SNe oO NP Neo Ne eee

a os ie a

ne IBRARIES SMITHSONIAN INSTITUTION NOJLONLILSNI SSINVUE

cc Fa a a re > i a.

= oO pra oO his. 2)

ow rma <0 i oo Pe

AD ee a a a a bas:

= ry a = aN =

_ is se - = =

m z Sh z o ok

y NOILNLILSNI NVINOSHLINS S3IY¥VYUGIT LIBRARIES SMITHSONIAN

” = wo z pe ” -

= vee = . ee Ny = a

ar z = uh fey = zi

> O ae Blo oe SS a. 5 ‘

g - 8SUwy = WO 8 g

Z E 2 “py : nee =

> = > aie = sa ae =

Pa w" ed o9) = Zz w”

) LIBRARIES SMITHSONIAN INSTITUTION NOILONLILSNI NVINOSHLIWS

= a. tif jg > a = WS cc

= “ hy) — < = 4 AG * <x

= «gy Ss cs GS WQ «=

: Uh: ; 2 NE

= aT : = J Z pa ae :

| NOILOLILSNI NVINOSHLINS S3SIYVYUYSIT LIBRARIES SMITHSONIAN _INSTITUTI

= ns he = [— = i ia

Oo = = 5

= og S Ens wo — ow

E Be NN za 20 os 2

a. NS st Be) - ee)

a = WY i n* mea :

Z pe ee az m

LIBRARIES SMITHSONIAN INSTITUTION NOILALILSNI_ NVINOSHLINS saiuvudgl

NVINOSHLIWS

NVINOSHLINS S3ZI1YVYdIT LIBRARIES

NVINOSHLIWS

Sx AQ

SMITHSONIAN

NWINOSHLIWS

SMITHSONIAN _INSTITUTIO

V i \

aN NS

NOILMLILSNI

NOILNALILSNI

NOILNLILSNI

LIBRARIES SMITHSONIAN INSTITUTION NOILNLILSNI saluvud

NVINOSHLINS

NOILALILSNI NVINOSHLIWS

SAIUVUSIT LIBRARIES

INSTITUTION

NVYINOSHLIWS | SASIYVed!IT LIBRARIES SMITHSONIAN

NVINOSHLINS S3I1Y¥YVuYal) LIBRARIES SMITHSONIAN

= w Pas x.

< = is a

ee = = 3

O a a Tag O

” YO y ” A

Ae Oi ba fu

s = 26 a

7 LIBRARIES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLIWS Sszluvag

; 2 7 o E & 3 \

=. «. ht yg > ac = AS oc

7 x hie i, <x 4 * WS Ne

: = aggy 5 : SAY

3 a “UY = in 2 "Re

y NOILALILSNI NVINOSHLINS S3IYVYUGIT LIBRARIES SMITHSONIAN_INSTITUTIC

= w : —= w “0 oss

: 2 Na 5 : 5 8%.

E 5 URNS OE 3 = “2

a aN ans a

I 2 SAA Ee a -, =

ae ae la EO Nf ee Oo gee

= : ed z zig z

-1ES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS SZiuVudIT LIBRA

= z i fe = Ae

° on © 0] ~ v ow Oo 109)

_~ x sa Cy \ og ed a

ky a = > rm =

- = X 2 = Es

Lop) [op] ig

= ~ a z e a: 2

JLSNI NVINOSHLINS Sa iINvuag Tul BRARI ES SMITHSONIAN _ 2 NOILN

<x = , AN os = =< =

Wks a z= ASS = > =

bg oO cr. Oo Ws. “ as O : ie

z g ZR 8 y

é a E WO 2 = Z

Z _ i =

e 3 7 » 3 = 5

R}ES SMITHSONIAN

S3aluvugil LIBRARIES

ul .

x. za

S“VGly ¢

po 5

onal Pus

ASNI =

5 °

2 =

> =

21ES SMITHSONIAN INSTITUTION

g Zz .

a Se

\ 2

\ Zz

JLSNI_ NVINOSHLIWS

NOILNLILSNI

R1ES SMITHSONIAN

S31YVNGIT LIBRARIES SMITHSONIA

re 4 Uy

ILSNI NWINOSHLINS

te 5

Yy -

RIES SMITHSONIAN

a z

i) vas

a =

x %

wo =

| a 5

| i -

1LSNI

oc Ze

o °

3 wy E

5 TUR SE

i ee | bo

NVINOSHLIWS

S3JIMVYAIT LIBRARIES

INSTITUTION

SAIYVYal)

INSTITUTION

NVINOSHLINS S3IuYVvudit

INSTITUTION NOILNLILSNI NVINOSHLINS Saluvugi7 LIBR:

LIBRARIES

NOILNLILSNI

SMITHSONIAN” INSTITUTION NOILN

INSTITUTION NOILALILSNI

SaIUVY@IT LIBRARIES

INSTITUTION

SSIYVUSI

NOILOLILSNI NVINOSHLINS S31u¥vVudi) LIBR,

“we

NVINOSHLIWS

SMITHSONIAN

NVINOSHLIWS

SMITHSONIAN

INSTITUTION NOILNA

2 z i

: = OFG.> :

c “tS Pe

= mM = m

OQ sani re) ba

=z a — |

NOILALILSNI NVINOSHLINS S31INWHSIT LIBR.

~s Pd F

< o Ws oe a

= 2 Ww = 0)

a) 4 Was = >

iF > = att

= ‘2 =

oe)

Z i Zz a

a +, _!NSTITUTION NOILf

< = < Ne =

z 1 = KY 4

oO: mF 5 co 7

WY ~ Ww - ep)

=) O 3 O

= z ae a

= % > > >

”~ PO A ae W) ; ee

pNOlnsitsni NVINOSHLIWS SsLavae yy

pam Ww

ME a a 5 A Hf 2

a ae =

: ZMK = =

+ ey = _

. ro) ~ ae O

al Pe ~. a9 <

LIBRARIES SMITHSONIAN INSTITUTION NOILE

i = 2 on =

“oe oO

oo — tw cat

2 = ey =

a ria = =

MAR 30 1976

Litsk AnILS ee

ENTOMOLOGIC —

SOCIETY of

BRITISH COLUMBIA

‘Vol. 72 Issued December 31, 1975

ECONOMIC

DOWNING & MOILLIET — Preliminary trials with Citrazon—a selective

acaricide

PROVERBS & NEWTON — Codling moth centrol by sterile insect release:

importation of fruit & fruit containers as a source of reinfestation

: MADSEN & MORGAN — Mites and insects collected from vineyards in the

Okanagan & Similkameen Valleys, British Columbia

| Be RASKE & ROBINS — Wood borer control in spruce logs with p-dichlorobenzene

and plastic sheeting (Coleoptera: Cerambycidae)

GENERAL

RUBIN & BEIRNE — The European fruit lecanium, Lecanium tiliae (L.)

(Homoptera: Coccidae) in southwestern British Columbia

_ DYER, HALL & SAFRANYIK — Numbers of Dendroctonus rufipennis (Kirby)

& Thanasimus undulatus Say at pheromone-baited poisoned &

unpoisoned trees

| ‘ CANNINGS — Some Chironomidae (Diptera) new to British Columbia &

| CHO-KAI CHAN & FORBES — Life-cycle of a spiral gall aphid, Pemphigius

spirothecae (Homoptera: Aphididae) on poplar in British Columbia

TAXONOMIC

STAINER — The status of Conocephalus fasciatus vicinus (Morse, 1901)

(Orthoptera: Conocephalidae)

BOOK REVIEWS

NOTICE TO CONTRIBUTORS

JOURNAL

of the

ENTOMOLOGICAL

SOCIETY of

BRITISH COLUMBIA

Vol. 72 Issued December 31, 1975

ECONOMIC

DOWNING & MOILLIET — Preliminary trials with Citrazon—a selective

Sa UNGN CRG MME RC MNY fee fap cept tL oe nee hs os. hie a big Sy Sg Oe o te ees, lo ee ae ew we a

PROVERBS & NEWTON — Codling moth control by sterile insect release:

importation of fruit & fruit containers as a source of reinfestation ............ 6

MADSEN & MORGAN — Mites and insects collected from vineyards in the

Okanagan & Similkameen Valleys, British Columbia ..................-0000. 9

RASKE & ROBINS — Wood borer control in spruce logs with p-dichlorobenzene

and plastic sheeting (Coleoptera: Cerambycidae) ............... 000 cece eee 15

GENERAL

RUBIN & BEIRNE — The European fruit lecanium, Lecanium tiliae (L.)

(Homoptera: Coccidae) in southwestern British Columbia .................2.. 18

DYER, HALL & SAFRANYIK — Numbers of Dendroctonus rufipennis (Kirby)

& Thanasimus undulatus Say at pheromone-baited poisoned &

AM DUGIS ONC OMECES Beretta te hic elterg o seaco «© GER Rey Niece qe ee ook w aca foe ech oh ere rei See es 20

CANNINGS — Some Chironomidae (Diptera) new to British Columbia &

(CHUM, 4d eet Neen a pea eee a es ner eee MR Ser mr ee ae oe eee er 23

CHO-KAI CHAN & FORBES — Life-cycle of a spiral gall aphid, Pemphigius

spirothecae (Homoptera: Aphididae) on poplar in British Columbia ........... 26

TAXONOMIC

STAINER — The status of Conocephalus fasciatus vicinus (Morse, 1901)

‘Orthoptera: Conocephalidae)...< 6 c0cses 55 0 sew cee sd paw we 6 oe dese e wae 6 34

PAMPER TAMPERE VMIEAVY 9 etrcites Silas, Sis ie oia'se. 4:'o)sace wena aa este Wis eG Sue a e'w a Wieost! wie. Siew hah a oe aL 17, 35

J. ENTOMOL. Soc. Brit. CoLUMBIA 72 (1975), Dec. 31, 1975

Directors of the Entomological Society of

British Columbia for 1975 - 1976

President

J. R. CARROW

Pacific Forest Research Centre,

506 West Burnside Rd., Victoria

President-Elect

H. S. GERBER

B.C. Dept. of Agriculture, Cloverdale

Past President

T. FINLAYSON

Simon Fraser University,

Burnaby

Secretary-Treasurer

N. V. TONKS

2819 Graham St., Victoria

Honorary Auditor

D. G. FINLAYSON

Research Station, C.D.A., Vancouver

Editorial Committee

H. R. MacCARTHY

Vancouver

J. CORNER

Vernon

Directors

B. D. FRAZER (2nd) P. J. PROCTER (2nd)

J. MYERS (1st) B. AINSCOUGH (1st) R. CHORNEY (ist)

Regional Director of National Society

J. P. M. MACKAUER

Simon Fraser University, Burnaby

J. EnTomo.. Soc. Brit. CoLuMBIA 72 (1975), Dec. 31, 1975 3

PRELIMINARY TRIALS WITH CITRAZON—A SELECTIVE

ACARICIDE!

R. S. DOWNING AND T. K. MOILLIET

Research Station, Agriculture Canada,

Summerland, British Columbia

ABSTRACT

Citrazon (Ethyl O-benzoyl 3 chloro-2, 6-dmethoxy benzohydroximate)

was compared with two organotin acaricides Plictran and Vendex for mite

control on apples and pears. Citrazon controlled the phytophagous

European red mite, Panonychus ulmi (Koch) as effectively as Plictran and

Vendex and all were low in toxicity to the phytoseiid mites, Typhlodromus

occidentalis Nesbitt and T. columbiensis Chant. Unlike Plictran and Vendex,

Citrazon was much less toxic to another predatory mite, Zetzellia mali

Ewing, and to the pear rust mite, Epitrimerus pyri (Nal.).

An essential feature of a good acaricide for

integrated mite control is that it be selective.

The ideal one would be toxic to all harmful

mites but innocuous to the beneficial mites.

When used at the half-inch green bud stage,

mineral oil is very selective as it is toxic to the

eggs of the European red mite, Panonychus

ulmi (Koch), but has little toxicity to the pred-

aceous phytoseiid mites, eg. Typhlodromus

occidentalis Nesbitt, or to apple rust mite,

Vasates schlechtendali Nal., (Downing 1967).

Rust mites are an important alternate food

source for phytosiids as shown by Collyer

(1964) and help to make integrated mite con-

trol a success. Oil, however is not the ideal

acaricide as it can be phytotoxic and cannot

be used with safety during the summer season.

Propargite and the new organotin acaricides

such as Plictran and Vendex are selective as

they are toxic to European red mite, McDaniel

spider mite, Tetranychus mcdanieli McG., and

have low toxicity to the predaceous mite T.

occidentalis. However, these acaricides are

toxic to rust mites and to another predaceous

mite, Zetzellia mali Ewing, and may under

certain circumstances do more harm than good.

