
The biology of 15 simuliid species in northern Alberta was studied. Simulium vittatum
Zetterstedt and Simulium venustum Say were the most abundant; Prosimulium travisi Stone
and Prosimulium onychodactylum Dyar and Shannon were rare. Characterictically, the univoltine
species (except Cnephia mutata Malloch) were autogenous throughout the area. C. mutata
was represented by both the triploid (parthenogenetic) and the rare diploid sexual forms. A
key for the identification of the 31 species reported from Alberta is given. Regular sampling
of simuliid larvae in the rivers and creeks shows that there are several peaks of abundance
every year (1963-1965) due to the occurrence of the larvae of more than one species in the
breeding localities, and that the dates, numbers, and composition of these differ slightly
depending on the date of the ice break-up and the march of temperature during the season. The
overwintered larvae of S. vittatum were present in the water and the ice. The susceptibility
of the larvae to DDT was measured and their migration downstream was investigated by the
use of plastic sampling cones. The infection rates of the adults and aquatic stages by nematodes
and microsporidian protozoans and an evaluation of both predators and parasites as control
agents are given.
Fredeen (1958) and Fredeen andShemanchuck (I960) investigated the
simuliids of Alberta, Saskatchewan and Manitoba. Strickland (1938,
1946) recorded eight species of black flies in Alberta; the number is
now 31.
In the United States additional regional lists of black flies have been
published: Western U.S.A., Stains and Knowlton (1940); Minnesota,
Nicholson and Mickel (1950); Alaska, Stone (1952) and Sommerman
(1953); Utah, Peterson (1955, I960); New York, Stone and Jamnback
(1955).
Ecological and biological studies were included in most of the above
papers. The control of black flies using chemicals was started in Canada
by Prevost (1947). Hocking, Twinn and McDuffie (1949) investigated
various insecticides. Further reports on this subject were published
by Arnason et al. (1949), Brown (1952), Brown et al. (1951), Hocking
(1950, 1953), Hocking and Richards (1952), Peterson and Wolfe (1958),
Peterson and West (I960), and West, Brown and Peterson (I960).
Cytological studies on black flies commenced with the work of Roth-
fels and Dunbar in 1953. Additional studies were reported by Rothfels
(1956), Dunbar (1958), Basrur and Rothfels (1959), Landau (1962) and
Pasternak (1964). The following species have been studied cytologically
in North America: Simulium vittatum Zetterstedt, Simulium tuberosum Lund-
stroem, Simulium aureum Fries, Simulium latipes Mg . , Cnephia mutata Malloch,
Prosimulium fontanum Syme and Davies , Prosimulium hirtipes Fries , Prosimulium
frohnei Sommerman, Prosimulium fulvum Coquillett, Prosimulium travisi Stone ,
Prosimulium formosum Shewell, Prosimulium fuscum Syme and Davies, Prosimulium
mixtum Syme and Davies.
114
Abdelnur
STUDY AREA
The Flatbush study area is about 100 miles north of Edmonton (54°
15!-50' N, 113° 30!-114° 15' W) and lies within the boreal forest region
of central Alberta. The field station was seven miles west of Flatbush
village (54° 40! N, 114° 10' W). Smith is 50 miles north of Flatbush,
Athabasca town is 40 miles east, and Hinton 200 miles west. All these
localities were used as centres during the survey.
The aspen and spruce forest is intact in long stretches and the cul-
tivated land (farms and pastures) is locatedaway from the rivers. There
are no large urban centres (Happold 1965a &: b) .
Hinton (elevation 3265 feet) is about 177 miles west of Edmonton.
It lies on the bank of the Athabasca River which has many riffles in which
S. arcticum and S. tuberosum breed.
Muskuta Creek and three other creeks flowing into the Athabasca
River above Hinton were surveyed for black fly species present. S. vittatum ,
s. venustum and S. arcticum were collected. Adults of Prosimulium travisi and
P. onychodactylum were captured in netsweeps.
Athabasca town is 40 miles east of Flatbush, situated on the Athabasca
River. In one locality downstream from the town, and many localities
above the town, S. arcticum was collected but in small numbers. Muskeg
Creek and three other creeks yielded large samples of black fly larvae,
S. venustum being the dominant species.
Climate
The long cold winter, characteristic of the continental climate,
commences in November and ends in March. The snow melts in April
and the ice breaks in the rivers and creeks in April and May. During
April the temperature rises to 40 F by day and drops to 20 F by night.
In May the temperature reaches 80 F and drops to 35 F at night. The
average maximum and minimum temperatures in June are 78 F and 42 F.
July and August are warm and the temperature stays above 40 F. In
September low temperatures are recorded.
The relative humidity records indicate an overall average of 61%
(40-92%) duringthe May to September period. The diurnal records show
fluctuations of relative humidity especially before sunset and fora short
period after sunrise. There seems to be apeak in the morning followed
by a drop at noon and a rise in the afternoon which continues well into
thenight. Temperature (air), relative humidityand rainfall records are
given in table 1. The average date of ice break-up in the Pembina River
over 10 years was April 17.
Vegetation
The forest plants include besides aspen and spruce, many shrubs
such as rose, cranberry, raspberry, and other berries; horsetails, and
grasses (Happold 1965a).
The plants come into leaf in May and by the end of September the
herbaceous plant life has ended and the leaves have fallen. The insect
population of this area is closely associated with the flora. All the
species of black flies were collected feeding or resting on plants.
Black Flies
115
TABLE 1. Temperature, relative humidity and rainfall records in the
field station at Flatbush : 1961-1965.
116
Abdelnur
TABLE 1 (cont. ).
1963
Black Flies
117
In the study area in running water very few aquatic plants were en-
countered. There were distinct differences in the composition and den-
sity of the vegetation in the various streams. The vegetation near the
water is composed of horsetails, mosses, and algae. The banks of the
river s are steep and devoid of vegetation but further away from the rivers
the valleys are forested. The creeks have low banks and the vegetation
is dense and in shallow water extends into the creek bed.
The following aquatic plants were found in the simuliid breeding sites:
Chlorophyceae: Stigeodonium, Pediastmm ; Fragilariaceae: Asterionella ;
Fontinalaceae: Fontinalis dalecarlica Linn. ; Equisetaceae: Equisetum sp. ;
Typhaceae: Typha latifolia Linn.; Spar ganiaceae: Spar ganium hyperboreum
Laestad, S. muhipedunculatum Morang; Najadaceae: Potamogeton americanus
C. and S. , P. richardsonii (Benn. ) Rybd. ; Alismaceae: Sagittaria australis
J. G. Sm. ; Butomaceae: Elodea canadensis (Pursh), Vallisneria spiralis Linn.;
Pontederiaceae: Pontederia {cor data Linn.?); Ceratophyllaceae: Ceratophyllum
spp. , {C. demersum Linn.?); Cruciferae: Radicula sp. ; Haloragidaceae:
Myriophyllum spicatum Linn.
Association with other Aquatic Organisms
Jamnbackand Collins (1955) and Jamnbackand Eabry (1962) used stan-
dard nets to measure quantitatively the stream or ganisms , in relation to
black fly control. Other workers had listed the groups of organisms en-
countered (Anderson and Dicke I960, Hocking 1950 and Hocking et al.
1949).
In the present study a 20 mesh per inch screen (5x5 feet) was used
to investigate the association of simuliid larvae and other stream or-
ganisms. The screen was fixed among the rocks in the breeding sites
and supported by diagonal poles in the back. The collector worked down-
stream from a point about 100 yards up from the screen, disturbing the
bottom substrata and turning stones and logs to dislocate the fauna which
was trapped on the screen. The following organisms were collected:
Mollusca - Gastropoda
Annelida -
Pulmonata
Hirudinea
Helobdella stagnalis Linn.
Theromyzon occidentalis Verrill
M ooreb della i err i da Verrill
Daphnia sp.
Gammarus sp.
Arthropoda - Crustacea
Insecta
Ephemeroptera Heptagenia sp.
(nymphs) Ephemerida sp.
Odonata Aeshna sp.
(nymphs) A grien sp.
Plecoptera
(nymphs Nemouta sp.
Trichoptera Limnephilus canadensis Banks
Brachycentrus occidentalis Banks
Helicopsyche borealis Hagen
Hydropsyche recurvata Banks
Hydropsyche sp.
118
Abdelnur
Trichoptera Leptocella sp.
(cont. ) Athripsodes sp.
Polycentropus sp.
May atrichia sp.
Diptera
(Chironomidae)
Coleoptera
(Hydrophilidae)
(Dytiscidae)
Hemiptera
(Corixidae)
Chordata - Pisces Esox lucius Linn.
Catostomus commersonii Lacepede
Moxostoma sp.
Pimephales promelas Rafinesque
No phoretic association was observed between the simuliid larvae
and any other organism. At the start of the season and when the water
levels were high the number of organisms was small but the populations
built up following the rise in water temperature and decrease in flow
which resulted in the formation of side pools in the rivers and areas of
shallow flow in the creeks.
The crustaceans and snails were late-comers in each season while
the other groups were usually present, in different numbers, in all sta-
tions all the season.
Rivers and Creeks
Some of this information was kindly provided by the District Engin-
eer, Water Research Branch, Department of Mines and Technical Surveys
(Calgary).
Athabasca River
The drainage area of this river is 29,600 sq. miles. It flows north
from the Rocky Mountains and pours into Lake Athabasca. The mean
discharge in April is 4, 700 cubic feet per second, in May 21,200 ft^/sec,
in June 33, 000 ft^/ sec, in July 32, 000 ft^/ sec, in August 29, 200 and in
September 25, 300 ft^/ sec. The mean velocity increases from 1.8 ft/sec
in April to 2. 8 ft/ sec in June and is nearly uniform in the period June-
September. The effects of the rains and melting ice in the mountains are
seen in the study area.
The riverbed is sandy with coarse gravel but a mud layer is slowly
deposited at the end of the June floods. The main stream is devoid of
vegetation except for some algal growth on rocks under the water, and
a narrow zone of horsetails and reeds at the edge.
Due to the gentle slope of the land in the study area there are no
rapids in the river but a few 'isolated riffles are present and S. arcticum
Malloch and S. tuberosum were found breeding in these.
Pembina River
The drainage area of this river is 4,550 sq. miles. The Pembina
flows north from the Rocky Mountains and conjoins the Athabasca River
Black Flies
119
10 miles north of Flatbush. From the low discharge of 320 ft^/sec in
April it reaches 2,230 ft'Vsec in May 1,320 ft^/ sec in June and July,
995 ft^/sec in August and 2, 000 ft^/sec in September. The velocity of
the current ranges from less than 1. 5 ft/sec in April to more than 2. 3
ft/ sec in May.
The river banks are steep and the river valley is bare but a fringe
of vegetation is present at the edge of the water consisting of horsetails
and willows. The stream bed is amixtureof fine sand, clay and gravel.
This condition resulted in abetter crop of aquatic foliage than in the Atha-
basca River, The Pembina River has large stretches of riffles which
extend at low water level. At low water also algae cover stones and
rocks, and their filaments and the stones provide suitable substrates for
attachment of black fly larvae. Seven species of simuliids, S. arcticum ,
S. tuberosum , S. luggeri Nicholson and Mickel, S. venustum Say, S. vittatum
Zetterstedt, S. decorum Walker and S. latipes , were found breeding in the
Pembina River,
Irish Creek
Irish Creek crosses Highway 44 65 miles north of Edmonton. It
drains the marshes east of the highway and flows into the Pembina River .
The creekis about 10 feet wide with steep banks. The water depth ranges
from 1 to 3 feet. It flows in part in the shade of forest. The creekis
rich in vegetation and although no overwintering larvae were found in it,
the larvae of four species of blackfly, Prosimulium decemarticulatum (Twinn),
Cnephia dacotensis (Dyar and Shannon) , Cnephia mutata (Malloch), and C. emergens
Stone, were collected in May. Simulium vittatum Say, Simulium vittatum Zet-
terstedt, and Simulium latipes (Meigen) were the dominant species later in
the season.
French Creek
This creek drains Cross Lake and flows west to the Pembina. The
creek is up to 18 feet wide and the water is one to two feet deep. The
current varies from one to two ft/sec near the junction of the creek and
the Pembina River. The creek is rich in vegetation especially reeds.
The effluence point and the numerous beaver dams provided suitable
breeding sites for black flies. The larvae and eggs of six species of black
flies were collected. The overwintering larvae of S. vittatum were present
in water under the ice in 1963, 1964, 1965.
Cross Lake Creek
This creek flows into Cross Lake draining swamps and small lakes
north of Cross Lake. The creekis eight to ten feet wide but the maximum
water depth is one foot. It flows through dense growth of vegetation and
is therefore shaded thus providing ideal breeding habitat for S. decorum .
Flatbush (Andy’s) Creek
This creek flows into the Pembina at Flatbush draining the swamps
east of the village. The creek channel is choked with vegetation in some
places, dammed in two places, but receives many small rills. Some
observations on repopulation of the creek by aquatic fauna especially
120
Abdelnur
black flies were made, after it was dammed.
Chisholm Creek
This creek flows into the Athabasca River at Chisholm (25 miles
north of Flatbush). It is dammed near the junction with the Athabasca to
provide water for the lumber mills in the village. The creek channel is
15 feet wide and the water depth varies from nine inches to 1.5 feet. The
overwintering larvae of S. vittatum were abundant and the highest rates of
infestation by parasitic nematodes were recorded here in three consecu-
tive years.
Water Analysis
The chemical and physical analyses of the water in the two rivers
and in the creeks gave closely similar results. The two rivers were
slightly cooler than the creeks; Irish and French creeks were cooler
than the others. The pH readings ranged from 7.5 to 8.5. It has been
reported in the literature that black fly breeding streams are slightly
alkaline (Anderson and Dicke (I960), Fredeen and Shemanchuck (I960),
Peterson and West (1958) and Sommerman et al. (1955). Albeit Peterson
and Wolfe (I960) mentioned that black flies can breed in water with pH
5. 8 to 8. 5: Anderson and Dicke (I960) recorded pH values as high as
8. 15 and 8. 95 in Wisconsin. The dissolved oxygen concentration ranged
from 8. 1 ppm to 10. 0 ppm and the calculated per cent of saturation showed
fluctuations over 100%. Wu (1931), Petersen (1924) and Radzivilovskaya
(1950) strongly upheld the theory that the function of the current is to
maintain the oxygen saturation. Rubtzov (1939) and Zahar (1951) came
to the conclusion that above a certain saturation there is no necessary
current requirement.
TAXONOMIC PROCEDURE
The family is very poor in fossil records (Smart 1945, Stone 1964).
Specimens recovered from Oligocene amber (English Purbeck) were des-
cribed by Westwood ( 1854) and Handlirsch (1908). Two species belonging
to two genera have been named: Simulium priscum Westwood 1854 orthotype
of Simulidium Westwood 1854 and Simulium humidum Brodie 1906 orthotype of
Pseudosimulium Handlirsch 1906.
Black flies are distinct and well separated from the other nemato-
cerous families yet they share the biting habitwith the Ceratopogonidae .
There are no species in the simuliids with affinities to the latter, nor to
the chironomids although Shewell (1958) andDavies, L. (1961) reported
on the similarities between the primitive simuliids and chironomids, es-
pecially in the larval stages. Grenier and Rageau (I960) suggested that
this highly evolved nematocerous family is a precursor of the Brachycera.
Seven subfamilies have been named by Enderlein (1937) : Simuliinae,
Prosimuliinae, Hellichiinae, Ectemniinae, Cnesiinae, Stegopterninae,
and Nevermanniinae. Other authors have accepted 2 or 3:
Edwards (1939), Stone (1964), andStone and Jamnback (1955); Simuliinae,
and Prosimuliinae.
Black Flies
121
Smart (1945): Simuliinae and Parasimuliinae.
Dumbleton (1963), Grenier and Rageau (I960), and Shewell (1958): Sim
uliinae, Prosimuliinae and Parasimuliinae.
Rubtzov (1959): Simuliinae and Gymnopaidiinae.
mere are ou generic names c
ature. The genera and subgenera
Simulium
Simulium
Eusimulium
Byssodon
Psilozia (TV eosimulium)
Hagenomyia
Gnus
Cnephia
Cnephia
Stegoptema
Ectemnia
.na louu specmc names in me liter-
accepted in North America are:
Prosimulium
Prosimulium
Helodon
Parasimulium
Parasimulium
Twinnia
Gymnopais
The family is cosmopolitan; Simulium and Cnephia are the most widespread
genera. There are species common to most of the adjacent zoogeograph -
ical regions.
Materials and Methods
Aquatic stages and adults were collected from the field and preserved
in 95% ethyl alcohol; some of the adults were pinned or mounted by gluing
them on paper points . Laboratory rearing was also used in the taxonomic
study. The eggs of some species were collected easily but other species
proved difficult as the eggs are scattered on the river bottom and no ef-
ficient method was found for their extraction. It was found that by com-
bining the eggs, larvae, and pupal skins with the adult, identification is
feasible. The pupae are more diagnostic than any other stage. Dissec-
tion of some stages was of value. The linear dimensions of eggs of the
species studied have an overlapping range so that eggs of the different
species proved difficult to identify positively.
On the other hand, the larval head capsule and its different structures
were repeatedly employed in keying the species. The antenna has four
articles and their colour and length are useful. The cephalic apotome
(frontoclypeus) has head spots which occur where the muscles attach to
the dorsal surface of the head capsule. These spots are constant in
anterior and posterior median, and anterior and posterior lateral groups.
The ventral side of the head capsule has a number of structures widely
used in identification of the species. The shape and size of the postgenal
cleft (throat, occipital, epicranial) vary from a slight groove extending
to less than one-fifth the distance between the occipital pits and the base
of the submental teeth, to a large bulbous opening with an apex almost
touching the base of the hypostomial teeth. The submentum (hyposto-
mium, mentum) has three sets of teeth: median tooth, lateral teeth (2
or 3) and a single corner tooth on each side of the laterals (fig. lc, d.
The cephalic fans (head fans or brushes) have short stalks (stems) and
the number of rays in the mature larva is fairly constant (usually inc-
122
Abdelnur
r eases with each instar). Under each primary fan there is a secondary
fan. The labrum, mandibles and maxillae are present. The hypopharynx
is of no taxonomic value.
The larval proleg has a circlet of hooks at its apex used for loco-
motion. Thelateral sclerite (plate) of the prolegis of subsidiary impor-
tance in identification of the species as it varies little from one species
to another. The pupal respiratory organ histoblast is of considerable
value.
The abdominal features utilized in the study are scales or setae,
coloration, ventral papillae (anal tubercles), anal sclerite (anal cross-
piece) and the posterior sucker (posterior circlet of hooks).
The pupa is usually surrounded by a cocoon, the shape of which is
characteristic. The pupal respiratory or gan consists of two to forty fila-
ments arising from a different number of stalks (trunks, petioles). The
filaments may be grouped or not. The hooks on the abdominal segments
and the terminal spines are specific. The pupa proved to be a reliable
tool of the utmost taxonomic value.
The adult black fly is very difficult to identify. The antennal flagel-
lum has 7-9 articles. Themaxillary palpus contains a sensory organ in
its third segment. The comparative length of vein R (stem vein, the
common base of R and Rs) and the distance to wing apex from the base
of Rs are widely used. The basal cell may be present in some species
(fig. le). The presence of setae or hairs on the ventral and dorsal sides
of the veins is a good character for keying some species . The first tar-
sal article of the hind leg (the basitarsus) may be extended posteriorly
in a flattened lobe (calcipala) and the second article may be notched dor-
sally (pedisulcus) . The tarsal claws are simple or toothed (forked, bi-
fid) (fig. la, b) .
The sexes are dimorphic and the males are holoptic; the upper fa-
cets of the eye in the males are larger than the lower ones. The male
genitalia consist of dark pigmented sclerites that can be used to separate
the species groups. On each side of the tip of the abdomen lies dorsally
the basistyle (coxite, basimere) and attached to it is the clasper (disti-
style, distimere) which has a single or many teeth on the inner side.
Between the basistyle and clasper is found a ventral plate, a median
sclerite and a paramere consisting of two arms and a fringe of hooks
(phallosome and aedeagus pile respectively). The female genitalia con-
sist of an ovipositor lobe attached to sternite eight, a genital fork under
tergite nine, an anal lobe and a cercus.
Key to the Genera of North American Simuliidae
(Adapted in part from: Davies, Peterson, and Wood 1962, and Wood,
Peterson, Davies, and Gyorkos 1963).
Adults
1. Costa with fine hairs only (microtrichia) no spiniform setae (macro-
trichia); Rs forked apically (fig. 1); no calcipala or pedisulcus. .2
Costa with macrotrichia intermixed with microtrichia; Rs not forked
at apex; or with a small fork at the extreme portion; calcipala and
pedisulcus present 5
Black Flies
123
2. A slight or well developed bulla behind the eye; antennal flagellum
with 7-9 articles 3
No bulla behind the eye; antennal flagellum with 9-11 articles . .
Prosimulium Roubaud
3. R joins the costa near the middle of wing; submedian fold apparen-
tly not branched; Rs fork distinctly ending before the termination
of costa at apex of wing; flagellum with 9 articles
Parasimulium Malloch
R joining costa well beyond middle of wing; submedian fold forked;
Rs fork reaching to or beyond termination of costa 4
4. Scutum with stout, erect hairs but no fine recumbent hairs; flagel-
lum with 7-9 articles Gymnopais Stone
Scutum with fine recumbent hairs only; 7-9 articles; male clasper
with one apical spine; female ovipositor short, not reaching the
anal lobes Twinnia Stone
5. Basal cell usually present; pedisulcus very small; length of R more
than one-third the distance from base of Rs to the wing apex, with
hairs dorsally Cnephia Enderlein
Basal cell absent or very small and incomplete; pedisulcus well
developed; R with or without hairs dorsally; its length less than
one-third the distance from base of Rs to wing apex
Simulium Latreille
Pupae
The pupa of Parasimulium has not been described.
1. Cocoon irregular, shapeless and reduced; abdomen with a pair of
large terminal spines 2
Cocoon well developed with definite anterior opening; abdomen with-
out terminal hooks 6
2. Almost no cocoon; dorsum without hooks; abdomen with ten hooks
onsternites four to six in more than one transvers e row; respiratory
filaments four (subarctic genus) Gymnopais
Cocoon covering part of the body; dorsum with hooks on some of the
tergites; if present, hooks on the sternites are in transverse rows
3
3. Tergites 6-8 with anterior row of hooklets 4
Tergites 6-8 without row of hooklets: a) Pupa 4.0 mm long; res-
piratory organ with three stout trunks branching in 16 filaments. .
Twinnia
b) Pupa 2. 0-3. 0 mm long; respiratory organ with two trunks bran-
ching in 15-23 (average 19) pale slender filaments
Cnephia abdita Peterson
4. Respiratory filaments arising from a rounded knob on a short pet-
iole Cnephia
Respiratory filaments not arising from a rounded knob on a short
petiole 5
5. Respiratory filaments 12 (rarely 14) or les s arising from two trunks
Cnephia
Respiratory filaments more than 12, if less than 12 not arisingfrom
two trunks Prosimulium
124
Abdelnur
6. Cocoon stalked and anterior margin not well developed . . Cnephia
Cocoon not stalked and anterior margin well developed; lateral mar-
gin of terminal segments without short, curved hooks, although se-
tae may be present Simulium
Larvae
1. Larva without cephalic fans; anal sclerite Y-shaped 2
Larva with two cephalic fans; anal sclerite X- shaped or absent. .3
2. Labrum normal; antenna extending beyond the short cephalic apo-
tome; mandible with no teeth on the subapical margin; submentum
with distinct teeth Twinnia
Labrum enlarged; antenna not extending beyond the narrow and elon-
gated cephalic apotome; mandible with small teeth on outer subapical
margin; submentum with no distinct teeth Gymnopais
3. Anal sclerite absent Cnephia (in part)
Anal sclerite present 4
4. Antenna with articles one and two pale, three and four darkly pig-
mented; secondary fan filaments form a straight line at their tips
when extended; median tooth of submentum tridentate (fig. Id) anal
gills with three simple lobes Prosimulium
Antenna with articles one and two yellow to brown and three and four
rarely dark brown; secondary fan filaments form an arc; median
tooth of submentum not tridentate (fig. lc);anal gill with three sim-
ple or compound lobes 5
5. Submentum with corner and median teeth large and subequal, lateral
teeth three and subequal (fig. 1 c) 6
Submentum not as above; anal lobe with three simple lobes . .
Cnephia (in part)
6. Ventral papillae absent or small; postgenal cleft either pointed api-
cally or suboesophageal ganglion and/or epidermis of postgenal
cleft distinctly dark, or both; head spots light or dark; anal gill
with three compound lobes (except Psilozia ) Simulium
Ventral papillae well developed; anal gill with three simple lobes
(except latipes) ; postgenal cleft not pointed apically; suboesophageal
ganglion and epidermis of postgenal cleft not black; head spots
dark (Eusimulium )
List of Species of Simuliidae Recorded from Alberta
(Publisher 's or collector's name and date of publication or collection
follow the colon. )
Simulium (Simulium) decorum Walker 1848 : Strickland 1938 .
hunteri Malloch 1914 : Strickland 1938.
tuberosum Lunstroem 1911 : Fredeen 1958.
luggeri Nicholson and Mickel 195 0:F redeen
1958.
venustum Say 1823 : Strickland 1938.
verecundum Stone and Jamnback 1955 : Ab-
delnur.
meridionale Riley 1886 : Fredeen 1958.
malyshevi Dor ogostajakij , Rubtzov and
Black Flies
125
Vlasov 1934 : Fredeen 1958
piper i Dyar and Shannon 1927 : Fredeen
1958.
rugglesi Nicholson and Mickel 1950: Fre-
deen 1958.
transiens Rubtzov 1949 : Fredeen 1958.
arcticum Malloch 1914 : Strickland 1938.
corbis Twinn 1936 : Fredeen 1958.
griseum Coquillett 1898 : Fredeen 1958.
bivittatum Malloch 1914 : Fredeen 1958.
vittatum Zetterstedt 1838: Strickland 1938.
aureum Fries 1824 : Fredeen 1958.
latipes (Meigen) 1804 : Fredeen 1958.
pugetense Dyar and Shannon 1927 : Fredeen
1958.
pictipes Hagen 1880 : Strickland 1938.
dacotensis Dyar and Shannon 1927 : Abdel-
nur 1965.
emergens Stone 1952 : Abdelnur 1965.
saskatchewana Shewell and Fredeen 1958 :
Shewell and Fredeen 1958.
mutata (Malloch) 1914 : Abdelnur 1965.
saileri Stone 1952 : Fredeen 1958.
tulvum (Coquillett) 1902 : Strickland 1938.
pleurale Malloch 1914 : Strickland 1938.
travisi Stone 1952 : Abdelnur 1965.
decemarticulatum (Twinn) 1936 : Abdelnur
1965.
onychodactylum Dyar and Shannon 1927:
Abdelnur 1965.
Twinnia biclavata Stone and Jamnback 1955 : D. M. Wood 1964.
Key to the Species Recorded from Alberta
(Adapted in part from Peterson (1960b), and Davies, Peterson and
Wood (1962).
Prosimulium
Adult females
1. Antenna with 11 articles 2
Antenna with 9 or 10 articles decemarticulatum
2. Claw with a strong thumb-like basal projection 3
Claw simple 4
3. Integument yellow or orange, frons narrow, nearly parallel sided.
onychodactylum
Integument black, frons normal pleurale
4. Integument yellow to orange tulvum
Integument brown or black travisi
Adult males
1. Antenna with 9 or 10 articles, clasper with one spine apically . ..
(Byssodon)
( Gnus)
(Fteilopelemia)
(Psdlozia)
(Eusimulium)
(Hagenomyia)
Cnephia ( Cnephia)
(Stegoptema)
( Cnetha)
Prosimulium (Prosimulium)
126
Abdelnur
decemarticulatum
Antenna with 11 articles 2
2. Hind femora at least, yellow 3
Hind femora brown or blackish, antenna black, ventral plate apically
with sharp lateral prongs between which lies a two-tined fork . . .
pleurale
3. Integument of thorax orange, clasper with a single apical spine . .
fulvum
Integument of thorax dark or brown-black 4
4. Apex of clasper pointed with two terminal spines; ventral plate
broad, shallow and V-shaped; basal articles of hind tarsus swol-
len and thus broader than other articles onychodactylum
Apex of clasper rounded, with two apical spines; ventral plate with
a narrow and sharply pointed median recurved lip; tarsal articles
not swollen travisi
Pupae
1. Respiratory organ consisting of two stout divergent trunks on a
short petiole, from the former arise 12-20 slender filaments . . .
onychodactylum
Respiratory organ not as above 2
2. Respiratory filaments 9, arranged in a whorl from a short base. .
decemarticulatum
Respiratory filaments 16 or more 3
3. Respiratory filaments 21 or more pleurale
Respiratory filaments 14 or 16 4
4. Respiratory filaments closely clumped together; dorsum of head
and thorax strongly rugose travisi
Respiratory filaments 16; not closely clumped together; dorsum
of head and thorax not rugose; pupa orange fulvum
Larvae
1. Submental median tooth distinctly shorter than corner tooth . . 2
Submental median tooth distinctly longer than corner tooth ... 3
2. Submental lateral teeth longer than other teeth; antenna longer than
cephalic fan stalk, 45 rays in cephalic fan; nine filaments in res-
piratory histoblast; anal sclerite subrectangular, lateral plate of
proleg very narrow decemarticulatum
Submental corner tooth longest; antenna longer than cephalic fan
stalk, 54 rays in cephalic fan, 21 or more filaments in respiratory
histoblast pleurale
3. Postgenal cleft simple, antenna reaches tip of cephalic fan stalk. .
4
Postgenal cleft biarctate, antenna extending three-fourths length of
cephalic fan stalk; respiratory histoblast with many filamentsaris-
ing from two trunks onychodactylum
4. Postgenal cleft slight, last lateral tooth on submentum as long as
median tooth, head capsule pale, dorsal pattern absent, 17-19 rays
in cephalic fan, 16 filaments in respiratory histoblast . . . fulvum
Postgenal cleft pronounced, last lateral tooth on submentum shorter
Black Flies
127
than median tooth, head capsule pattern consisting of a median bro-
ken line and two lateral spots on each side of it with a broad dark
area posteriorly travisi
Cnephia
Adult females
1. Tarsal claws simple 2
Tarsal claws each with a distinct basal tooth or a large projection.
3
2. Maxilla with retrorse teeth, mandible serrate, calcipala large ,
broad, rounded mutata
Maxilla without teeth, mandible not serrate, calcipala short, pointed
emergens
3. Tarsal claws with distinct teeth basally, calcipala small, pedisulcus
indistinct or absent, scutum brownish with three narrow pale lines
dacotensis
Tarsal claws with large basal projections 4
4. Scutum with three pale gray vittae, median narrow and straight,
lateral broader and sinuous; scutellum with long, erect, white and
few black hairs saskatchewana
Scutum gray, clothes with yellow recumbent hairs, scutellum red-
dish brown with long, erect pale hairs saileri
Adult males
1. Clasper with one apical tooth 3
Clasper with two teeth 2
2. Galea of maxilla reduced, shorter than labrum- epi pharynx ....
emergens
Galea of maxilla normal, as long as labrum- epipharynx
mutata
3. Upper facets not distinctly enlarged dacotensis
Upper facets distinctly enlarged 4
4. Clasper apical tooth very small, basistyle large irregular with an
inner apodeme saskatchewana
Clasper apical tooth well developed, basistyle stout, subquadrate .
saileri
Pupae
1. Respiratory filaments 12, arising from two main trunks (dorsal 7,
ventral 5) mutata
Respiratory filaments 12 or more arising from more than two trunks
2
2. Respiratory filaments 12 arising from 3 main trunks; dorsal with
4, lateral with 3 and ventral with 5 filaments emergens
Respiratory filaments more than 12 3
3. Respiratory filaments 17-19 on very short trunks arising from a
bulbous base saskatchewana
Respiratory filaments more than 30 4
4. Respiratory filaments 3 0-40 in 6 or 7 main groups arising from a
128
Abdelnur
short bulbous base dacotensis
Respiratory filaments 35-45 arising near base, no trunks . msaileri
Larvae
1. Postgenal cleft reaching base of submentum 2
Postgenal cleft not reaching base of submentum 3
2. Postgenal cleft reaches beyond base of submentum, 57 rays in fan,
35-45 filaments in respiratory histoblast, submentum teeth very
small sailed
Postgenal cleft reaches only the base of the submentum, latter with
13 blunt teeth, 17-19 filaments in respiratory histoblast
saskatchewana
3. Antenna shorter than the cephalic fan stalk dacotensis
Antenna long extending well beyond cephalic fan stalk 4
4. Head capsule with distinct brown spots on cephalic apotomeand pos-
terior region of gena, entire margin of postgenal cleft narrowly
pigmented, submentum teeth heavily sclerotized, distal two articles
of antenna darker than basal articles, eye spots normal . . mutata
Head capsule with indistinct spots, postgenal cleft with lateral mar-
gins heavily pigmented, submentum teeth weakly sclerotized, eye
spots reduced emergens
Simulium
Adult females
1. Vein R with hairs dor sally 2
Vein R without hairs dor sally 4
2. Postnotum with a patch of yellow hairs (recumbent scales); scape
and pedicel pale brown; legs bicolored; tarsal claws bifid ....
aureum
Postnotum bare; antenna dark; claws bifid 3
3. Legs brown with distal portion of each part dark; basitarsus of fore-
leg long and slender; seven to eight times as long as wide; arms of
genital fork diverging from stem at a point half way of total length
of fork pugetense
Legs uniformly brown; basitarsus of fore-leg short and broad:
five to six times as long as wide; arms of genital fork diverging
from stem at a point two-thirds the total length of fork . . . latipes
4. Tarsal claw with a small subbasal tooth or a basal projection . . 5
Tarsal claw simple 9
5. Claw with a strong basal projection 6
Claw with a small subbasal tooth 7
6. Frons and terminal abdominal segments shining; fore coxa yellow
rugglesi
transiens
Frons and terminal abdominal segments pollinose; fore coxa dark
meridionale
7. Scutum without vittae; hair on stem vein pale arcticum
corbis
malyschevi
Black Flies
129
Scutum with distinct dark vittae 8
8. Pale species, fore coxa yellow, tibia with white pollinose, legs bi-
color hunteri
Dark species, fore coxa dark, no white pollinose on tibia . .piped
9. Abdomen with distinct black and light grey pattern; fore coxa dark;
precoxal bridge absent; fore tibia with conspicuous broad white
patch anteriorly, extending two-thirds the length of tibia; vittae on
dorsum vittatum
Abdomen without pattern 10
10. Abdomen blackish or brown 12
Abdomen greyish-yellow 11
11. Yellowish species; scutum with orange stripes (vittae) or meso-
notum with seven stripes of contrasting colors; frons and abdom-
inal segments pollinose bivittatum
Yellowish-grey species; no vittae or stripes; frons and terminal
abdominal segments pollinose griseum
12. Frons and terminal abdominal tergites distinctly pollinose; anal
lobe large, subquadrate but narrow dorsally and broadening ven-
trally, anteroventral margin rounded with a short posteroventral
projection under cercus 13
Frons and terminal abdominal tergites shining black; anal lobe not
as above 14
13. Fore tibia with a very distinct patch of white pollen .... decorum
Fore tibia with no distinct patch of white pollen pictipes
14. Fore tibia with a narrow greyish-white streak on anterior surface
covering not more than one-third the width of tibia; small dark
species tuberosum
Fore tibia with a bright yellowish-white patch on anterior surface
covering more than one-half the width of tibia 15
15. Subcosta without a row of hairs on ventral surface .... lugged
Subcosta with a row of hairs ventrally 16
16. Inner margin of ovipositor lobe straight, anterior margin of lobe not
more sclerotized than rest of lobe venustum
Inner margin of lobe concave (with an oval space between the two
lobes); anterior margin of lobe distinctly more sclerotized than
rest of lobe verecundum
Adult males
1. Vein R with hairs dorsally 2
Vein R without hairs dorsally 4
2. Postscutum with a patch of appressed yellow hair; legs bicolored;
ventral plate with a laterally compressed median keel . . aureum
Postscutum bare; legs uniformly brown; ventral plate withno med-
ian keel 3
3. Ventral plate broad with a medial V-shaped depression . . pugetense
Ventral plate broad with no depression latipes
4. Clasper with 3 or more apical spines vittatum
Clasper with 2, 1 or no apical spines 5
5. Clasper with a stout spine or tubercle at base internally .... 6
Clasper without spine or tubercle at base 8
130
Abdelnur
6. Base of clasper with a stout spine internally hunteri
piperi
Base of clasper with a distinct rounded tubercle internally ... 7
7. Basistyle with a number of short stout spines tuberosum
B as i style with hairs only rugglesi
transiens
8. Ventral plate compressed, with denticles on margins 9
Ventral plate broadly rounded, without denticles on margins . . .
meridionale
pictipes
9. Ventral plate narrow (compressed), an inverted Y, with a ventral
process or keel 11
Ventral plate broad, without a ventral process or keel .... 10
10. Toothed (serrated) margins of ventral plate pointing outwards, vis-
ible in profile venustum
Toothed margins folded inwards, not visible in profile or dor sally.
verecundum
11. Ventral keel of ventral plate setose, forming an angle before apex
of median portion of plate decorum
Ventral keel of ventral plate concave in profile, the angle it forms
being at apex of plate 12
12. Clasper shorter than basistyle, former flat, quadrate .... 13
Clasper longer than basistyle, cylindrical 14
13. Thorax grey with greenish tinge, median area of scutum not orange
griseum
Thorax dark brown to black, with two anterior pollinose spots .
bivittatum
14. Basal arms of ventral plate each with a prong but parameral hooks
are small malyschevi
luggeri
Basal arms of plate without prongs, some parameral hooks large.
15
15. Parameral hooks consist of distinct small hooks and much larger
ones, intermingled arcticum
Parameral hooks gradually lengthening towards center . . corbis
Pupae
1. Respiratory filaments 4 . . 2
Respiratory filaments more than 4 4
2. Anterior margin of cocoon with a long median projection anteriorly
ladpes
Anterior margin of cocoon without a projection 3
3. Dorsal respiratory filament strongly diverging from other three. .
aureum
Dorsal respiratory filament not divergent 4
a) Respiratory filaments paired, distinctly petiolated . . .pugetense
b) Petioles very short transiens
4. Six respiratory filaments tuberosum
. verecundum
. . venustum
Black Flies
131
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Respiratory filaments more than 6 5
Respiratory filaments 8 6
Respiratory filaments 9 or more 9
Cocoon loosely woven anteriorly; respiratory filaments in more
than three groups 7
Cocoon variably thickened anteriorly; respiratory filaments in three
groups 8
Respiratory filaments thick, in three short-petiolate pairs, plus two
singly decorum
Respiratory filaments thin, in 4 petiolate pairs rugglesi
Respiratory filaments whitish, long and slender, the dorsal and
medial groups on short petioles, the ventral group ona long petiole;
anterior margin of cocoon with only slightly thickened, narrow rim
griseum
Respiratory filaments shorter and thicker, branching fan-like near
base of short petioles; anterior margin of cocoon broader and dis-
tinctly thickened bivittatum
Respiratory filaments 9, diverging in a semicircle from center;
cpcoon boot- shaped pictipes
Respiratory filaments 10 or more 10
Respiratory filaments 10 11
Respiratory filaments 12 or more 12
Cocoon boot- shaped corbis
Cocoon with an anterior projection piperi
Respiratory filaments 12 13
Respiratory filaments 14 or more 14
Cocoon with broad collar and many openings anteriorly . .arcticum
Cocoon with narrow collar and one large opening anteriorly . .
luggeri
Respiratory filaments 14 or 16; cocoon slipper-shaped . .vittatum'
Respiratory filaments 16; cocoon boot-shaped malyschevi
Respiratory filaments more than 16 15
Respiratory filaments 22-26 meridionate
Respiratory filaments 100 or more hunteri
Larvae
1. Anal gill with three simple lobes 2
Anal gill with three compound lobes 4
2. Ventral papillae conspicuous, conical; head spots dark; suboeso-
phageal ganglion and epidermis in postgenal cleft pale; respiratory
filaments in histoblast 4 3
Ventral papillae small or absent; suboesophageal ganglion and/or
epidermis in postgenal cleft usually black; respiratory filaments
in histoblast variable 4
3. Antenna dark and conspicuous; submentum darker than adjacent
area; lateral head spots double; anal gill lobes with secondary
bumps pugetense
Antenna pale; posterior half of submentum concolorous with adjacent
area; dorsal head pattern consisting of longitudinal patches ....
aureum
132
Abdelnur
4. Submentum with median tooth as long as corner teeth; second an-
tennal article with a single lobed ventral pale spot; anal gill with
no accessory lobes; postgenal cleft slight and rounded apically . .
vittatum
Submentum with median tooth longer than corner teeth; second an-
tennal article with a bilobed ventral spot; anal gill with numerous
accessory lobes; postgenal cleft extending to more than half the
distance to the base of submentum pictipes
5. Pigmented area anteroventral to eye conspicuous, suboesophageal
ganglion and epidermis in postgenal cleft pale, second antennal ar-
ticle more than twice as long as third, respiratory histoblast with 4
filaments latipes
No pigmented area anteroventral to eye 6
6. Suboesophageal ganglion and epidermis in postgenal cleft pale .
pi pen
Suboesophageal ganglion and/or epidermis in postgenal cleft dark.
7
7. Spots on cephalic apotome (head spots) dark; antenna shorter than
cephalic fan stalk; abdomen pale yellowish - brown; respiratory
histoblast with 12 filaments; postgenal cleft bulbous extending one
half the distance to base of submentum luggeri
Head spots pale 8
8. Antennae longer than the cephalic fan stalk; the entire two distal
articles extending beyond apex of stalk of cephalic fan 9
Antennae shorter than cephalic fan stalk 12
9. Respiratory histoblast with 6 or 10 filaments 10
Respiratory histoblast with 12 or 16 filaments 11
10. Respiratory histoblast with 6 filaments; postgenal cleft uniformly
tapering; 43 rays in cephalic fan tuberosum
Respiratory histoblast with 10 filaments; dorsal head pattern lacking
isolated spots; postgenal cleft extending to just below the base of
submentum, approximately 50 rays in cephalic fan corbis
11. Respiratory histoblast with 12 filaments; submentum teeth equal
in length, 50 rays in cephalic fan arcticum
Respiratory histoblast with 16 filaments, postgenal cleft extends to
base of submentum; the submentum withlong, distinct median tooth;
49 rays in cephalic fan malyschevi
12. Ventral papillae conspicuous rugglesi
transiens
Ventral papillae absent 13
13. Postgenal cleft extending to less than half the distance to base of
submentum hunteri
Postgenal cleft extending to more than two-thirds the distance to
base of submentum 14
14. Infuscation around head spots wide and extending beyond outer edge
of anterolateral spots; arms of anal sclerite broadly fused medially
15
Infuscation around head spots narrow, not extending beyond inner
edge of anterolateral spots; arms of genital sclerite narrowly fused
medially; respiratory histoblast with 8 filaments .... decorum
Black Flies
133
griseum
bivittatwn
15. Lateral plates of proleg lightly sclerotized; cephalic fan with about
52 rays; anal hooks in 66 rows; postgenal cleft not bordered by a
fulvous area verecundum
Lateral plates of proleg heavily sclerotized; cephalic fan with less
than 42 rays; anal hooks in about 70 rows; postgenal cleft bordered
by a narrow fulvous band venustum
HABITATS, BEHAVIOR AND LIFE HISTORIES
Alberta Simuli ids In General
Eggs
Simuliid females lay eggs in running water. There is no record of
oviposition in stagnant water. Cameron (1922), Edwards (192 0), and
O'Kane (1926) suggested that the eggs of some species of black flies
(S. arcticum , S. latipes and P. hirtipes respectively) withstand desiccation.
They may be subjected to this through water receding or the drying up of
intermittent streams. Jobbins-Pomeroy (1916), Smart (1944), and Wu
(1931) concluded from field observation and experimental evidence that
the eggs are not resistant to desiccation. Fredeen (1959b) devised a
method for the extraction, sterilization and low temperature storage of
black fly eggs collected from the field. He found that the eggs of arctic
and temperate species overwinter and remain viable for longer periods
in storage than the eggs of those species which pass the winter as larvae.
I tested batches of eggs of Simulium venustum , S. vittatum , and S. decorum
for desiccation resistance as follows: egg batches were obtained from the
breeding places and divided into three groups. The first group was used
as a control and was firmly anchored or clearly marked in the breeding
site. The second group was left on filter paper in the laboratory during
the test periods (48, 144, and 264 hr) and then returned to water. The
third group of eggs was used as a laboratory control, covered by water
in clean, open museum jars. The results are shown in table 2.
The recorded (room) relative humidity was 67-74% and the temper-
ature was 56-69 F. The eggs of these species need water for hatching
and show no resistance to desiccation.
Table 3 shows the average number of eggs laid by the females of ten
species. The eggs of a batch mature at the same time but there are dif-
ferences in the numbers of eggs laid within and between species. This
was also recorded by Davies and Peterson (1956) for many species, in
most genera. In a few species there is usually a decrease in the number
of eggs in the second gonotrophic cycle. This results from degeneration
of some ovarioles in which the eggs from the previous ovarian cycle were
retained.
The simuliid egg is conical in ventral view and sub-triangular in
lateral view. There is a bulge on one side of the egg and the side opposite
that is the longest in profile.
Linear measurements were taken from the lateral view. The length
134
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was taken as the maximum measurement along the egg axis parallel to the
longest side and the width dor soventrally and perpendicular to this (table
4). Davies (1950) and Davies and Peterson (1956) compared the dimen-
sions of eggs of various species belonging to all the North American si-
muliid genera. The eggs of Gymnopais and Prosimulium were found to be
larger than these of Cnephia and Simulium except for S. pictipes , also the eggs
of Prosimulium and Cnephia are narrow and eggs of other genera are sub-
triangular in profile.
The angles, table 5, were measured with an eyepiece goniometer.
TABLE 2. The progress of hatching of the eggs of three simuliid species
in relation to drying.
Breeding sites - The simuliid larvae were found only in rivers and
creeks. The young larvae of some species aggregate at the exits of
creeks from lakes and bogs. The older larvae are more evenly distri-
buted downstream and the mature ones are in the pupation sites which are
in slow water and usually near the bank.
The head waters of the Pembina and the Athabasca rivers are at an
altitude of about 3800 feet and the altitude is 2000 feet at Flatbush and
1690 feet at Athabasca town.
For about 4 to 7 miles downstream from big villages and towns there
was a decreased population of simuliids. I attribute this to the influence
of domestic and industrial waste disposal in the rivers. The creeks may
be dammed for agricultural or industrial purposes for short or long per-
iods during the season. Although they may be dry for some time, when
there is a leak or overflow they get repopulated in the same season.
Beaver dams are common in the area, usually giving rise to favorable
breeding sites.
Black Flies
135
Fig. 1. a. Bifid claw of Cnephia sp. , BT - basal tooth; b. Simple claw of Simulium sp. ; c. Submentum of Simulium sp. ;
d. Submentum of Prosimulium sp. , MT C median tooth, LT = lateral and corner teeth, e. Wing of Prosimulium sp. female,
BC = basal cell.
136
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TABLE 3.
Species
S. arcticum
nulliparous
parous
S. aureum
S. decorum
nulliparous
parous
S. latipes
S. luggeri
S. tuberosum
nulliparous
parous
S. venus turn
nulliparous
parous
S. vittatum
nulliparous
parous
C. dacotensis
C. emergens
Number of eggs per gonotrophic cycle in some Simuliids,
counts and published records, means ± standard deviations,
number of counts in brackets, range.
No. of eggs per female Authority
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137
TABLE 4.
Species
S. arcticum
S. aureum
S. decorum
S. latipes
S. luggeri
S. tuberosum
S. venus turn
S. vittatum
C. dacotensis
C. emergens
TABLE 5.
S. venus turn
S. vittatum
S. decorum
The length and width of mature eggs of some simuliid species.
L ength Width
Egg angles of three simuliid species measured in lateral
view using eyepiece goniometer.
Angles (degrees)
Head Bulge Third (tail)
Range Mean ± S. D. Range Mean ± S. D. Range Mean ± S. D.
Number of readings, range.
138
Abdelnur
The larvae of S. arcticum were limited in their distribution to the two
rivers in the study area, albeit they have been collected from streams
elsewhere (Fredeen (1958), Fredeen and Shemanchuk (I960) in southern
Alberta, Peterson (1956) in Utah, and Sommerman et al. (1955) in Alas-
ka). The current velocity was 1. 5 to 5 ft/sec throughout the breeding
sites except that mature larvae pupated in slower water near the banks
of the rivers. The water was about three feet deep over the young larvae
but only 8 to 14 inches above the pupae. Frequently pupae were exposed
when the water receded; Equisetum stems are preferred pupation sites
as the plant grows near the water edge and in the water. The water tern -
perature ranged from 32 to 61 F during occupation by the species col-
lectively.
Closely associated with S. arcticum in the Pembina River was S. luggeri .
The latter was sparsely distributed on the same substrata although stones
and rocks were utilized especially for pupation. It was collected also
from the lower reaches of French Creek in similar positions.
S. tuberosum larvae aggregated on stones and vegetation exposed to the
sun; the preferred current velocity was 0. 6 to 3. 5 ft/sec and the water
depth was 3 to 18 inches. This species bred in the rivers and creeks.
S. verecundum , S. venustum and S. vittatum bred more in the creeks than
in the rivers; the Pembina River usually had a bigger population of aqua-
tic stages per square foot than the Athabasca (fig. 4). The current speed
ranged from a trickle in one inch of water to about 5 ft/ sec in more than
three feet of water. The first two species appear when the temperature
rises to 40 F.
S. decorum larvae were found to concentrate on shaded substrata in 3
to 12 inches of water and 0. 5 to 1 ft/sec current. During the occupation
of this species the temperature was 51 to 72 F.
The larvae of S. aureum were encountered only at above 50 F on trail-
ing vegetation in streams with patchy growth in the water. The preferred
current velocity was 0. 5 to 2 ft/ sec in 5 to 12 inches of water. The max-
imum temperature was 71 F.
The distribution of the larvae of S. latipes indicated a discontinuity in
the rivers and abundance in the creeks. The larvae were attached to the
vegetation, sticks and pebbles in the S. aureum breeding sites except that
the temperature requirements were more eurythermic (starting from 40
F).
The larvae of C. dacotensis and C. emergens were collected from veget-
ation, logs, and bottom stones in 1. 5 to 2. 5 ft/ sec current speed in one
to three feet of water. The temperature was 38 to 51 F. The overwin-
tered larvae of C. mutata were attached to the bottom pebbles and sticks
in the same conditions.
Prosimulium decemarticulatum was well distributed in Irish and Flatbush
Creeks. The larval attachment substrata were dead or trailing veget-
ation, sticks, stones, and logs under 4 to 13 inches of water and 0. 5 to
2 ft/ sec of current. The water temperature reached 36 F before the lar-
vae appeared.
Population density assessment - Two methods were employed in determining
population densities. The first method was the direct counting of the
numbers of larvae in a square foot of the river bottom. Two weekly col-
Black Flies
139
lecting stations were selected in the Pembina River, one in the Atha-
basca River and one in each creek. Each station was about three miles
long. A wooden frame was applied to a selected area (with suitable at-
tachment substrata) delimiting one square foot of the bottom and the sub-
strata were investigated (average 8 ft^ counts). Bottom pebbles, debris,
vegetation, sticks, stones, rocks and logs constituted the substrata (the
last two usually encompassing more than one square foot). This method
has been used in ecological studies and control assessments. Arnason
et al. (1949), Anderson and Dicke (I960), Fredeen et al. (1953), Jamn-
backand Eabry (1962), Metcalf (1932) and Sommerman et al. (1955), and
Wolfe and Peterson (1959) used a five minute stone count in selected
areas.
The secondmethod was based on artificial attachment sites. These
consisted of hollow, white matt surfaced polystyrene-butadiene rubber
("high impact polystyrene") cones , 0. 01 inch final thickness , 20 cm long,
with a 10 cm base diameter and 30* apex, vacuum formed from 0.03"
sheet by Spencer-Lemaire Plastics of Edmonton. One set of these was
freely suspended by wire through the apices to wooden spikes fixed in the
collection stations. Depth adjustment was attained by using cork or lead
weights. Another set was fixed with the apices pointing upstream by
fixing them to pegs through holes in the spikes. A similar method was
employed by Peterson and Wolfe (1958), Phelps and DeFoliart (1964)
and West et al. (I960).
In every collecting station there were control cones which were not
changed during the season; but the other were checked and the larvae
removed for counting every week.
Although the projected area of the cone is only approximately l/9th
of a square foot, the number of larvae on a trailing cone was subequal
to the number of larvae in a square foot of bottom. This may be due to
attraction of simuliid larvae to bright objects or perhaps to the nature
or shape or movement of the surfaces. This is supported by the finding
that cones painted yellow, brown, red, green or blue yielded less larvae
than the white cones (table 6). The relative brightness of the cones to
insects was estimated for me by Mr. Peter Kevan who photographed
them by diffuse daylight through a quartz lens. Except for yellow, a
fairly good direct relationship between brightness and numbers of larvae
attaching is seen. Most measurements of spectral sensitivity in insects
indicated low sensitivity in the yellow (Dethier 1963). Similar trends
were observed by Wolfe and Peterson (1959) using painted parts of a
spruce log.
The fixed cones gave very low numbers at all depths, the freely sus-
pended cones had an optimum depth between, 2 and 11 inches with a roughly
inverse relationship between turbidity and optimum depth.
Peterson and Wolfe (I960) interpreted the population graph obtained
in their study as representing three generations of all the species encoun-
tered in the period June to July with a small peak in May which resulted
from the overwintered larvae and egg hatch (of all species) in spring. In
my study area there was overlapping of the generations of one and all
species whenever they were associated. This resulted in peaks in the
population graphs (figs. 2-7) corresponding to the life histories of more
140
Abdelnur
than one species in any station. For ease of comparison data have been
adjusted in such a way as to synchronise the date of ice break-up.
TABLE 6. Numbers of simuliid larvae on plastic cones of different
colors at different depths in the Pembina River, weekly col-
lections, July and August 1965.
Depth in inches:- 2 : 4 : 6:8: 10 : 12 : 14 : 16
Relative
brightness
Average number of larvae per cone/week
(5 counts)
TABLE 7. Average numbers of simuliid larvae picked up per cone in six
hour period (in the Pembina River, July and August 1965).
Time
The spring peak depends on the abundance of the overwintered larvae
and eggs and the effect of winter on both stages. The high water of spring
flood is of great advantage to the larvae as more substrata and organic
drift are provided by the invasion of new areas (Anderson and Dicke
(I960), Carlsson (1962 1966), Fredeenand Shemanchuk (I960), Peter-
son and Wolfe (I960), and Phillipson (1956 & 1957). There are adverse
Black Flies
141
effects of the high water as some of the larvae may be washed away and
perish and there may be depositions of silt over the substrata.
The summer peak (or peaks) may result from the combined presence
of the first generation larvae of those simuliid species with high tern -
perature requirements, successive ovipositions of some species in the
first generation and influx of larvae of the second generation. This may
be prolonged until August and overlap the small fall generation.
Anderson and Dicke (I960) recorded 2000 to 4000 larvae/ft^ (300 to
800 larvae on grass blade 0.5" wide and 6" long). Metcalf (1932) recor-
ded 2880 and 1500 larvae on two rocks and 300 larvae/ft^, Peterson and
Wolfe (I960) reported 2400 larvae/cone.
According to Hocking and Pickering (1954) the current gradient is
important in the positioning of larvae on the substrata after the larvae
attach. The fact that the cones suited the requirements of larvae is il-
lustrated by the high catch recorded.
Fig. 2. Total population densities of simuliid larvae in the Pembina River : May to September 1963-1965
(adjusted for dates of ice break-up).
Direct count, 100's of larvae/sq. foot of bottom
142
Abdelnur
10 -
8-
6 -
4-
2 -
Larval migration _ The adult females fly upstream and oviposit, their
eggs hatch and the larvae accumulate in these oviposition sites for short
periods. They are passively carried downstream by the current. These
young larvaewere reported by Peterson and Wolfe (I960) tosecrete silk
threads to suspend themselves in the current. The larvae populate all
the favorable breeding sites in the streams and the mature larvae migrate
to slower water to pupate.
Rubtzov ( 1939) concluded from his studies on the migration of simuliid
larvae that they migrate downstream continuously during the night and
settle on different substrata in the day. He attributed the migration to
the decrease in current velocity in one site inducing the larvae to seek
higher velocity levels. Radzivilovskaya (1950) reported the larvae mig-
rating during the day and settling during the night and attributed this to
lowered oxygen content at the attachment site. Peterson and Wolfe (I960)
reported the larvae migrating during the night and settling during the
day. Yakuba (1959) suggested that migration may be stimulated by the
rapid rise in water level.
M J
J
A
S
Fig. 3. Total population densities of simuliid larvae in the Pembina River : May to September 1963-1965
(adjusted for dates of ice break-up).
Black Flies
143
10-
8-
6
4
2 *
— i — — — ■
M J
J A S
Fig. 4. Total population densities of simuliid larvae in the Pembina River : May to September 1964-1965
(adjusted for dates of ice break-up).
The total numbers attaching decreased with the advancing season in
a comparable manner to the total larval density (fig. 2). Attachment,
and hence probably numbers migrating downstream seems to be greatest
when light intensity is increasing, and to be restricted by the very low
light intensity when there is neither moon nor sun. Perhaps decreasing
light intensity invokes release, and increasing light, attachment. They
may be dislodged by other larvae, drifting objects or as a result of the
movement of the attachment object.
144
Abdelnur
Fla tbush Creek was dammed in July 1963 and the bottom of the stream
below the dam was dry. No eggs were found in June 1964, but the water
overflowed the dam in July and continued to flowup to the end of the sea-
son. The stream was repopulated by simuliids in July and this was mainly
done by females ovipositing below the dam and by larvae migrating from
above the dam. In 1965 the simuliid populations in this creek were as
high as in other creeks and the species of simuliids were: C. mutata ,
P. decemarticulatum , S. venustum , S.vittatum , S. latipes , and S. aureum .
Black Flies
145
Fig. 6. Total population densities of simuliid larvae in French Creek,
1964.
Laboratory Rearing
Laboratory rearing of simuliid larvae was attempted by Fredeen
(1959a), Hocking and Pickering (1954) , Mackerras and Mackerras (1948),
Puri (1925), Smart (1934), Dalmat (1955), Wood and Davies (1965) and
Wu (1931). Only Boophthora erythrocephala de Geer has been reared from the
pupa through two generations (Wenk 1963).
146
Abdelnur
The methods employed were compressed air to circulate the water
in breeding jars, using stone or fritted glass air breakers , and the move-
ment of water: by the shaking or rotation of a platform carrying the
breeding jars, by flow through tanks and troughs or by propulsion with
propellers. The water used was chlorinated tap water, from aquarium
tanks richin algae or stream water. Rubtzov (1956a) suggested that the
maintenance of larvae in the laboratory may be facilitated by rearing them
in water rich in micro-organisms . This was attempted by some workers;
by supplying bakers' yeast, powdered skim milk and bacteria. At opti-
mum temperature, oxygen saturation and current velocity, food was not
an important problem in the laboratory rearing of simuliids.