This is a report of laboratory and field trials

with a new acaricide, Citrazon.

MATERIALS AND METHODS

Citrazon was introduced by Nippon Soda

Co. Ltd., Tokyo, Japan, and is being developed

in Canada by Ciba-Geigy Canada Ltd. Its

chemical identity is Ethyl 0-benzoyl 3-chloro-

2, 6-dimethoxy benzohydroximate. Citrazon,

20% emulsifiable concentrate was compared

with the following selective acaricides in labora-

tory and orchard experiments:

Plictran 50% wettable powder,

tricyclohexyltin hydroxide. Vendex

50% wettable powder, Hexakis (beta,

beta-dimethylphenethyl)-distannoxane.

‘Contribution No. 415,

Canada, Summerland, B.C.

Research Station, Agriculture

Laboratory and Greenhouse Experiments

Toxicities of Citrazon and Plictran against

the native mite predators, T. occidentalis, T.

columbiensis Chant and Z. mali, were tested

in a Potter Spray Tower. Five predators were

placed on waxed black paper. This was floated

on cotton saturated with water in petri dishes.

Dishes were placed in the spray tower and ex-

posed to 2 ml of the spray mixture. Treatments

were replicated 6 times. Examination of the

predators with a steremicroscope was made

1, 2, and 3 days after treatment and the per-

centage mortalities obtained were corrected for

natural mortality in the check plots according

to the method of Abbot (1925).

European red mites were reared on potted

Red Delicious apple trees in a greenhouse and

these were sprayed on a turntable with a

Kellog-American compressed-air paint gun

sprayer that produced a fine even spray at a

pressure of 15 lb. per square inch (1 kg per sq.

cm). Volume of spray was not measured but

each tree was thoroughly sprayed to runoff.

Treatments were replicated 5 times. Estimates

of mite populations were made 3 and 10 days

after spraying by taking 5 leaves from each

tree and processing them by the method of

Henderson and McBurnie (1943) as modified

by Morgan et al. (1955).

Orchard Experiments

Sprays were applied with a high volume

hand gun sprayer operated at 425 p.s.1.

(30 kg per sq. cm) and the trees were sprayed

until dripping. Orchard trees were either Red

or Golden Delicious on semi-dwarf rootstalk

or Bartlett pears, all spaced 7% ft. by 15 ft.

(2.28 m x 4.57 m). Plot size was 3 trees with

3 replicates per treatment except for the ex-

periment summarized in Table 3 in which only

2 replicates were available. Estimates of mite

populations were made on 25-leaf samples

taken from the middle tree of each replicate and

processing these as above.

4 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

RESULTS AND DISCUSSION

Laboratory and Greenhouse Experiments

Table 1 shows that neither Citrazon 20%

E.C. 0.5 pt (284 ml) nor Plictran 50% W. P.

4 oz. per 100 gal. (25 gm per 100 1) were toxic

to the 2 predaceous phytoseiid mites, T.

occidentalis or T. columbiensis Chant: that

Citrazon was not toxic to the predaceous stig-

maeid mite, Z. mali, but Plictran was. T.

occidentalis is the most important of the 3

predators but under certain conditions the

other predators may be valuable in regulating

the densities of European red mite. T. colum-

biensis is much more cold-hardy than T. occi-

dentalis and sometimes after a very cold winter

is the only phytoseiid species that is present in

commercial orchards. Z. mali unlike T. occi-

dentalis, can usually survive when prey den-

sities are very low and is sometimes the only

predeaceous mite found in some commercial

orchards.

TABLE 1. Corrected percentage mortalities of mites in petri dishes 3 days after application of

acaricides in a Potter Spray Tower.

Acaricide per 100 gal.

Citrazon 20% E. C. 0.5 pt.

Plictran 50% W. P. 4 oz.

Citrazon and Plictran were equal in toxicity

to the European red mite and T. occidentalis

on apple trees in greenhouse trials. Both acari-

cides controlled the phytophagous mite and

allowed some survival of the predaceous mite

as shown in Table 2.

T. occidentalis T. columbiensis Z. mali

0 3 0

0 0 78

Orchard Experiments

Vendex and Citrazon showed a low toxicity

level when tested against JT. occidentalis on

Red Delicious apple trees. Even 1 pt per 100

gal. concentration (125 ml per 100 litre) of Cit-

razon, which is twice the concentration of

TABLE 2. Numbers of mites per 25 leaves after application of acaricides to potted apple trees

in a greenhouse.

Acaricide per 100 gal.

Citrazon 20% E. C. 0.5 pt

Plictran 50% W. P. 4 oz.

Check - no treatment

active ingredient of either Vendex or the lower

rate of Citrazon, allowed good survival of this

predatory species (Table 3). On Golden Delic-

ious trees, Citrazon gave quicker control of

European red mite and was almost non toxic to

Z. mali. Vendex, on the other hand, was slow

in controlling the red mite and quite toxic to

the predator Z. mali as summarized in Table 4.

European red mite T. occidentalis

3 days 10 days 3days 10 days

12 a 6 1

12 10 1 2

260 378 11 ue

Citrazon was compared with Plictran

against the pear rust mite, Epitrimerus pyri

(Nal.), and as shown in Table 5, Citrazon 20%

E.C. at 0.5 pt. or 1 pt. per 100 gal. (62.5 ml or

125 ml per 100 1) did not give adequate con-

trol whereas control with Plictran was excel-

lent.

TABLE 3. Numbers of T. occidentalis per 50 leaves before and after application of acaricides to

orchard apple trees with a high volume hand gun sprayer, 18 July 1973.

Acaricide per 100 gal.

Citrazon 20% E. C. 0.5 pt

Citrazon 20% E. C. 1.0 pt

Vendex 50% W. P. 4 oz.

Check - no treatment

Before spraying After spraying

July 17 July 24 Aug.1 Aug.9

90 21 23 24

119 11 9 8

99 15 17 10

112 29 28 17

J ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), DEc. 31, 1975 5

TABLE 4. Numbers of mites per 75 leaves before and after application of acaricides to orchard

apple trees with a high volume hand gun sprayer, 26 June 1973.

Before spraying After spraying

Acaricide per 100 gal.

June 26 July 3 July 11 Aug. 3 Sept. 5

European red mite

Citrazon 20% E. C. 1 pt 608 0 8 60 96

Vendex 50% W. P. 4 oz. 1208 121 192 7 33

Check - no treatment 688 348 3082 58 0

Zetzellia mali

Citrazon 20% E. C. 1 pt 10 8 37 113 204

Vendex 50% W. P. 4 oz. PA oS 0 3 OZ

Check - no treatment 29 44 251 174 62

This low toxicity to eriophyid mites such

as the pear rust mite or its close relative, the

apple rust mite, may be more of an advantage

for integrated control programs on apple be-

cause, as stated earlier, rust mites are an excel-

lent alternate food source for predaceous phy-

toseiid mites. Citrazon appears to have

qualities that will make it an excellent acaricide

for integrated mite control programs on apple.

red mite to reduce an outbreak to subeconomic

levels. The low toxicities of Citrazon to the

predaceous mites, T. occidentalis, T. colum-

biensis and Z. mali, and most likely to the

alternate food source for the predators, the

apple rust mite are very desirable properties

of a selective acaricide and would make Cit-

razon useful for integrated mite control pro-

grams on apple.

It seems to be sufficiently toxic to European

TABLE 5. Numbers of pear rust mite per 75 leaves after application of acaricides to Bartlett pears

with a high volume hand gun sprayer, 16 July 1974.

Before spraying After spraying

Acaricide per 100 gal.

July 15 July 22 July26 Aug.7 #Aug.13

Pear rust mite

Citrazon 20% E. C. 0.5 pt 30,500 245 296 417 940

Citrazon 20% E. C. 1.0 pt 19,400 80 170 543 846

Plictran 50% W. P. 4 oz. 30,200 4 8 6 28

Check - no treatment 18,900 3016 2016 1704 2108

References

Abbott, W. S. 1925. A method of computing the effectiveness of an insecticide. J. econ. Ent. 18:

265-267.

Collyer, E. 1964. The effect of an alternative food supply on the relationship between two Typh-

lodromus species and Panonychus ulmi (Koch) (Acarina). Entomologia exp. appl. 7:

120-124.

Downing, R. S. 1967. Petroleum oils in orchard mite control. J. Entomol. Soc. Brit. Columbia,

64: 10-13.

Henderson, C. F., and H. Y. McBurnie. 1943. Sampling technique for determining populations

of citrus red mite and its predators. U.S. Dep. Agric. Circ. 671.

Morgan. C. V. G., et al. 1955. Methods for estimating orchard mite populations, especially with

the mite brushing machine. Can. Ent. 87: 189-200.

CODLING MOTH!

IMPORTATION

J ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), DEc. 31, 1975

CONTROL BY STERILE INSECT RELEASE:

OF FRUIT AND FRUIT CONTAINERS

AS A

SOURCE OF REINFESTATION 2

M. D. PROVERBS AND J. R. NEWTON

Research Station, Agriculture Canada

Summerland, British Columbia

ABSTRACT

A program of codling moth, Laspeyresia pomonella (L.), control by the

sterility principle is planned for the entire Similkameen Valley of British

Columbia. If the program is successful, reinfestation by moth fly-in is un-

likely because the Valley is fairly well isolated. Importation of host fruits

and fruit containers (bushel boxes) for roadside fruit stands could lead to

reinfestation unless the boxes are fumigated. Localized annual releases of

sterile moths around fruit stands may also be necessary. Orchard bins, used

by commercial packinghouses, are unlikely to be a serious source of

codling moth reinfestation.

INTRODUCTION

It has been shown that the codling moth,

Laspeyresia pomonella (L.), can be controlled

effectively by release of sterile moths, but the

method is about twice as expensive as

chemical control if releases have to be made

over the entire area every year (Proverbs 1974).

Results of small scale sterility programs, in

which treated orchards were exposed to fly-in

of inseminated female moths from nearby

orchards, have indicated that even under these

conditions of reinfestation it is usually un-

necessary to apply control measures in the

first year following termination of sterile moth

release, and that in the second year only one

spray is required instead of the normal 3-spray

program.

An area-wide sterile moth release program is

planned for the Similkameen Valley of British

Columbia. Because this Valley is semi-isolated,

moth fly-in would be virtually eliminated and

the effects of the program should persist for

some years. Pockets of reinfestation would

likely occur from time to time, but it should be

possible to eliminate these incipient infesta-

tions by localized release of sterile moths. Con-

sequently, in the long run, area-wide control

by the sterility procedure probably would be

cheaper than chemical sprays.

The validity of this premise was questioned

by fruit growers who pointed out that there

is some movement of fruit and fruit contain-

ers into the Similkameen Valley from distant

fruit-growing areas. Plywood bins used for

transporting fruit from orchards to packing-

houses are moved annually into the Similka-

meen to service a few growers who have their

fruit packed in the neighboring Okanagan

Valley. The imported empty bins may contain

‘Lepidoptera: Olethreutidae.

*Contribution No. 417, Research Station, Summerland

spun-up larvae and pupae of the codling moth.

A more likely source of reinfestation, however,

is from boxes of apples and pears that are

brought into the Similkameen for sale at road-

side fruit stands. Before the fruit is sold and

transferred to the purchaser’s container, some

mature larvae leave the fruit and spin-up in the

boxes where they complete development and

emerge as adult moths the following spring.

This report examines the importance of fruit

and fruit containers imported into the Simil-

kameen Valley as sources of codling moth re-

infestation after a _ theoretically successful

program of moth control by the sterility

method.

MATERIALS AND METHODS

The numbers of moths likely to emerge

from empty fruit containers in spring were

determined as follows. In early April, before

the start of adult moth emergence, 50 one-

bushel (ca. 36 dm*) wooden boxes, the stan-

dard fruit container used by fruit stand opera-

tors, were taken at random from each of 5 fruit

stands in the Similkameen Valley. The boxes

were placed in a mothproof room in which the

daily temperature fluctuation was between 21°

and 27° C and the light/dark regime was 18/6

hr. A screen-mouthed glass jar containing

ca. 100 laboratory-reared diapausing larvae

was placed in the room to determine whether

environmental conditions were satisfactory

for pupation and subsequent adult emergence.

A similar jar of larvae was held in the labora-

tory at ca 27° C and a light/dark regime of 18/6

hr. Because there was some doubt about the

health of the diapausing insects, 20 mature

nondiapausing larvae and 20 pupae were also

placed in the room in separate jars. Control

nondiapausing insects were kept in the labora-

tory. A 40-watt black light trap was installed

to capture the wild moths as they completed

development and emerged from the boxes.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 ff

The efficiency of the trap was determined,

prior to the start of the adult emergence, by

introducing into the room a known number of

laboratory-reared moths that were marked

externally with Day Glo® fluorescent powder.