Fig. 7. Total population densities of S. vittatum and S. venustum larvae in Chisholm Creek, 1964.
Black Flies
147
In the present study two methods were successfully utilized in the
study of life histories and other investigations. Compressed air was
bubbled into breeding bowls and museum jars. This method was found
satisfactory in raising early stages of S. venustum , S. vittatum i and S. decorum
and for insecticide susceptibility tests. Larvae were induced to attach
on glass plates facilitating the change of water. As Hocking and Pickering
(1954) suggested, autointoxication may be responsible for the mortality
observed in jars after four to six days when the water was not changed.
15% to 30% mortality was recorded in 500 cc jars with less than 75
larvae; 40 to 80% in jars with more than 75 larvae. The average used
was 250 larvae per 1500 cc bowl with the mortality increasing with in-
crease in the number of larvae.
Two acrylic plastic troughs (described under DDT susceptibility
tests) were used in rearing efforts. These simulated breeding conditions
in streams and the young larvae from the jars were transferred to the
troughs and easily reared to pupae. Water was collected from breeding
sites and bakers' yeastwas the onlyfood added. The larvae of S. venustum
were observed to scrape the aggregated yeast cells off the walls of the
containers. Algal growth and other microorganisms in the water were
not removed.
Field investigations of nutrition were conducted by Anderson and
Dicke (I960), Davies and Syme (1958), Hocking and Pickering (1954),
Fredeen (1958 and 1964b) and Peterson (1956). The larval gut contents
yielded soil particles (sometimes 100%), organic debris ’.diatoms, algal
filaments, spores, pollen grains, pieces of green and decayed vegetation
and chitinous pieces of invertebrate body.
In the laboratory the larvae filled their guts with yeast cells, phyto-
plankton and other inorganic particulate matter. Starved mature larvae
emptied their guts in 9 to 17 days; 67% pupated and 12% survived for 21
days without filling their guts again. Larvae of S. vittatum without distinct
visible histoblasts took 4 to 7 days to empty their guts and survived for
11 to 18 days.
The feeding process was as described by Hocking and Pickering
(1954), Peterson (1956) and Osborn (1896). Internal fluid pressure and
the current may be responsible for extending the fans. The fans were
closed (drawn towards the mouth) two to 23 times in a minute. The sec-
ondary fan filaments maybe employed to decrease the area between the
filaments of the primary fan, thus enabling the larva to strain out smaller
particles, e. g. , yeast cells.
Puri (1925), Peterson (1956), and Wu ( 193 1) described cocoon spin-
ning. The observed procedure agrees with previous descriptions except
that the larvae of S. venustum , S. vittatum , and S. decorum took more than 60
minutes to finish the cocoon in the laboratory.
Pupae
Pupae of P. decemarticulatum were recovered mainly from the bottom
sand of Irish Creek and in the laboratory the mature larvae pupated in
the bottom of the rearing bowls where they spun loose cocoons. Pupal
aggregates were encountered in vegetation, rocks, and other substrata
located inslowand shallow water. Peterson (1959b) suggested that there
148
Abdelnur
may be a positive thigmotropic response facilitating the pupal develop-
ment. Stranded pupae of S. arcticum , S. decorum f S. venustum f and S. vittatum
were observed exposed as a result of a drop in water level. The pupal
mass was kept moist by the fine spray from the water splash but when
dried the pupae perished.
Carlsson (1966) indicated that each species has a certain pupal op-
timum temperature but the range between the maximum and minimum
developmental temperatures is broad. In the laboratory I noticed that
the duration of the pupal stage of S. vittatum , S. venustum , S. decorum , and
S. arcticum (obtained from the same batch of mature larvae of each species)
took from three to eleven days, and that the position of the pupa in the
mass did not influence its duration; but as in the field the emerging
adult maybe trapped under the pupal mass and perish. Organic and in-
organic drift sediment piling above the pupal mass may interfere with
the emergence of the adult.
Rubtzov (1956b) indicated that there is a correlation between the num-
ber of pupal respiratory filaments and the character of the stream in
relation to oxygen supply, i. e. , pupae in swift water have less filaments
than those in slow current. I found that S. latipes with four filaments
breeds in the same stream as C. dacotensis which has numerous filaments ,
S. vittatum with 16 filaments and S. venustum with 6 filaments. Pupae kept
in vials with moist cotton pads matured in less time than others of the
same group left in the breeding troughs.
The adult emerged through a longitudinal split on the dorsal surface
of the pupal skin pushing its thorax out first followed by the head and
swiftly rising in a bubble of gas to the surface where it took off or was
carried by the current to a near support.
Adults
Various methods have been used in studying populations of adult
simuliids. Davies (1950), Davies and Syme(1958), Hocking and Richards
(1952) and Ide (1940) used emergence traps. Light traps were employed
by Davies (1955), Davies and Williams (1962), Fredeen (1961) and Wil-
liams (1948). The baited trap was preferred by Andersonand DeFoliart
(1961), Bennett (I960) and Fallis (1964). Fredeen (1961) utilized "sil-
houette traps" which consisted of wooden frames in shape of animals
(cow, sheep and horse) and covered by cloth of appropriate color to match
the animal it represented. Hocking and Richards (1952) and Davies (1961,
1963) applied sweep-netting and fly-boy-hour counts. The latter method
was recommended by the World Health Organization in relation to control.
I used a light trap (ultraviolet) in the period July to September 1963
and June to August 1964, at the field station (4 miles from the river);
the total catch was: 91 female S. venustum , 49 female S. decorum , 36 fe-
male and 24 male S. arcticum and 18 female S. latipes. This represents a
low yield compared to some records by the above workers.
Nylon gauze and paper coated with castor oil and sticky traps (tangle-
foot and flypaper) were hung near bird nests and on vegetation near the
breeding sites. The adults caught were utilized in the life histories stu-
dies. Quantitative study of the abundance of adult simuliids was attemp-
ted by sweep netting of flying, feeding, and resting flies; the average
No. of flies in 10 sweeps
Black Flies
149
number of flies in ten sweeps is plotted in figure 8.
The diurnal activity pattern consisted of a peak of activity two hours
after sunrise and a peak starting from two hours before sunset and con-
tinuing until after dark. The latter peak was more conspicuous as it
consisted of many species and more individuals than the former.
The emergence pattern of the adults was investigated in the labor-
atory and the field using emergence cages (20 mesh per inch nylon
screens). The investigation was on S. vittatum in July 1965; approximately
100 pupae were selected from the breeding site for each period (two hour
observation); to obtain pupae of similar age dark colored individuals
were used. In general agreement with the published data, the observed
adult emergence in the field was between 5:30 AM and 1:30 PM. In the
laboratory it commenced two hours before sunrise and reached a climax
at 9:00 AM but continued throughout the rest of the day in a random pat-
tern (fig. 8) .
Fig. 8. Populations of adult simuliids, all species (sweep-netting) Flatbush, 1964 and 1965.
Number of adult flies emerging/two hours.
150
Abdelnur
2 4 6 8 10 12 14 16 18 20 22 24
TIME
Fig. 9. Adult S. vittatum emergence pattern, July 1965.
Black Flies
151
Species and their Life Histories
Prosimulium (P.) decemarticulatum
This ornithophilic species was collected in 1965 from Irish and Flat-
bush creeks. The larvae were abundant in May but not before that, in-
dicating that the species passes the winter as eggs. Mature larvae and
pupae were taken on June 17. The first adult (a male) emerged in the
laboratory on June 24, the females emerged on June 26. In the field a
net collection on June 27 yielded only males, later collection yielded
both sexes. The females showed no maturation, but were fertilized and
most of them had fed on blood. These blood fed females matured their
eggs in six days in the laboratory. A few parous females were also
collected indicating that the females completed more than one gonotrophic
cycle. After July 20 the aquatic stages were encountered singly or in a
very random pattern. Similar data were reported by Anderson and Dicke
(I960) from Wisconsin. Davies (1950) and Davies et al. (1962) from On-
tario, and Sommerman et al. (1955) from Alaska.
Although females did not feed on sparrows in captivity most of the
trap collections were from near nests of birds . Females were aspirated
from young sparrow chicks in the nests. This is in accordance with the
reported host preference for the species (Bennett i960, Davies and Pet-
erson 1956, and Davies et al. 1962).
Prosimulium (P.) onychodactylum
Three larvae and two pupae of this species were collected in July
1965 and four females and one male were collected on October 2-4 ,
1964. Except for P. travisi this was the rarest species in the study area.
Aquatic stages were collected only from the Athabasca River in the Hin-
ton area, above 3000 ft. Both sexes were attracted to the collector but
neither landed nor fed on him. Two dissected females contained well-
developed ovaries, i. e. the eggs more than half mature.
Sommerman et al. (1955) reported this species to overwinter in the
eggs in Alaska and to have one generation annually extending from April
to September. Peterson (1959b) collected only larvae in Utah and sug-
gested that the species has one generation a year there.
Prosimulium (P.) travisi
On October 4 in the Hinton area a single male of P. travisi was col-
lected in a net sweep from the vegetation on the bank of the Athabasca
River, together with six females of S. arcticum . Neither aquatic stages
nor females of this species were encountered.
Sommerman et al. (1955) collected P. travisi from July to September.
It was suggested that it has one generation a year with the eggs hatching
in June.
Cnephia (S.) mutata
Basrur and Rothfels (1959) discovered that the populations of C. mutata
in southern Ontario contain bisexual diploid forms and parthenogenetic
triploid forms (females only). Davies (1950), Davies and Peterson (1956),
152
Abdelnur
and Davies et al. (1962) found that 90-100% of the individuals collected
in Ontario were triploid females.
Basrur and Rothfels (1959) reported the species as univoltine in Peel
County; the eggs of the diploid form hatch in January to February and
the triploid form then dominates from mid-April to May.
Anderson and Dicke (I960) found that this species passes the winter
as eggs in southern Wisconsin and as larvae in the north.
Davies (1950) collected males and females of the diploid form of the
species emerging in mid-May and the peak of emergence of the triploid
was in late May extending into June (with an odd female collected in Aug-
ust). This attenuated emergence led Basrur and Rothfels to suggest
two generations for this species in southern Ontario.
In the study area larvae of C. mutata were collected after the ice break-
up. They commenced to pupate on May 14 (1965). The females emerged
ten to fifteen days later with their ovaries well-developed, containing
between 190-250 eggs three-fourths mature. These eggs took five to
seven days to mature in the laboratory, without fertilization, the females
being fed on water and sugar crystals. In the field unfertilized females
were collected feeding on horses and to a lesser extent on cows. These
females were examined by me and showed indications of a previous ov-
arian cycle. There were mature eggs in one or both ovaries intermixed
with very immature eggs and plenty of follicular relics.
Fallis (1964) quoted various authors reporting C. mutata feeding on
deer, hare, cow, and man (ear).
On one occasion an ovipositing female was observed flying low over
the surface of water against the current and tapping the water with the
tip of its abdomen, it finally fell into the water.
There were no collections of adults or aquatic stages after June.
Cnephia (C.) dacotensis
C. dacotensis is univoltine and fully autogenuous species. It breeds in
Irish Creek and was not collected from any other locality. The eggs
hatched after the ice break-up and the larvae appeared in May and com-
menced to pupate in May 17-20. The first male was collected on May
20 and the females two days later. In the laboratory the females raised
from pupae showed the eggs almost three-quarters mature. The females
fed on water and sugar, matured their eggs in four to six days. In the
field females netted from the vegetation on May 24 were all fertilized,
their eggs three-fourths mature and the abdomens distended with liquid
in the stomach, diverticula and oesophagus. Mating took place on rocks
and stones near the water edge occupying from less than a minute to three
minutes. No fertilization plugs or spermatophores were detected.
The females oviposited while flying low over the water. The total
number of eggs in their ovaries was 276 to 288. Gravid females netted
from the vegetation showed indications of partial oviposition, i.e. 20 to
30 ovarioles extended although the eggs were in the same degree of ma-
turation.
The mouthparts of the female were reported as weak, reduced and
incapable of feeding (Krafchick 1943, Peterson and Wolfe I960. Nicholson
1945 and Stone 1964). Twinn (1936), Davies (1950) and Davies and Pet-
Black Flies
153
erson (1956) compared the size of the male eye with other species and
concluded that the eyes are reduced and there is a lack of phototaxis
rendering this species incapable of forming a mating swarm. In the
present study no feeding or blood engorged females were encountered.
The last date on which the aquatic stages were seen was Tune 29;
although Fredeen (1961 in Davies et al. 1962) reported some eggs hat-
ching in autumn.
My findings are in accordance with the reports of Anderson and Dicke
(I960), Davies (1950), Davies and Peterson (1956), Davies et al. (1962)
and Nicholson and Mickel (1950), Sommerman et al. ( 1955) , Stone(1964)
and Stone and Jamnback (1955).
Cnephia (C.) emergens
C. emergens was taken as larvae and pupae on May 27 and June 10 res-
pectively from Irish and Flatbush creeks. As no overwintered larvae
were detected it is considered to pass the winter in the egg. No females
were taken in the field but laboratory raised females contained half ma-
ture eggs. The eggs ranged from 125 to 211 per female. The females
fed on water and sugar crystals but not on a sparrow, a cat or my arm.
In describing the species Stone (1952) pointed out the reduction in arm-
ament of the mandibles and maxillae which indicated inability to feed on
blood. The same condition was reported by Davies and Peterson (1956)
and Peterson and Wolfe (1958). Davies et al. (1962) and Sommerman
et al. (1955) found a single generation annually, which I confirm.
Simulium (G.) arcticum
This species is the cattle pest of western Canada. Serious out-
breaks have been reported since 1912 in Saskatchewan (Arnason et al.
1949, Cameron 1918 and 1922, Curtis 1954, Fredeen 1958 and I960,
Fredeen et al. 1951 and 1953, Hearle 1932 and Rempel and Arnason
1947). The life history and control measures were studied in detail by
these authors.
On no occasion were the eggs of this species collected from the
breeding sites although presumed ovipositing females were captured in
several instances from the Athabasca and less frequently the Pembina
rivers. Ovipositing females were seen flying over the breeding sites
which were mainly rapids and ripples in the rivers. They lay the eggs
singly and they do not dive under water to lay (Cameron 1922 and Fredeen
1958 and I960). The eggs are scattered in the bottom of the river but
my efforts to recover them by brine flotation were not successful. Fe-
males captured while ovipositing were kept alive in vials in the laboratory
for four days; they did not oviposit and the dissected eggs did not hatch.
Larvae were collected on May 10 1964 and May 11 1965. They ac-
cumulate in favorable sites within the breeding localities. They attach
to pebbles, stones, rocks and vegetation, although the first three are
more abundant in these breeding stations than vegetation it was noticed
that there was an aggregation of larvae in the different instars on par-
ticular substrates, i. e. up to the third instar larvae are found on smal-
ler pebbles and stones, later instars on stones and rocks, and mature
larvae and pupae on rocks and vegetation in slower flowing water. This
154
Abdelnur
indicates a definite migration pattern. Larvae and pupae were collected
from the two rivers only although in the southern parts of the province
they have been collected from the tributaries of the South Saskatchewan
River and from irrigation canals (Fredeen 1958 and I960).
The data indicate that there are four generations per year with an
obvious overlapping of successive generations (as indicated by larval
density assessment, fig. 5). The species overwinters in the egg stage
as no larvae were collected from under the ice and because the larvae
appear after the ice break-up in April. These newly hatched larvae
reach maturity at different times in the period from April 20 to May 19
(1964-1965). Pupation of these larvae commences on May 28 and the
adult emerges in six to ten days. In the field males were collected two
days before the first females were encountered. The overall ratio of
females to males was 1 : 4 near the breeding sites and 16 : 1 near gra-
zing cattle and horses; random samples of pupae in the laboratory yielded
a 1 : 1 ratio. Average date of pupation for the first complete summer
generation is July 1, second generation August 2, the last seasonal gen-
eration September 1.
Females emerging from the overwintering eggs have their ovaries
well-developed indicating an autogenous condition: thus this species fits
into Rubtzov's (1955, 1956a, and 1958 ) category of "facultative blood
suckers" which includes all the species of blood sucking groups that
utilize the larval food reserves for the development of the first batch of
eggs. Fredeen (1963) and Fredeen et al. (1951) observed this fact and
were able to determine the number of previous ovarian cycles using the
criterion of the follicular relics. Females that seek a blood meal have
mated, oviposited, and usually have fluid in their crops sweet to taste
and giving a positive reaction with Benedict solution. In the present
study females feeding on cattle and horses were dissected and the ov-
aries were noticed to be empty except for a few (1-3) mature eggs and
in an expanded condition.
Simulium (S.) aureum
Dunbar (1958, 1959) reported seven cytological forms of this species
from larvae collected within its range. The two forms studied were:
Form A: Southern and central Ontario (the only form in Algonquin
Park, Davies et al. 1962), with two generations extending from May-
October (Davies and Peterson 1956) andfemales feeding on birds on trees
about 20 feet above the ground (Davies et al. 1962, Bennett I960). Form
B: southern Ontario; two or more generations a year.
Jobbins-Pomeroy (1916) reported that S. aureum has five or six gen-
erations annually in southern California; two generations were reported
from Illinois (Forbes 1912), Britain (Edwards 1920), France (Pacaud
1942), Ontario (Davies 1950), Davies and Peterson 1956), New York
(Stone and Jamnback 1955) and Ontario (Davies et al. 1962). Stone (1964)
reported two or more generations annually from Connecticut; Peterson
(1956) reported three or four generations a year in Utah and Sommerman
et al. (1955) reported one or two generations per annum in Alaska.
This species passes the winter in the egg stage throughout its range.
In the study area eggs hatch in late May or early June but adults were
Black Flies
155
first collected in the period June 17-19 (1963-1965). The second gen-
eration pupated from July 11 to 17 and the third pupated from August 9
to 15. Adult collections indicated three peaks corresponding to the ob-
served increases in the aquatic stages.
Females emerged with their ovaries very small and the eggs not
developed (stage 1: Christophers' clas sification I960) . No mating swarms
were seen although females collected feeding on cattle and on sticky traps
were fertilized. These showed no follicular relics. It may be concluded
that S. aureum requires a blood meal for each gonotrophic cycle. They
were not attracted to humans or to other moving objects.
Ovipositing females were observed and sampled from Irish and Flat-
bush creeks only, which may explain the deficiency in larval contribution
to adult nutrients and the slow maturation of the larvae as these are clear
streams with only patchy vegetation.
Simulium (S.) decorum
The species is abundant in the area. The overwintering eggs hatch
in May and mature larvae and pupae were encountered in 1964-65 between
May 30- June 7. These aquatic stages are found as aggregates on under-
surfaces of stones, culvert walls, embankments, beaver dams and veg-
etation leaves. Three more generations were recorded: the pupation
commenced in June 16-20, third July 22-25, and fourth August 11-19
(1963-65). Apparent overlapping is observed between the first and se-
cond generations early in the season and third and fourth generations
later in the season. Previous records show the species with two or more
generations from Alaska southwards (Davies 1950, Sommerman et aL
1955, Stone and Jamnback 1955, Peterson and Wolfe I960, Anderson and
Dicke I960, and Davies et al. 1962).
Ovipositing females were observed on beaver dams, sticks, stones,
logs, cement embankments and vegetation, dipping their abdomens in the
water and laying the eggs in mats; up to seven females used the same
spots (cumulative ovipositing), 1500 eggs were counted; often dead fe-
males were found stuck to these mats.
No mating swarms were encountered but all the females collected
were fertilized. Females of the first generation emerged with their ov-
aries well-developed (eggs in third stage) and the eggs in the laboratory
reached maturity without the females mating or feeding; in the later
generations there was a decrease in the ovarian development and females
failed to develop their eggs without feeding. Fertilized females were
collected from feeding swarms of S. venustum ; attracted to the collector,
females started biting on the neck and arm. Females were observed
feeding on horses (June 14-17 1964, July 18-21 1965). Up to 70 flies
were counted on a single horse at one time.
Simulium (E.) latipes
This is a holarctic species complex* In the palearctic it was re-
ported that the overwintered larvae gave rise to a single generation a
year and adults feed on cattle and humans (Davies et al. 1962, Edwards
1920, Smart 1944, and Steward 1931).
In North America the species pas ses the winter in the egg stage, has
156
Abdelnur
one to three generations a year, feeds on birds, chickens, and man (An-
derson 1956, Anderson and DeFoliart 1961, Bennett I960, Davies 1950,
Davies et al. 1962, Davies and Peterson 1956, Fallis 1964, Fallis and
Bennett 1958, Hearle 1932, Hocking and Richards 1952, Peterson 1958,
Shewell 1958, Sommerman et al. 1955, Stone and Jamnback 1955, and
Stone 1964).
In the study area S. latipes has two generations per annum. The over-
wintered eggs hatch in May and mature larvae and pupae appear between
June 17 and 20 (1963-65). Commencing on August 17, pupae and mature
larvae of the second generation were encountered in increasing numbers .
Females of this species emerged with no ovarian development (eggs
in stage II - Christophers' classification 196 0) . Females induced to feed
on chickens and young sparrows failed to develop their eggs beyond stage
III and died four days after a blood meal. Fertilized females netted in
the field took blood meals from a chicken, a sparrow and the collector's
arm, developed their eggs to maturity in 11 days but all died before lay-
ing. Davies and Peterson (1956) stated that S. latipes developed its eggs
in captivity in 5 days at room temperature. Parous females took less
than 11 days to develop their eggs in the second ovarian cycle, i. e. it
takes less time for each successive cycle due to the fact that the first
bloodmeal is utilized in overall development of the gonads and the eggs.
Other likely factors maybe the decrease in the number of functional ov-
arioles and higher temperatures.
Simulium (S.) luggeri
S. luggeri is not a common species in the area. It breeds in the rapids
and riffles of the Pembina River. The dates of pupation of the three an-
nual generations are June 13-20, July 21-28 and August 20-26. Nicholson
and Mickel (1950) described the species as having three generations in
Minnesota, Fredeen collected pupae from mid- June to early July (the
first generation) on the Canadian prairies; Hocking and Pickering (1954)
collected pupae in northern Manitoba in August; Anderson and Dicke
(I960) recorded two generations per annum in Wisconsin; Twinn (1936)
as S. nigroparvum ) described three generations of the species in eastern
Canada (Mostly from the Ottawa River, Ontario). S. luggeri passes the
winter in the egg stage. Adults mated in small swarms near the breed-
ing sites; fertilized females developed their first batch of eggs without
blood meals but fed on horses and cattle before the second gonotrophic
cycle. After that no females were encountered. Oviposition was not
observed and no egg aggregations were detected, it is assumed that,
since the known breeding sites yielded no eggs, the females scatter the
eggs in the river.
Simulium (S.) tuberosum
Cytologically this Holarctic species was reported by Landau (1962)
to consist of "four well-defined breeding units and a likely fifth, all sym-
patric" in Ontario and with no evidence of hybridization. Davies et al.
(1962) suggested the presence in Ontario of two or more undescribed
forms of the species which are different from the Palearctic form of
S. tuberosum .
Black Flies
157
Previous records revealed two to four generations a year (Smart
1944, Davies 1950, Sommerman et al. 1955, Stone and Jamnback 1955,
Anderson and Dicke I960, Davies et al. 1962). In the study area as else-
where S. tuberosum overwinters as eggs. It has three generations per
annum: maturing larvae and pupae were collected on June 14-17, July
19-24 and August 20-24.
Larvae were seen to occur in dense mats on submerged surfaces or
rocks and stones exposed to the sun in the Pembina and Athabasca rivers ;
they were usually well inside the stream and away from the banks.
Females required a blood meal for the first gonotrophic cycle and
after mating they attacked cattle and were attracted to the collector in
large numbers but only a few fed on my arms and legs and rarely on the
neck or face.
Oviposition probably was on the surface of the water when the fe-
males were observed to descend from the air and settle on the water;
eggs scattered in the water.
Larvae of S. tuberosum were closely as sociated with those of S. venustum .
At low water larvae of the latter sharedmostof the substrates previously
occupied by S. arcticum and S. tuberosum .
The last (third generation was more abundant in the southern part of
the study area than in the north.
Simulium (S.) verecundum
Separated from S. venustum in 1955 (Stone and Jamnback) , this species
proved difficult to study separately. Stone and Jamnback (1955) suggested
two or three generations a year; Davies et al. (1962) found the same in
Ontario. In the study area the collection of aquatic stages from the Pem-
bina River revealed a prolonged duration of larvae and pupae from May
to August. This suggests three generations per annum. Adults were not
attracted to the collector but were captured feeding on cattle.
Simulium (S.) venustum
This Holarctic species was second only to S. vittatum in abundance;
aquatic stages were discovered in every breeding site and adults were
regularly captured in the period May-September.
Stone and Jamnback (1955) questioned the value of the previous bio-
logical record of the species as a complex containing S. verecundum . They
suggested that S. venustum has one generation annually (obligatory diapause).
The S. venustum - S. verecundum complex was shown to have more than one
generation resulting in a build-up of an almost continuous population of
adults in each season (Smart 1944, Davies 1950, Hocking and Richards
1952, Sommerman et al. 1955, Fredeen 1958 and I960, Anderson and
Dicke I960 and Davies et al. 1962).
In this study three definite peaks were detected in the larval and pu-
pal densities suggesting a three generation pattern for the species: The
generation derived from the overwintered eggs is extremely large and
reached a peak on June 10-17. The other two generations are smaller
but they overlap to cover the rest of the season. Eggs are abundant as
they are laid by females in mats sometimes twenty eggs deep and con-
taining more than 1000 eggs . Females dive under water , settle on water,
158
Abdelnur
vegetation, rocks, stones or logs and usually share an oviposition site
together. Eggs were recovered easily up to Setpember 20. July 10-15
and August 14-17 were the dates of pupation of the second and third gen-
erations respectively.
Females require a blood meal for the first gonotrophic cycle. Mat-
ing swarms were encountered and sometimes induced by the presence of
the collector or the white top of a car. Females showed a definite pre-
ference for humans over cows and for cows over horses. After they land
on a cow, a calf or a horse they are difficult to attract, but before land-
ing they were observed to assemble towards a human host in the presence
of other hosts. Females were collected feeding on a dog, on young spar-
rows and on pigs inside a barn.
Simulium (S.) vittatum
S. vittatum was the most abundant species in the study areas. Its
aquatic stages were encountered in all the breeding sites examined. In
the Athabasca River there was a noticeable decrease in the density of
aquatic stages in the Hinton area but a gradual increase downstream
(northwards) .
Overwintered larvae were detected under the ice in the Pembina
River, French, Chisholm and Blackmud (12 miles south of Edmonton)
creeks. After the ice break-up the larvae of this species are predomin-
ant; they mature and pupate by May 11 to 13. Another peak of mature
larvae and pupae was observed on May 28 to 30; this may be an emer-
gence from overwintered eggs. S. vittatum was reported to pass the win-
ter in the larval and egg stages in Alaska (Sommerman et al. 1955),
British Columbia (Hearle 1932, Saskatchewan (Cameron 1922, 1918),
Ontario (Davies 1950), Connecticut (Stone 1964) and Wisconsin (Ander-
son and Dicke I960).
Pupation of the second generation commences on June 25 to 28, of
the third generation on July 27 to 30 and the last generation on August
24 to 29. Overwintering larvae were common in September. Anderson
and Dicke (I960) reported the species to have four to five generations a
year in Wisconsin; Davies (1950) reported two generations in Ontario;
Davies et al. (1962) recorded S. vittatum as multivoltine in Ontario; De-
Foliart (1951) assigned three or four generations to S. vittatum in the Ad-
irondack Mountains (New York State); Fredeen and Shemanchuck (I960)
found the species to pass through four generations in a season; Som-
merman et al. (1955) recorded two and three generations of S. vittatum
depending on the habitat; Stone and Jamnback (1955) reported three to
four generations in New York; Stone (1964) reported one to five gener-
ations in Connecticut; Twinn (1936) described two to three generations
in eastern Canada.
Females developing from overwintered larvae had well-developed
ovaries with the eggs almost mature on emergence. Mating swarms
were observed from 1800-1900 hours; fertilized females from these
were gravid five days later in the laboratory as also were females reared
from pupae and not mated. Ovipositing females settled on different sub-
strates mainly well to the middle of the creeks and started depositing
eggs in strings. The communal oviposition method was observed with
Black Flies
159
four to seven females laying on the trailing leaves of vegetation. Females
were collected later in the season, including those from overwintered
larvae which had oviposited, feeding on horses and cows (mainly on the
ear of the latter) .
The females of this species were attracted to the collector in large
numbers; they crawled inside the front of the shirt thus gaining access
to the body. They started biting on the chest and the belly. Those out-
side the clothing started biting on the back of theneckand the arms. Fe-
males still feeding on cattle were carried inside the barns. They ac-
cumulated on windows where they were collected dead. Ants and spi-
diers shared the daily crop of flies. Engorged females were seen flying
under the barn lights at night. The preferred regions of feeding on cat-
tle seem to be the ears and to a lesser extent the underside of the belly
and the inside of the thighs. Only ear-feeding resulted in severe wounds .
The swarming females are common; cattle and horses in the pastures
are annoyed by these which are attracted to both moving and stationary
objects. Females striking against the collector's face are inhaled and
taken in the mouth.
Anderson and DeFoliart (1961) in Wisconsin and Wu (1931) in Mich-
igan found the females to feed on cattle and horses but not to bite man
although they are attracted to him. Zoophilic and anthropophilic ten-
dencies were reported by Cameron (1922), Davies (1950), Davies et al.
(1962), Hearle (1932), Hocking (1953), Jobbins-Pomeroy (1916), Jones
(1961), Knowlton (1935), Knowlton and Maddock (1944), Malloch (1914),
Sailer (1953), and Stone and Jamnback (1955).
CONTROL
Susceptibility of Larvae to DDT
Fairchild and Barreda (1945) investigated DDT as a larvicide against
simuliid larvae in Guatemala and reported the effectiveness of the method.
This led to further investigations and resulted in widespread black fly
control for medical veterinary and agricultural purposes (Africa: Barnley
(1958), Brown (I960 and 1962), Garnham and McMahon (1947), Hitchen
and Goiny (1966), McMahon (1957 and et al. 1958), Wanson et al. (1949
and 1950). North America: Arnason et al. (1949), Gjullin et al. (1949
and 1950), Goulding and Deonier (1950), Hocking (1950, 1953), Hocking
and Richards (1952), Hocking et al. (1949), Jamnbackand Collins (1955),
Jamnback and Eabry (1962), Kindler and Regan (1949), Peterson and
Wolfe (I960), Peterson and West (1*958), Twinn (1950), Travis et al.
(1951) and West et al. (I960), and Prevost (1947), Central America:
Lea and Dalmat (1954), Vargas (1945). Europe: Petrishcheva and SaP -
yanova (1956) and Rubtzov and Vlasov (1934)). Various insecticides and
formulations were investigated for the control of both aquatic stages and
adults. Albeit eradication was not feasible, spectacular results were
obtained.
Laboratory studies were started by Lea and Dalmat in 1954 using
screened tubes for container s and circulating river water through them.
One and ten parts per million of toxicant in water were used. This method
was adopted by the W. H. O. (W. H. O. tech. Rep. ser. 87, 1954, pp. 2l«*
160
Abdelnur
24). 820 chemicals were investigated in the period Jan. 1952 to Jan.
1953.
Jar tests
Muirhead-Thomson (1957) reported on the reaction of the larvae in
the laboratory to DDT and Dieldrin using compressed air to circulate
water in test jars.
Jamnback (1962) suggests twomethods. The first method involves
the use of a pump to circulate water in a reservoir pan to induce the
larvae to detach from field substrata, insecticide exposure bags and
then employing compressed air to circulate the water in the observation
jars. The second method (W. H. O. , 1964) employs wooden troughs, the
water circulated by a pump from a reservoir tank. This method was
modifiedby Travis and Wilton (1965) . They used V-shaped metal troughs
for the tests and nylon bags to return the larvae to the stream for the
observation period.
I used 500 cc museum jars fitted with glass plates (3.25" x 4"),
compressed air, and stream water. The larvae were introduced into the
jars and left overnight to attach to the glass plates. After the larvae
were selected and the jars were cleaned of excess larvae and substrata,
the insecticide was introduced (solutions of DDT in ethanol added to the
water to give the required concentration). The exposure time was one
hour and after rinsing the jars to remove the insecticide, 500 cc of river
water were added to commence the 24 hour observation period. The
tests were carried out at room temperature (63 to 67 F); the insecticide
was supplied by the W. H. O. in their mosquito larvae test kit (pp‘ isomer
in ethanol). The species composition of the larvae tested was S. vittatum
40%, S. venustum 30%, S. tuberosum 10%, S. decorum 10%, and S. arcticum 10%.
Results are given in table 8.
Trough tests
Two plastic (acrylic) troughs approximately 6 ftlong, 7 . 5 inches wide
and 2 inches deep (corrugated transversely; the ridges one inch apart
and 3/8 inch deep), were used as simulated breeding sites. The water
circulated from a "baby" bathing tub (22 liter s capacity) using a 3-gallons
per minute discharge pump. One trough and one tub (reservoir) were
used in the tests with insecticides, the other was used for the control .
It was found necessary to allow more time for attachment of larvae than
the overnight period for the jars. It is easier to use the troughs as there
is no handling of the larvae (usually a calculated risk) . The disadvantage
is the amount of water needed to conduct the tests and the large number
of troughs required for a set of tests for various concentrations.
Results
Results are given in table 8.
Biotic Control
Predation on adults was not studied. The larvae associated with
other stream organisms were accessible for study. In the study it was
observed that predators play a minor part in regulating the numbers of
Black Flies
161
larvae present at any one point. The larvae of Trichoptera, nymphs of
Plecoptera, Ephemeroptera, and Odonata were limited in their distri-
bution within a single breeding site and therefore they had access to
TABLE 8. Results of tests of susceptibility of black fly larvae to DDT,
Flatbush 1964 and 1965.
Concentration of DDT (ppm)
Percentage mortalities corrected by Abbott's formula
162
Abdelnur
limited populations of simuliid larvae. The above groups were positively
recorded as larval predators when their guts on dissection yielded whole
larvae or remains of larvae. Other important groups consisted of
leeches, birds, and fish. The leeches increased in the creeks, espec-
ially late in the season, and the fish and birds were uniformly scarce
throughout the season. The two protozoan genera Thelohania and Caudospora
(Protozoa: Microsporidia) are the most common of the simuliid para-
sites. Davies (1957) recorded T. bracteata Strickland and T. fibrata Strick-
land from Simulium spp. and Caudospora sp. from Prosimulium . The infec-
tion rates were 4 to 36%. In the present study the infection rate with
microsporidians was estimated as 27 to 33% in the creeks and 0 to 45%
in the Pembina and Athabasca rivers. It was observed that the infection
with these parasites increased in the second generations but decreased
rapidly in the middle of August and did not recover again until the end
of the season. Adult infection was highest in May- June (2 to 8%).
Nematodes - Mermithid nematodes are parasites of invertebrates and
Welch (1963) collected 153 world records of simuliids parasitized by
species belonging to the five aquatic genera: Isomermis , Limnomermis ,
Gastromermis f Mesomermis and Tetradonema . Rubtzov (1964) reported simu-
liid parasitism by sphaerularids (Nematoda: Sphaerularidae) in Russia.
The overwintered larvae of S. vittatum had infection rates of 7 - 47%,
mean 26. 1% (22 samples from seven localities in 1963 - 1965 seasons).
The only species of mermithid parasitizing these larvae was Gastromermis
viridis Welch. A single record of 79% infection was obtained in a sparse
population in Chisholm Creek, in July 22 1964. Other species breeding
in the same locality were not infected. S. venustum was infected by
Mesomermis flumenalis Welch. The infection rates were 35 to 64%, mean
45. 1% (approximately 89 samples from 7 to 13 sites per season: 1963
to 1965). Sparse and isolated populations of this species, especially in
the creeks and the Pembina River reached 94% infection rates. S. arcticum i
S. aureum and S. tuberosum were infected at very low rates . Their parasites
were Limnomermis sp. Pupal and adult infections were estimated as 14 to
23% and 7 to 9% respectively (calculated on the basis of total collections:
1963 - 1965). In the laboratory seven females and four males of S. vittatum
(raised from infected larvae) emerged in July 1964 with nematode infec-
tions. The above data indicate that the parasites are specific, infected
larvae were retarded (metathetely) , most of them died and pupal and
adult infection contributed to the infestation of the upper reaches of the
streams. Dr. H.E. Welch kindly helped with the identification of the
mermithid nematodes.
DISCUSSION AND CONCLUSIONS
The 15 simuliid species recorded in this study represented the com-
mon species in central and central western Alberta. The study area ex-
tended from the southern limit of the boreal forest and the northern boun-
dary of the Parkland to the eastern edge of the boreal cordilleran veg-
etation region (Moss 1955).
Black Flies
163
The seasonal differences in the dates of ice break-up, river dis-
charge and weather conditions were slight in 1963 and 1964 but 1965
river discharge was higher than the average. This seemed to be with-
out effect on the populations of the aquatic stages.
The systematics of the family are not clear; Cnephia overlaps
Prosimulium and Eusimulium (subgenus of Simulium ); the two new genera,
Paracnephia Rubtzov and Crozetia Davies were erected to accommodate
species included in Cnephia (in the Ethiopian region). The same problem
of Cnephia species exists here. The lack of distinctive morphological
characteristics at the species level has resulted in the species comp-
lexes encountered in the simuliid fauna here. Cytological investigations
have revealed distinct forms within the species of many genera in the
Arctic simuliids.
S. vittatum underwent no diapause, while the univoltine species
C. dacotensis , C. emergens, C. mutata , and Prosimulium decemarticulatum , and pro-
bably P. onychodactylum and P. travisi underwent obligatory diapause. The
other species were facultative with the eggs only overwintering but there
was no indication of summer aestivation.
Mating swarms were not commonly observed but the females attrac-
ted to the collector, to other animals, moving objects, and in birds'
nests were fertilized. It is suggested that mating precedes blood feed-
ing; this may be the reason why many species failed to feed in the lab-
oratory as they did not mate in captivity. It follows that parthenogenetic
species should be easily induced to feed and oviposit. Two species
(Boophthora erythrocephala DeGeer and Wilhelmia salopiensis Edwards) are now
known to mate, feed, and oviposit in the laboratory (Wenk 1963, 1965) .
The oviposition of females in captivity has rarely been reported. C. mutata
was the only parthenogenetic species in the area, cytological investiga-
tions (Basrur and Rothfels 1959) revealed the presence of both the tri-
ploid (parthenogenetic) and the diploid bisexual forms in Ontario. Only
females were captured in the 1965 season in the study area but a few
males were bred out of pupae collected in 1963 and 1964.
Autogeny was exhibited by univoltine species with weak mouthparts
which are incapable of piercing the vertebrate skin, e. g. , C. dacotensis and
C. emergens ; females of the former had their eggs almost mature on emer-
gence, the females of the latter species had much stored nutrients and
eggs were only half developed. Other species (S. arcticum , S. vittatum ,
and S. decorum ) were autogenous in the first gonotrophic cycle in the first
generation, taking a blood meal for the second ovarian cycle in the first
generation and for the first cycle in the subsequent generations . F redeen
(1963) observed that S. arcticum females accumulate after oviposition in
the fir st generation and attack in swarms under favorable weather con-
ditions, to obtain a meal for the second gonotrophic cycle.
The third group of females were anautogenous . These were char-
acterized by the large number of eggs in each ovarian cycle, usually laid
in masses. These build up large populations of larvae in the breeding
sites (S. venustum , S. aureum , S. latipes and P. decemarticulatum). This crow-
ding led to competition among the larvae for food and substrata,and
might have contributed to the lack of stored nutrients carried over to
the adult stage. Lack of stored nutrients could be also inferred from
164
Abdelnur
the quality and quantity of food available to the larvae, the morphology
of the cephalic fan (spacing of the filaments) being an important factor.
The adult feeding habits of these females indicated no preference. Mam-
malophilic S. venustum fed on 5 different hosts, including a sparrow; the
other 3 species fed on different bird hosts. They were at an advantage
as they were not exposed to the risks of long flights. Securing a blood
meal with such ease contributed to the longevity of the females and en-
sured repeated ovarian cycles.
The larval development commenced before the growth of vegetation
but the species differed in their developmental thresholds of tempera-
ture. These differences occurred in all generations of all species in
each year. The overwintered larvae have low, and the overwintered egg
(embryo) have high temperature requirements.
The seasonal prevalence of the different species indicated by the
total population densities of the larvae in the rivers and creeks did not
show much fluctuation in the last three years. In June 1965 there was
an apparent reduction in the total larval population which could have been
due to the effect of adverse weather conditions on the adult population of
S. arcticum , and other riverine factors.
Larval migration downstream from upstream oviposition sites as
well as the influx of migrant females accounted for the repopulation of
streams. Predators and parasites would migrate or drift downstream
also. There is a possibility that the eggs of those species that lay them
singly drift or are washed downstream by the current. It has been re-
ported that inseciticides in the stream induce the larvae to release their
grip and be carried downstream where they perish. In the present study,
laboratory tests of susceptibility of the larvae to DDT indicated the ex-
treme toxicity of the insecticide to the larvae; calculated LC50 was
0. 00213 ppm DDT for 1 hour (pp1 isomer in ethanol). Similarly, high
mortalities resulting from field applications and laboratory tests with
low doses of insecticides have been reported.
Laboratory rearing of simuliids ended with the emergence of the
adults from the pupae. As Wenk (1965) reported, the problems involved
were mating, feeding, and oviposition in the laboratory and these dif-
ficulties were overcome with the discovery of two laboratory mating
species in Europe. All other species fed on blood developed sterile eggs
and oviposited without mating. Eggs dissected out of wild gravid mated
females did not hatch. The latter phenomenon suggests that eggs are
fertilized in the common oviduct prior to oviposition.
Emergence of aquatic as of many other species follows a diel per-
iodicity, c.f. chironomid pupae (Palmen 1958), gall midges (Barnes
1930) and Drosophila (Brett 1955). Davies (1950) studied the factors that
affect the emergence of adult simuliids. There was general agreement
that light intensity was the main stimulus and that emergence was tem-
perature independent, although the temperature exerted some control on
the hourly emergence. I observed that in the laboratory there existed
an attenuated emergence between 10 PM and 3 AM (two hours after sun-
set to about an hour before dawn). In the field the adult yield in the em-
ergence traps dropped considerably after sunset and did not recover ex-
cept at dawn. The variations in these emergence patterns are likely due
Black Flies
165
to temperature fluctuating less indoors than in the stream, or to lights
being on at night. Temperature maybe responsible for initiation of em-
ergence.
Adult activity observations revealed a diurnal periodicity. There
were two peaks of flight activity; the first commenced about two hours
after dawn, continued for three hours after sunrise and the second oc-
curred irregularly two to three hours before sunset and for sometime in
the night. The same pattern of activity was described by Davies (1957)
for S. omatum Mg. Davies (1963) and Wolfeand Peterson (I960) reported
on studies on the nulliparous and parous females concluding that parous
females tended to fly in the late afternoon. Lewis (1958, I960) observed
S. damnosum to fly at noon. My studies were on S. v etuis turn , S. vittatum ,
S. arcticum (mammalophilic species), and S. tetipes and S. aureum (ornitho -
philic species). Sweep-netting near the breeding sites yielded a large
number of nulliparous and a few gravid females and males. The com-
position of the population of females on the wing was varied. The em-
ergence of the adults of a species of any of the above groups changed
the age composition of the flying simuliids. Nulliparous females were
dominant at the beginning of the season (late May and early June). The
number of flies eventually decreased, and the parous females outnumbered
the nulliparous. This pattern continued throughout the season.
Diurnal activity was influenced by the daily weather and meteorol-
ogical conditions as reported by Dalmat (1954, 1955), Davies (1952),
Davies (1957) , Wolfe andPeterson (1959, I960), Wenk (1963, 1965), and
Zahar (1951), which indicated a similarity in different regions. In the
present study no species exhibited any preference for any set of condi-
tions but there was a uniformity in abundance in both periods of activity
with a slight increase in numbers in .the afternoon- evening peak. The
low light intensity, moderate wind and high relative humidity were the
main factors concerned and these were fulfilled in the above periods.
Biotic control agents of simuliids included mermithid nematodes,
microsporidians , and predators. The value of Gregarinida (Protozoa:
Sporozoa) was not investigated as these parasites were not very common.
Microsporidian infections were fatal to the larvae and adults but their
importance as biotic control agents of simuliids was not definite. The
low incidence of infection with this parasite suggested a secondary value.
On the contrary, the mermithid nematodes were efficient parasites reach-
ing 94% in some larval populations (although it maybe said here that in-
fected larvae were slow to migrate and to pupate and this led to isolations
of these populations which contributed to the high rate of infection ob-
served). Host specificity of the nematodes was significant and was con-
sidered a disadvantage from the control viewpoint. The value of the pre-
dators (on the aquatic stages) might not exceed that of the microsporid-
ian infection.
ACKNOWLEDGEMENTS
I would like to express my sincere gratitude to Dr. B. Hocking,
chairman of my committee, who has guided this study, for his helpful
166
Abdelnur
suggestions and his valuable aid in the preparation of this manuscript.
My special thanks are extended to the World Health Organization who
through the Eastern Mediterranean Regional Office provided me with a
fellowship.
I thank Drs. B.V. Peterson (Entomology Research Institute, Ot-
tawa), H.E. Welch (University of Manitoba, Winnipeg) and Messrs. A.
Nimmo (University of Alberta, Edmonton) and F. J.H. Fredeen (Canada
Department of Agriculture, Saskatoon) for help in identification.
I wish to offer my sincere appreciation to Mr. Shewell (Entomology
Research Institute, Ottawa) for the loan of blackfly material, Drs. D.M.
Davies (McMaster University, Hamilton, Ontario), A. Stone (U.S. Nat**
ionalMuseum, Washington D. C. ), A. M. Fallis (Ontario Research Foun-
dation, Toronto), K. M. Sommerman (Arctic Health Centre, College,
Alaska), A. S. West (Queen's University, Kingston, Ontario), K. H.
Rothfels (University of Toronto, Ontario), P. Wenk (Tropical Institute,
University of Tubingen, Germany), H. F. Clifford (University of Alberta) ,
Mr. A. W.R. McCrae (Vector Control Division, Ministry of Health, Ugan-
da), and Mr. R. W. Crosskey (Commonwealth Institute, London, U.K.)
for reprints and helpful notes on the study.
I thank Dr. J. Sharplin, Dr. J. Holmes, and Mr. R. Leech (Univer-
sity of Alberta, Edmonton) for critical reading of this manuscript. Fin-
ally, I would like to extend my gratitude to Colonel and Mrs. Hughes and
Mr. and Mrs. N. Hughes of Flatbush for their kindness and helpful as-
sistance in carrying out this study.
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Quaestiones
entomologicae
A periodical record of entomological investigations,
published at the Department of Entomology, Uni-
versity of Alberta, Edmonton, Canada.
VOLUME IV
NUMBER 4
OCTOBER 1968
QUAESTIONES ENTOMOLOGICAE
A periodical record of entomological investigations published at the
Department of Entomology, University of Alberta, Edmonton, Alberta.
Volume 4 Number 4 11 October 1968
CONTENTS
Editorial 17 5
Krishnan - Lipid metabolism in Blattella germanica L. : composition during
embryonic and post embryonic development 177
Matthews - A paleoenvironmental analysis of three late Pleistocene col-
eopterous assemblages from Fairbanks, Alaska 202
Tawfik - Effects of the size and frequency of blood meals on
Cimex lectularius L 225
Editorial - On the Life and Death of Information
Statements have appeared in print recently concerning the half-life
of biological information which, if they were to be taken seriously, would
make a mockery of our best efforts in publishing this periodical and in-
deed of printing generally. The estimate of this supposed half-life is
put at ten years; the author of the statements would be better employed
at developing a printing ink which would fade to half its intensity in ten
years than in biological research. Think of the forests that could be
saved from the hungry pulp mills; and the waterways from their pollu-
tion. But think too of the damage to the economy.
Does information die? If so, what constitutes its death -- lack of
use? This seems to be analogous to the theory -- moribund, perhaps,
but surely not dead -- of use and disuse as a mechanism of evolution.
But are theories information anyhow? Or hypotheses? Perhaps they
should be regarded as historical information; but we must bear in mind
that history repeats itself. The information recorded by Aristotle has
considerable influence today, at about 2“2 00 of its original strength;
unless perhaps it is only modern information that is so highly mortal.
If this be true it maybe because of our own inadequate use of preceding
information; because, in other words, pur information is not really
new; not, strictly speaking, information at all.
In the physical sciences, and especially perhaps in chemistry, one
hears it said that there is no point in holding back files of periodicals
more than ten years. This may be just wishful thinking on the part of
overburdened librarians; I cannot believe it to be true. To carry such
a proposition over into biology generally, where the very framework of
the subject goes back formally to 1758 and informally to the origins of
recorded information would, of course, be nonsense. No biologist,
surely, would maintain that only 0. 0001% of the information produced
by Linnaeus is "alive" today.
As we all know, in biological research, tenyears is by no means an
unusual time lapse between a discovery and its appearance in print. I
176
once published an account of a piece of work thirty years after doing it --
when it was 87. 5% dead. Gregor Mendel's work, though published, was
not discovered until it was 95% dead-- what an impact it might have had
earlier! Much work, unquestionably, appears before its time, when its
viability must increase with age and its immortality must, I think, be
conceded. Of course there is also much work that produces results of
real interest for a limited time only; new techniques and methods which
will in turn by superseded by others, new hyoptheses which ultimately
prove untenable. Here, it may be legitimate to speak of a half-life, but
preferable to refer to a limited information content; for there are ele-
ments in all such work which will endure. Information, as I see it, en-
dures; applications of it, the clothes it wears, may fade. On a human
time scale, publications endure well, although sometimes one wishes
they wouldn't. If an author feels that his work has a half-life of only ten
years; if he feels that publication is a question of now or never, he should
probably refrain and content himself with telling his friends and col-
leagues about it, for it may be half dead before it appears.
B. Hocking
177
LIPID METABOLISM IN BLATTELLA GERMANIC A L. :
COMPOSITION DURING EMBRYONIC AND POST EMBRYONIC DEVELOPMENT
Y.S. KRISHNAN
Department of Entomology
University of A Iberta Quaes tiones en tomologicae
Edmonton, Canada 4: 177- 204 1968
Changes in the lipid composition of Blattella germanica L. during embryonic and
post embryonic development were investigated by a combination of column, thin-layer
and gas-liquid chromatography . During embryogenesis the loss of dry matter was mainly
due to utilization of triglycerides. Hydrocarbon and sterol content increased slightly.
Mono- and di-glyceride and free fatty acid content increased substantially. Fatty acid
analysis revealed the presence of 17 fatty acids ranging in chain length from Cq to C22-
Oleic acid was the most abundant followed by palmitic acid. Phospholipid content in-
creased during embryonic and post embryonic development. Lecithin, cephalin and
sphingomyelin were the major phospholipids. During nyrnphal development all the lipid
fractions increased approximately in proportion to the increase in body weight. Nymphs
and adults had similar lipid composition.
Lipids include neutral fats, phospholipids, cerebrosides , sterols
and fat soluble vitamins. Many earlier works on insect lipid were res-
tricted to gross quantitative analysis. The chemistry of insect fats has
been reviewed by Timon-David (1930), Scoggin and Tauber (1950) and
Hilditch (1956). In the past decade the volume of literature on the lipid
composition of insects has increased tremendously as is evidenced by the
publication of a number of reviews (Niemierko 1959, Babcock and Ruts-
chky 1961, Gilmour 1961, Kilby 1963, Fast 1964, Gilby 1965, Kinsella
1966b, Gilbert 1967a). The remarkable growth in this field has been
principally due to the development of better analytical techniques. The
advent of thin-layer and gas -liquid chromatography in particular has
enormously facilitated the purification and identification of complex lip-
ids .
Lipids have a high caloric value and their catabolism yields 2. 2 and
1. 6 times as much energy per gram as carbohydrates and proteins, res-
pectively. They also yield twice as much metabolic water which plays
an important role in terrestrial animals. Much of the food eaten by in-
sects during the immature stages is converted into fat and stored in cells
of the fat body.
Blattella germanica L. has long been employed as a subject of physio-
logical and toxicological investigations but lipid biochemistry has been
neglected. My purpose was to investigate the qualitative and quantitative
changes in the lipid composition of B. germanica during embryonic and
post embryonic development.
178
Krishnan
REVIEW OF LITERATURE
Embryonic Stages
During embryonic development important qualitative and quantita-
tive changes may occur in the lipid fraction. In insects, neutral gly-
cerides serve as the major energy source. Needham (1931) proposed a
theory of a succession of energy sources during ontogeny; the embryo
first utilizing carbohydrate primarily, then protein and finally fat.
A number of studies on lipid content of orthopteran eggs indicate
that, in general, the lipid content ranges from 2. 5 to 14% of the wet
weight. The lipid concentration declines during development of the em-
bryo. A large part of the loss appears to be in the triglyceride fraction;
lipids are the major source of energy for the developing embryo. The
greatest loss of lipids occurs during the later stages of development.
Probably the earliest work on the lipid content of an orthopteroid
egg was that of Dubois (1893), who reported that newly laid eggs of the
Algerian locust, Acridium peregrinum Oliv. contain 4 to 5% fatty material
(wet weight basis) and this was considerably reduced during development.
No quantitative estimate of the loss was given. Slifer (1930) reported
that 9 to 12% of the wet weight of the newly laid eggs of Melanoplus differentialis
(Thomas) was fatty acid. During embryogenesis 54% of the initial fatty
acid reserve was catabolized. Most of the loss occurred in the post
diapause period. The iodine value remained constant during embryonic
development. This was confirmed by Boell (1935) and Hill (1945). On
the basis of respiratory studies, Boell (1935) calculated the loss of fatty
acids as 67% of the initial store. Hill (1945) showed that carbohydrate
formed the major energy source during the first 5 days of development.
Protein and fat were chiefly used in the prediapause and diapause per-
iod. During post diapause fat catabolism accounted for 90% of the oxygen
consumed.
Carausius (Dixippus) morosus (Br. and L. ) used 26% of the lipid reserve
during embryonic development and the fat content was reduced from 31%
of the dry matter to 23% at the time of hatching (Lafon 1950).
Blackith and Howden (1961) and Allais et al. (1964) recorded loss
of lipids during embryogenesis in Locusta migratoria (L. ). The latter authors
observed that lipids accounted for 26% of the dry weight in the newly
laid eggs (78.5% triglycerides, 19.5% phospholipids and 2% sterols) and
showed a total decrease of 31.2 % to form 20. 7% at the end of embryonic
development (triglycerides 66%, phospholipids 19. 5% and sterols 3%).
They concluded that this decline in lipid content was due only to catabo-
lism of triglycerides . Phospholipids consisted chiefly of lecithins (70. 5%)
and cephalins (26. 5%) and a small amount of sphingomyelin. The phos-
pholipid content increased by 60% during embryogenesis, but no quali-
tative changes were observed. Sterol content remained constant and for
the most part was in the free form.
Kinsella and Smyth (1966) and Kinsella (1966a, c, d) made an exhaus-
tive study of the lipids of Periplaneta americana L. During embryogenesis ,
total extractable lipids decreased from 39.5% to 23. 2% of the dry weight,
mainly due to catabolism of the triglyceride fraction. There was an in-
crease inthemono- and di-glyceride fractions (Kinsella and Smyth 1966) .
Lipid Metabolism
179
Sterol content remained constant during development. The sterol esters
of newly extruded oothecae contained mainly palmitic, stearic, oleic and
linoleic acids. Palmitic and stearic acid content decreased during dev-
elopment (Kinsella 1966d). Sphingomyelin, lecithin and cephalin are
the major phospholipids. Small amounts of lysolecithin, phosphatidyl
inositol and cerebroside were also found. Total phospholipid content
increased fourfold during development. Sphingomyelin and cephalin con-
tent tripled and lecithin content doubled (Kinsella 1966a). There was
close similarity in the fatty acid composition of the total lipid, neutral
lipid and triglyceride fractions. Palmitic, stearic, oleic and linoleic
acids content accounted for 95% of the total fatty acids. The phospho-
lipid fraction, however, had a greater amount of linolenic acid (Kinsella
1966c).
The lipid picture for the period of embryogenesis in Leucophaea maderae
(Fabr.) was characterized by a decreasing content of embryonic trigly-
ceride and an increasing proportion of phospholipids (Gilbert 1967b).
Post Embryonic Stages
The lipids of post embryonic stages of orthopteroid insects vary over
a wide range (1.7 to 16% of the wet weight). The immature stages, in
general, have a higher lipid content.
T sujimoto (1929) analyzed the fat of Oxya japonica (F abr . ) . This species
contained 3% fat (dry weight basis) and had a saponification number of
175, an iodine value of 122.6and 15 . 7% unsaponifiable matter . Palmitic,
stearic, oleic and linoleic acids were identified. Seventy-five per cent
of the fatty acids were unsaturated. Body lipids of Acheta mitrata constituted
2.4 % of the fresh weight. Unsaponifiable matter made up 11. 3% of this
and contained 45. 5% sterols.
Sacharov (193 0) reported that 3 to 5 day old nymphs of L. migratoria
contained 2.8% fat. Matthee ( 1945) investigated some of the biochemical
differences between the solitary and gregarious phases of L. migratoria and
Locusta pardalina Walk. The fat content of L. migratoria solitaria adult was 11. 0%
of the dry weight and increased to 14. 0% in L. migratoria gregaria . Similarly
the fat content of the solitary phase adults of L. pardalina increased from
12.8 to 14.6% (dry basis) in the migratory phase. Fawzi, Osman and
Schmidt ( 196 1) recorded a much higher fat content in the migratory phas e
of L. migratoria ; 10. 4% of the wet weight in females and 14. 6% of the wet
weight in the males.
The lipid content of the German cockroach, B. germanica was studied
by Mellampy and Maynard (1937). The lipid content of the nymphs, fe-
males with egg capsules and males was 5. 7, 4. 8 and 1. 7% of the wet
weight respectively. The Iodine Number was 69 for the nymphs and 74
for the females and males. In a later study McCay (1938) reported that
of the dry weight of adults 15. 6 to 17. 1% was ether extractable material.
Lipid content of P. americana adults has been studied by a number of
investigators. Schweet (1941) reported that the lipid content of adult
females and males was 28. 6 and 25. 5% of the dry weight. According to
Munson and Gottlieb (1953) the lipid content of the nymphs, adult males
and females was 7. 7%, 7. 1% and 8. 9% of the wet weight respectively.
Siakotos and Zoller (I960) and Kinsella and Smyth (1966) reported that
180
Krishnan
30% of the dry matter was lipids. Lofgren and Cutkomp (1956) recorded
much lower values, 13. 9% and 14. 5% of the dry weight in females and
males. Kinsella (1966a, c, d) compared the lipid composition of the
nymphs and adults with those of the various stages of the embryo. The
lipid composition of nymphs and adults was quite similar. Neutral lipid
accounted for 75% of the total lipids. Lecithin, cephalin and sphingo-
myelin were the predominant phospholipids in that order of abundance
(Kinsella 1966a). The fatty acid pattern of the various lipid fractions
was similar to those found in the embryo (Kinsella 1966c).