Later, when emergence of wild moths from the

boxes had commenced, the efficiency of the

trap was rechecked with moths marked in-

ternally with calco oil red. This marking

method was adopted to prevent pigment trans-

fer to wild moths which could lead to misidenti-

fication of the wild insects. The experiment

was discontinued 2 weeks after the last capture

of a wild moth.

_ The procedure for estimating the numbers

of moths likely to emerge from bins was essen-

tially the same as that used for boxes. The ex-

periment was conducted in a large storage room

in a packinghouse with 500 so-called standard

bins (0.8 m*) from the Summerland district.

The daily temperature fluctuation in the room

was between ca. 23° and 29° C and the light/

dark regime was 17/7 hr. Three screen-

mouthed glass jars, each with ca. 100 diapaus-

ing larvae, 3 with 10 nondiapausing larvae

and 10 pupae, and 2 with ca. 30 adult moths

each, were placed at different locations among

the bins. Four black light traps were installed,

and trapping efficiency estimated, prior to

emergence of wild adults, by release of a known

number of marked moths. The numbers of

traps were later increased to 8, and trapping

efficiency reassessed before emergence of wild

adults. The experiment was discontinued 3

weeks after the last capture of a wild moth.

Boxes

The environment in the room used for pro-

cessing the boxes was satisfactory for codling

moth development; adult emergence from the

caged nondiapausing insects was 95.0% in

the room vs. 92.5% in the laboratory. Emer-

gence from caged diapausing insects was much

less than that—an estimated 40% in the room

and laboratory. Microscopic examination of

dead and moribund larvae indicated that poor

emergence with caged diapausing insects was

due to a severe infection of granulosis virus.

Use of a single black light trap proved to be

an effective way of capturing adult moths in

the room. In the first trapping efficiency test

25 marked moths were released and they were

all captured within 3 days; in the second test

92 moths were released and 84 were captured.

Thus the average trapping efficiency was

93.16%.

Twelve wild (unmarked) moths were cap-

tured in the black light trap in the 7-week

period in which the 250 boxes were exposed to

long photophase at 21-27° C.

With respect to importation of fruit during

the growing season, only a very small number

of codling moths are likely to be introduced

with cherries, plums, apricots, and peaches. The

fruit itself would not be a carrier for only very

rarely are stone fruits infested with the codling

moth in British Columbia. If the boxes were

used the previous year for handling apples and

pears, virtually all the overwintered larvae

that were spun-up in the boxes would have

completed development and emerged as adult

moths before the commencement of stone fruit

imports, usually in early and mid July.

Moths could be introduced with imports of

late maturing cultivars of peach if the boxes

were used earlier in the year for very early

maturing cultivars of apples and pears. How-

ever, the numbers of moths introduced in this

way probably would be extremely small.

Very early maturing cultivars of apples,

which might be imported during the third week

of July, could be infested with small numbers

of late maturing first generation larvae. How-

ever, such imports would not contribute

measurably to reinfestation since the volume of

these imports is relatively small and by the

third week in July many or most of the first

generation larvae have already completed

development and left the fruit.

Large-volume imports of apples and partic-

ularly pears normally start in mid August

and it is these imports which could play an im-

portant role in reinfestation. Some of the fruit

would be infested with second generation larvae

and virtually all of those that develop to the

fifth instar would enter diapause and be po-

tentially capable of starting a new infestation

next spring.

We do not know what percentage of the

diapausing larvae spin up in the boxes, but

because the number of infested apples and

pears per box is very small, it seems reasonable

to assume that the vast majority of the larvae

would hibernate in or on the boxes for there

are many attractive spin-up sites in cracks and

corners of the boxes. Future investigations will

show whether larvae do leave the boxes and

whether artificial oviposition sites are needed

to trap these larvae.

Fruit stand operators normally use each

box several times yearly, sometimes for im-

ported fruit, other times for locally-grown fruit.

Despite this it is still possible to estimate the

approximate number of overwintered moths

that originate from imported fruit if we know

the total number of boxes used in the fruit

stand business, and the respective volumes of

imported and locally-grown fruit sold through

this outlet. We must also assume (and there is

no reason to believe otherwise) that the per

cent codling moth infestation is about the same

for imported and locally-grown fruit.

Fruit stand operators use a total of ca.

17,800 boxes in their business, and we estim-

ate that ca. 20% of apples and pears sold after

mid August (i.e, that period in which fruit is

8 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975) Dec. 31, 1975

infested with second generation larvae) are

imported. On the basis of the experiment con-

ducted with the Similkameen boxes, we would

expect 917 moths to emerge in spring from

17,800 boxes. About 20% of these, i.e. 183

moths, would be from imported fruit. Since

most of the moths would emerge in a 2-3-week

period, they could easily start new infestations

once sterile insect release is discontinued. The

most practical method of eliminating this

source of reinfestation is by fumigation of all

boxes with methyl bromide during winter.

Even though only small numbers of non-

diapausing insects are likely to come into the

Valley in boxes of stone fruits and early matur-

ing cultivars of apples and pears, they could

conceivably start new infestations. Traps, bait-

ed with the synthetic sex pheromone of the

codling moth, should be deployed around all

fruit stands to monitor adult moth populations.

Results of monitoring would indicate whether

yearly localized releases of sterile moths should

be made around all fruit stands, at least until

fruit stand owners can be convinced that they

should discontinue importing apples and pears,

and that only codling moth free boxes should

be used for importing stone fruits.

Bins

The environment in the room used for pro-

cessing the bins was satisfactory for comple-

tion of codling moth development; adult emer-

gence from caged nondiapausing insects was

93.3%. Emergence from caged diapausing

larvae was abnormally low, as in the previous

experiment with boxes.

Four black light traps were too few to give

maximum moth capture in the large room of

the packinghouse. When 49 marked adult

moths were released only 42 were captured.

Caged adult moths lived for several days indi-

cating that the relatively low trapping effi-

ciency (85.7%) was not due to poor adult sur-

vival. There was an appreciable increase in

trapping efficiency when the number of traps

was increased to 8; 94 of 100 released moths

were captured within 4 days.

Five wild (unmarked) moths were captured

in the light traps during the 7-week period in

which the 500 bins were exposed to long photo-

phase at 23-29° C. On the basis of 94% trapping

efficiency, emergence in spring would be 1.06

moths/100 bins.

About 2% of the Similkameen fruit growers

use imported bins to ship their fruit to Okana-

gan Valley packinghouses or to outside mar-

kets. Import of so-called half bins (0.4 m‘)

for the stone fruit harvest is unlikely to con-

tribute to codling reinfestation. Since Golden

Delicious is the only host fruit cultivar shipped

in half bins, their re-use for host fruits in any

one year is very restricted. Consequently,

there is only a very limited opportunity for

diapausing larvae to spin-up in the bins.

Furthermore, the few overwintered larvae

that might have been present would have

mostly completed development and emerged

as adult moths by the time the bins were im-

ported.

We estimate that ca. 530 standard and 290

half bins are shipped into the Similkameen

Valley every year for the apple and pear har-

vest. Empty bins are sometimes imported in

spring before adult emergence from overwin-

tered insects is complete. On the other hand,

imports are sometimes delayed so long that

some of the bins may have already been used

for early-maturing host fruits, and consequent-

ly may harbor small numbers of nondiapausing

larvae and pupae of the first generation. How-

ever, the probability of reinfestation is likely

to be very low since only ca 820 bins are in-

volved, and only ca. 8 moths should emerge in

spring from these bins on the basis of the

experiment conducted with Summerland bins.

The chances of reinfestation could be further

reduced by importing as many bins as possible

in early July, i.e., after adult emergence of over-

wintered insects, but about one week before

harvesting host fruits.

There soon may be another potential source

of codling moth reinfestation. The British

Columbia tree fruit industry is being reorgan-

ized and it is possible that some packinghouses

may eventually handle only certain species or

cultivars of fruit. This would entail a fairly

considerable movement of fruit and bins be-

tween fruit-growing areas, with consequent

increase in the chances of reinfesting the Simil-

kameen Valley. There is only a slight chance

that mature larvae will leave infested fruit after

it has been imported because the bins of fruit

are put into cold storage immediately on arrival

at the packinghouses. It is prior to transport,

when harvested fruit is often left in orchards

for 1 or more days, that mature larvae are

likely to leave the fruit and spin-up in the bins.

These will be almost entirely diapausing larvae.

Consequently, the contribution of imported

bins to reinfestation would be limited almost

exclusively to the following spring.

The number of moths that emerge from bins

in spring evidently is not large enough to create

a serious problem of reinfestation. About

11,500 bins are used in the packinghouse opera-

tions in the Similkameen Valley. On the basis

of our experiment at Summerland, this number

would contribute 122 adult moths to the over-

wintered codling moth population. However,

it seems unlikely that more than one-fourth of

the bins, i.e. 30 moths, would originate from

outside the Valley. If the standard bins were

held at Similkameen Valley packinghouses

until early July, it should be possible, by re-

leasing small numbers of sterile moths around

the packinghouses, to prevent emerging adults

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 9

from starting new infestations. The half bins

can be fumigated if they have to be distributed

to stone fruit growers before all the overwin-

tered insects have emerged. Of course, no bins

should be imported before early July in order

to avoid introducing overwintered insects.

In conclusion, it seems that the greatest

danger of codling moth reinfesting the Similka-

meen Valley after discontinuance of sterile

moth release would be through importation of

boxes of apples and pears for the fruit stand

trade. Incipient infestations could be sup-

pressed or avoided by fumigating the empty

boxes and by localized release of sterile moths.

At this time the numbers of imported bins are

so small that they are unlikely to contribute

to codling moth reinfestation.

Reference Cited

Proverbs, M.D. 1974. Codling moth control by the sterility principle: estimated cost and some

biological observations related to cost. Pages 81-88. In Proc. Panel on The Sterile-Insect

Technique and its Field Applications. I.A.E.A., Vienna, Austria.

MITES AND INSECTS COLLECTED FROM VINEYARDS IN THE

OKANAGAN AND SIMILKAMEEN VALLEYS,

BRITISH COLUMBIA!

B. J. MADSEN AND C. V. G. MORGAN

Research Station, Agriculture Canada,

Summerland, B.C.

ABSTRACT

Five species of mites and 122 species of insects were collected from

leaves, stickyboards and beating trays in 14 vineyards in 5 different areas

in southern British Columbia between May and October 1972. Two mite

species and 5 insect species are potential economic pests in British Columbia

but only one insect species, the Virginiacreeper leafhopper, Erythroneura

ziczac Walsh requires control measures.

INTRODUCTION

A survey of vineyards in the Okanagan and

Similkameen Valleys was made in 1972 to deter-

mine the species of insects and mites present,

their distribution, parasites and predators.

METHODS

Mites and insects were collected from yellow

stickyboards hung in vineyards, from grape

leaves examined under a binocular micro-

scope and from beating trays. In each vineyard

and for each variety the samples consisted of

10 leaves collected randomly, one beating tray

‘Contribution No. 403, Research Station, Summerland, B.C.

count from each of 10 vines and one yellow

stickyboard hung on the top trellis wire.

Samples were taken and stickyboards changed

at weekly intervals from 30 May to 6 October.

Insects were mounted or pinned and sent to

taxonomists at the Biosystematics Research

Institute, Ottawa, for identification. Mites

were identified by us along with R. S. Downing

and T. K. Moilliet of the Research Station,

Summerland, British Columbia. Varieties of

grapes sampled were Foch and Bath at West-

bank; Campbell Early, Patricia, Himrod, and

Sheridan at Kelowna; Riesling, Bath, Diamond

and S-10878 at Oliver; Foch at Cawston;

S-9549, Diamond and numerous experimental

varieties at Summerland.

J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), DEc. 31, 1975

Insects and Mites Collected in Vineyards in the Okanagan and

Similkameen Valleys, British Columbia, 1972

Species Nos.

ACARINA

Phytoseiidae

Typhlodromus pyri Scheuten 370

Typhlodromus occidentalis (?) 36

Tetranychidae

Tetranychus urticae Koch 33

Panonychus ulmi (Koch) 250

Tydeidae

Tydeus sp 954

COLEOPTERA

Anobiidae

Coelostethus quadrulus LeC 1

Anthicidae

Anthicus sp. 2

Lappus nitidulus LeC. 4

Buprestidae

Anthaxia deleta LeC. 1

Anthaxia sp. a

Carabidae

Bembidion mutatum Gemm. 1

& Har.