On a wet weight basis, the adults of the grasshopper Melanoplus atlanis
Riley consisted of 0. 8% neutral fat and 2.4% fatty acids (Giral, Giral and
Giral 1946). The free fatty acids consisted of stearic, palmitic, ara-
chidic, and unsaturated C16, Cl8, C20 and C22 acids. Linolenic acid
was not present but triethenoic acids of the C2O-C22 series appeared to
be present. The polyunsaturated acids with more than 18 carbons were
present in large amounts (46. 2% of the total fat).
Components of the body fat of Taeniopoda auricomis Walk, was reported
by Giral, Giral and Giral (1943). Fatty acids of the females consisted
of 35% saturated acids, 6. 5% oleic acid and 58. 5% linoleic acid. Fatty
acids of the males contained 15. 5% saturated acids, 24. 0% oleic and
60. 5% linoleic acid. The lipids of the females contained 5. 1% unsaponi-
fiable matter; of the males 6. 5%.
Giral ( 1946) found that the lipids extracted from the adults of Sphenarium
purpurescens (Charp. ) contained a very high proportion of free fatty acids.
Glycerides were present in very small amount. The fatty acids consisted
of 22. 1% saturated acids, 9.6% palmitoleic acid and 35.5% oleic acid.
Of the fatty acids, 25. 8% had a chain length of more than 18 carbons.
Barlow (1964) found that palmitic, oleic, linoleic and linolenic acids
accounted for 95% of the fatty acids in the body fat of Melanoplus sanguinipes
(Fab.).
MATERIALS AND METHODS
Laboratory Rearing of the Roaches
The roaches were fed rabbit pellets (3. 5-4. 5% lipids) and were
kept in battery jars with pieces of folded paper which served as resting
and hiding space. A one pound narrow mouthed jar was used as a water
reservoir and a cotton wick was provided, the upper end being wrapped
with absorbent cotton to make it fit tightly in the mouth of the bottle.
Water and food was replenished once every three weeks. The roaches
were raised at a temperature of 30 ± 1 C. Two to three hundred indi-
viduals were raised in one jar and adults were collected once every three
days. Adults collected on the same day from different jars were pooled,
maintained under the same conditions as described above, and used for
lipid analysis after one week.
Extraction and Purification of Lipids
The procedure of F oleh, Lees and Sloane -Stanley (1957) was followed.
The insects were placed in a glass vial with 20 volumes of a chloroform:
Lipid Metabolism
181
methanol mixture (2: 1 v/v) and homogenized in a Potter-Elvehjem homo-
genizer for 30 minutes and filtered through a sintered glass funnel into
a glass stoppered vial. The filtrate was shaken for 3 to 4 minutes with
0.2 volumes of 0.90% sodium chloride solution. The mixture was centri-
fuged for 5 minutes at 400 g and the upper methanohwater : salt layer was
removed with a fine pipette. To ensure complete removal of the solutes
in the upper phase, the interphase was rinsed three times with a small
volume chloroform:methanol: saline (3:47:48 v/v/v). The lower phase
was evaporated to dryness in a rotary flash evaporator, dissolved in a
small volume of chloroform and stored at -10 C under nitrogen until fur-
ther use.
Separation of Lipid Class Spectrum
The total lipid extract was placed on a 30 g silicic acid:Hyflo super
cell column (2:1 w/ w; column dimensions 2. 2 x 14 cm) and eluted first
with 200 ml of chloroform to obtain the neutral lipids. The phospholipids
retained on the column were then eluted with 200 ml of chloroformimeth-
anol (1:1 v/v) mixture. The eluates were then evaporated to dryness and
weighed. The neutral lipid fraction was then placed on a 30 g de-activated
florisil column (2.2 cm x 15 cm) and the lipid classes were eluted ac-
cording to the method of Carrol (1961). The solvents of the isolated li-
pid classes were first removed in a flash point evaporator and were then
placed in a vacuum oven at 40 C in tared planchets and the solvents re-
moved. The planchets were reweighed to obtain the weights of the indi-
vidual classes. The efficiency of the separation of these classes of com-
pounds was checked by thin-layer chromatography (Mangold 1961).
Analysis of Fatty Acids by Gas Liquid Chromatography
Aliquots of lipid fractions were transmethylated by refluxing in 5 ml
of 5% sulfuric acid in dry methanol (w/ v) for 3 hours (Patton, Durdan and
McCarthy 1964). An equal volume of distilled water was added and the
methyl esters extracted three times with a small volume of redistilled
petroleum ether (30-60C). The combined ether extract was dried over
anhydrous sodium sulfate and the petroleum ether removed under a stream
of nitrogen. The methyl esters were then dissolved in a small volume
of spectranalyzed n-hexane and small aliquots were used for separation
by gas -liquid chromatography.
Qualitative and quantitative analyses of fatty acid methyl esters were
made with a Beckman Model GC 5 Gas Chromatograph equipped with a
dual hydrogen flame ionization detector . Copper columns (15* long, 1/8"
O D) containing Chromosorb P (60-80 mesh) coated with DEGS (diethylene
glycol succinate, 20% by weight of the solid support) were used. Since
the column was continuously maintained at 200 C, the amount of liquid
phase in time was reduced. This resulted in reduction of retention time.
Standard methyl esters of fatty acids for comparative purposes and quan-
titation were obtained from Mann Research Laboratories . Unknown peaks
were tentatively identified by logarithmic plot by the method of James
(1959).
182
Krishnan
Thin Layer Ghromatography of Phospholipids
Phospholipid content was determined by silicic acid Hyflo super
cell chromatography. The individual phospholipid classes were sep-
erated by thin-layer chromatography on 0. 5 mm thick Silica gel G plates
according to Wagner, Horhammer and Wolff (1961). The developing
solvent was chloroform:methanol:water (65:25:4 v/ v) . The developing
chamber was lined with filter paper saturated with the solvent mixture.
Following the chromatographic run, the thin-layer plates were air dried
and exposed to iodine vapour for visualization of the phospholipids . Iden-
tification of the individual phospholipid was accomplished by comparison
of the Rf with those of pure standards obtained from Applied Science Lab-
oratories, State College, U.S.A. and specific color reactions. Quanti-
tation of the major phospholipids was based on the phosphorus content,
determined colorimetrically according to the method of Bartlett (1959).
Three determinations were made for each stage.
RESULTS
Dry Matter Content
The wet weight, dry weight (obtained by drying at 100 C) and water
content of the ootheca, nymphs and adults of the German cockroach are
given in table 1. The proportion of water in the egg was initially
about 62%. This remained constant during the first five days of embryonic
development and increased to about 75% by the 15th day. When calculated
on a per egg basis, the wet weight of the egg increased from 1. 276 mg
to 1.617 mg, while the dry matter decreased from 0.486 mg to 0.399
mg (table 2). There was a slight drop in the per cent water content be-
tweenthe 1st and 3rd nymphal instar s . In the subsequent nymphal instars
and the adult water content remained more or less constant.
Total Lipids
Table 2 reveals that the total lipid content of the eggs decreased
during embryonic development. The newly formed eggs, on anaverage,
contained 0. 178 mg of lipids which in 15 days of embryonic development
decreased to 0. 112 mg, representing a loss of 37% of the original lipid
component. During the first 5 days of embryonic development, lipid
catabolism accounted for 50% of the loss of dry matter; between the 5th
and 10th day 56% of the loss of dry matter was due to lipid loss; nearly
all of the dry matter loss between the 10th and 15th day of incubation was
due to lipid utilization. This indicates that during the early part of em-
bryonic development, some other component(s) must have beenused for
fulfilling the energy requirements.
There was a progressive increase in the amount of lipids per indi-
vidual insect as the development of the nymphs proceded, reaching a max-
imum in the 6th instar (table 2). However, the lipid content dropped con -
siderablyin the adult stage. The females had twice as much lipid as the
males .
Lipid Metabolism
183
TABLE 1. Wetweight, dryweightand water content at thevarious stages
of embryonic and post embryonic development of B. germanica ,
means ±S.D. based upon 10 replicates.
Lipid Class Spectrum
At the beginning of embryonic development the neutral lipid consti-
tuted 94. 6% of the total lipid, but by the time the eggs were 15 days old,
it decreased to 86% of the total lipid content (table 2). Embryonic dev-
elopment resulted in a 43% loss of the neutral lipid reserve. During
nymphal growth the neutral lipid content per individual increased more
or less proportionally to the increase in body weight, reaching a maxi-
mum in the 6th instar. The adults have a lower neutral lipid content than
the last instar nymphs.
The neutral lipid was fractionated into the following classes: hydro-
carbons, free sterols, sterol esters, triglycerides, diglycerides, mono-
glycerides and free fatty acids. Table 3 is a summary of the analyses
conducted at the various stages of development. The values are based
on three analyses for each stage. This table shows that the neutral lipid
fraction consisted predominantly of triglycerides in all the stages. Dur-
ing embryonic development the level of triglyceride fell from 94% to 76%
of the neutral lipid fraction. Gravimetrically there was a 54% loss of the
triglyceride content. The loss in the triglyceride content (2. 58 mg) was
greater than the loss of dry matter (2.51 mg) and neutral lipid (2. 16 mg) .
The proportion of mono- and di-glyceride as well as the free fatty acid
content increased considerably during incubation. Quantitatively (table
4) the mono- and di-glyceride content increased 6 and 10 times of the
TABLE 2. Wet and dry weight, total lipid, phospholipid and neutral lipid content per individual during embryonic
and post embryonic development of B. germanica L.
184
Krishnan
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Values presented are means of 10 replicates. These data appear also in table 1.
Values presented are means of 3 replicates.
Lipid Metabolism
185
initial concentration per individual respectively. The free fatty acid con-
tent increased 7 fold.
TABLE 3. Proportion of various lipid classes in the neutral lipid frac-
tion of the German cockroach (% of neutral lipid fraction),
means of three replicates for each stage.
F ree
The relative proportion of the various fractions remained more or
less constantin all the nymphal stages. Quantitatively, all the fractions
increased in each successive nymphal instar (table 4). Adult females
had a neutral lipid class spectrum similar to the nymphs. Adult males
had a slightly lower triglyceride level compared toother post embryonic
stages.
Sterol content was the same on day 5 as on day 0 of embryonic dev-
elopment. There was a drop between the 5th and 10th daybutan increase
to a higher amount by the 15th day (table 4). The proportion of esteri-
fied sterol progressively increased from 26% in the newly formed oothecae
to 48% in the 15 day old oothecae (table 3). Total sterol content in-
creased in successive nymphal instars. The proportion of free and es-
terified sterol fluctuated. Sterol of females was predominantly in the
esterified form while in the males the free forms predominated.
Hydrocarbon content increased gradually at successive developmental
stages of the embryo. During nymphal development, the increase in the
hydrocarbon content more or less paralleled the increase in the total
TABLE 4. Lipid class spectrum of the neutral lipid fraction during various stages of B. germanica , means of three
replicates. Weights in mg per ootheca, nymph, and adult.
186
Krishnan
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Lipid Metabolism
187
lipid content.
Phospholipids
The total phospholipid present in each stage is shown in table 2.
The per cent phosphorus content of the major phospholipid fractions
(lecithins, cephalins and sphingomyelin) at various stages of development
are recorded in table 5. From this the amount of the major phospholipid
fractions (in terms of phosphorus content) were calculated and shown in
table 5.
During the embryonic development total phospholipid content as well
as the three major fractions increased. The proportion of phospholipid
at the beginning of embryonic development averaged 6% of the total lipid
content. In the 15 days of embryonic development it rose to 13% of the
total lipid. Gravimetrically the total phospholipid content increased one
and a half times. This indicates a synthesis of phospholipids. Once the
nymphs had started feeding, the increment in the phospholipid content
was in proportion to the increase in total fat content. During the six
subsequent nymphal instars the level of phospholipids remained nearly
constant at about 18% of the total lipids.
Phosphatidylcholine (lecithin) and phosphatidyl ethanolamine (ceph-
alin) were the principal phospholipids. In addition to the above two and
sphingomyelin, which were quantitated, phosphatidyl serine, phosphatidyl
inositol, lysolecithin and phosphatidic acid were detected in trace amounts
in all stages studied. During embryonic development the lecithin/ cephalin
ratio decreased. However, the total increase in lecithin content was
greater than the increase in cephalin. The relative proportion of the
three major phospholipid fractions remained constant in the nymphal
stages. Based on lipid phosphorus, the percent composition of lecithin,
cephalin and sphingomyelin was 57, 33 and 6%o respectively. The leci-
thin/cephalin ratio varied from 1.63 to 1.77. The phospholipid compo-
sition of males and females was similar.
Fatty Acid Composition
Figure 1 shows an analysis of fatty acids from an adult female sam-
ple. This analysis revealed the presence of 17 fatty acids ranging in
carbon chain lengthfrom 6 to 22. Of these C14.0, C^.^, C^g-g,
Ci8: i> C 18:2’ and Cl8:3 mixed with C200 were quantitated. With the
columnused C18;3and C20:0COU1<1 not be separated. Table 6 represents
a summary of the gas chromatographic analysis of the fatty acids in the
total lipid extract at 12 different stages of development.
Oleic acid (Cig:l) was the largest component in all the stages and
accounted for 42 to 48%) of the total fatty acid fraction (table 6). Palmitic
acid (Cib;o) was next in order of abundance. About 7 0%o of the fatty acids
were unsaturated. Besides oleic acid, linoleic acid (C^g.2) was present
in fair amount (16 to 19%o). Of the remaining 3 0%o saturated fatty acids,
palmitic acid (C^g-g) was the most abundant (25 to 3 0%o).
The proportion of myristic acid (C^q-g) in the nymphs and adults
was three times as much as in the embryonic stages. Palmitic acid
content in the 0 and 5 day old oothecae was quite similar but it dropped
to a lower percentage in the 10 and 15 day old oothecae. The reverse
TABLE 5. Changes in the distribution of lipid phosphorus and phospholipid fractions during embryonic and post
embryonic development of B. germanica , means of 3 replicates.
188
Krishnan
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Lipid Metabolism
189
was the case with oleic acid. The percentage of the remaining major
fatty acids were quite similar in all the fatty acid composition between
sexes. During nymphal growth, the proportion of palmitic and palmi-
toleic acid increased, but the proportion of linoleic and linolenic acid
decreased.
18 20 22 24 26 28 30
Fig. 1. Gas chromatographic separation and identification of fatty acid
methyl esters of total lipids of adult female B.germanica . C6:0 caproate;
C8:0 caprylate; Ci0:0 caprate; Cl2:0 laurate; Ci4:o myristate; Cl4:l
myristoleate; Cl6:0 palmitate; Cig. 1 palnoitoleate; C^7;o heptadecanoate;
Ci7;i heptadecenoate; Ci8:0 stearate; C^g:l oleate; Cig:2 linoleate;
Ci8;3 linolenate; C20-0 arachidate . Instrument Settings: Column, 15* x
1/8" OD, 20% diethylene glycol succinate on Chromosorb P; Detector,
hydrogen flame ionization; Detector temperature, 240 C; Injection port
temperature, 250 C; Column temperature, 200 C; Hydrogen flow rate,
25 ml per minute; Carrier gas and flow rate, helium 40 ml per minute.
TABLE 6. Fatty acid composition of the total lipid extract of B. germanica L. at various stages of the life cycle.
190
Krishnan
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Lipid Metabolism
191
Fatty acids contained in the isolated neutral and phospholipid frac-
tions of the 4th instar nymphs, adult males and females were also sep-
arated by gas -liquid chromatography. Qualitatively there was no dif-
ference between the three types of lipids. Only 8 fatty acids were quanti-
tated. Table 7 shows the relative proportion of these fatty acids. A
comparison of the data shows that the proportion of these fatty acids in
the neutral lipid fraction approximated the composition in the total lipid
extract in all the 3 stages studied. Fatty acid composition of phospholipid
fraction showed some differences. The proportion of myristic, palmitic
and palmitoleic acids was reduced to half the relative proportion of these
acids in total and neutral lipid fractions. The proportion of linoleic acid,
on the other hand, was doubled. The phospholipid also contained slightly
higher proportion of linolenic and arachidic acids. The fatty acids of
the neutral lipid fraction had a higher proportion of saturated fatty acids
(40%) than phospholipids (28%).
TABLE 7. Percent fatty acid composition of the total lipid, and isolated
neutral and phospholipid fractions of B. germanica . *
Stage
4th instar nymph Adult males Adult females
Fatty
* Values presented are the means of 3 replicates. TL - total lipid ; NL - neutral lipid;
PL - phospholipid.
Cl 4:0 myristic acid; C 18:0 palmitic acid; C]6 i palmitoleic acid; Cl 8:0 stearic acid;
Cl 8:1 oleic acid; Ci8;2 linoleic acid; Cl 8:3 linolenic acid; C20:0 arachidic acid.
192
Krishnan
DISCUSSION
Data presented indicate a progressive increase in the wet weightand
a decrease in the dry matter content during embryogenesis. The changes
reported here agree, in general, with those of Roth and Willis (1955a,
b). Ross (1929) and Parker and Campbell (1940) suggested that the wall
of the ootheca of B. germanica in contact with the female's genital pouch
may be permeable to water. Rothand Willis (1955b) demonstrated a dif-
ference in permeability between the anterior and posterior end of the
ootheca of B. germanica . The anterior end, held by the female is lighter
in color and less sclerotized, was more permeable. They concluded
that the increase in wet weight was due to absorption of water from the
female. A similar phenomenon has been observed in Blattella vaga Hebard
(Roth and Willis 1955b) and Diploptera dytiscoides (Serv. ) (Roth and Willis
1955c).
The loss of dry matter was accompanied by a loss in the total lipid
content. On the average, 75% of the loss of dry matter was accounted
for by lipid catabolism. Many workers who studied the embryonic period
have found that fat forms the main source of energy of the developing
embryo (Tichimirov 1885, Rudolfs 1926, Fink 1925, Slifer 1930, Busnell
1937, Lafon 1959, Rainey 1950, Rothstein 1952, Gilbert and Schneider-
man 1961, Kinsella and Smyth 1966, Gilbert 1967b). The only exception
was Tenebrio molitorL,. which utilized glycogen for energy requirements
(Ludwig and Ramazzotto 1965). The loss in the initial lipid supply was
comparable to the general average of 55% reported by Needham (1931)
for various terrestrial animals.
A comparison of the neutral lipid content of newly extruded ootheca
and 15 day old ootheca shows a 43% reduction of the initial supply. Of
the various lipid classes of the neutral lipids, only triglyceride shows
considerable reduction. There is an increase in the mono- and di-gly-
ceride content. These findings agree with those of Slifer (193 0), who
showed that 54% of the neutral lipids are catabolized by M.differentialis dur-
ing embryonic development. Tichimirov (1885) observed that neutral
glyceride fatty acids diminished by 46% during embryonic development in
Bombyx mori. Malacosoma americam (Fab.) utilized 87% of neutral lipids during
incubation (Rudolfs 1926). Gilbert and Schneiderman (1961) reported
that the moth Hyalophora cecropia (L. ) catabolized 57% of the initial neutral
lipids during incubation. The Japanese beetle, Popillia japonica Newman
loses 58% of the initial neutral lipid content during incubation, Allais
et al. (1964) showed 53% loss of neutral lipidmoiety. Kinsella and Smyth
(1966) and Gilbert (1967b) observed 55% loss of neutral lipids during em-
bryogenesis in P. americana and L. maderae „
In the present work it has been shown that the hydrocarbon and sterol
content increased only slightly. With the development of the embryo,
the proportion of the esterified sterols increases. Tichimirov (1885),
Allais et al. (1964) and Gilbert (1967b) reported similar findings during
embryonic development of Bombyx mori (L. ), L. migrator ia and L. maderae
respectively, whereas Rudolfs (1926) reported that the cholesterol in the
eggs of M. americana disappeared by the time of hatching. Kinsella (1966d)
and Gilbert (1967b) also observed an increase in the proportion of esteri-
Lipid Metabolism
193
fied sterols during incubation. The more or less constant sterol content
ties well with the theory that insects lack the ability to synthesize sterols
(Black et al. 1956). However, it is rather difficult to correlate it with
the known function of sterols, being a major constituent of cellular mem-
branes. During morphogenesis, it would be expected to increase, unless
the sterol stored in the yolk is sufficient to meet the requirements for
membrane formation.
During nymphal growth and in the adults the sterol content increases
in proportion to the increase of the total fat content. It has been shown
that some dietary sterols canbe converted into cholesterol(Gilmour 1961).
During nymphal development, all the lipid fractions increase. In
order to compare the rate of increase of lipids with that of wet weight,
log of wet weight and log of total lipids of the different nymphal instars
were plotted and a straight line was drawn. The total amount of fat was
related to the wet weight by the equation y = b x^1, where k is known as
the heterauxetic constant. The same formula may also be written in the
logarithmic form log = log b + k log x. The value of k was close to 1
indicating that the rate of accumulation of fat during nymphal growth
occurs more or less at the same rate as that of the total body weight.
Similarly, k values were calculated for neutral lipids against total lipids,
phospholipids against total lipids, triglycerides against neutral lipids,
sterols with neutral lipids and hydrocarbons with neutral lipids (fig. 2a-
h) . In all the cases the k value.was close to unity indicating that all the
rate of increase of each fraction paralleled the increase in the other
fraction. In holometabolous insects, on the other hand, the k value is
greater than unity (Finkel 1948, Fast 1964) indicating that the weight of
lipid increases more rapidly during larval growth than the total weight.
Accumulation of large amount of fat is advantageous for holometabolous
insects, because considerable energy is required for transformation into
adult. In addition many adults do not feed and depend upon fat reserves.
The fatty acid composition of B. germanica closely resembles that of
P. americana (Kinsella 1966c) . The predominance of oleic acid and palmitic
acid is in conformity with other insects (Fast 1964). Only aphids and
coccids are peculiar in having a large proportion of myristic acid and
low level of oleic acid (Strong 1963, Barlow 1964, Fast 1964). Only trace
amounts of fatty acids having carbon chain length more than 20 were
found in B. germanica . This is in agreement with the observations of most
workers. Giral (1946) and Giral, Giral and Giral (1946) reported 25. 8%
and 46. 2% of fatty acids were more than 2 0 carbon chains long in S.
purpurescens and M. atlanis respectively. Albrecht (1961) reported 72%
stearic acid in Schistocerca gregaria Forsk. whichis a very high value when
compared with the iodine number. Usually stearic acid content in in-
sects is lower than 10% (Fast 1964).
The fatty acid composition of all the nymphal instars and the adults
are quite similar. These results may be interpreted to mean that there
is no selective synthesis or accumulation of any fatty acids during nym-
phal growth.
The loss in triglyceride is greater than dry matter loss during em-
bryonic development. It is possible that part of the triglycerides are
hydrolyzed to 1, 2 diglyceride and utilized for the synthesis of phospho-
Log phospholipid (mg/nymph) Log total lipid (mg/nymph)
194
Krishnan
Fig. 2 (a-d). Double-log plot of (a) total lipid against wet weight; (b)
neutral lipid against wet weight; (c) phospholipid against wet weight and
(d) neutral lipid against total lipid. Graphs are from data in table 2.
Log hydrocarbons (mg/nymph) Log phospholipid (mg/nymph)
Lipid Metabolism
195
Fig. 2 (e-h). Double-log plot of (e) phospholipid against total lipid; (f)
sterols against neutral lipid; (g) hydrocarbons against neutral lipid and
(h) triglycerides against neutral lipid. Graphs are from data in table 2
and 4.
196
Krishnan
lipids via phosphatidic acid. Part of the loss is accounted for by the in-
crease inmono- and di-glyceride content during embryonic development
(Kinsella and Smyth 1966, Gilbert 1967b). The fatty acids released from
the glycerides may be oxidized completely or utilized for the synthesis of
sterol esters.
The phospholipid content increases during embryonic and post em-
bryonic development. During incubation, the increase in the proportion
of phospholipids has been shown to be partially due to synthesis and par-
tially due to utilization of triglycerides for energy requirements . Phos-
pholipids are parts of cellular and subcellular membranes (Ansell 1964)
and hence will increase during morphogenesis. Similar lipid patterns
have been reported by Tichimirov (1885) in M. americana ; by Pearincott
(I960) in Musca domestical^. ; Bieber et al. (1961) in Phormia regina (Meigen);
Allais et al. (1964) i n L. migratoria ; Kinsella (1966a) in P. americana ; and
Gilbert (1957b) in L. maderae .
The relative proportion of the three major phospholipid classes
lecithin, cephalin and sphingomyelin was quite similar to that reported
by Allais et al. (1964) in A migratoria and Siakotos and Z oiler (I960) and
Kinsella (1966a) in P. americana . Many dipterans are characterized by
the predominance of cephalin over lecithins (Fast 1964).
When calculated on a per individual basis, the lipid phosphorus con-
tent increased throughout development as a result of incorporation of
non-lipid phosphorus into the phospholipid fraction. Chojnacki (1961)
and Chojnacki and Piechowska (196 1) studied the mechanism of synthesis
in Celerio euphorbiae (Fab. ) and found it to be similar to biosynthesis inver-
tebrate liver. Phosphocholine (or phosphoethanolamine) is activated by
reaction with cytidenetriphosphate to yield cytidinediphosphate- choline
(or ethanol-amine) intermediate which then reacts with a, b diglyceride
to yield choline (or ethanolamine) phosphatide.
The three roach species whose lipid metabolism during embryo-
genesis has been studied, have different oviposition habits. In P. americana
the ootheca is extruded and carried by the female for only a short period
and then deposited. In B. germanica the ootheca is extruded and carried by
the female until the eggs hatch. In L. maderae the ootheca is extruded, then
subsequently retracted into a brood sac until or shortly before hatching
(Roth and Willis 1954). The incubation period of P. americana is twice as
long as that of the other two species. The lipid metabolism pattern is,
however, similar in all the three species. Thus oviposition or incuba-
tion period has very little effect on lipid metabolism.
SUMMARY
During the embryonic development of B. germanica there is an increase
in the moisture content and a decrease in the dry matter and lipid content.
The reduction in the lipid content was due to catabolism of triglycerides.
The neutral lipid and triglyceride content decreased by 43% and 54% res-
pectively. The decrease occurs mostly in the second half of development.
On the other hand, the mono- and di-glyceride content increased through-
out incubation. Phospholipid content increased by 60% during embryo-
Lipid Metabolism
197
genesis. The major components of the phospholipid fraction are phos-
phatidyl choline, phosphatidyl ethanolamine and sphingomyelin. In ad-
dition phosphatidyl inositol, lysolecithin and phosphatidic acid were pre-
sent in small amounts. Hydrocarbon and sterol content showed slight
increase. With the progress of embryonic development the proportion
of esterified sterols increased. The overall decrease of 75% of the in-
itial lipid store shows that lipids play a dominant role in fulfilling the
energy requirements of developing eggs.
During nymphal development, the insect accumulates large amounts
of lipid. Increase in the total lipid, neutral lipid and phospholipid con-
tent is proportional to the increase in the wet weight of the body. Though
the adults had a lower fat content than the last instar nymphs, the lipid
patterns are similar. In all the stages studied, triglycerides were the
predominant fraction.
Fatty acid analysis of the phospholipid, neutral lipid and total lipid
extracts revealed the presence of 17 fatty acids during all stages of the
life cycle ranging in carbon chain length from 6 to 22. Palmitic, oleic
and linoleic acids were the major fatty acids. Unsaturated fatty acids
predominated in the various fractions with oleic acid comprising about
45% of the total fatty acids in all the fractions studied. Palmitic acid
was the second most abundant in the neutral lipid fraction, but linolenic
was the second most abundant in the phospholipid fraction. Fatty acids
of the phospholipids were more unsaturated than the fatty acids of the
neutral lipids .
ACKNOWLEDGEMENTS
I thank Dr s. W. G. Evans, R. H. Gooding and B. Hocking, Department
of Entomology, and Dr. J. P. Bowland, Department of Plant Science,
University of Alberta, for their valuable suggestions and discussion
during the course of this study and for comments on the manuscript.
Many thanks also go to Dr. S. Krishnamurthi, Department of Animal
Science, University of British Columbia, and Dr. D. Hadjijev and Dr.
P.V. Sane, Department of Plant Science, University of Alberta, for many
discussions and much help.
This work was partly financed by Fellowships from Cyanamid of
Canada and the University of Alberta which are gratefully acknowledged.
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A PALEOENVIRONMENTAL ANALYSIS OF
THREE LATE PLEISTOCENE COLEOPTEROUS ASSEMBLAGES
FROM FAIRBANKS, ALASKA
JOHN V. MATTHEWS, JR.
Department of Geology
University of Alberta
Edmonton, Canada
Quaestiones entomologicae
4:202-224 1968
Fossils of beetles (Order Coleoptera) and other insects are abundant in Pleistocene silts
and peats from interior Alaska. Three Wisconsin age silt samples from the Eva Creek expo-
sure near Fairbanks, Alaska were examined for their content of fossil insects. A study of the
coleopterous fauna - and primarily the carabid (ground beetle) portion of the coleopterous
fauna - of each of these samples revealed that at the time of their deposition the environ-
ment of Fairbanks, Alaska was similar to alpine tundra at higher elevations or coastal tundra
in other parts of the state. This conclusion concerning the paleoenvironment of lowland in-
terior Alaska agrees with conclusions reached by the author and other workers after exam-
ination of fossil pollen spectra and fossil mammals from the Eva Creek mining cut and
similar exposures near Fairbanks. Minor variations among the three coleopterous assem-
blages are provisionally related to local environmental differences rather than to changes of
the macroclimate of interior Alaska during Wisconsin time.
Like the Quaternary peats and organic silts of Europe, the frozen
colluvial silts exposed by placer gold mining in Alaska contain abundant
fossils of insects — predominately beetles (order Coleoptera) . InEurope
fossil insects have created interest for a long time (see Frey (1964) for
a review of the early literature) ; however, only within the last ten years
have such fossils become important for the study of paleoenvironments .