Bradycellus californicus LeC. 1

Lebia guttula LeC. 1

Lebia viridis Say 1

Chrysomelidae

Crioceris duodecimpunctata(L.) 1

Epitrix tuberis Gentner 1

Phyllotreta sp. 2

Cleridae

Phyllobaenus humeralis Say or 9

near

Coccinellidae

*Cycloneda polita Csy. i

Hippodamia convergens Guerin 3

Hippodamia quinquesignata 6

(Kirby)

Microwesia sp. 4

Scymnus sp. 1

Stethorus sp. 3

Curculionidae

Brachyrhinus sulcatus (F.) 2,

Miccotrogus picirostris (F.) 1

Sitona cylindricollis Fahr. 1

Dermestidae

Cryptorhopalum sp. 1

Elateridae

Agriotes ferrugineipennis LeC. 1

Locality

Kelowna

Westbank, Summerland

Oliver, Cawston

Westbank, Summerland

Kelowna, Westbank,

Summerland

All areas

Kelowna

Oliver

Kelowna, Westbank

Kelowna

Kelowna, Summerland

Cawston

Westbank

Kelowna

Oliver

Westbank

Cawston, Oliver

Cawston

Vernon

Kelowna, Westbank,

Cawston

Kelowna

Kelowna, Westbank,

Summerland

Cawston

Kelowna, Westbank,

Summerland

Kelowna, Westbank

Summerland

Westbank

Summerland

Cawston

*Collected at Vernon, B.C. at single sampling.

Collection

Method

leaves

board

tray

board

tray

board

tray

board

board,

tray

board

board,

tray

board

tray

board

Month

Collected

May-Sept.

May-Oct.

July-Oct.

June-Oct.

May-Oct.

July

July-Aug.

July

June

Sept.

June

June & Aug.

July

Sept.

June

June & Aug.

Aug.

June

July-Sept.

July & Oct.

July

Oct.

July

June

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

Cardiophorus edwardsi Horn

Dalopius sp.

Limonius infuscatus Mots.

Melanotus longulus oregonensis

LeC.

Lathridiidae

Lathridius minutus L.

Melandryidae

Anaspis atrata Champion

Anaspis sp.

Melyridae

Anthocomus sp. nr. nigrinus

Fall

Eurelymis atra LeC.

Listrus sp.

Malachius antennatus R. Hopp.

Mordellidae

Mordella atrata Melsheimer

Scarabidae

Onthophagus nuchicornis L.

Tenebrionidae

Coelocnemis californica Mann.

COLLEMBOLA

Entomobryidae

Entomobrya sp. perhaps

nivalis (L.)

Willowsia buskii Lubbock

DIPTERA

Ceratopogonidae

Atrichopogon sp.

Forcipomyia sp.

Chironomidae

Ablabesymia sp.

Chironomus sp.

Dicrotendipes sp.

Micropsectra sp.

Parachironomus sp.

Phaenopsectra sp.

Tanytarsus sp.

Dolichopodidae

Chrysotus sp.

Drosophilidae

Drosophila sp.

Ephydridae

Philygria opposita Lw.

Sciaridae

Bradysia sp.

Conioscinella sp.

Thaumatomyia glabra var.

EPHEMOROPTERA

Baetis sp. ?

HEMIPTERA

Anthocoridae

Orius tristicolor (White)

le a ee oe Nl el NS)

Summerland, Cawston

Oliver

Westbank

Westbank, Summerland

Cawston

Summerland

Kelowna, Summerland

Summerland

Kelowna

Summerland

Kelowna, Westbank,

Summerland

Westbank

Oliver

Kelowna

Oliver

Summerland

Westbank

Westbank, Summerland

Westbank

Summerland

Westbank

Kelowna

Summerland

all areas

Summerland, Cawston

Kelowna, Oliver

Westbank

Kelowna, Westbank

Summerland

board June

board April

board June-July

tray June

board June-July

board July

board June

board July

board June

board July

board Aug.

soil at base Nov.

of grapevine

tray Aug.

tray July

tray Oct.

tray June

tray Sept.

tray June

board June

tray June

tray Sept.

tray June-Oct.

tray July & Sept.

tray June & Aug.

tray Aug.

board June-Sept.

tray

12 J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

Lygaeidae

Geocoris bullatus (Say) 1

Nysius ericae (Schilling) 13

Rhyparochromus chiragra 12

californicus Van D.

Sphragisticus nebulosus (Fallen) 1

Miridae

Campylomma verbasci (Meyer) 1

Ceratocapsus sp. 1

Deraeocoris (Camptobrochis) 19

brevis (Uhler)

Ilnacorella sulcata Kngt. 1

Lygus columbiensis (Kngt). 1

Lygus desertus (Kngt.) 1

Lygus elisus (Van D.) 1

Plagiognathus obscurus Uhler 2

Prepops sp. 1

Nabidae

Nabis ferus (Linn.) 67

Neididae

Neides muticus (Say) 2

HOMOPTERA

Aphididae

Esigella sp. 5

Cicadellidae

Aceratagallia sp. 1

Erythroneura ziczac Walsh 5000 +

Euscelidius schenki ( Kirsch.) 1

*Helochara communis Fitch 1)

Osbornellus borealis DeL. & Mohr 1

Stenocoelidia lineata (Baker) 1

Coccoidea

Lecanium sp. prob. coryli L. 200+

Phylloxeridae

Phylloxera vitifoliae (Fitch) 450+

Psyllidae

Psylla pyricola (Forster)

Psylla sinuata group 3

—

HYMENOPTERA

Bethylidae

Goniozus sp. 1

Braconidae

Bracon xanthonotus (Ashm.) 1

Lysiphlebus sp. 1

Orgilus sp i

Praon sp. 1

Torymidae

Torymus sp. 1

Encyrtidae

Aphycus maculipes How. 65

Aphycus sp. 1

Copidosoma bakeri How. 1

Microterys sp. i

Ooencyrtus nr. clisiocampae 1

(Ashm.)

Summerland

Summerland, Cawston

Oliver, Cawston

Summerland

Kelowna

Summerland

Kelowna, Oliver

Westbank, Oliver

Oliver

Summerland

Oliver

all areas

Westbank, Oliver

Summerland

Missing when specimens returned from Ottawa

all areas

Summerland

Vernon

Kelowna

Summerland

All areas

Kelowna, Westbank,

Oliver

Summerland

Oliver

Summerland

Kelowna

Summerland

Oliver, Cawston

Kelowna

Oliver

Kelowna

board July

board June-July

board July-Aug. |

board Aug.

board July

tray

board Aug.

tray June

tray Aug.

board Aug.

tray July

tray Aug.

tray Aug.-Oct.

tray Aug.-Sept.

tray Sept.

tray, June-Oct.

leaves, board

tray June

board Sept.

tray Sept.

tray Aug.

leaves July-Sept.

board Aug.

tray Sept.

board Aug.

tray June

tray Sept.

tray Oct.

tray Sept.

tray Oct.

board, tray Aug.

tray Sept.

tray Aug.

J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

Eulophidae

Euplectrus platyhypenae How. 2 Summerland tray Oct.

Eurytomidae

Harmolita sp. 1 Westbank board June

Figitidae

Anacharis nr. marginata (Prov.) 1 Oliver tray Aug.

Ichneumonidae

Campoletis argentifrons (Cress.) 2 Kelowna board June

Cremastus incompletus (Prov.) 2 Cawston board June

Diplazon laetatorius Fab. 1 Oliver board July

Itoplectis quadricingulata (Prov.) 1 Westbank tray Sept.

Mesoleiini 1 Oliver board Aug.

Stenomacrus sp. i Summerland board July

Symplecis sp 1 Cawston board June

Mymaridae

Anagrus epos Girault 475 all areas board July-Sept.

Polynema sp. il Oliver tray Aug.

Platygasteridae

Platygaster sp. 1 Kelowna tray June

Proctotrupidae

Proctotrupes rufigaster Prov. 1 Cawston board July

Pteromalidae

Habrocytus sp. 1 Summerland tray Sept.

Sphegigaster (poss. n. sp.) 1 Summerland tray Sept.

Scelionidae

Telenomus sp. A+ B 6 Oliver board July

Trissolcus sp. A 1 Kelowna tray June

Trissolcus sp. B il Westbank tray June

Trichogrammatidae

Oligosita sanguinea sanguinea 1 Oliver board July

Girault

LEPIDOPTERA

Lyonetidae

Bucculatrix sp. prob. 150 Summerland, Oliver tray Sept.

salutatoria Braun Cawston

Lyonetia sp. 1 Oliver tray July

NEUROPTERA

Chrysopidae

Chrysopa oculata Say 1 Summerland board July

Raphidiidae

Agulla adnixa (Hagen) 4 Summerland board June

PSOCOPTERA

Psocidae

Lachesilla pedicularia (L.) 12 Oliver, Cawston tray Sept.

Psocus sp. nr. oregonus 1 Summerland tray Sept.

THYSANOPTERA

Thripidae

Frankliniella tritici (Fitch). 9000+ all areas leaves, June -Oct.

board, tray

RESULTS phylloxera, Phylloxera vitifoliae (Fitch),

A total of 122 species of insects representing

54 families was collected by the three sampling

methods. Six of these species are grape pests

in the Okanagan-Similkameen area but only

one, the Virginiacreeper leafhopper, Erythro-

neura ziczac Walsh which causes leaf and fruit

injury requires control measures. The grape

although important in other grape growing

regions, has not yet been determined to be an

economic problem in British Columbia. Other

potential grape pests which at present cause

only minor injury and do not warrant control

measures in British Columbia are the flower

thrips Frankliniella tritici (Fitch); a lecanium

14 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), DEc. 31, 1975

scale, Lecanium species probably coryli L.,

which may heavily infest grape vines (Phillips

1965); the black vine weevil, Brachyrhinus

salcatus (F.) and the clickbeetle Limonius

infascatus (Mots.).

Several predaceous insects were collected

by each sampling method and two parasites

were reared from their hosts, Anagrus epos

Girault the egg parasite of the Virginia-

creeper leafhopper and Aphycus maculipes

How., which parasitizes L. coryli. Six species

of Coccinellidae were collected including a

Stethorus sp. which is predaceous only on

mites. Other predaceous insects were three

Hemiptera, Neides muticus (Say), Nabis ferus

(Linn.), and Orius tristicolor (White) which feed

on thrips, aphids and other small insects; and

two Neuroptera. Agulla adnixa (Hagen) and

Chrysopa oculata Say, which attack a wide

range of insects.

Five species of mites were found on the leaf

samples. The twospotted spider mite, Tetrany-

chus urticae Koch, and the European red mite,

Panonychus ulmi (Koch), are _ potential

economic pests. The other three species are

mite predators with one, Typhlodromus pyri

Scheuten, having been recorded only once

previously in the Okanagan Valley (Downing

and Moilliet 1971). Another phytoseiid,

Amblyseius andersoni Chant found in 1974

on grape leaves from Westbank, had not been

recorded previously in the Okanagan Valley

(Chant and Hansell 1971).

The majority of insects collected from the

boards and beating trays were not directly

associated with grape plants, but originated

from cover crops or native plants near vine-

yards. For example, 150 specimens of Buccu-

latrix salutatoria Braun whose host is the sage-

brush, Artemisia tridentata Nutt., were taken

from beating trays.

Vineyard pests not encountered in the 1972

survey are several species of cutworms, a Pul-

vinaria scale and the grape erineum mite,

Eriophyes vitis (Pgst.). These pests have been

found in separate isolated vineyards in the

Okanagan-Similkameen area.

References

Chant, D. A., and R. I. C. Hansell. 1971. The genus Amblyseius (Acarina: Phytoseiidae) in

Canada and Alaska. Can. J. Zool. 49(5): 703-758.

Downing, R. S., and T. K. Moilliet. 1971. Occurrence of phytoseiid mites (Acarina; Phytoseiidae)

in apple orchards in central British Columbia. J. Entomol. Soc. Brit. Columbia 68: 33-35.

Phillips, J. H. H. 1965. Notes on species of Lecanium Burmeister (Homoptera: Coccoidea) in the

Niagara Penninsula, Ontario, with a description of a new species. Can. Entomol. 97:

231-238.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 15

WOOD BORER CONTROL IN SPRUCE LOGS WITH P-DICHLORO-

BENZENE AND PLASTIC SHEETING

(COLEOPTERA: CERAMBYCIDAE)

A. G. RASKE'! AND J. K. ROBINS?

Canadian Forestry Service, Northen Forest Research Centre,

Edmonton, Alberta

ABSTRACT

Fumigation under plastic sheating of white spruce (Picea glauca

(Moench) Voss) logs with crystalline p-dichlorobenzene (PDB) for 26 days

killed more than 95% of cerambycid and other wood borer larvae under the

bark and in the wood, at the lowest dosage of 8g of chemical per cubic meter

of log plus air space volume. The long treatment-duration promoted the

discoloration of logs by stain fungi. When treatments were shortened to 2,

4 and 7 days, and the PDB was dissolved in trichloroethylene, the lowest

dosage at the shortest duration killed more than 80% of the wood borer

larvae.

INTRODUCTION

The lumber industry has expressed growing

concern over the degrading of lumber caused by

wood borers in decked logs. Some methods of

chemical preventative control have been pub-

lished (Becker and Abbot, 1961, Ross and

Downton, 1966, Gardiner 1970), and one study

(Buffam and Lucht 1968) reported that excess

heat in slash piles covered with clear poly-

ethylene sheeting killed bark beetles under the

bark. This paper reports the results of a pilot

study testing the effects of fumigation with

p-dichlorobenzene (moth balls), under plastic

sheeting, on mortality of wood borer larvae

under the bark.

METHODS

Two trials were made with borer-infested

logs of white spruce (Picea glauca (Moench)

Voss), in a clearing at the Kananaskis Forest

Experiment Station, Alberta. The logs were

covered with 6-mil clear plastic sheeting and

chemical placed under the covering. All logs

were collected about 80 km W of Olds. They

were less than one year old, and were severely

infested with mature wood borer larvae.

In the first test crystalline p-dichloro-

benzene (PDB) was used on fifteen log ‘‘decks’’,

three for each of the following: a control, plas-

tic covering only, plastic covering plus 8, 32,

and 128 g of PDB per cubic meter of wood plus

air space volume. The decks were about 0.6 m?

in volume and consisted of three to seven logs

each 67 cm long. Treatments began on 23 Sep-

tember 1968, and the decks remained covered

till 19 October 1968, when all the fumigant of

the largest dosage had evaoporated. Then all

live and dead larvae under the bark and in the

wood were removed, identified and counted.

' Present address: Canadian Forestry Service, Newfoundland

Forest Research Centre, St. Jon’s, Newfoundland.

* Present address: Box 514, Devon, Alberta.

About one-tenth of the larvae classified as dead

were kept at room temperatures for 24-48 hours

to verify this.

In the second test dissolved PDB was used

on one replicate each according to the experi-

mental design of Table 2. Treatment decks were

about 0.4° in volume and consisted of two 130

cm long white spruce logs, about 36 cm in dia-

meter. Treatment began on 22 May 1969 and

lasted 2, 4 or 7 days. The fumigant was dis-

solved in trichlorethylene’® at the rate of 1 gm

of PDB per 1 ml of solvent, distributed over the

deck, and the deck then covered with plastic

sheeting. The cover was removed after the pre-

scribed duration and all dead and live larvae

under the bark and in the wood were removed,

counted and identified about 10 days after

treatment.

RESULTS AND DISCUSSION

More than ninety percent of the wood

boring insects present in all logs were Tet-

ropium parvulum Casey (Cerambycidae). The

larvae of other species present in decreasing

numerical order were: Buprestidae— mainly

Melanophila supp.; Cerambycidae-Monocham-

us spp., Anoplodera spp., Acmeops sp., Tet-

ropium cinnamopterum (Kirby); and Meland-

ridae-Serropalpus sp. Differential mortality

among species apparently did not occur, and

the data were therefore combined.

Crystalline PDB The fumigant in crystalline

form gave effective control of wood borer lar-

vae under the bark at all dosages (Table 1).

The total mortality given in Table 1 includes a

percentage of natural mortality, which is

assumed to approximate the percentage mor-

tality (20%) in the controls. Natural mortality

was recognized by a brown discoloration of the

‘Supplied by Dow Chemical of Canada Ltd. of Calgary un-

der the trade name of ‘‘Neu-tri’’.

16 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

TABLE 1—Mortality of wood borer larvae in three replications of white spruce log ‘‘decks’’ fumi-

gated with granular crystalline p-dichlorobenzene for 26 days, under plastic sheeting.

Treatment

Control

Plastic sheeting only

8 g/m?’ of PDB

32 g/m?’ of PDB

128 g/m’ of PDB

larvae, or by fungal growth on the dead larvae.

Heat built up under the plastic apparently did

not contribute appreciably to larval mortality

in this experiment since mortality was also

low (26%) in the plastic-only treatment.

Crystalline PDB also penetrated into the logs

or into the plugged larval tunnels, killing larvae

in the pupal cells 10 cm in the log.

In all PDB treatments, live larvae were very

sluggish compared to those in control and plas-

tic-only logs. Bark beetle larval mortality was

estimated at 60%, 90%, and 98% at dosages

of 8, 32, and 128 g per m’ of log deck, respec-

tively.

Of special interest is that parasitic larvae,

mainly Braconidae, exhibited a much greater

tolerance to PDB than did the wood borer

larvae. Mortality of parasites in cocoons could

not be judged, but mortality of free parasitic

larvae was negligible, except at the heaviest

dosage, when it reached about 75%.

The high humidity and temperatures main-

tained under the plastic sheeting promoted:

severe discoloration of logs by blue-stain fungi,

which would degrade lumber from logs treated

in this way as much as would the ‘‘worm-

No. live No. dead

wood borer wood borer Percent

larvae larvae mortality

Totals of three replications

265 66 199

378 138 26.8

16 379 96.0

7 305 97.8

2 398 99.5

holes’. It is therefore important that decks be

covered with plastic for a short fumigation

period only.

Dissolved PDB The dissolved fumigant

treatments increased mortality of wood borer

larvae compared to the control, at all durations

(Table 2), but the total mortality was less than

it was with crystalline PDB. Many live larvae

were found where logs contacted the soil, indi-

cating that the fumigant apparently did not

penetrate these areas within seven days. Treat-

ed logs showed no perceptible increase in wood

stain from fungi during treatment.

A treatment with only the solvent, which

is slightly toxic, was not done. The addition of

the solvent did not increase mortality appreci-

ably, because the total mortality of chemical

plus solvent was lower than that with crystal-

line PDB.

Since both the plastic and PDB are

inexpensive compared to the value and volume

of the logs treated, utilizing this chemicaal in

liquid form may be feasible if applied in June or

July when wood borer larvae are in the early

stages of development, and have not yet bored

into the wood. Estimated cost for insecticide

and 6-mil plastic sheeting, based on a deck 5 m

TABLE 2 — Mortality of wood borer larvae in white spruce log ‘‘decks’’ fumigated with dissolved

p-dichlorobenzene under plastic sheeting.

2 days 4 days 7 days

No. No. % No. No. % No. No. %

Treatment live dead dead live dead dead live dead dead

Control 42 12 2252

Plastic

sheeting 11 10 47.7

only

8 g/m? 8 62 88.6 15* 48 76.2 | 47 87.2

32 g/m? 0 22, 100 5 35 85:3" “tar 24 68.6

128 g/m? 1 28 96.7 0 Pag 100 9* 25 67.6

*Live larvae in portion of log in contact with soil.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 17

wide, and 60 m long is 10° to 15° per 2.36 m°

(=M bd. ft.) (1969 prices). If care is taken

to prevent snagging and tearing, the sheeting

can be reused, thus greatly reducing the cost

of treatment.

A present PDB is one of the _ safest

chemicals in use agains insects. Its ability to

penetrate into wood and kill boring insects in

a relatively short time may have wide applica-

tion in the lumber industry.

Acknowledgements

We thank B. M. Dahl for his help in setting

up the experiment and in collecting data, Dow

Chemical of Canada who supplied the p-

dichlorobenzene and solvent, and Dr. H.

Cerezke for critically reading the manuscript.

Resume

La fumigation des billes d’Epinette blanche (Picea glauca (Moench)

Voss) au p-dichlorobenzéne (PDB) cristallin pendant 26 jours a tue plus de

95% des larves de perce-bois sous |’ecorce des billes et dans le bois ’ 4 la dose

minimale de 8 g de produit chimique par metre cube de bille plus volume

spatial d’air.LLalongue duree du traitement a cause la decoloration des billes

par des Champignons de decoloration. Les periodes de traitement ont éte

reduites a 2, 4 et 7 jours et le PDB a eté dissous dans du trichloroethyléne.

La dose minimale a la plus courte duree a tue plus de 80% des larves de

perce-bois.

References

Becker, W. B., and H. G. Abbott. 1961. Prevention of insect damage to decked pine sawlogs in

Massachusetts with BHC emulsion sprays. J. Forestry 59: 366-369.

Buffam, P. E., and D. D. Lucht. 1968. Use of polyethylene sheeting for control of Ips spp. in log-

ging debris. J. econ. Ent. 61: 1465-1466.

Gardiner, L. M. 1970. New northern Ontario spruce beetle compels May start on log spraying.

Canadian Forest Industries, July 1970.

Ross, D. A. and J. S. Downton. 1966. Protecting logs from long-horned borers with lindane

emulsion. For. Chron. 42: 377-379.

BOOK REVIEW

Borden, J. H. and Herrin, B.D. 1972. Insects

in the Classroom. B.C. Teachers’ Federation,

Vancouver. 147 pp. $3.50

Years ago this society discussed the idea

of producing a school book on insects and even

struck committees to investigate the problems.

It is ironic that when a member independently

authored such a book, the society as a whole

appeared to be unaware of it. Another society

has taken note, and with approval (see Bull.

Ent. Soc. America 20(3) p. 218. 1974).

The book is a three-way collaboration. Pro-

fessor Borden of Simon Fraser University

supplied the basic knowledge; his co-author, a

teacher in Vancouver, supplied the presenta-

tion; and the artist, Poul Neilson, supplied

much of the interest. The Teachers’ Federation

and some named individuals also contributed.

Physically, the book is 8% x 7 inches, with

Paper covers, perforated pages and plastic

spine, so that it lies perfectly flat when open.

Some of the typography is open to criticism.

Chapter and sub-heads in lower case letters

with no capitals are followed by sub-sub-heads

in large, block capitals. Both gimmicks are out

of place, but perhaps the authors are not re-

sponsible. The line drawings range from ade-

quate to excellent.

There are two parts. The first covers the

necessary systematics, including four non-

insectan Arthropod Classes and 22 Orders of

insects. Each taxon is given one page on which

is included: a line drawing of a typical repre-

sentative; the derivation of its ordinal name and

the common names; and characteristics, habits

and importance in a paragraph apiece. Within

the constraints of available space, these are

very well done. Short chapters on metamor-

phosis, populations, and good and bad insects

complete Part 1.

Part II is more ambitious, with longish

chapters on collecting, rearing, experimenting

and getting information, plus a bonus of three

pages on possible and probable disasters.

Little is missed that could possibly be included,

except a note on avoiding otherwise inevitable

damage by dermestids in collections. Experi-

ments with choice chambers, temperature

preferences, tasting and feeding in flies, soil

insects, flight mills, nutrition, etc. are described

with a maximum of ingenuity and a minimum

of expense. Good directions are given for rear-

ing Drosophilia, flour moths, blowflies, meal-

worms and locusts.

The last chapter (9) is a useful annotated

list of biological supply houses, books, films

etc., Provincial Entomologists and State Ex-

tension Directors. A detailed 8-page index

completes this excellent, and for its avowed

purpose, highly recommended book.

H. R. MacCarthy

J ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

THE EUROPEAN FRUIT LECANIUM, LECANIUM TITLIAE (L.)

(HOMOPTERA: COCCIDAE), INSOUTHWESTERN

BRITISH COLUMBIA

AMOS Y. RUBIN* AND B. P. BEIRNE

Pestology Centre, Department of Biological Sciences,

Simon Fraser University, Burnaby, B.C. V5A 1S6

ABSTRACT

Lecanium tiliae normally has one annual generation in southwestern

British Columbia. There was a partial second in a year following a mild

winter. The heaviest infestations were on horse chestnut, Japanese plum,

hawthorn, and maple, in that order. Hawthorn was damaged. The propor-

tion of males tended to be higher in high than in low populations, and to

decrease with increasing altitude. Severe winter cold caused marked popu-

lation decreases and cold weather in June noticeable decreases. Natural

enemies found in 1969-72 are listed.

The European fruit lecanium, Lecanium

tiliae (L.) (formerly referred to as L. coryli

(L.)), was introduced into southwestern

British Columbia about 1903, probably from

Holland (Lyne 1927). There were severe in-

festations in the Vancouver area in 1925-30,

1937-46, and 1964-72. The following observa-

tions on the biology and ecology of this scale

were made in 1969-72, during a study of its

natural enemies reported elsewhere (Rubin and

Beirne 1975). They supplement observations

by Glendenning (1925, 1931, 1933, 1934) and

by Graham and Prebble (1953) on earlier in-

festations, and are based on collections of

infested leaves or twigs.

Life-Cycle

There is normally one generation per year

in British Columbia. The crawlers hatch from

the eggs in May and feed on the leaves until

late August when they become second instar

larvae and migrate to the twigs and small

branches, where they feed until September or

October. Here they overwinter. No evidence

could be found that they overwinter or fallen

leaves, which sometimes happens in Europe

(Krassilstchik 1915). The males appear early

in April, after a pupation period of about a

month. Egg-laying starts in May.