Well preserved fossil insects occur in silts and peats in Alaska and
Canada yet no paleoenvironmental studies such as those by G. R. Coope
in England (Coope 1965) have thus far been published. This paper rep-
resents an initial attempt to interpret Pleistocene environments in Alas-
ka using the evidence derived from insect fossils.
Previous Investigations
The success of Pleistocene insect studies in Europe is largely due
to the efforts of G. R. Coope and his associates F.E. Shotton and P. J.
Osborne at the University of Birmingham, England. This team has gained
valuable insight to the glacial, interstadial, and interglacial climates of
England since the mid-Pleistocene by comparing the former distributions
of fossil Coleoptera with the distributions of their modern counterparts
(Coope 1962; Coope 1965, general summary; Coope et al. 1961; Shotton
and Osborne 1965). Similar studies have been carried out at Cambridge
University by R. Pearson (1962, 1963).
Coleopterous Assemblages
203
Coope began his studies "blissfully unaware " of the doubts which
many entomologists harbored concerning both the geologic longevity of
insect species and the possibility of making specific identifications using
only single skeletal parts or fragments thereof (Coope 1965). His work
was to reveal the fallacy of this skepticism. Nearly all species of Col-
eoptera have a longevity which greatly exceeds the length of the late
Pleistocene and specific identifications often are possible when the mor-
phology of the fossil is compared in detail with modern museum speci -
mens. These two facts form the base for all other studies of fossil in-
sects including this one; however, before identifications of fossil Col-
eoptera can lead to paleoenvironmental conclusions, two other conditions
must be satisfied: the classification of the more important insect groups
(in this case certain families of Coleoptera) must be sound, and the eco-
logy or at least thepresent distribution of the taxa represented byfossils
must be known.
Some beetles are of more value than others as indicators of past en-
vironments. A fossil of a stenophagous , phytophagous species may be of
value in indicating the pr es ence of a certain plant; however, it will yield
little dir ect information about the macro- environment in which the insect
originally lived. The family Carabidae (ground beetles) provides the
greatest amount of environmental information since its members are
predators living in most instances on the surface of the ground and thus
under the direct influence of the macro-climate. Some carabid beetles
are even restricted to certain types of soils and sediments.
Impliedin the use of assemblages of fossil insects to interpret Pleis -
tocene environments is the assumption that the habitat requirements of
the species represented by fossils have remained stable. Some workers
have considered this assumption to be unacceptable. Greenslade (1965)
has cited evidence that certain species of carabid beetles do occupy en-
tirely different habitats in different areas, and he doubts that the ecolo-
gical requirements of some species canbe considered as stable as have
been assumed (Greenslade 1965, written communication). Several of
the North American carabids, e. g . Carabus chamissonis Fisch. and Nebria
nivalis Payk. possess ecologically disjunct distributions which might be
interpreted as being evidence of a great variability in habitat require-
ments. In such cases, where for example a species common on the tun-
dra is occasionally found in woodland areas, the explanation for the ano-
maly is best sought by looking for the pos sibility of accidental dispersal
of individuals to areas which only locally fulfill the habitat requirements
of the species. Lindroth has invoked this reasoning to explain the oc-
currence in the coniferous zone of Norway of a colony of the carabid Amara
alpina Payk., normally an obligate tundra inhabitant (C. H. Lindroth 1965 ,
written communication). Problems of this sort need not prohibit the
use of insect fossils as long as the ecology of the species is interpreted
in a broad sense and conclusions are based on groups of fossils rather
than single specimens . Yet some fossil assemblages still possess ano-
malous characteristics. For example, studies in England reveal insect
assemblages which contain a mixture of now disjunct species (Coope et al.
1961), but in all such cases the assemblages possess an internal consis-
tency which makes the possibility that some species have changed their
2 04
Matthews
ecologic requirements the least likely of several alternative explanations
(Coope 1965).
Physical Environment and Biota of Interior Alaska
F airbanks is located in interior Alaska at the south side of the Yukon-
Tanana Upland and adjacent to the Tanana River (fig. 1). The climate is
characterized by short, warm summers, cold winters and meager pre-
cipitation. The mean annual temperature is -3.28 C (26. 1 F) andmean
annual precipitation is 29.4 cm (11. 6 inches) (Pewe and Paige 1963).
Despite a mean annual temperature below 0 C, permafrost in the Fair-
banks area has a discontinuous distribution, which has a strong effect
on drainage and in turn on local plant communities (Pewe 1966a, Pewe
et al. 1965), South facing, well drained slopes support stands of white
spruce, birch, and quaking aspen while poorly drained north facing slopes
and valley bottoms support more open communities of black spruce, wil-
lows, larch (on the poorest drained sites) , and sedges (Pewe et al. 1965),
Coniferous trees and other upright arboreal species are generally absent
above an elevation of 1000 meters.
In Alaska, unlike central Canada, the division between tundra and
closed woodland is a complex transition zone. Below the upper limit of
conifers in Alaska is an open woodland, usually accompanied by a thick
cover of mosses and lichens. This area, is often referred to as the Hud-
sonian Zone (after Merriam's lifezones) by entomologists (Mason 1956,
1965). Beyond this zone is the tundra, the lower parts of which in in-
terior Alaska are quite shrubby. The tundra in northern Alaska, such
as at Barrow (fig. 1), is characterized by a reduced number of plant
taxa and a paucity of shrub-like arboreal species (Britton 1966). This
type of tundra might be consider ed equivalent to the "true Arctic tundra"
of the Canadian literature or " regio alpina media" in Scandinavia (Mason
1965).
A peculiar situation exists in the distribution of part of the Alaskan
insect fauna. Whereas in eastern Canada the boundary between forest
and tundra is as sharp with respect to insects as plants (Brown 1965),
in Alaska members of the Hudsonian insect fauna extend well beyond
coniferous treeline. For example, Brown (1965) has described the col-
eopterous fauna at Umiat (fig. 1) as "primarily Hudsonian", and Mason
(1956) considers the insect fauna of all the treeless areas south of the
north portion of the Seward Peninsula and including the Aleutian Islands
to be Hudsonian in character . Lindroth (1961, 1963b, 1966) in his mono-
graphs on the carabid beetles of Canada and Alaska seldom uses Mer-
riam's lifezones. Apparently he considers coniferous treeline to be an
important ecologic boundary with the under standing that the distribution
of some species seems to be more or less independent of it.
The Origin of the Frozen Silts in the Fairbanks Area
Although interior Alaska was only locally glaciated during the Pleis-
tocene, heavy glaciation in the Alaska Range and the Brooks Range af-
fected the interior indirectly by changing the fluvial regimes of its two
major trunk streams, the Tanana and the Yukon Rivers. During periods
of marked glacial advance and retreat in the Alaska Range, the Tanana
Coleopterous Assemblages
205
River at Fairbanks was an outwash stream with a wide, sparsely vege-
tated, silty flood-plain. Silt removed by wind from the flood-plain was
deposited on the hills near Fairbanks as loess, so that today silt partially
fills the valleys and mantles the slopes to depths of more than 100 feet
(Pewe 1955, 1966a). The loess of the valleys is different from that on
the slopes. The valley silt is bedded, per ennially frozen, highly or ganic ,
and fetid (which explains the miner's term for it -- "muck"). The upland
silt facies like the loess of the mid-continent of North America is mas-
sive, oxidized, buff brown in color, and compared to the valley bottom
facies, quite unfos silifer ous . Pewe (1966a, et al. 1965) believes that
the "muck11 facies is colluvium formed by redeposition of loess from the
slopes .
Most exposures of frozen "muck" near Fairbanks have been created
by placer gold mining. The muck overlies early Pleistocene gravels
that contain gold; consequently, the overburden of silt must be hydraul-
ically removed before actual mining can begin. An operation of this sort
creates a mining "cut" with walls of frozen silt. One such mining cut is
at Eva Creek, ten miles west of Fairbanks (fig. 1). During the summer
of 1964 R.D. Guthrie (University of Alaska) and I made extensive fossil
collections at this site.
Fig. 1. Alaska. Localities mentioned in text.
206
Matthews
The Eva Creek cut is of particular significance because it exposes
all of the silt units which Pewe has described for the Fairbanks area
(Pewe et al. 1965 and unpublished MS); however, since this report in-
volves only samples from Wisconsin age sediments, details of the other
stratigraphic units will not be discussed.
Tne thickness of the entire silt exposure at Eva Creek is approxi-
mately 35 m of which 11 m are of Wisconsin age. The Wisconsin silt is
overlain by a Holocene silt unit containing, at some localities, buried
forest beds (fig. 2). It rests unconformably on silt thought to be of II-
linoian age (Pewe 1965, personal communication) (fig. 2). This uncon-
formity is related to a long period of thaw and erosion (Pewe 1966a) pro-
bably representing the Sangamon interglacial.
Fig. 2. Eva Creek Exposure, 1965.
Coleopterous Assemblages
207
Sample Localities within the Wisconsin Unit (Eva Creek)
The Wisconsin portion of the Eva Creek exposure may be divided
into three sub-units (fig. 2) which are differentiated by color, ice con-
tent, and organic content. Some of these sub-units are probably only of
local extent.
Sample Eva 3-1A comes from the basal two feet of Wisconsin silts .
It is part of sub-unit 1 which is characterized by an extremely high con-
tent of wood (including a few stumps of small trees) and other plant frag-
ments, most of which seem to be from mosses. This unit thickens to-
ward the axis of the north- south trending valley and dips in a down val-
ley direction. M. A. Geyh of Niedersachsisch.es Landesamt Fur Boden-
forschung, Hanover, has attempted C- 14 analysis of a spruce stump (Hv.
1328) from several feet above the sample interval, but still within sub-
unit 1. A final d$.te is not yet available, but Geyh states (1967, written
communication) that the first tests indicate an age greater than 56, 900
years B.P. This date may not, however, indicate the time of deposition
of the sediments in sub-unit 1 since the tree stumps in that unit could
have been derived from older sedimentary units (Sangamon forest bed?).
A second sub-unit -- not sampled -- lies immediately above sub-
unit 1. It consists of greenish, inorganic silt with a high content of
seam ice (Taber ice, sirloin ice).
Sub-unit 3, from which samples 3-3B and 3-3C were taken is the
thickest of the three sub-units and most like the dark brown Wisconsin
"muck" at other frozen silt exposures in the Fairbanks area. Sample
3-3B was taken from a level 5. 5 m above the base of the Wisconsin unit;
sample 3-3C was collected 3. 7 m above 3-3B. The only criteria used
for selection of the two samples from sub-unit 3 was that they come
from different levels in the sub-unit. A radiocarbon date of 24,400 ±
650 years B. P. (1-2116) was obtained on wood from the site of sample
3-3C. No radiocarbon date is available for 3-3B, but its position with
respect to 3-3C and 3-1A indicates an age greater than 24,400 years B.
P. and less than the age of the early Wisconsin sediments of sub-unit 1.
Sampling Procedure and Processing Notes
The insect fossils reported on in this paper were collected in con-
junction with a search for small mammal fossils. The procedure fol-
lowed for each sample was to take several thousand pounds of silt from
a two foot interval at the exposure. This was then screened through 40
mesh per inch screens. A portion of the organic extract that remained
on the screens was then processed for fossil insects. Since insect fos-
sils are very abundant often only a small portion of the total residue from
a sample was required in order to obtain a large number of specimens.
This portion of the residue was washed through 80 mesh per inch screens
in order to remove any remaining silt.
A process developed by G.R. Coope (1961) was used to concentrate
the insect fossils in order that they might be more readily extracted
from the organic residue. In this process, the residue remaining in the
80 mesh screens is immersed in light weight oil. When the oil soaked
mass of residue is placed in hot water many insect fragments rise to the
surface. The concentration of insect fossils obtained in this manner is
208
Matthews
stored in alcohol and later examined with a binocular microscope. In-
sect fossils are mounted on slides similar to those used in the study of
Foraminifera. This facilitates storage of the fossils, prevents their
warping when they have dried, and allows detailed examination under
high magnifications.
Identification Notes
The most striking feature of the faunal list (table 1) is the imbalance
in the level of identifications . With few exceptions specific determinations
were possible only among the carabid fossils. Generic determinations
must suffice for the other families because of my unfamiliarity with many
of these families and the real scar city of knowledge concerning the col-
eopterous fauna of Alaska. Generic determinations of beetles often have
little paleoenvironmental value inasmuch as few genera are restricted
to specific habitats . Tabulation of the identified genera within each fam-
ily and especially a recognition of the number of specimen types (species ? )
within each genus nevertheless permits an estimate of the total number
of taxa present in each fauna. For the same reason, fossils which could
not be identified to the familial or generic level are listed in table 1.
Were it not for the fact that the ecology and taxonomy of the carabid
beetles of Alaska are now reasonably well documented, a paleoenviron-
mental analysis such as the one presented here would be impossible.
Except for fossils of curculionid beetles (weevils) the carabids are the
most abundant group within each of the fos sil as semblages . Fortunately,
the anatomical parts which are of particular value in carabid identifi-
cation -- the pronotum, head, and elytra -- are often well preserved
in organic silts and peats.
Most of the carabid fossils can be identified using C. H. Lindroth's
detailed descriptions (Lindroth 1961, 1963b, 1966) and comparative mu-
seum specimens. Determinations within one group, however, the sub-
genus Cryobius of the genus Pterostichus , are very difficult. Specific iden-
tification of members of Cryobius is critical in this study because of the
importance of Cryobius species in present arctic and subarctic habitats.
A recent revision of Cryobius by G.E. Ball (1966) has placed the classifi-
cation of the group on a firm basis, but the similarity among members
of certain species pairs causes specific determinations of some fossils
to be very uncertain. Indeed, to identify many living specimens to the
specific level requires an examination of the median lobe of the male
genitalia which is rarely encountered as a fossil in Pleistocene silts.
I have hesitated to assign specific names to many of the Cryobius fos-
sils, this being especially the case where the fossils (pronota) were
broken or otherwise damaged. Ball (1966) has divided the species of the
subgenus Cryobius into species groups; therefore, in those cases in which
I have not been able to make a specific determination, I have, neverthe-
less, carried the identification as far as the species group level. Cer-
tain of the species groups are restricted to specific habitats, and thus
yield definite paleoenvironmental information. For example, the mem-
bers of the similis subgroup are largely tundra inhabitants. A determin-
ation to the ochoticus subgroup level has certain special implications . One
of the species of this group, P. gerstlensis Ball, may be eliminated from
Coleopterous Assemblage
209
consideration because it is quite distinct and readily identified. Thus,
an ochoticus subgroup determination implies that P. gerstlensis Ball, a wood-
land inhabitant, has been ruled out as a possibility. All the remaining
members of the group are tundra residents (Ball 1966). This is not the
place to consider in detail the pitfalls of identification of fossil Cryobius
specimens, but because the Cryobius identifications are so important for
the conclusions reached in this paper and because my confidence in the
specific identifications varies , I have indicated in table 1 with a question
mark (?) those determinations which are suspect.
TABLE 1. Coleopterous fauna of Eva Creek samples 3-1A, 3-3B, 3-3C.
Taxa
Carabidae
Carabus truncaticollis Eschz.
Carabus chamissonis Fi s ch .
Notiophilus sp.
Notiophilus semistriatus Say
Notiophilus borealis Harr.
Diacheila polita Fald.
Elaphrus riparius L. or
pallipes Horn
Dyschirius sp.
Dyschirius nigricornis Mtsch.
Bembidion sp.
Bembidion (Plataphodes) sp.
B. (Plataphodes) arcticum Lth.
B. (Peryphus) sp.
B. (Peryphus) grapei Gyll.
B. (Peryphus) dauricum Mtsch.
Pterostichus ( Cryobius) s p .
P. (Cryobius) pinguedineus grp.
P. ( Cryobius) ochoticus subgrp.
P. (Cryobius) so peri Ball
P. (Cryobius) kotzebuei Ball
P. (Cryobius) tareumiut Ball
P. (Cryobius) gerstlensis Ball
P. (Cryobius) chipewy an Ball
P. (Cryobius) similis subgrp.
P. ( Cryobius) similis Mann.
P. (Cryobius) par asimilis Ball
P. ( Cryobius) pinguedineus E s chz .
P. (Cryobius) auriga Ball
Number of Ecol-
individuals ogy*
3-1A 3-3B 3-3C
1
2
3
2
2
6
1
1
3
1
1
1
1
2
1
18
5
5
2
9
1?
3
4
3
2
1?
4
1
2 5
1
9 9
2 19
3 2
6 9
4 4
6 27
2
2
3
1
1 2
1?
A
Be
BeF
BeF
BeF
BeF
A
BeF
A
Bx
Bx
Bx
CF
Ba
A
BaF
210
Matthews
TABLE 1 (cont. ).
Taxa
Number of Ecol-
individuals ogy*
3-1A 3-3B 3-3C
P. ( Cryobius) ven tricosus grp.
P. (Cryobius) ventricosus Eschz.
P. (Cryobius) caribou Ball
P. (Cryobius) brevicornis grp.
P. (Cryobius) brevicornis Kby.
P. ( Cryobius) mandibularoides Ball
P. (Cryobius) nivalis Sahib.
P. (Stereocerus) haematopus Dej.
Agonum quinquepunctatum Mtsch.
Amara alpina Payk.
Cymindis sp.
Prichocellus porsildi Brown
Genus sp.
Dytiscidae
Colymbetes sp.
Staphylinidae
Staphylininae
Acylophorus sp.
Paederinae
Lathrobium sp.
Omaliinae
Olophrum sp.
Micralymma sp.
Tachyporinae
Tachinus sp. A
Tachinus s p . B
Genus sp.
Steninae
Stenus sp. (A and B)
Stenus sp. A
Stenus sp. B
Dianous sp.
2
8 14
1
15 7 12
11 6 11
2? 2? 2?
34 6 5
2 4 1
1
3 5 5
1
2 6
1 1
1
1 1
9
30 4
4 36
7 2 1
2 5
1
6
2
2
7
Be
A
BaF
A
Ba
CF
A
Bx
Aleocharinae
Genus sp.
8
Coleopterous Assemblage
211
TABLE 1 (cont.).
Taxa
Number of
individuals
3-1A 3-3B 3-3C
Silphidae
Silpha trituberculata Kby. or
sagax Mann. 1
Scydmaenidae
Veraphis sp.
Scarabaeidae
Aphodius sp. A
Aphodius sp. B
Byrrhidae
Curimopsis sp.
Caenocara sp.
Simp lo car ia sp.
Morychus sp. A
Morychus sp. B
Elateridae
Genus sp. A
Genus sp. B
Genus sp. C
C ryptophagidae
Cryptophagus sp. A
Cry ptophagus sp. B
Chrysomelidae
Chrysolina sp. A
Chrysolina sp. B
Curculionidae
Lepyrus gemellus Kby.
Genus spp.
2
1
1 1 35
1 17 2
1 2
1 2
1
2
1
1 12
1
1 4 1
68 165 240
2 spp. 5 spp. 5 spp.
Family and Genus unknown
Genus sp. A
Genus sp. B
Genus sp. C
Genus sp. D
Genus sp. E
1
2 13 1
3
2 1
1
Ecol-
ogy*
212
Matthews
TABLE 1 (cont. ).
Number of Ecol-
Taxa individuals ogy*
Total individuals 312 330 488
* Ecologic class symbols are explained in the text.
Notwithstanding the proven longevity of many coleopteran species,
the similarity of some of the species of the subgenus Cryobius seems to
indicate relatively late divergence; in fact, Ball (1963a) in his first
zoogeographical paper on the group suggested that speciation may have
occurred as late as Wisconsin time. Now (Ball 1966) he feels that the
last episode of taxonomic splitting occurred earlier than 90, 000 years
ago, but he emphasizes that this must be supported by fossil evidence of
which there was little available when he published the revision. Fossil
evidence substantiating Ball's statements on speciation within Cry obius
would add strength to the assumption that all of the Cryobius fossils in the
three Eva Creek samples represent extant species. Such fossil evidence
does exist, but not from Eva Creek.
A peat sample from the McGee cut (fig. 1) 100 miles west of Fair-
banks in the T ofty mining district has yielded partially articulated speci-
mens of carabid beetles, particularly Cryobius. In many specimens the
male or female genitalia are preserved allowing positive specific iden-
tifications. The following species of the subgenus Cryobius were identi-
fied: P. (Cryobius) similis Mann., P. (Cryobius) parasimilis Ball, P. (Cryobius)
pinguedineus Eschz. , P. (Cryobius) brevicornis Kby. , P. (Cryobius) nivalis Sahib. ,
P. (Cryobius) mandibularoides Ball, and P. (Cryobius) tareumiut Ball. Of these
parasimilis and similis are thought by Ball (1966) to have been among the most
recent to evolve. The sample comes from the base of the Wisconsin por-
tion of the exposure (D.M. Hopkins 1966, personal communication). A
radiocarbon analysis indicated an age greater than 39, 900 years B.P.
(1-2248) for the fos siliferous horizon.
The evidence from the McGee cut thus indicates that Pm parasimilis
Coleopterous Assemblage
213
Ball and P. similis Mann, along with a few other species of Cryobius were
inexistence during early Wisconsin time. This evidence certainly does
not confirm all of Ball's (1966) phylogenetic speculations concerning the
time of evolutionary divergence within the subgenus Cryobius, but it does
show that he was correct in those instances for which fossil evidence is
now available. This enhances the probability that fossils of Cryobius in
the oldest Wis consin sample at Eva Creek do represent extant taxa. Un-
published work by the author dealing with Alaskan insect faunas much
older than those reported on in this paper indicates that the other carabid
taxa in the faunal list (table 1) have geologic longevities which greatly
exceed the age of the oldest sample considered here (Eva 3-1A).
Derivation of Quantitative Data
In order that each of the three faunas might be compared quantitat-
ively, thenumberof individuals represented by each taxon was tabulated.
This number indicates the maximum number of individuals which could
be represented by summing one diagnostic fragment (right elytron, pro-
notum, etc.). For example in Eva 3-3B the staphylinid genus , Micralymma ,
is represented by 36 heads. A tabulation of the elytra (seven right, six
left) can account for only seven individuals. Thus, the greatest number
of individuals (36) is represented by heads. In Eva 3-3C the staphylinid
genus, Stenus is represented by six pronota, but an examination of Stenus
elytra, which represent fewer than six individual beetles, indicates that
two species are probably present. Therefore, the faunal list indicates
six individuals of Stenus including at least two species.
The particular anatomical part that was used for tabulation varied
from one group to another. The pronotum was used for all members of
the genus Pterostichus , the elytra for members of the genus Bembidion ; and
in one exceptional case, Silpha sp. from Eva 3-3C, the scutellum was
diagnostic. Only elytra were used for the tabulation of miscellaneous
species. In manv cases an elytron is represented by only a basal or
apical fragment; therefore, tabulations were weighted so that two such
fragments from the same beetle would not be counted as two individuals .
Coope (1961) has questioned the validity of using quantitative infor-
mation for making faunal comparisons. His argument, based on tests,
is that human bias is introduced during the extraction of fossils with the
microscope. The biggest and most brightly colored species are often
represented by the most fossils, while the small species are reciprocally
under-represented. At Eva Creek this type of bias does not seem to be
important. The largest and most spectacular species are often rep-
resented by very small fragments. Fortunately, such species ( Carabus
trucaticollis Eschz. is a good example) may be identified by examination
of the small fragments, but very little may be said about individual abun-
dance. Ten fragments could as easily have come from one insect as ten,
but the faunal list must record the minimum number -- 1. The same
situation applies to other large beetle fossils from the Eva Creek sam-
ples. Small fossils often are well preserved, and easily located atmag-
nifications of 20X. While I do not claim that human bias of the type des-
cribed by Coope (1961) is absent in this study, I do not believe that it is
sufficiently significant to prohibit the use of quantitative data.
214
Matthews
Ecologic Classification of Fossils
In order that the environment represented by each fossil assemblage
can be discussed those fossils which have been positively identified to
species (Carabidae) are assigned to ecologic classes A, B or C accor-
ding to the habitat preference of their living counterparts (see table 1).
The letter A indicates that a species is an obligate tundra inhabitant.
Some of those species listed in table 1 do not now occur on the alpine
tundra of interior Alaska, but this is probably an artifact of limited col-
lecting.
The letter B indicates that a particular species occurs both in tun-
dra and woodland areas. The suffix "e" is attached when it is known that
the species prefers "open" environments when it occurs below coniferous
treeline. For example, I have collected Diacheila polita Fald. in the Fair-
banks area. It is most often found on the tundra, but at Fairbanks it
occurs in a Carax bog -- an open (treeless) habitat. In addition to those
species such as Pterostichus (Cryobius) trevicornis Kby . which occur both in
closed boreal forest and on tundra (Ba), class B includes many species
which are known to occur on tundra but about which there is some doubt
concerning their occurrence at lower elevations. These cases of uncer-
tainty are designated by the suffix "x".
The species placed in class "C" are those which have never been
collected above the limit of coniferous treeline. One of these species ,
Agonum quinquepunctatum Mtsch., occur s in wet, openhabitats (bogs). Species
which have been collected at Fairbanks or nearby at the same elevation
are indicated in table 1 by the letter "F".
Fossil Evidence, excluding Insects, from Eva Creek
Other fossil evidence is available with which information yielded by
fossil insects may be compared. Large mammal fossils frommany late
Pleistocene localities near Fairbanks include extinct taxa such as Mammuthus
sp. , Equus sp. , Camelops sp. , Bison priscuc ( sensu lato ) and others which
presumably required an open grassy habitat (Guthrie 1 96 8 , Pewe
1966a) as well as extant taxa -- Rangifertarandus, Ovis nivicola , and Ovibos
moschatus -- that are now restricted to alpine or coastal tundra (Pewe
1966a). Small mammal fossils have been collected from the three sample
intervals which yielded the coleopterous faunas reported in this paper.
They, like fossils of large mammals indicatenot only thatthe Wisconsin
"mucks" of the Fairbanks area were deposited in an open, largely tree-
less environment, but specifically that the three samples (3-1A, 3-3B,
3-3C) at Eva Creek represent such an environment. Fossils of Dicrostonyx
sp. and Micro tus gregalis have been found in the three sampled intervals
(Guthrie in press). Both of these microtines are now found on the tun-
dra; however, neither occurs on the alpine tundra of the Tanana hills
near Fairbanks.
Fossil pollen was extracted by the author from the silts of each of
the three sampled levels. The pollen spectra from the three localities
(table 6) are similar and indicatea treeless environment -- an environ-
ment too cold to support abundant dwarf birchs, alders, and ericaceous
shrubs (Matthews MS).
Thus, fossils of vertebrates and pollen indicate that at the timedur-
Coleopterous Assemblages
215
which the three insect assemblages accumulated, treeline was significan-
tly lower in interior Alaska. This conclusion will be compared with the
environmental inferences derived from an analysis of the three fossil
Coleoptera assemblages.
Discussion
The results presented in table 1 may be analyzed in two ways. One
may compare the taxonomic content of each of the assemblages with the
taxonomic composition of various contemporary Alaskan environments.
The contemporary environment which most closely matches that of the
fossil assemblage is judged to be the one that represents the paleoenvir -
onment in which the fossils lived. This is the method thatCoope has used
in the analysis of fossil assemblages in England. Table 2 represents
such an analysis using only specifically identified beetles from each
assemblage. It is immediately apparent that the number of taxa available
for a comparison of this type is small (maximum of 21 species). This
results from the fact that specific determinations were possible only
within the family Carabidae. In order to counter the effect of this small
sample size I have chosen to compare the three assemblages quantita-
tively. The validity of the quantitative data presented in table 1 has been
discussed in a previous section.
A quantitative approach similar to thatused with the qualitative data
(table 2) would be desirable. Unfortunately this is impossible since it
requires that carabid faunas of the major environments in Alaska have
been analyzed quantitatively. No such studies have been attempted. In
lieu of such information I have proceeded on the basis of several assum-
ptions relating to the way in which a fossil assemblage might theoreti-
cally reflect the environment in which it was deposited. First, in the
three assemblages of fossils, the numerically dominant species will be
those which resided at the site of deposition. A minority of the fossils
will represent beetles which lived in habitats other than those existing
near to or at the site of deposition. Whether this latter group of fossils
is in fact a minority depends on the former diversity of the beetle fauna
at the site of deposition, the powers of dispersal of species in former
neighboring habitats, and the proximity of those habitats to the site of
deposition. For example, a community proximal to the site of deposi-
tion of a fossil assemblage and possessing a great number of actively
flying beetles might have contributed more fossils to the assemblage
than a community with a beetle fauna composed of non-flyers. The beet-
les from the neighboring community might well form the majority of the
members of a fossil assemblage if the fauna of that community was tax-
onomically diverse and numerically abundant relative to the fauna at the
site of deposition of the sample. It is unlikely that a large fraction of
the carabid portion of each Eva Creek assemblage consists of fossils of
such allochthonous beetles, since the dominant element of each assem-
blage is of the subgenus Cryobius (genus Pterostichus) , all species of which
are constantly flightless.
Interpretation of the fossil assemblages from Eva Creek is made
more complex by the retransported or colluvial character of the fossil
bearing sediments. Theoretically, insects which lived in habitats at
216
Matthews
higher elevations on the slopes near Eva Creek and which werepenecon-
temporaneous with insects at low elevations could have been retransported
with the silt into the valley bottom. Also, since deposition of sediments
in one area, usually implies erosion in another, some of the fossils in
each assemblage may have been derived from older sediments. Many
insect fossils would probably not survive this type of redeposition es-
pecially when the sediments from which the fossils were derived were
much older geologically than the sediments in which they were finally
deposited. Contamination of the fossil insect assemblages by penecon-
temporaneous mixing during accumulation of the assemblage can be eva-
luated only indirectly -- by examining the consistency of the environ-
mental implications of each assemblage.