Host-Preferences

The lecanium scale feeds on various deci-

duous trees and shrubs. Regular surveys were

made of the number of scales on leaves and on

50 cm of twig or branch, on six species of trees,

selected as being common host-plants in the

Vancouver area. A total of 241 random samples,

containing 50,022 scales, were taken from the

trees at different times. In addition, six

selected samples, containing a total of 6,401

scales, were taken from heavy infestations on

unidentified maple.

The average numbers of scales in the ran-

dom samples of 50 cm of twig or branch were:

horse chestnut 319 (17 samples); Japanese

plum 81 (41); hawthorn 67 (48); maple 60 (29);

black cherry 37 (25); and red alder 33 (15).

Average on apple was 52 (3) and on sweet

cherry 7 (2). The average for the selected

samples from the heavy infestations on maple

was 1,089 (6). The single most heavy infesta-

tion had 3,072 scales per 50 cm of maple

branch.

Pest Significance

The scale becomes a pest by sucking juices

from leaves and twigs of the trees and by pro-

ducing honeydew that is a nuisance when it

drops on cars and clothing and on which grows

a black fungus or “sooty mould’, Fumago

spp., that inhibits photosynthesis.

Its pest importance is not always related

directly to its population density. Trees such as

horse chestnut that have large crowns suffer

less damage than do trees with small crowns

such as Japanese plum and hawthorn, even

when horse chestnut has a more dense popula-

tion than the others. Young trees are damaged

most because they have the highest proportion

of the young twigs on which the scales tend to

concentrate. Hawthorn appeared to be par-

ticularly affected by scale attack in 1969-72:

many infested twigs and small branches dried

up and died; and infested leaves were usually

smaller and sometimes thicker than non-infest-

ed ones. Tree damage in the 1925-30 infestation

was sufficiently severe to warrant extensive

*Present address: Nature Reserves Authority, 16 Hanatziv Street, Tel-Aviv, Israel.

J ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975 19

spraying annually, which, incidentally, may

have intensified that infestation by killing

parasites of the scale.

Scales, especially males, were sometimes

found trapped and drowned in the honeydew

and in the secretions from the buds of some

trees, notably of red alder.

Sex Ratio

In Europe males are usually rare, repro-

duction commonly is parthenogenetic, the sex

ratio can be much influenced by climate, and

the proportion of males decreases with increas-

ing altitude (Thiem 1932). Glendenning (1925)

found that males were much more numerous

than females by about 3:1. In the present

study, 19,359 scales were examined to de-

termine their sex: 19.7% were males, or about

There was wide variation in the proportion

of males in scale populations on different host

plants. It was above the average on Japanese

plum (30%), horse chestnut and sweet cherry

(27% each), but lower than the average on haw-

thorn (16%) and maple (14%, but 18% on the

heavily infested trees), and much lower on red

alder (8%) and black cherry (7%). In general,

the proportion of males tended to be higher on

hosts with high scale densities than on hosts

with low ones.

Surveys of infestations at altitudes of up

to 500 m indicated that, as in Europe, there is

a decrease of 19% in the proportion of males

with each increase of 100 m of altitude (signi-

ficant at 5%). There was a decrease of 8% in

the proportion of males with each increase

of 10°C (significant at 5%).

Influences of Weather

At times in 1969-70 scale populations, as

indicated by numbers per 50 cm of branch,

decreased markedly. Some of these decreases

coincided with the occurrence of weather ex-

tremes, as follows:

There were decreases on three species of

host plants between November 26 and Decem-

ber 31, 1971: from 307 to 122, 301 to 83, and:

396 to 82 scales per 50 cm. December 1971

was very cold, with average temperatures of

-0.6° and 0.6°C at Burnaby Mountain and

Vancouver Airport, respectively, as compared

with the long-term winter monthly averages

at those locations of 0.5°C and 1.7°C. Decreases

on various host plants in the fall of 1970, from

31 to 7 between September 9 and 24, 62 to 12

between September 24 and October 8, 2,346 to

114 between November 15 and 21, coincided

with a cold autumn and the beginning of a

severe winter. There was also a decrease from

121 to 61 between February 1 and 16 and, ona

similar plant, from 226 to 59 between March 3

and 12, both in the severe winter of 1970-71.

In 1971 a cold June was followed by a

warmer than average July and August. Some

scale populations decreased on various host

plants from 133 to 35 between June 24 and

July 15, 39 to 3 between June 30 and July 31,

and 102 to 39 between June 30 and August 31.

The scale became active earlier than usual

in the spring of 1970, following a very mild

winter. This extension of its active period pre-

sumably was why there was an abnormal

partial second generation in the fall of 1970.

It appears from these observations that

temperature can be important in regulating

scale populations.

Natural Enemies

The most important natural enemies in

1969-72 were the hymenopterous parasites

Blastothrix longipennis (How.), Metaphycus

kincaidi Timb., and Coccophagus lycimnia

(Walk.). They are discussed elsewhere (Rubin

and Beirne 1975).

The following is a list of the predators en-

countered:

Arachnida. Araneae (det. D. J. Buckle):

Araneus diadematus Cl., Araneus sp., Por-

homma sp., Coriarachne brunneipes Banks;

Acarina (det. R. S. Downing): Typhlodromus

pyri Scheut., Amblyseius masseeit Nesb., A.

morgani Chant, and various Tydeiade and

saprophytic mites.

Insecta. Dermaptera (det. R. J. Lamb):

Forfiucula auricularia L.; Hemiptera (det. G. J.

Fields): Anthocoris antevolens White; Cole-

optera (det. J. .V. Richerson): Chilocorus fra-

ternus LeC.; Neuroptera (det. K. H. Martin):

Hemerobius_ pacificus Banks, Hemerobius

sp. prob. humulinus L., Chrysopa_harrisii

Fitch.?, C. carnea Steph.?.

References

Glendenning, R. 1925. The lecanium scale outbreak in Vancouver, B.C. Proc. Ent. Soc. Br.

Columb. 22:21-26.

Glendenning, R. 1931. The lecanium scale, an insect affecting fruit and shade trees on the Pacific

coast. Canada Dept. Agric. Circ. No. 77. 4 pp.

Glendenning, R. 1933. A successful parasite introduction into British Columbia. Can. Ent. 65:

169-171.

Glendenning, R. 1934. On the control of Eulecanium coryli (L.) in British Columbia by the para-

site Blastothrix sericea (Dalm.). Proc. Fifth pac. Sci. Cong., Canada 1933, 5: 3543-3545.

Graham, K. and M. L. Prebble. 1953. Studies on the lecanium scale, Eulecanium coryli (L.), and its

parasite Blastothrix sericea (Dalm.), in British Columbia. Can. Ent. 8% 153-181.

20 J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

Krassilstchik, I. M. 1915. (Report on the work of the Bio-Entomological Station (of Bessarabia)

during 1914. Govt. of Bessarabia, Kishinev, 1915, 49 pp. In Russian) Abstract in Rev.

Appl. Ent. 3: 395-398.

Lyne, W. H. 1927. Lecanium coryli. Spec. Publ. Calif. Dept. Agric. No. 73, p. 35.

Rubin, A. and B. P. Beirne. 1975. Natural enemies of the European fruit lecanium, Lecanium tiliae

(L.) (Homoptera: Coccidae), in British Columbia. Can. Ent. 107: 337-342.

Thiem, H. 1932. Pleisozontie als Arterhaltungsprinzip. Jenaische Z. naturw. 67: 488-492.

NUMBERS OF DENDROCTONUS RUFIPENNIS (KIRBY) AND

THANASIMUS UNDATULUS SAY AT PHEROMONE-BAITED

POISONED AND UNPOISONED TREES

E. D. A. DYER, P. M. H

ALL AND L. SAFRANYIK

Department of the Environment

Canadian Forestry Service

Pacific Forest Research Centre

Victoria, B.C.

ABSTRACT

Four times as many spruce beetles, Dendroctonus rufipennis (Kirby),

were killed at spruce trees (Picea engelmannii Parry, Picea glauca (Moench)

Voss) baited with frontalin and sprayed with insecticide than at trees baited

but unsprayed. Many clerid predators, Thanasimus undatulus Say, were also

killed at the baited and sprayed trees. Their numbers were correlated with

those of killed spruce beetles. Other correlations show that sprayed and

unsprayed trees were exposed to the same attacking spruce beetle popula-

tion and that predation on the spruce beetles was occurring.

INTRODUCTION

A synthetic pheromone, frontalin (Kinzer

et al., 1969) causes aggregation in both sexes

of spruce beetle (Dendroctonus rufipennis

(Kirby)) and a clerid predator (Thanasimus

undatulus Say), when released from polyethy-

lene capsules on living spruce trees (Picea

glauca (Moench) Voss, P. engelmannii Parry)

(Dyer, 1973). Insecticide sprayed onto the lower

3.0 m (10 ft) of tree boles kills all arriving in-

sects, and thus prevents the establishment of

galleries by spruce beetles and predation by

T. undatulus (Dyer, 1973). Without insecticide,

some arriving spruce beetles enter the bark of

baited trees and attempt to reproduce, even

though resistance by the tree may prevent

subsequent egg hatching or development of

brood. The predators, attracted to baited trees,

arrive at about the same time as the first

beetles, which gives them an opportunity for

predation, which would probably not occur

during natural attacks when some _ spruce

beetles would have entered the bark before

producing pheromone (Dyer, 1973). The follow-

ing experiments carried out in 1973 and 1974

were designed to determine any differences in

numbers of spruce beetles and predators at

baited trees sprayed with insecticide, and the

numbers of spruce beetles in baited, unsprayed

trees.

METHODS

Near Prince George, B.C., 133 spruce trees,

about 20.1 m (66 ft) apart in a line around a

stand perimeter in the Naver forest, were

baited with 1.0 ml of 1 part frontalin and 2

parts alpha-pinene, in May 1973. Two polyethy-

lene capsules, containing the frontalin-pinene

mixture, were placed on each tree on opposite

sides at breast height. Every tenth tree was

sprayed to drip with insecticide (lindane

0.5% in water) on the basal 3.0 m and was fitted

with a wire-screen basket at the base (Dyer,

1973).

Collections from the baskets were made

about twice a week, from June 14 to the end of

August. In August, bark samples of 20.3 x 25.4

cm (8 x 10 inches) were removed from 25 trees

randomly chosen out of the 91 attacked trees.

A minimum of four samples was taken from

each tree, one from each of the north and south

aspects at breast height and at the base. If the

attack height was greater than 1.8 m (6 ft) a

further two samples were taken from the north

and south aspects midway between breast

height and attack height. The number of

attacks, i.e. entrance holes, was counted for

each sample.

In 1974, ten pairs of spruce trees were

selected at about 403.3 m (1320 ft) intervals,

in the Naver forest near the 1973 experiment.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), DEc. 31, 1975 21

Each pair had approximately the same dbh

(+5 cm) and the trees were spaced about 20 m

apart. Both trees of a pair were baited with

frontalin and alpha-pinene, as was done in the

1973 experiment and one tree from each pair

was sprayed with lindane and fitted with a

screen basket as described. Screen baskets

were also placed on seven of the ten unsprayed

trees. Collections were made from all screen

baskets about twice per week, from June 4 to

August 28. Fragments of spruce beetles, such

as pairs of elytra, were collected from baskets

on unsprayed trees as evidence of arthropod

predation.

At the end of the spruce beetle flight period

in August, from five to 14 randomly distributed

(20.3 x 25.4 cm) bark samples were removed

from the unsprayed trees to obtain an estimate

of the mean attack density. The estimated num-

ber of beetles was calculated by using the total

attacked surface area of each tree, attack

density, and the male to female ratio found in

the sprayed-tree collections. Analysis of these

data included three correlations: (1) between

the number of spruce beetles and the number of

Thanasimus caught on each date at the sprayed

trees; (2) between the number of Thanasimus

caught at each sprayed tree and the number

of predator-killed spruce beetles at the corres-

ponding unsprayed tree, and (3) between the

number of spruce beetles caught at each spray-

ed tree and the estimated numbers under the

bark of each corresponding unsprayed tree.

RESULTS AND DISCUSSION

In 1973, the average numbers of spruce

beetles and T. undatulus killed per sprayed

tree were 130.5 and 73.7, respectively. The aver-

age number of spruce beetles in the unsprayed

trees was 43.5 (Table 1), or one-third the num-

ber killed at sprayed trees. At the sprayed

trees, the ratio of JT. undatulus to spruce

beetles was 1 to 1.8.

TABLE 1. Numbers of D. rufipennis and T. undatulus caught at insecticide-sprayed and unsprayed

trees baited with frontalin in 1973.

Dendroctonus caught at

sprayed trees

Thanasimus caught at

sprayed trees

Estimated no. of

Dendroctonus in attacked

unsprayed trees

1/ 95% confidence belt

In 1974, the average numbers of spruce

beetles and T. undatulus killed per sprayed

tree were 1703.8 and 418.0, respectively. The

average number of spruce beetles in the un-

sprayed trees was 395.7 (Table 2); about one

fourth the numbers at sprayed trees. One T.

undatulus was killed for each four spruce

beetles on the sprayed trees, nearly half the

ratio found previously. Fragments of spruce

beetles were found in the screens on the un-

sprayed trees (Table 2), indicating that preda-

tion was occurring.

In the 1974 study, the follwing three pairs

of variables were linearly related with signifi-

cant (P <.01) correlation coefficients: (1) the

number of D. rufipennis caught at sprayed

trees and the number in unsprayed trees

(r=0Q.77); (2) the number of D. rufipennis and

T. undatulus caught at sprayed trees (r=0.87);

and (3) the number of 7. undatulus and the

number of predator-killed D. rufipennis at

paired trees (r=0.88).

Since the numbers of D. rufipennis at spray-

No. of trees Mean no./ Std. error %33/

sampled tree of mean

130.5 44.68 40.1+0.2

ed and unsprayed trees were significantly

correlated, each of a pair of trees was exposed

to the same or similar attacking populations.

Therefore, some factor other than available

population determined the difference in num-

bers at the sprayed and unsprayed trees. Since,

at sprayed trees, the number of J. undatulus

caught was correlated with the number of D.

rufipennis caught and, at unsprayed trees, with

the number of D. rufipennis destroyed, preda-

tion was one factor that reduced the number

of beetles entering unsprayed trees. However, a

precise count of the number of D. rufipennis

killed by T. undatulus is difficult to obtain

because some evidence of predation is lost in the

bark crevices and spider webs on the tree boles;

moreover, other insect predators may have

killed attacking beetles. Table 2 shows that each

T. undatulus would have had to remove about

three spruce beetles to account for the reduced

number in the unsprayed trees compared to

those caught at the sprayed trees.

In 1974, the estimated ratio of predator to

22 ~ J. Entromot. Soc. Brit. COLUMBIA 72 (1975) Dec. 31, 1975

TABLE 2. Numbers of D. rufipennis and T. undatulus caught at insecticide-sprayed and unsprayed

trees baited with frontalin in 1974.

Dendroctonus caught at

sprayed trees

Thanasimus caught at

sprayed trees

Estimated no. of

Dendroctonus in attacked

unsprayed trees

Predator-killed

Dendroctonus at

unsprayed trees

1/ 44.4% 3 + 0.16% (95% confidence belt)

No. of trees

sampled

Std. error

of mean

Mean no./

tree

1703.8'/ 274.21

2/ Based on parts of D. rufipennis, such as pairs of elytra, in screen baskets at tree bases.

prey decreased from that of 1973, which should

have resulted in a higher proportion of the

arriving spruce beetles entering the trees,

if predation were the only factor influencing

attack density. However, the proportion was

less in 1974 (0.23: 1) than in 1973 (0.33:1),

indicating that some mechanism other than

predation influenced the number of beetles

entering the unsprayed trees. Nijholt (1973),

studying another’ scolytid, Trypodendron

lineatum (Oliv.), showed that the presence of

males masked the secondary attraction of fe-

males. Hedlin' found that when using an in-

secticide on logs, the natural secondary

attraction of Trypodendron females in the logs

continued to attract other beetles longer and in

‘A. F. Hedlin personal comminciation.

greater numbers to treated rather than to un-

treated logs, presumably because the males

were killed before they could join the females.

An _anti-aggregative pheromone MCH

(3-methyl-2-cyclohexen-l-one) is produced by

spruce beetles after entering the host tree

(Kline et al., 1973; Rudinsky et al., 1973).

MCH repelled D. rufipennis from attractive

host logs and felled trees when released nearby.

Since it is probable that MCH was produced by

the beetles after both sexes had entered the un-

sprayed trees, later arriving beetles in similar

numbers would have been repelled from entering

the unsprayed trees while the sprayed trees

would have continued to be attractive through-

out the flight period.

Résume

Les auteurs rapportent que 4 fois plus de Dendroctones de l’Epinette,

Dendroctonus rufipennis (Kirby), furent tues sur des Epinettes (Picea en-

gelmanii Parry, Picea glauca (Moench) Voss) appatees avec de la frontaline

et arrosees avec un insecticide, que sur des arbes appates mais non arrosés.

Plusieurs predateurs Clérides appartenant a Thanasimus undatulus Say,

ont également eté tues sur des arbres appates et arroses. leurs nombres ont

ete misencorrélation avec ceux des Dendroctones. D’autres corrélations

ont demontré que les arbres arroseés et non arroses ont egalement éte

exposes aux attaques par la meme population de Dendroctones et que la

predation sur les Dendroctones avait lieu.

References

Dyer, E. D. A. 1973. Spruce beetle aggregated by the synthetic pheromone frontalin. Can. J. For.

Res. 3: 486-494.

Kinzer, G. W., A. F. Fentiman, Jr.,

T. F. Page, Jr.,

R. L. Foltz, J. P. Vité, and G. B. Pitman.

1969. Bark beetle attractants; identification, synthesis and field bioassay of a new com-

pound isolated from Dendroctonus. Nature 221: 477-478.

Kline, L. N., R. F. Schmitz, J. A. Rudinsy and M. M. Furniss. 1974. Repression of spruce beetle

(Coleoptera) attraction by methylcyclohexenone in Idaho. Can. Ent. 106: 485-491.

Rudinsky, J. A., C. Sartwell, Jr., T. M. Graves and M. E. Morgan. 1974. Granular formulation

of methylcyclohexenone: an antiaggregative pheromone of the Douglas fir and spruce

bark beetles (Col., Scolytidae). Z. ang. Ent. 75: 254-263.

Nijholt, W. W. 1973. The effect of male Trypodendron lineatum (Coleptera: Scolytidae) on the

response of field populations to secondary attraction. Can. Ent. 105: 583-590.

J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), DEc. 31, 1975 23

SOME CHIRONOMIDAE (DIPTERA) NEW TO

BRITISH COLUMBIA AND CANADA

ROBERT A. CANNINGS

Department of Zoology, University of British Columbia,

Vancouver

During recent research on the chironomid

fauna of saline lakes in the southern interior

plateau region of British Columbia, a number of

species new to Canada or British Columbia

were encountered.

The following list cites those species that

have been identified to date with certainty

and gives the water bodies from which these

insects have been taken in emergence traps.

Species new to Canada are identified in the

text by a double asterisk (**) and those new to

British Columbia by a single asterisk (*).

The lakes studies are shown in Table 1

and are the same as those considered by

Scudder (1969). Further details of the study

area and the ecology of the chironomid species

will be published later.

Family Chironomidae

Subfamily Tanypodinae

Tribe Macropelopiini

Subtribe Macropelopiina

*Derotanypus (Merotanypus)

(Malloch)

alaskensis

B.C.—Barnes L., Round-up L., L. Lyle, Boi-

tano u., L. Jackson, L. Greer, Rock L., Near

Phalarope, Westwick L., Sorenson L., Near

Opposite Crescent, Box 17, Barkley L.,

East L. and Box 27.

Previous records: Alaska, Yukon Territory,

Northwest Territories, Alberta, Sask-

atchewan and Manitoba (Roback, 1971).

Subtribe Procladiina

*Procladius (Procladius) dentus Roback

B.C.—Barnes L., Round-up L., L. Lye, Boitano

L., Rock L., Westwick L., Sorenson L., Near

Opposite Crescent, Barkley L. and East L.

Previous records: Alaska, Northwest Terri-

tories, Saskatchewan, Manitoba, Quebec

and Labrador (Roback, 1971).

*Procladius (Procladius) clavus Roback

B.C.—Barnes L., Round-up L., L. Lye and

Boitano L.

Previous records: Spence Bay and Ceillini

Lake, Northwest Territories (Roback, 1971).

Tribe Pentaneurini

*A blabesmyia (Karelia) peleensis (Walley)

B.C.—Barkley L., East L. and Box 27.

Previous records: Alberta and Ontario, Wis-

consin and Iowa east to New York and

south to South Carolina (Roback, 1971).

Subfamily Orthocladiinae

Tribe Orthocladiini

*Cricotopus abanus Curran

B.C.— Box 17, Barkley L., East L., and Box 27.

Previous records: Manitoba (Sublette and

Sublette, 1965; Sublette, 1967).

*Cricotopus flavibasis Mailoch

B.C.— Round-up L., L. Lye, Boitano L., L. Jack-

son, L. Greer, Rock L., Near Phalarope,

Westwick L., Sorenson L., Near Opposite

Crescent, Box 17, Barkley L. and East L.

Previous records: Alberta (Strickland, 1938)

and Illinois (Sublette and Sublette, 1965).

*Cricotopus trifasciatus (Meigen)

B.C.—L. Greer, Near Phalarope and Barkley L.

Previous records: Germany, Idaho, east to

Ontario and New York, south to Missouri

and Florida (Sublette and Sublette, 1965).

** Acricotopus nitidellus (Malloch)

B.C.—a single male from Sorenson L.

Previous records: Illinois and New York (Sub-

lette and Sublette, 1965; Sublette, 1970).

*Psectrocladius barbimanus Edwards

B.C.—Barnes L., Round-up L., L. Lye, Boitano

L., L. Jackson, L. Greer, Rock L., Near

Phalarope, Westwick L., Sorenson L., Near

Opposite Crescent, Box 17, Barkley L.,

East L. and Box 27.

Previous records: northern and western Europe

and Stoughton, Saskatchewan (Saether,

1969).

**Psectrocladius zetterstedti Brundin

B.C.— Box 27

Previous records: Sweden (Brundin, 1949).

First record for North America.

Subfamily Chironominae

Tribe Chironomini

*Chironomus atrella (Townes)

B.C.—one male from Sorenson L.

Previous records: Alberta to Prince Edward

Island and south to California, Colorado and

Massachusxetts (Sublette and Sublette,

1965).

*Finfeldia pagana (Meigen)

B.C.—Barnes L., Round-up L., L. Lye, Boitano

L., L. Jackson, L. Greer, Rock L., Near

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

Table 1. Location and characteristics of water bodies studied in the Cariboo and Chilcotin areas of

British Columbia. Names in parentheses are those used by Scudder (1969).

Area Mean depth Max. depth

Mean conductivity

(microhmos / cm.

Water body Location (ha) (m) (m) at 25°C)

Barnes L* 52°0’30’’N 122°28’00’°W 17.20 2.0 4.5 11816

(Box 47)

Round-up L.* 52 02 122 30°30 30.84 2.6 6.2 6885

(Phalarope?T)

L. Lye* _ 52 O1 122 29 30 46.50 2.8 5.4 6548

(Box 20-21T)

Boitano L.** 5157 122 08 80.70 2K 4.5 4108

L. Jackson* 52 00 122,27 30 5.83 1.4 2.3 2766

(Nr. Opposite

Box 4T)

L. Greer* 51 59 30 122 26 15.18 1.0 2:3 1602

(Box 897)

Rock L.* 51 58 122725 34.60 del 2.5 1496

Near 52 02 122,31 5.06 1.3 3.0 1334

Phalaropet

Westwick L.** 51 59 122,09 58.32 3 4.5 1287

Sorenson L.tt 52 00 122-10

Nr. Opposite 515930 12227 6.88 1.4 3.3 810

Crescentt

Box 177 51 59 30 122 26 30 2.67 hel 3.3 741

Barkley L.* 52 00 122 28 4.53 0:7 Zee 592

(Opposite Box 47)

East L.* 5s 9 30 122,26 27.03 1.9 6.5 372

(Racetrack?)

Box 27t o1 59 122-25 4.30 0.5 1.5 16

**Official names cited in the Gazetteer of Canada. British Columbia Canadian Board of Geograph-

ical Names, Ottawa (1953).

* Official names adopted on the Chilcotin Training Area Composite Map MCE 120 (Edition 2).

Mapping and Charting Establishment, Department of National Defence, Ottawa (1968).

+t Unofficial names used by Scudder (1969). The ‘‘Box’”’ series refer to duck nest boxes put up

near the water body by the Game Branch of the B.C. Department of Recreation and Conserva-

tion in the 1950s: other names are convenience descriptive terms used for the water bodies by

Scudder and his students over the years.

++Unofficial name used locally for the western half of the old Westwick L. which is now split into

two by a road. The name Westwick L. as used here refers to the lake to the east of the road.

Note: Characteristics of water bodies taken from Scudder (1969) and Topping (1969).

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), DEc. 31, 1975 20

Phalarope, Westwick L., Sorenson L., Near

Opposite Crescent, Box 17, Barkley L.,

East L. and Box 27.