TABLE 2. Abundance of species of Carabid beetles in each ecologic class.
Total of
Assemblage Ecologic Class* A, B, and C
* See text for explanation of class symbols.
* * Number o f species.
Table 3 shows the relative abundance of beetles in each ecologic
class . The dominance of class B is partly related to its containing species
about which extralimital woodland occurrences are in doubt (class Bx) .
If more detailed ecologic information were available, class A would no
doubt be larger and class Bx smaller. Nevertheless, the remarkable
feature of table 3 is the preponderance of fossils in classes A and B and
the paucity of fossils in class C.
To duplicate any of the fossil assemblages with a collection of mod-
ern carabid beetles, one would have to go to a locality near to or above
the altitudinal or geographic limit of coniferous forest. A similar con-
clusion may be derived from the taxonomic analysis (table 2). But a
statement that each of the assemblages represents a tundra environment
might be challenged on the premise that all of the obligate tundra fossils
(group A) are allochthonous --having been included in the fossil assem-
blages by retransportation with the silt from higher elevations. If this
were the case, the fossil assemblages might well have formed below
treeline in the Hudsonian Zone. This is clearly not the case since the
carabid fossils which would be expected to represent that zone are not
present in any of the fossil assemblages. For example, Pterostichus adstrictus
Coleopterous Assemblages
217
Eschz. , Calathus ingratius Dej. , Asaphidion yuk.onense'Wic'k. , Harpalus fulvilabris
Manh. Bembidion mutatum G. andH. , Carabus vietinghoffi Adams, and Trichocellus
cognatus Gyll. , are common elements of the woodland carabid fauna of
Alaska. Ea'ch of these beetles is morphologically distinct, they occur
in a variety of habitats although most prefer open situations, and most
of them range on to the tundra in parts of Alaska (Lindroth 1953, 1961,
1963a, 1963c, 1966). If any of the assemblages accumulated in a habitat
which was below or near treeline, fossils of some of these species would
be expected. They do not occur in any of the Eva Creek assemblages;
therefore, all three of the assemblages no doubt represent a tundra en-
vironment. The position of coniferous treeline must have been below
the present elevation of Eva Creek (230 m - 750 feet) during that part
of Wisconsin time when each of the assemblages formed, and the Fair-
banks area was largely, if not completely, treeless.
This conclusion agrees with the alternate fossil evidence presented
earlier. The colder climate which must have been responsible for the
lowered treeline is also indicated by inactive or remnant ice wedges in
the sediments at Eva Creek. Currently such features are forming only
in those areas where the mean annual temperature is at least 2 C colder
than the present mean annual temperature of Fairbanks (Pewe 1966b).
TABLE 3. Abundance of individuals of carabid beetles in each ecologic
class.
Total of
Assemblage Ecologic Class * A, B, &: C
* See text for explanation of class symbols.
* * Number o f individuals .
Though all three of the fossil assemblages were evidently deposited
in a tundra environment, each of the assemblages possesses certain dis-
tinctive characteristics. Statistical tests (table 4) are used to establish
the mutual relationship, if any, of the assemblages, and an attempt is
made to provide environmental interpretations for the observed differ-
ences among the three fossil assemblages.
Several of the statistical comparisons in table 4indicate that samples
Eva 3-3B and 3-3C are more closely related to each other than either is
to Eva 3-1A. The basis for this conclusion is the lack of statistically
significant differences between 3-3B and 3-3C. The failure of a com-
218
Matthews
parisonof two samples to be statistically significant implies that the two
samples could have been drawn from the same parent population. In this
paper such a conclusion will be taken to imply that the two compared as-
semblages represent the same type of paleoenvironment.
TABLE 4. Statistical tests*.
Computed
Type of comparison N Comparison %2 • 05
Relative preservation of
Carabidae skeletal ele-
ments in each assemblage
180
Pronota - 262
196
198
Right elytra - 129
179
189
Left elytra - 237
190
Number of individuals in 759
Coleoptera families com- 730
mon to all assemblages 609
Number of taxa in families 112
of Coleoptera common to
all assemblages
Number of individuals of 819
Curculionidae in each 805
assemblage 652
Number of individuals in 197
the genera Pterostichus, 260
Amara and Bembidion 205
Number of individuals in 120
the species groups of 173
Pterostichus ( Cryobius) 139
* x2 test of independence for binomial and multinomial populations.
** Nonsignificant yfl values are in italics.
Coleopterous Assemblages
219
Differential preservation of certain fossils could bias conclusions
concerning the taxonomic and numerical relationships of 3-3Band 3-3C.
To test this contingency I have made a statistical comparison of the pre-
servation of carabid fossils in the three assemblages (table 4). The re-
sults of these comparisons indicate that differential preservation does
exist; however, the relationships of the three as semblages based on pre-
servation are different from those based on qualitative and quantitative
taxonomic composition. Thus, the qualitative -quantitative comparisons
showing 3-3B and 3-3C to be related are probably not initially biased by
differences in preservation of the fossils. It is interesting that the two
samples which are shown to be related by the statistical analyses re-
present the same sub-unit in the Wisconsin portion of the Eva Creek ex-
posure.
Samples Eva 3-3Cand 3- 1A display the greatest degree of taxonomic
and quantitative difference. Some of the major differences cannot be
explained at this time, yet their existence, established in part by the
statistical tests, is assumed to be evidence of paleoenvironmental dif-
ferences. For example, the obvious difference between the two assem-
blages is indicated in the miscellaneous species section of table 1. There
are very few species common to both assemblages 3-1A and 3-3C. The
relative abundance of individuals of curculionid beetles (weevils) is also
markedly different in the two assemblages, but only one curculionid,
Lepyrus gemellus Kby. was identified specifically, and this species is rare
in all three assemblages.
Finally, Eva 3- 3C differs from 3-1A (and 3-3B) by its relative abun-
dance of fossils of the scarabaeid genus Aphodius. In England, Coope has
observed a correlation of concentrations of large mammal fossils with
an abundance of Aphodius fossils, the explanation being that Aphodius has
copraphogous habits (Coope Sands 1966). But Landin(1961) pointed out
that some species of Aphodius are not coprophagous , and of the few species
thatare known from Alaska, some are associated with smallmammals such
as Marmota rather than ungulates (W. J. Brown 1967 , written comm . ) . Thus ,
at the present time and until specific identifications are forthcoming, lam
hesitant to invoke Coope 's explanation for the abundance of Aphodiusfossils .
Those differences between 3-1A and 3-3C which are subject to in-
terpretation occur within the family Carabidae. The greatest contrast
is within the subgenus Cryobius, genus Pterostichus . In 3-3C (and 3-3B) the
species P. (Cryobius) kotzebuei Ball is abundant. In Eva 3-1A this species
is rare, and P. (Cryobius) nivalis Sahib, is abundant (see table 1). P. (Cryobius)
kotzebuei Ball has been collected by Ball (1967, personal communication)
on rather dry tundra, and since it is a dominant element in the carabid
fauna of Eva 3-3C, I conclude that dry tundra was probably present at
the site of deposition of that assemblage approximately 24, 400 years ago.
Supporting this conclusion is the presence in 3-3C (and 3-3B) of indivi-
duals of the species Bembidion dauricum Mtsch.which inhabits xeric tundra
sites that are almost devoid of vegetation (Lindroth 1963b). Notiophilous
semistriatus Say, occurring in both 3-1A and 3-3C, occupies similar hab-
itats (Lindroth 1961) and Cymindis sp. represented by one fossilin 3-3C,
often occurs in xeric habitats (Ball 1963b).
P. (Cryobius) nivalis Sahib, has been collected on rather dry tundra, but
220
Matthews
Ball (1966) states that it is also associated with "deep moss". The or-
ganic residue from which the fossils of 3-1A were extracted possessed
an abundance of moss fragments. P. (Cry obius) nivalis Sahib, evidently lived
in the environment at the site of deposition of 3-1A -- hence its abun-
dance in the fossil assemblage. P. ( Cry obius) tar eumiut Ball and P. (Cryobius)
similis Mann. , both of which occur in 3-1A and probably not in 3-3C are
found presently on rather moist tundra (Ball 1963c, 1966). Several of
the carabid fossils from assemblage 3-1A indicate that an aquatic en-
vironment may have existed near the site of deposition. Bembidion arcticum
Lth. occurs now along the barren and gravelly mar gins of small streams
(Lindroth 1963b). Both species of Elaphrus listed in table 1 for the one
Elaphrus fossil in 3-1A are found in a similar habitat -- areas, usually
near streams or ponds, which are devoid of vegetation (Lindroth 1961).
Agonum quinquepunctatum Mtsch. is a hygrophilous species. It may not have
lived at the site of deposition of 3-1A, but its pres ence in the assemblage
is further evidence for the existence of an environment near by which was
favorable for its survival. It is of interest that Lindroth (1966) lists
Dischirius nigricornis Mtsch. , another beetle restricted to assemblage 3-1A,
as a contemporary associate with Agonum quinquepunctaturr, Mtsch. inabog
near Edmonton, Alberta. Eva 3-3C contains a fossil of an aquatic beet-
le, Colymbetes , but the absence of any other identified beetles which indi-
cate an aquatic or near aquatic environment suggests that Colymbetes does
not represent a community near the site of deposition of 3-3C.
With the exception of the fossils of P. (Cryobius) kotzebueiBa.ll and A
(Cryobius) nivalis Sahib, the differences between the carabid portions of the
two assemblages, 3-1A and 3-3C, are subtle; consequently, the environ-
mental interpretations are somewhat speculative. A more definite con-
cept of the meaning of the variation of the two assemblages might be ob-
tained if they could be compared quantitatively and qualitatively with data
from contemporary environments . As I have said earlier no such infor-
mation is available, but the fossil assemblage from McGee Cut near
Tofty, Alaska (fig. 1) is suitable for such a comparison (table 5).
Many of the beetle fossils extracted from the peaty silt at the McGee
cut were partially articulated, and almost only those that were so pre-
served are included in table 5. Thus the assemblage is made up of those
beetles which lived at or very near the site of deposition of the peaty
silt. The fact that many of the fossils are better preserved than dead
specimens collected in the contemporary environment indicates that some
of the fossil beetles probably died during hibernation.
Pollen analysis of the sediments from which McGee fos sils were ex-
tracted reveals an unusual pollen spectrum consisting of more than 70%
sedge pollen and 20% willow pollen (Matthews MS). This is a clear case
of over-representation in the pollen spectrum by elements of the local
fossil plant community; that is, the plants growing at the site of depo-
sition -- the habitat in which the fossil beetles originally lived.
Assemblage 3-lAis more similar to the McGee assemblage than is
3-3C. I consider this to be further evidence that the environment re-
presented by assemblage 3-1A was more moist than that represented by
assemblage 3-3C. The differences between 3-lAand the McGee assem-
blage are best explained by the depositional histories of the two samples.
Coleopterous Assemblages
221
The McGee assemblage, consisting of well preserved fossils derived
from peaty silt, represents a local, monotypic habitat. The Eva 3-1A
assemblage derived as it is from colluvial silt no doubt represents a
polytypic habitat. This explains the association in 3-1A of fossils of
Pterostichus haernatopus Dej. , Carabus chamissonis Fisch. , Notiophilus semistriatus
Say, and Notiophilus borealisH^r r . (beetles normally found in areas of scant
vegetation) with fossils of beetles indicative of a moist tundra habitat.
The implication is that the taxonomic diversity of the carabid fauna of
3-1A is a reflection of the diversity of the paleoenvironment in which the
fossil beetles lived. Compared toassemblage 3-1A the carabid fauna of
3-3C is much less taxonomically diverse, even though the sample size
of 3-3C is larger and the diver sity at the familial level is greater. Per-
haps this implies that the paleoenvironment represented by 3-3C was
both drier and more uniform than that represented by 3-1A.
TABLE 5. Fossil Coleoptera from the McGee cut.
Taxa
Number of
individuals
Carabus truncaticollis Eschz, 3
Diacheila polita Fald. 4
Pterostichus (Cry obius) pinguedineus grp. 6
Pterostichus (Cry obius) ochoticus subgrp. 1
Pterostichus (Cry obius) tareumiut Ball 2
Pterostichus (Cry obius ) similis subgrp. 10
Pterostichus ( Cryobius) similis Mann. 22
Pterostichus (Cry obius ) parasimilis Ball 11
Pterostichus ( Cryobius) pinguedineus Eschz. 4
Pterostichus (Cryobius) ventricosus grp. 1
Pterostichus ( Cryobius) ventricosus E s chz . 1
Pterostichus (Cryobius) brevicornis Kby. 13
Pterostichus (Cryobius) mandibularoides Ball 3
Pterostichus ( Cryobius) mva/is Sahib. 1
Agonum quinquepunctatum Mtsch. 1
Amara alpina Payk. 8
Total 91
Fossil assemblage 3-3B from Eva Creek was shown by the statist
tical tests to be allied with 3-3C; however, in some respects it differs
from both 3-3C and3-lA. Of these differences, one, fewer taxa in 3-3B ,
is probably related to the smaller sample size of 3-3B. Other character-
istics of 3-3B maynot be explained so easily. For example, it contains
an abundance of fossils of the staphylinid genus Micralymma, the species
of which are tundra inhabitants (M. Sanderson 1967, written communi-
222
Matthews
cation) and the byrrhid genus, Curimopsis , presently a very rare insect.
Though these differences are not subject to detailed environmental inter-
pretation, I do believe they indicate that the paleoenvironment of Eva
Creek was not identical when as semblages 3-3C and 3-3B accumulated.
Minor differences in the content of plant macrofossils and the pollen
spectra of 3-3Cand 3-3B tend to support this conclusion (Matthews MS) .
To what extent are the different tundra environments represented
by the fossil insect assemblages indicative of climatic change? Paly-
nologists working in arctic Alaska have found that late Pleistocene clim-
atic changes produced only subtle modifications of the composition of
former tundra plant communities (Colinvaux 1964, Livingston 1955).
Also, there is abundant evidence that world wide climatic oscillations
occurred in the time interval during which the three Eva Creek insect
assemblages were deposited. These facts seem to imply that the ob-
served variability of the insect assemblages is a reflection of such cli-
matic change.
It is necessary to refer to evidence of fossil pollen in order to test
this implication. Because pollen is more easily and more widely dis-
persed than insects, fossil pollen provides a more generalized picture
of the environment of a region such as interior Alaska, and it is changes
in the general environment which are coupled with macroclimatic change .
Though the three pollen spectra associated with the insect fossils are
not identical (table 6), they are similar enough to be placed in the same
pollen zone according to the system of pollen zonationnow in use in nor-
thern Alaska (Livingston 1955). This means that similar climates ex-
isted in the Fairbanks area when each insect assemblage formed. Ac-
cordingly, the differences among the insect assemblages cannot have
major climatic significance. More than likely those differences reflect
features of a local environment such as the Eva Creek watershed. The
position of permafrost, proximity of water, exposure to sunlight, amount
of vegetation cover, and rate of deposition of loess are just a few of the
variables in such a local environment which may have influenced the com-
position of the insect assemblages.
TABLE 6. Fossil pollen spectra associated with Eva Creek fossil in-
sect assemblages.
Percentage of pollen types
- Indicates only a trace of pollen seen.
+ Indicates less than 3%.
Coleopterous Assemblages
223
ACKNOWLEDGEMENTS
The study presented in this paper was supported by grants from the
Society of Sigma Xi and the Otto Geist Fund at the University of Alaska.
I wish to thank R.D. Guthrie, C. L. Rowett, C.H. Hoskins (University
of Alaska); T.L. Pewe, R. Reger (Arizona State University); and G. R.
Coope, F.E. Shotton (University of Birmingham, England) for advice
criticism, and technical support. The leaseholder of the mining proper-
ty at Eva Creek, Mr. J.E. Wiegers, kindly allowed me access to the
exposure at all times.
I owe a particular debt of gratitude to C.H. Lindroth (University of
Lund, Sweden) without whose encouragement and gracious help this study
would certainly not have been possible and to G. E. Ball (University of
Alberta, Canada) whose help was equally valuable in dealing with the
difficult subgenus Cryobius and in obtaining comparable museum speci-
mens. In additionW. J. Brown (Canada Department of Agriculture) kindly
examined specimens from the families Byrrhidaeand Scarabaeidae, and
M. Sanderson (Illinois Biological Survey) aided with identification of
fossils representing the family Staphylinidae.
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(Coleoptera, Carabidae, Pterostichus ) with special reference to the
Bering Land Bridge and Pleistocene refugia: in Gressitt, J. L. ,
Pacific basin biogeography, Honolulu, Hawaii. Bishop Museum
Press, 133-151.
Ball, G.E. 1963b. Carabidae: in Arnett, R.H. The beetles of the
United States (a manual for identification) . Washington D. C. , Cath-
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Ball, G.E. 1963c. Descriptions of eleven new species of the beetle sub-
genus Cryobius ( Pterostichus , Col. Carabidae) from Alaska and north-
western Canada. Opusc. ent. 28 : 1-26.
Ball, G.E. 1966. A revision of the North American species of the sub-
genus Cryobius Chaudoir ( Pterostichus , Carabidae, Coleoptera). Opusc.
ent. , supplm. 28 : 166 pp.
Britton, M. E. ^966. Vegetation of the arctic tundra: Corvallis, Ore-
gon. Oregon State University Press, 64 pp.
Colinvaux, P.A. 1964. The environment of the Bering Land Bridge.
Ecol. Monogr. 34 : 297-329.
Coope, G.R. L961. On the study of the glacial and interglacial insect
faunas. Proc. Linn. Soc. Lond. 172 : 62-65.
Coope, G.R. 1962. A Pleistocene coleopterous fauna with arctic affin-
ities from Fladbury, Worcestershire. Q. J. geol. Soc. Lond. 118 :
103-123.
Coope, G. R. 1965. Fossil insect faunas from late Quaternary deposits
in Britain. Advance. Sci. (March) : 564-575.
Coope, G.R. and C.H.S. Sands. 1966. Insect faunas of the last glac-
iation from the Tame Valley, Warwickshire. Proc. R. Soc. (B)
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Matthews
165 : 389-412.
Coope, G. R. , F. W. Shotton, and I. Strachan. 1961. A late Pleistocene
flora and fauna from Upton Warren, Worcestershire. Phil. Trans.
R. Soc. (B), 24 : 379-421.
Frey, D. G. 1964. Remains of animals in Quaternary lake and bog sed-
iments and their interpretation. Ergebnisse der Limnologie, Heft
2 : 114 pp.
Greenslade, P. J. M. 1965. On the ecology of some British carabid
beetles with special reference to life histories. Trans. Soc. Brit.
Ent. 16 : 149-179.
Guthrie, R. D. 1968. Paleoecology of the large mammal community in inter-
ior Alaska during the late Pleistocene. Amer. Mid. Nat. 79 : 346-363.
Landin, B. O. 1961. Ecological studies on dung-beetles. Opusc. ent. ,
supplm. 20 : 288 pp.
Lindroth, C.H. 1953. The carabid beetles of Newfoundland. Opusc.
ent. , supplm. 12 : 160 pp.
Lindroth, C. H. 1961. The ground beetles of Canada and Alaska, 2.
Opusc. ent. , supplm. 20 : 1-200.
Lindroth, C. H. 1963a. The Aleutian Islands as a route for dispersal
across the North Pacific. In Gressitt, J. L. , Pacific basin bio-
geography. Honolulu, Hawaii. Bishop Museum Press, 121-131.
Lindroth, C.H. 1963b. The ground beetles of Canada and Alaska, 3.
Opusc. ent. , supplm. 24 : 201-408.
Lindroth, C. H. 1963c. The fauna history of Newfoundland. Opusc.
ent., supplm. 23 : 112 pp.
Lindroth, C. H. 1966. The ground beetles of Canada and Alaska, 4.
Opusc. ent., supplm. 29 : 409-648.
Livingston, D.A. 1955. Pollen profiles from arctic Alaska. Ecology
36 : 587-600.
Mason, W.R.M. 1956. Distributional problems in Alaska. Proc. 10th
int. Congr. Ent. 1 : 703-710.
Mason, W.R.M. 1965. Ecological peculiarities of the Canadian North.
Arctic Circular 16 : 15-17.
Pearson, R. G. 1962. The Coleoptera from a late-glacial deposit at St.
Bees, West Cumberland. J. Anim. Ecol. 31 : 129-150.
Pearson, R. G. 1963. Coleopteran as sociations in the British Isles dur-
ing the late Quaternary period. Biol. Rev. 38 : 334-363.
Pewe, T.L. 1955. Origin of the upland silt near Fairbanks, Alaska.
Geol. Soc. Amer. Bull. 66 : 699-724.
Pewe, T. L. 1966a. Permafrost and its effect on life in the north.
Oregon State University Press, 40 pp.
Pewe, T.L. 1966b. Paleoclimatic significance of fossil ice wedges.
Biuletyn Peryglacjalny (15) : 65-73.
Pewe, T. L. and Paige, R. A. 1963. Frost heaving of piles with an ex-
ample from Fairbanks, Alaska: United States. Geol. Surv. Bull.
111-1, 332-407.
Pewe, T. L. , O. J. Ferrians, D. R. Nichols, and T. N. V. Karlstrom. 1965
INQUA guidebook F (Central and southcentral Alaska) : Nebraska
Academy of Sciences, 141 pp.
Shotton, F. W. and P. J. Osborne. 1965. The fauna of the Hoxnian in-
terglacial deposits of Nechells , Birmingham. Phil. Trans. R. Soc.
(B) 248 : 353-378.
EFFECTS OF THE SIZE AND
FREQUENCY OF BLOOD MEALS ON CIMEX LECTULARIUS L.
MONIB SAYED TAWFIK
Department of Entomology
University of Alberta Quaestiones entomologicae
Edmonton, Canada 4 : 225-256 1968
Successive small blood meals can induce moulting in C. lectularius. Interval
between meals is important in the effect on moulting. The food conversion efficiency
in the different instars varies between 25.6 and 37%. Protein conversion efficiency in
the different instars ranged between 28.0 and 65.3%. Unfed females did not lay eggs
and the number of eggs laid per female as well as longevity showed good correlation
with the amount of blood ingested.
Accounts of the biology of Cirnex lectularius , reared under various con-
ditions, have been published by Bacot (1914), Hase (1917, 1919, 1930),
Cragg (1923), Jones (1930), Kemper (1930), Janisch (1933, 1935), Kas-
sianoff (1937), Johnson (1939, 1940a, 1940b, 1942), de Meillon and Gol -
berg (1946, 1947), and Bell and Schaefer (1966). More recently Usinger
(1966) published a monograph on Cimicidae reviewing most of the work
done on this groupof insects. Similarly studies on fertilization and phy-
siology of reproduction of the adults have been published by Cragg (1915,
1920), Mellanby (1935, 1939a) and Davis (1964, 1965a, 1965b). Although
a relationship between food supply and the growth of C. lectularius has been
demonstrated (Titschack 1930 and de Meillon and Golberg 1946 and 1947),
the effect of the size and frequency of bloodmeals has not been studied.
This investigation was undertaken with a view to filling some gaps in the
knowledge of bedbug biology.
METHODS
The threshold of hatching, nymphal development, and adult activity
is between 13 and 15 C (Hase 1930, Mellanby 1935, Kemper 1936, John-
son 1942). The thermal death point is 44 C. Omori (1941) found that
development ceased at 36 or 37 C. The temperature of 80 F (26.7 C)
and 75% R.H. used for the stock culture proved to be in the range of
optimum conditions for development, and was used for the experiments ,
The insects were kept in 4 x 4 x 1 . 5 cm plastic boxes with folded pieces of
filter paper and were allowed to feed twice every week on human blood.
The insects fed through the organdie covering a 3 cm diameter hole in
the lid of the plastic box. The eggs were laid on the folded filter papers
which were collected in new b^xes where the eggs were allowed to hatch
at the same temperature and relative humidity.
Two series of experiments were conducted for studying the effects
of different blood meal sizes on C. lectularius .
In the first series newly moulted insects, taken from the standard
culture, were kept singly in 2 x 7 cm specimen tubes with a 2 cm^ piece
of folded filter paper. The insects were fed only once on the second day
after moulting. Feeding periods of five or six different lengths were
used for each instar to provide the different meal sizes. For each feed-
ing period 20 insects were used from every instar. Observations on
subsequent moulting and longevity were recorded daily.
226
Tawfik
The efficiency of the various instars in converting human blood into
body tissue and extra- cellular fluid was determined by the method given
by Friend et al. (1965). The amount of blood required to produce 1 mg
gain in body weight was calculated. The average differ ence in body weight
between instars divided by the weight of the blood meal and multiplied
by 100 is the food conversion efficiency % (Friend et al. 1965). Twenty
first instar nymphs were taken from the standard culture immediately
after hatching for determining the weight changes during development
and the food conversion efficiency of the different instars. These insects
were fed to capacity on the second day after hatching and once every ten
days at least thereafter. The changes in body weight were recorded
during development till the insects reached maturity, Thi«= way of es-
timating food conversion efficiency is subject to certain errors. Cal-
culation of food conversion efficiency is always done on a dry weight
basis, but is still subject to some errors. The most important of these
arise from changes and differences in water content of both blood and
insects, and from the presence of blood residues in the gut.
Newly moulted adults were used for studying the effects of different
blood meal sizes on fecundity, longevity, and the duration of the preovi-
position period. The following combinations of males and females and
blood meal size were studied:
unfed female x engorged male
female fed for 60 seconds x engorged male
female fed for 120 seconds x engorged male
female fed for 240 seconds x engorged male
engorged female x unfed male
engorged female x engorged male
engorged female x male fed for 60 seconds
engorged female x male fed for 120 seconds
engorged female x male fed for 240 seconds.
For each combination 20 pairs were used and each pair was put in a sin-
gle 2x7 cm specimen tube together with a 2 cm^ piece of filter paper.
In the second series of experiments eggs were taken from the stan-
dard culture and put separately in 2 x 7 cm specimen tubes each with a
piece of filter paper. The insects were fed on the second day after hat-
ching. Eighty insects in four groups of 20 were used for the study of the
effects of each feeding period. The four groups were given the blood
meal of known duration at frequencies of 2, 4, 8, and 16 days respect-
ively. Observations were carried out daily and the effects of the different
feeding periods and their frequencies on the duration of the nymphal
stadia, and on the preoviposition period; fecundity, longevity, and weight
changes during development were recorded.
As most of the insects did not reach the adult stage when the feeding
periods were 15, 60, or 120 seconds, at the different frequencies, an
additional experiment was conducted. One hundred and sixty pairs in
four groups of forty were taken from the standard culture as soon as
they moulted from the fifth instar and used to complete the study of the
effects of the size and frequency of blood meals on fecundity, longevity
and the duration of the preoviposition period of the female and male.
The feeding periods used were 15, 30, 60, and 120 seconds at the same
Blood Meals
227
frequencies as before. Ten pairs were used for each frequency.
Effects of the Size of One Blood Meal
On the Nymphal Instars
The effects of the size of one blood meal per instar onper centmoul-
ting, duration of the nymphal stadia, longevity and mortality rates were
studied. Statistical analysis was undertaken to determine the level of
correlation between the amount of blood ingested and each of duration of
the nymphal stadia and longevity. A theoretical straight line relationship
was assumed for the effect on the duration of the nymphal stadia and the
longevity. The average decrement in the duration of the nymphal stad-
ium and the average increment in the longevity per unit increase in the
weight of the blood meal were estimated by calculating the coefficient of
linear regression. The discrepancies between the observed values and
the theoretical ones were shown by calculating the chi square to test the
goodness of fit to the straight lines.
The effect of the size of one blood meal per instar on the percentage
of nymphs which moulted in the different instars is shown in figs, la -
e. No insect in any instar moulted if fed for 30 seconds or less. In all
instars 100% moulting occurred if the insects were fed till engorgement.
In all five nymphal instars there were positive correlations between the
size of the blood meal and the percentage of nymphs which moulted; the
correlation coefficients ranged between 0.916 and 0. 999.
The minimum feeding period fora single bloodmeal to induce moul-
ting was 60 seconds in the first and second instars, 40 seconds in the
third instar, and 120 seconds in both the fourth and fifth instars. These
periods are all less than half of the maximum feeding periods. Friend
et al. (1965) stated that R. prolixus nymphs of all instars will moult nor-
mally when fed less than 50% of the maximum meal and for the third in-
star only 24.7% of the maximum was required. Locke (1958) caused
fourth-instar nymphs of R. prolixus to moult by feeding them 35% of the
maximum meal. The blood meal supplies the nutrients and stretches
the abdomen. The latter initiates the hormone cycle that results inmoul-
ting (F riend et al. 1965) . Wigglesworth (1963) demonstrated that nutrients
alone do not stimulate moulting and this was supported by the work of
Beckel and Friend (1964). The latter workers explained that release of
the moulting hormone, and activation and division of the epidermis is
caused by stretching and they claimed that in their experiments, because
of either inadequate nutrient or some undiscovered factor, the moulting
cycle was halted and the animal died prematurely. Locke (1958) studied
the effect of the blood intake on the diameter of the tracheae produced.
He found that the increase in the diameter at moulting in many of the
tracheae in Rhodniusis proportional to the size of bloodmeal. From these
studies on C. lectularius it was found that, in all the nymphal instars, moul-
ting can be induced by blood meals much smaller than the full bloodmeal
and that there is always a positive correlation between the size of the
blood meal and the percentage of moulting insects.
Figs, la-e also show the effect of the size of the bloodmeal on
the longevity of the different instars. The longevity of all five instars
increased gradually with the increase in the size of the bloodmeal. The
correlation coefficients ranged from 0. 773 to 0. 993. In the first four
228
Tawfik
instars chi square tests showed departure from a straight line relation-
ship. In the fifth instar, on the other hand, the relationship proved to
be a straight line.
Blood meal in mg
0 . 027 . 054
. 108
. 216
. 26
0 . 046 . 092
Blood meal in mg
. 184
. 368
.481
engorged
Feeding period in seconds
Fig. 1. Effect of the size of a single blood meal on the longevity and
moulting of nymphs of C. lectularius . a. first instar; b. second instar.
Longevity in days Longevity in days
Blood Meals
229
Blood meal in mg
0 . 12 . 24 .48 . 96 1. 08
Blood meal in mg
0 0.35 0.70 1.40 2.86
Feeding period in seconds
engorged
Fig. 1
c. third instar; d. fourth instar.
% moulted
230
Tawfik
Blood meal in mg
0 1.08 2.16 4.32 5.53
engorged
Feeding period in seconds
Fig. 1. e. fifth instar.
The effect of the size of the bloodmeal on the duration of the nymphal
stadia was determined from those insects which moulted in each group.
The duration of the nymphal stadium was taken as the period elapsing
between the moult before feeding and that after feeding. The results are
shown in table 1. In all the five nymphal instars there was a slight de-
crease in the duration of the nymphal stadium with the increase in the
size of the blood meal. The correlation coefficient ranged between -0.79
and - 0. 99.
To estimate the effect of the size of a single bloodmeal on the mor-
tality rate of the nymphal instar s , the data were analyzed by probit method
(Finney 1947). The LT50 was found for each blood meal size from the
provisional probit line (figs. 2a to 2e). The reliability of the estimate
is such that if the experiment is repeated there is 5% chance of getting
an LT50 value that is not within the fiducial limits.
The LT50 values and their fiducial limits are shown in table 2. In
all the five nymphal instars it was found that the LT50 increases with the
increase in the size of the blood meal.
Blood Meals
231
TABLE 1. Effect of the size of a single blood meal on the duration of
the different stadia of C. lectularius .
Stadia:
Feeding period in seconds
6-7
x = average weight of the blood meal in mg.
y = mean duration of the stadium ±S.E.
(number of insects)
range
Probit Probit
232
Tawfik
Log days
Fig. 2. Probit lines for longevity at various meal sizes in C. lectularius .
a. 1st instar; b. 2nd instar.
Fig. 2. c. 3rd instar;
d. 4th instar; e. 5th instar.
234
T awfik
Log days
Fig. 2. e. 5th instar.
Fig. 3 shows the average weight changes during development of
the nymphal instars when they take a full bloodmeal in each instar. The
sudden rise in weight after taking the blood meal is followed by a rapid
fall which is mostly due to the passage of the water and some other con-
stituents of the blood during the first day after the meal. Over the per-
iod preceding the next meal the weight keeps dropping at a progressively
slower rate. Titschack (1930) published a similar curve with small dif-
ferences in weights. Przibram has proposed that the weight of an insect
is doubled at each instar and the linear dimensions increased by 1. 26 at
each moult ( Wigglesworth 1965). Although this rule is more applicable
to Hemimetabola than to Holometabola, it is of doubtful value for C. lectularius
because its growth curve appears discontinuous due to the ingestion of
blood meals 3 to 5 times the body weight.
Blood Meals
235
TABLE 2. Effect of the size of a single blood meal on the LT50 in the
different instars of C. lectularius .
Feeding period in seconds
* x = average weight of the blood meal in mg.
** y = LT50
(95% confidence limit)
236
Tawfik
Days
Fig. 3. Weight changes during development of C. lectularius .
Table 3 shows that the food conversion efficiency in the different
nymphal instars of C. lectularius varies between 25. 6 and 37. 0%. It takes
3 to 4 mg of human blood to cause a 1 mg increase in the body weight
about 10 days after feeding. The third instar is less efficient than are
theothers. Comparison of table 7 with the results of Jones (1930) shows
a similarity in the trend of the food conversion efficiency in the different
instars with small differences in the values. The values shown in John-
son's Table III (I960) are all higher than mine because he weighed the
nymphs a short period after feeding. There is a difference in food con-
version efficiency between the fifth instar and the adult male and female.
This was overlooked by Jones (1930) and Johnson (I960).
Blood Meals
237
TABLE 3. Food conversion efficiency in the nymphal instar of C. lectularius.
No., of insects was 20 in each test.
Food conversion efficiency% = Average difference in body wt . x 100
Average wt. of blood meal
On the Duration of the Preoviposition Period
The effect of the size of the blood meal on the duration of the pre-
oviposition period is shown in figs. 4a and 4b. In fig. 4a the males were
fed till engorgement and the females for different periods. No ovipos-
ition took place when the females were unfed. An increase in size of the
female's blood meal caused a gradual decrease in the preoviposition
period (r = -0.908). The highly significant value for chi square (49.8)
shows departure from the theoretical straight line relationship.
In fig. 4b the females were fed till engorgement and the males for
different periods. There was no significant difference in the duration of
the preoviposition period.
On Fecundity
From fig. 5 it is clear that the size of the female's blood meal has
a profound effect on the percentage of females which lay eggs when the
mating males were fed till engorgement. No eggs were produced by un-
fed females. The more the females were fed the larger the number of
females which laid eggs.
Fig. 6 shows no effect of the size of the mating males' blood meal
on the percentage of females laying eggs when the latter were fed to
capacity.
Figs. 5 and 6 also show the relationship between the size of the fe-
males' and mating males' blood meals and the number of eggs laid per
female. Fig. 5 shows the effect of the size of the females' blood meal
on the number of eggs laid per female when the mating males were fed
to capacity. As shown in fig. 5 the more the females were fed the more
eggs they laid.
238
Tawfik
Blood meal in mg
0 1.44 2.88 5.76 6.48
Blood meal in mg
0 1.3 2.6 5.2 6.2
engorged
Feeding period in seconds
Fig. 4. a. Effect of the size of the female's blood meal on preoviposition
period of C. lectularius ; males engorged, b. Effect of the size of the mat-
ing male's blood meal on the preoviposition period of engorged female
C. lectularius.
Fig. 5 also shows the relationship between the size of the females'
blood meal and the number of eggs per milligram of blood. There is a
slight increase in the number of eggs laid per milligram of blood with
the increase in the size of the female's blood meal within the range of
feeding periods from 60 and 240 seconds. On the other hand, there is
a high increase when the feeding period increased from 240 to engorge-
ment.
CH-
"d
Cfl
OJO
be
<D
M-l
o
6
£
Blood meals in mg 239
0 1. 44 Z. 88 5. 75 6. 48
o 10
60 120 240 269
engorged
Feeding period in seconds
Fig. 5. Effect of the size of the blood meal of female C. lectularius on the
percentage laying eggs, number of eggs laid per female, number of eggs
laid per mg of blood, and percentage of infertile eggs.
Egg laying in C. lectularius has been studied under various conditions
(Hase 1930, Titschack 1930, Omori 1941, Johnson 1942). Inmost blood-
sucking insects, the number of eggs produced by a female is correlated,
within limits, with the quantity of food taken ( Wigglesworth I960). The
results shown in fig. 5 indicate that C. lectularius is no exception to this
rule. Cragg (1923) wrote that the number of eggs is dependent on thea-
mount of food obtained by the males as well as the females, and that fe-
males impregnated by unfed males do not produce as many eggs as fe-
males impregnated by fully nourished males. My studies confirm the
240
T awfik
Blood meal in mg
0 1.3 2.6 5.2 6.2
engorged
Feeding period in seconds
Fig. 6. Effect of the size of the mating males’ blood meal on the per-
centage of females laying eggs, number of eggs, and the percentage of
infertile eggs laid by engorged female C. lectularius .
former statement but indicate that the latter should be modified to read
"fertile eggs". My unfed females did not lay eggs, although it was re-
ported by Titschack (1930) and Johnson (1942) thatunfed females can lay
eggs. Jones (1930) claimed that the number of eggs produced by unfed
females is probably related to the food reserves acquired in the previous
instar. Davis (1964) studied the vitellogenesis of C. lectularius female that
had mated but were starved and he found that no maturation occurs.
Gooding (1963) postulated that although the most obvious function of the
meal in human lice is that it provides the material and energy for growth
of the nymphs and the maturation of eggs in the adult stage, it may also
function as a stimulant resulting in the formation and release of hor-
mones. Johansson (1964) said "after an adequate meal the 'nervous?’
stimuli from the gut activate the corpus allatum by way of the brain.
Blood Meals
241
Hormones from the corpus allatum and the neurosecretory cells in the
brain stimulate the ovaries and accessory glands. In the absence of ad-
equate food the brain inhibits the corpus allatum and the hormone titre
remains too low for the ovaries and accessory glands to function nor-
mally. " In C. lectularius it seems that there are more subtle factors in-
volved in the production of eggs than mere quantities of blood taken.
Bell and Schaefer (1966) found that the highest average egg production in
C. lectularius (5.4) was by those fed on 9:1 mixture of whole rabbit blood
and insect Ringer's, and the minimum was with females fed on Ringer's
alone.
Figs. 5 and 6 show that although the size of the female's blood meal
has no significant effect on the percentage of infertile eggs laid, the size
of the blood meal of the mating male has a significant effect on the per-
centage of infertile eggs laid by the female.
Titschack (1930) found that the percentage of sterile eggs increased
from 0 to 1% during the fertile period of C. lectularius . Mellanby (1939a)
found that mating is a necessary process for egg production. Davis
(1965b) studied theeffectof insemination in activating the corpus allatum
of female C. lectularius and he found that the mechanical aspects of insem-
ination play no role in this activation and concluded that the presence of
spermatozoa in the conceptacula or lateral oviducts stimulates the corpus
allatum. He found that 3 to 4 hours are required for seminal stimulus
to become effective and this period corresponds with the time required
for the spermatozoa to reach the genital tract. He also suggested that
the seminal stimulus results from summation of stimuli of many re-
ceptors in the genital tract.
On Longevity of the Adult
The effect of the size of the blood meal on the longevity of the adult
female is shown in fig. 7. Analysis of the data was undertaken on the
basis of dividing. The results were divided into females which did not
lay eggs, females which laid eggs, and both together; the correlation
coefficients were 0.99, 0.91 and 0.97 respectively. The straight line
relationship for females which did not lay eggs and for all females did
not hold for females which laid eggs. This indicates that when the fe-
males take smaller blood meals, egg production may have an influence
on their longevity.
Fig. 7 also shows that the males lived longer when the blood meal
was increased in size and that the relationship was a straight line.
Effects of the Size and Frequency of Blood Meals
On the Nymphal Instars
The effects of the size and frequency of the blood meals on moulting,
duration of the nymphal stadia, and mortality were studied.
The size and frequency of blood meals have a profound effect on
moulting of the insects in all instars (fig. 8). When the feeding period
was 15 seconds on every 4th, 8th, or 16th day the first instar nymphs
did not moult. At a frequency of every 2nd day only about 30% of the in-
sects reached the second instar.
242
Tawfik
Blood meal in mg
0 1. 44 2. 88 5. 76 6. 48
Blood meal in mg
0 1.3 2.6 5.2 6.2
engorged
Feeding period in seconds
Fig. 7. Effect of the size of a single blood meal on the longevity of the
female and male C. lectularius .
% moulted % moulted % moulted
Instar 1 Instar 2
100
60
20
0
Instar 3
Instar 4
Instar 5
No. of meals in 16 days
| | 15 seconds
60 seconds
120 seconds
§£§ 24 seconds
H engorged
Fig. 8. Effect of the size and frequency of blood meals on moulting in
the different instars of C. lectularius .
All insects fed for 60 seconds every 2 days reached the third instar
but thereafter the number of nymphs thatmoulted decreased and only 15%
of the insects reached the adult stage. When the interval between the
blood meals was prolonged to 4 days all the insects reached the second
instar and only 25% reached the fifth instar. At a frequency of every 8
days the number of insects that didnot moult increased from the first to
the fourth instar and 2. 5% reached the fourth instar. When the insects
were fed for 60 seconds every 16 days 55% reached the second instar.
244
Tawfik
All insects reached the third instar when fed for 120 seconds over
the range of intervals between meals of 2 to 16 days. At a frequency of
every 2nd day all the insects reached the adult stage. The number of
insects that reached the adult stage decreased with the increase of the
period between meals.
As the insects in the first four nymphal instar can engorge in less
than 240 seconds, the effect of this feeding period and its frequency is
shown in the fifth nymphal instar. For this experiment the insects were
taken from the group which were fed till engorgement to the fourth instar
at the different frequencies. When the fifth instar nymphs were fed for
240 seconds, in the range of frequencies studied, only one did not moult
to the adult stage.
All insects which were fed till engorgement at any frequency reached
the adult stage.
In general the number of insects which moult after the first meal at
any instar increases with the increase in the size of the blood meal.
Maximum moulting took place after taking the second meal, if the first
meal did not bring about more than 50% moulting.
When the nymphs were given a series of blood meals, the percentage
of moulting insects depended upon the size of bloodmeals as well as the
intervals between them. Wigglesworth (1934) was unable to get the fifth
instar nymphs of R . prolixus to moult by feeding them a series of small
blood meals at intervals. Friend et al. (1965), on the other hand, found
that third and fifth instar nymphs of R. prolixus can be induced to moult on a
succession of small meals at 30 day intervals. Unfortunately they did
not study the effect of the interval between feeding on moulting. My
studies also show that successive small meals can induce moulting and
that, in C. lectularius , the interval between feeding is very important. It
seems that when the nymphs are fed a series of small meals within cer-
tain interval limits they achieve a physiological stage after which moul-
ting can be induced by blood meals of small size. Friend et al. (1965)
claimed that this might be due to some moulting hormone produced under
the influence of small bloodmeals and stored until it reaches an effective
titre when moulting results. Theyadded thatthe cells may becomemore
responsive to the moulting hormone after they have assimilated the nu-
trients supplied by small meals. This might be so in C. lectularius because
the size and frequency of blood meals has no significant effect on the
period between the last meal and the day of moulting.
The frequency of feeding has a profound effect on moulting and this
effect is dependent on the size of the blood meal (fig. 8). The smaller
the blood meal and the longer the interval between feeding the lower the
percentage of the nymphs moulting. This maybe due to the effect of the
duration of the interval between feeding on the stored moulting hormone
suggested by Friend et al. (1965).
The duration of any nymphal stadium increases with the increase in
the number of meals required to induce moulting, and with the decrease
of frequency of feeding. On the other hand, neither the size and inter-
val between blood meals nor the number of meals have a significant ef-
fect on the period between the last meal and moulting. Jones (1930) re-
ported that bedbugs that took two meals during the third stadium moulted
Blood Meals
245
at a different time from others, but did not say whether this was earlier
or later.
It was found that the mortality increased with the decrease in the
size and the frequency of blood meals at any instar. Also the longevity
of the insects that did not moult at any instar increased with the increase
in the size and frequency of feeding.
On Weight Changes during Development
Figs. 9a to 9f show the relationship between the size and the fre-
quency of blood meals and the difference in body weight of the different
instars. The first instar was weighed one day after hatching and the
other instars on the day of moulting.
The difference in body weight between any two successive instars
increases with the increase in the size of the blood meals and with the
decrease in the interval between feeding. Similarly, the ratio of the
difference in body weight to the total weight of blood meals usually in-
creases with the increase in the size of the blood meal and its frequen-
cy. This increase may be due to an increase in the food conversion ef-
ficiency with or without a difference in the weight of the unassimilated
blood in the gut. The increase in this ratio with the increase in the size
of the blood meals when the nymphs were fed every 16 days is mostly
due to an increase in the food conversion efficiency.
On the Pre oviposit ion Period
Fig. 10 shows the effect on the preoviposition period. The effect of
frequency of feeding depends upon the size of the blood meal. The smal-
ler the blood meal the larger the effect of frequency of feeding. In gen-
eral, the more the insects feed and the shorter the interval between
feeding the shorter the preoviposition period.
On Fecundity
The effect of the size and frequency of blood meals on fecundity is
shown in fig. 11. Owing to the small number of insects which reached
the adult stage as well as their small range in the size and frequency of
blood meals, the experiment was completed using adults taken from the
standard culture. The size and frequency of blood meals which the adults
were fed had a marked effect on the number of females which laid eggs
and the number of eggs laid per female. None of the females laid eggs
when the feeding period was 15 seconds, at any frequency, nor when fed
for 30 seconds every 8th or 16th day. The number of females which
laid eggs and the number of eggs laid per female increase with the de-
crease in the interval between feeding and increases in size of the blood
meals. There is a high positive correlation coefficient (0. 99) between
the weight of blood meals taken by the female and the number of eggs
laid per female.
Fig. 12 shows the relationship between the number of eggs laid per
milligram of blood and the size of the blood meal and its frequency. The
data of the insects reached the adult stage alone did not show clearly the
relationship and the correlation coefficient was small (0.45). When an-
alysing these data together with those of the insects taken from the stan-
Difference in body weight
246
Tawfik
a
Feeding period
C
Fig. 9. Effect of the size and frequency of bloodmeals on the difference
in body weight between successive instars of C. lectularius . a. 1st to 2nd
instar; b. 2nd to 3rd instar; c. 3rd to 4th instar; d. 4th to 5th instar.
Blood Meals
247
■ engorged
★ 240 sec
• 120 sec
A 60 sec
i
c
60
120
240
306
2
4
8
f
o
.5
1.0
60 120
240 290
4
2 4
No- of meals/16 days
8
Feeding period in seconds
Fig. 9. e. 5th instar and adult female; f. 5th instar and adult male.
dard culture, to complete the experiment, the correlation coefficient
was 0.7 0. The effect of frequency of feeding on the number of eggs laid
per milligram of blood (fig. 12a) depends upon the size of the blood meal.
The smaller the blood meal the larger the effect of frequency of feeding.
When the insects were fed till engorgement the maximum number of eggs/
mg of blood was when the insects fed every 4 days. Increasing the fre-
quency of feeding causes a decrease in the number of eggs /mg of blood;
the amount of blood taken is then more than enough for optimum egg pro-
duction. Decreasing the frequency of feeding also decreases the num-
ber of eggs/mg of blood, because some of the blood is needed for main-
tenance metabolism. When the feeding periods were 240, 120, 60, and
30 seconds the number of eggs /mg of blood increased with the increase
in frequency of feeding.
Also the effect of the size of the blood meals depends upon the fre-
quency of feeding (fig. 12b). When the interval between meals was 2
days the number of eggs/mg of blood increases with the increase in the
size of the blood meal and the optimum egg production was when the
feeding period is in the range of 120 to 240 seconds. When the interval
between feeding was four days the shape of the curve is changed from
convex to step-like with a maximum number of eggs /mg of blood when
the insects were fed till engorgement. This indicates that optimum egg
production takes place when the feeding period is in the range between
240 seconds and engorgement. The change in the shape of the curve to
concave and sigmoid when the intervals between meals were 8 and 16 days
respectively shows that taking these blood meals at these intervals was
not optimum for egg production and the number of eggs/mg of blood in-
creases with the increase in the size of the blood meal.
248
Tawfik
Figs. 10, 11 & 12. Effects of the frequency (a) and the size (b) of (10)
blood meals on the preoviposition period in C. lectularius ; (11) blood meals
on the number of eggs laid per female C. lectularius ; (12) blood meals on
the number of eggs laid per female C. lectularius. ( insects taken from
standard culture).
Blood Meals
249
Comparing fig. 5, the relationship between the size of a single blood
meal and the number of eggs laid per mg of blood, with the curve con-
necting size of the blood meal and the number of eggs laid per mg of
blood when the interval between feeding was two days (fig. 12b), it is
clear that the values when the insects were fed for 60, 120, and 240
seconds are lower than that in fig. 12b. This indicates that the amount
of blood responsible for these differences in the values is not directed to
egg production but might, for example, stimulate ovarian activity. On
the other hand, the number of eggs laid per mg of blood when the insects
were fed till engorgement is larger in fig. 5 than in fig. 12b. This in-
dicates that the first feeding period required for optimum egg production
is in the range between 240 seconds and engorgement.
There is little correlation (r = 0. 32) between the weight of the fe-
male after the fifth moult and the number of eggs laid per female. On
the contrary, there is a high positive correlation coefficient of 0. 97 be-
tween longevity and the number of eggs laid per female.
Fig. 13 shows the effect of the mating male’s blood meals and their
frequencies on the percentage of infertile eggs laid by the females. The
smaller the size of the blood meals the larger the effect of frequency of
feeding. The correlation coefficient r between the size of the males'
blood meals and the percentage of infertile eggs was -0.42 and -0.56 for
the data of the insects which reached the adult stage alone, and these
data together with those of the insects taken from the standard culture
respectively.
The results of the experiments on blood intake and egg production in
C. lectularius are similar to those reported by Roy (1936) and Friend et al.
(1965). Roy (1936) studied A. aegypti and found that 0.82 mg of blood
was required before the insect would lay eggs. In addition, the number
of eggs laid per female was not dependent on the weight of the insect be-
fore feeding but there was a good correlation between the size of the
blood meal and the number of eggs laid. Friend et al. (1965) found
that female R . prolixus would not produce eggs until 56. 6 mg of blood were
fed and the correlation coefficient for the body weight before feeding and
egg production was only 0. 30.
In some other blood-sucking insects fecundity is influenced mainly
by the weight of the female before feeding as long as a certain minimum
meal is consumed. Barlow (1955) proposed that the reason for the cor-
relation between the body weight of Aedes hexodontus and fecundity is because
larger females tended to consume more blood than smaller ones.
On Longevity
Fig. 14 shows the effect of the size and frequency of blood meals on
longevity of the female. Statistical analysis of these data showed that the
correlation coefficient between the size of blood meals and longevity of
the females was 0. 97. The longevity of the males increases with the
increase in the size of the blood meal and with the decrease in the inter-
val between feeding (fig. 15) . Analysis of the data showed a correlation
coefficient (r) between the size of the blood meal and longevity of the
males of 0. 92.
T awf ik
250
60
50
„ 40
o
o>
“ 30 - -
0\c 20
J0--
0
Figs. 13, 14, & 15. Effects of the frequency (a) and the size (b) of (13)
mating male's blood meals on the percentage of infertile eggs laid by fe-
male C. lectularius ; (14) blood meals on the longevity of female C. lectularius;
(15) blood meals on the longevity of the male C. lectularius. ( insects
taken from standard culture).
Blood Meals
251
PROTEIN CONTENT AND RESPIRATORY
RATE IN THE DIFFERENT INSTARS OF C. LECTULARIUS
Methods
The protein content in the different instars of C. lectularius was deter-
mined using Folin phenol reagent (Lowry et al. 1951). Insects used in
this experiment were taken from the standard culture. First instar
nymphs were taken immediately after hatching and starved for five days.
The other nymphal instars were taken on the day of moulting and starved
for about ten days. For the adult stage two tests were undertaken. In
the first test, fifth instar nymphs were taken from the standard culture
and were given a full blood meal and put separately on 2 cm^ piece of
folded filter paper in 2 x 7 cm specimen tubes. After 12 days protein
content of the females and males was estimated. In the second test,
females and males were put together and given a full blood meal on the
second day of moulting. Twelve days later the protein content of the fe-
males and males was estimated. The protein content of the eggs was
also determined.
Oxygen consumption and carbon dioxide output in the different instar s
were measured in a Warburg constant volume respirometer using the
direct method of Umbreit et al. (1964). Insects used were taken from
the standard culture one day after moulting and were given a blood meal
before starting the experiments . The respiratory quotient in the different
instars was determined.
Results
Protein Content
The protein content in the different instars of C. lectularius is shown in
fig. 16. The weight of protein per female was greater than that per
male. Females which were kept separately had a higher protein content
than those which were kept with males. Oviposition seems to be respon-
sible for this difference because the females which were kept withmales
laid eggs while those which were kept alone did not. Similarly, the dif -
ferencein protein content of the males may be due to sperm transfer as
well as to the activity in courtship and mating. The percentage of pro-
tein ranged from 21. 8 to 27% in the nymphal instars. In the females it
was 26. 1 in those which were kept alone and 18. 2% in those which were
kept with males. In the males it was 27. 2 in those kept alone and 25.4 %
in those kept with females.
Spector ( 1956) gave the following chemical composition of the human
blood:
water 83. 000 g/ 100 ml
total protein 21. 800 g/ 100 ml
lipids 0. 560 g/ 100 ml
carbohydrates 0.439 g/ 100 ml
From this the amount of protein in the blood meal, in the different in-
stars, was calculated. Lipids and carbohydrates contribute very little
in the chemical composition of human blood as compared to protein.
252
Tawfik
Assuming that there is no conversion from the lipids and carbohydrates
of the blood into protein, the efficiency by which the bedbugs, in the dif-
ferent instars, can convert the blood protein into body protein can be
estimated (table 4). Protein conversion efficiency in the different in-
stars of C. lectularius ranged between 28. 0 and 65. 3%. Similar results to
those of the food conversion efficiency (table 3) would be expected only
if the chemical composition of bedbug tissue were similar to that of hu-
man blood.
Fig. 16. Relationship between the body weight and protein content in the
different instars of C. lectularius .
TABLE 4. Protein conversion efficiency in the different instars of
C. lectularius.
Instar
Wt. of blood
meal (mg)
Protein content
of blood
meal (mg)
Increase in
body protein
content (mg)
Protein
conversion
efficiency %
Blood Meals
253
Rate of Respiration
The respiratory rates in the different instars of C. lectularius are
shown in fig. 17. The oxygen uptake per insect per hour increases from
the first nymphal instar to the adult stage. Oxygen uptake by the females
was greater than by the males. The oxygen uptake, expressed as mi-
croliters/milligram of body weight/hour, was the same in the first two
nymphal instars and then increased to a maximum in the adult stage.
The respiratory quotient in the different instars ranges between 0. 88
and 0. 95 which indicates that either protein or fat or both are included
in the metabolism.
¥
u
P
o
rP
tuO
a
00
O
=L
P
o
X
o
CD
cfi
P
00
o
d_
Fig. 17. Oxygen uptake in the different instars of C. lectularius.
254
Tawfik
From the weight of the total protein in the blood meal and the in-
crease of protein content in the different instars, the weight of protein
in the blood meal which is metabolized plus that which is not absorbed
can be determined. Assuming that there is no interconver sion between
the chemical constituents of the blood meal during metabolism the weight
of protein which is metabolized plus the protein which is not absorbed
per day was estimated (table 5). It was found that the rate of metabolism,
expressed as mg of protein/day, like that expressed as microliter oxy-
gen/insect/day, increases from the first to the fifth nymphal instar.
TABLE 5. Rate of metabolism in the different nymphal instars of
C. lectularius.
The method by which the weight of protein, which is metabolized
plus that which is not absorbed, is shown in table 6. It is clear that the
weight of protein which is metabolized plus that which is not absorbed,
like the rate of respiration, is greater in the adult female than in any
nymphal instar.
TABLE 6. A partial protein budget in the adult female C. lectularius.
Weight of blood meal
Protein content of the blood meal
Weight of protein/ egg
Number of eggs laid/female
Weight of protein in all the eggs
Weight of protein metabolized +
protein not absorbed
Mean longevity
Weight of protein metabolized +
protein not absorbed
Respiratory rate
6. 48 mg
I. 40 mg
0. 034 mg
II. 55 eggs
0. 393 mg
1. 007 mg
39.6 days
2. 5 x 10“2 mg/day
0.88 pi O2/ female /hour
Blood Meals
255
GENERAL DISCUSSION AND SUMMARY
The size of the blood meal has its effect in two ways. The first one
is the volume of the blood ingested that causes either stretching of the
abdomen and moulting in the nymphal instars or stimulates oviposition
in adult females. The second is the quantity of nutrients in the blood in-
gested and its effects on development or reproduction. It seems that
taking a threshold quantity of blood as a single meal is more important
to C. lectularius than taking the same quantity over a period of time in more
than one blood meal. Also the blood of different hosts may have its ef-
fect on C. lectularius through the differences in the nutritive value of blood.
The results of the effects of the size and frequency of blood meals
on C. lectularius can be summarized as follows:
1. Moulting can be induced in all the nymphal instars by blood meals
smaller than the full blood meal and there is always positive cor-
relation between the size of the blood meal and the percentage of
insects moulting.
2. The duration of the nymphal stadia decreases with the increase in
the size of the bloodmeals. It also decreases with the decreases in
the number of successive meals required to induce moulting. Neither
the size and interval between blood meals nor the number of meals
have a significant effect on the period between the last meal and the
day of moulting.
3. The food conversion efficiency in the different instars varies be-
tween 25. 6 and 37. 0% and the third instar is less efficient than the
others. It takes about 3 to 4 mg of human blood to cause a 1 mg in-
crease in the body weight about 10 days after feeding. Protein con-
version efficiency in the different instars ranged between 28. 0 and
65. 3%.
4. The increase in the size of the females' blood meals causes a de-
crease in the preoviposition period. The size of the male's blood
meal has no significant effect on the preoviposition period of a fe-
male mated with him.
5. No eggs were produced by unfed females. The more the females
were fed the larger the number of eggs laid per female. There was
no significant correlation between the body weight of the female and
the number of eggs laid. There was no effect of the size of the mat-
ing male's blood meal on the percentage of females laying eggs.
The percentage of sterile eggs increased with the decrease in the size
of the mating males' blood meals.
6. There is always a significant correlation between the size of the
blood meals and the longevity of any instar.
It seems important to study the role of crowding on frequency of
mating and also the traumatic effects of repeated mating.
7.
256
Tawfik
ACKNOWLEDGEMENTS
I should like to express my sincere thanks to Professor B. Hocking,
Entomology Department, University of Alberta, for his guidance and
many valuable suggestions during the supervision of this study. Thanks
are also due to Dr. R. Gooding for his valuable advice and kind assist-
ance, and to my external examiner, Dr. R. L. Usinger, University of
California, Berkeley, California. This study was made possible by the
financial as sistance of theU.S. Army Grant No. 63-G83 (Hocking Trust) .
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