Previous records: Europe; Idaho, South

Dakota, Michigan and New York (Sublette

and Sublette, 1965). In Canada the only

other record is from Saskatchedwan (Driver,

1971).

*Cryptochironomus psittacinus (Meigen)

B.C.— Round-up L., L. Lye and Boitano L.

Previous records: Europe; Alaska to New

York and south to Oregon and Kentucky

(Sublette and Sublette, 1965).

*Cryptotendipes ariel (Sublette)

B.C.—Barnes L., Round-up L., L. Lye and

Tribe Tanytarsini

*Tanytarsus gracilentus Holmgren

B.C.—Barnes L., Round-up L., L. Lye and

Boitano L.

Previous records: northern Europe, Alaska and

Northwest Territories (Ellesmere Is.) (Sub-

lette and Sublette, 1965).

**Tanytarsus holochlorus Edwards

B.C.—Barnes L., L. Lye, Boitano L., Westwick

L., Sorenson L., Box 17, Barkley L. and

Box 27.

Previous records: Europe (Mundie, 1957).

ACKNOWLEDGEMENTS

I thank Dr. D. R. Oliver and Dr. J. E.

Sublette for identifyting the species. Dr. Oliver

Boitano L.

Previous records:

Sublette, 1965).

also kindly criticized the manuscript. The re-

search was supported by a National Research

Council grant to Dr. G. G. E. Scudder.

California (Sublette and

References

Brundin, L. 1949. Chironomiden und andere Bodentiere der Sudschwedischen Urgebirgsseen.

Rep. Inst. Freshwat. Res. Drottningholm 30: 1-914.

Driver, E. A. 1971. Range extensions and habitat data of two Chironominae ( Diptera: Chirono-

midae) from Saskatchewan. Can. Ent. 103: 1017-1019.

Mundie, J. H. 1957. The ecology of Chironomidae in storage reservoirs. Trans. R. ent. Soc. Lond.

109: 149-232.

Roback, S.S. 1971. The adults of the subfamily Tanypodinae (=Pelopinae) in North America.

Monogr. Acad. Nat. Sci. Philad. 17: 1-410.

Saether, O. A. 1969. Some Nearctic Podonominae, Diamesinae and other Orthocladiinae (Diptera: -

Chironomidae). Bull. Fish. Res. Bd. Canada. 170: 1-154.

Scudder, G. G. E. 1969. The fauna of saline lakes on the Fraser Plateau in British Columbia. Verh.

int. Ver. Limnol. 17: 430-439.

Strickland, E. H. 1938. An annotated list of the Diptera (flies) of Alberta. Canad. Jour. Res., Sect.

D, zool. Sci. 16: 175-219.

Sublette, J. E. 1967. Type specimens of Chironomidae (Diptera) in the Cornell University

collection. J. Kansas Entomol. Soc. 40: 477-564.

Sublette, J. E. 1970. Type specimens of Chironomidae (Diptera) in the Illinois Natural History

Survey collection, Urbana. J. Kansas Entomol. Soc. 43: 44-95.

Sublette, J. E. and M.S. Sublette. 1965. Family Chironomidae (Tendipedidae) in Stone et al. (ed.).

A catalogue of the Diptera of America north of Mexico. U.S. Dept. Agr. Handbook.

276: 1-1696.

Topping, M. S. 1969. Giant chromosomes, ecology, and adaptation in Chironomus tentans. Ph.D.

diss., University of British Columbia.

26 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

LIFE-CYCLE OF A SPIRAL GALL APHID, PEMPHIGUS

SPIROTHECAE (HOMOPTERA: APHIDIDAE), ON POPLAR IN

BRITISH COLUMBIA!

CHO-KAI CHAN ANDA. R. FORBES

Research Station, Agriculture Canada

Vancouver, British Columbia

ABSTRACT

Pemphigus spirothecae Pass. was inadvertently introduced into North

America only recently. Upon hatching in spring on lombardy poplar, the.

fundatrix feeds on a leaf petiole, which bends and then spirals into a spiral

gall. The fundatrix produces about 100 fundatrigeniae within the gall. These

produce winged sexuparae which leave the gall and settle on the poplar

bark, where they produce up to eight progeny, males and females. Each

female lays a single large egg which overwinters on the bark. This aphid

is thus monoecious and holocyclic.

INTRODUCTION

The gall aphid, Pemphigus spirothecae

Pass., was studied on lombardy poplar, Populus

nigra L. var. italica, on the campus of the Uni-

versity of British Columbia during 1973 and

1974. This aphid produces unique spiral galls

(Fig. 1) on the petioles of the leaves. P. spiro-

thecae is apparently common in Europe but

was found only recently in North America in

Quebec (Alleyne & Morrison 1974) and at about

the same time in British Columbia. Its life-

cycle in Europe has been described by Toth

(1939). The present stydy was undertaken to

determine the life-cycle of the aphid in British

Columbia and to describe the aphid-host plant

interaction.

DEVELOPMENT OF THE GALL

In general, the formation of a gall has an

early phase, a trophic phase, and a post-trophic

phase (Mani 1964). In the spiral gall of P. spiro-

thecae the early phase can be sub-divided into

three stages: bending, spiralling and swelling

(Gerhardt 1922); swelling of the gall continues

through the trophic phase. Upon emerging

from the egg, the fundatrix or stem mother,

begins to feed on the petiole of a leaf produc-

ing first bending (Fig. 2b) then spiralling until

three loose spirals have been produced (Fig. 2,

c & d). Subsequent swelling of the gall seals

the gall cavity and increases its size (Fig 2,

e,f & g).

The time taken to produce the three coils

on petioles of lombardy poplar outdoors at

Vancouver was 3-4 weeks, considerably longer

than the 6 days reported by Dunn (1960) for

attaining the same stage in the laboratory.

If the first instar stem mother dies while the

gall is forming, no further development takes

place and incomplete galls result with one or

‘Contribution no. 362, Research Station, Agriculture

Canada, 6660 N. W. Marine Drive, Vancouver, British Colum-

bia, V6T 1X2.

two coils. Subsequent feeding by the newly

enclosed fundatrix stimulates the coils of the

gall to grow laterally, sealing the walls. In-

crease in length of the coils expands the gall

and increases the size of the cavity.

The galls reach maturity in late August

and September, gradually changing from green

to orange-red or brown. When mature, the

galls measure about 15 x 13 x 9 mm. The gall

cavity is lined by numerous short, papillate

unicellular hairs, with some longer multicellular

ones among them. When the gall is mature,

one or two ostioles develop (Fig. 3) between the

coils to serve as emergence holes for the aphids,

or sometimes the coils loosen, producing a long

slit in the gall, allowing a mass escape of the

inhabitants. In this post-trophic stage, the

galls deteriorate and fall from the tree with the

leaves. The total life of a gall is from 20-25

weeks.

We could find no evidence that the presence

of a gall on a leaf weakened the leaf or reduced

its size. Galled leaves, however, fell from the

tree sooner than non-galled ones.

LIFE CYCLE OF THE APHID

In late March or April at Vancouver the

fundatrix emerges from the overwintered egg,

at a time when the young poplar leaves begin

to appear. The first instar fundatrix (Fig. 4)

is small, brownish green, and has very well

developed hind legs, 4-segmented antennae

(Fig. 4a) and normally developed labium and

stylets (Fig 5). In fact, its stylets are very

much like those of Myzus persicae (Sulzer)

(Forbes 1969) with each madibular stylet inner-

vated by two dendrites. The fundatrix settles

to feed on a leaf petiole, initiating the formation

of the gall. The fundatrix moults for the first

time as soon as the spiralling of the petiole has

been completed, or almost completed ie.,

about 3-4 weeks after hatching. After the

fourth moult the fundatrix is mature and starts

to reproduce parthenogenetically. The mature

COLUMBIA 72 (1975), Dec. 31, 1975

J. ENTOMOL. Soc. BRIT.

aC Oty

lombardy poplar.

Fig. 1. Fully formed spiral gall of Pemphigus spirothecae Pass. on the petiole of a leaf of

Fig. 2. Stages in the formation of the gall: a, a non-galled leaf; b, bending of the petiole

spiralling of the petiole; e, f, & g, swelling of the gall.

Fig. 3 Mature gall with an ostiole (arrow).

28 J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

Fig. 4. First instar fundatrix of P. spirothecae with an enlargement of an antenna (4a).

Magnification: whole aphid | |= 0.5 mm

antenna | —_____}= 0.1mm

Fig. 5. Transmission electron micrograph of a cross section of the stylets of a first instar

fundatrix. | |= lu

Fig. 6. Mature fundatrix with an enlargement of an antenna (6a).

Magnification: whole aphid Tmt RAD aS aaa a 018)

antenna pos 0.1 mm

Fig. 7. Mature fundatrigenia with an enlargement of an antenna. Magnification as for Fig. 6.

Fig. 8 Sexuparae inside an opened gall.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

* RS

H9sqy

9. Mature sexupara with an enlargement of an antenna (9a). Magnification as for Fig. 6.

Fig. 10. Mature male (sexuale) with an enlargement of an antenna (10 a). Note the rudimentary

mouthparts. Magnification as for Fig. 6.

Fig. 11. Mature female (sexuale) with an enlargement of an antenna (11a). Note the rudimentary

mouthparts. Magnification as for Fig. 6.

Fig. 12. Female laying her egg.

Fig. 13. An egg with wool-like wax.

30 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

fundatrix (Fig. 6) is pale yellow and has short

4-segmented antennae, (Fig. 6a) and well-de-

veloped labium and stylets.

At Vancouver the fundatrices mature be-

tween mid-june and the beginning of July.

During July and August each fundatrix pro-

duces about 100 progeny, the fundatrigeniae.

The mature fundatrigenia (Fig 7) is pale and

can be distinguished from the mature funda-

trix by its longer, 6-segmented antennae (Fig.

7a). The fundatrigeniae moult four times before

they start producing the sexuparae.

The sexuparae are produced in August and

September and are present in the galls (Fig. 8)

from early August until lat November. The

mature sexupara (Fig. 9) is winged and has 6-

segmented antennae with transverse secondary

sensoria on the third and fourth antennal seg-

ments (Fig. 9a). The head and thorax are black

and the abdomen is_ yellow-green. Each

sexupara produces a maximum of six females

and two males on the bark of the tree and then

dies. The females and males moult three times

in a period of 36-40 hours and then mate. The

male (Fig. 10) is small and pale green with

4-segmented antennae (Fig. 10a). The female

(Fig. 11) is also small with 4-segmented anten-

nae (Fig. lla) but the abdomen is long and

contains a single, very large egg (Fig. 12) which

is laid in the crevices of the bark or under the

lichen (Cetraria sp.) often found on the bark.

The newly laid egg (Fig. 13) is 0.55 x 0.28 mm

and is almost the size of the female’s abdomen.

It is white and covered by wool-like waxy secre-

tions from the abdominal wax glands. In 3 or

4 days the egg changes to light green and then

to a bright yellow-brown. The egg overwinters

on the bark.

The sexuales do not feed since they do not

have functional mouthparts. The labium is re-

duced to a small papilla and stylets are absent.

The rudimentary condition of the mouthparts

can be seen on the heads in the photomicro-

graphs of the antennae in Figs. 10 and 11.

Thus all the morphs of P. spirothecae are

found on the bark or in the galls on lombardy

poplar. The aphid is therefore monoecious and

holocyclic.

DISCUSSION

The formation of the spiral gall on the

petiole of lombardy poplar is a dramatic ex-

ample of the way in which aphids can change

the growth processes of plants for their own

advantage. The plant tissue completely sur-

rounds and encloses the fundatrix and her pro-

geny. Only late in the season does the gall open

and release the sexuparae.

Other species of Pemphigus living on poplar

produce markedly different galls. The form of

the gall, therefore must be due to the specific

feeding behaviour of the aphid when gall forma-

tion is initiated and to chemical substances

injected into plants with the aphid’s saliva

(Miles 1968). The details of the feeding be-

haviour of the fundatrix of P. spirothecae have

been described by Dunn (1960).

The spiral gall provides the aphid with an

environment protected from parasites, preda-

tors and weather conditions; only the sexuales

spend their entire life outside of the gall. Prob-

ably just as important to the aphid is the fact

that the galling apparently supplies the aphid

with improved nutrition by changing the

physiology of the plant (Forrest 1971).

References

Alleyne, E. H., and F. O. Morrison. 1974. Pemphigus spirothecae (Homoptera: Aphidoidea), an

aphid which causes spiral galls on poplar in Quebec. Canad. Ent. 106(11): 1229-1231.

Dunn, J. A. 1960. The formation of galls by some species of Pemphigus (Homoptera-Aphididae).

Marcellia 30 (Suppl.): 155-167.

Forbes, A. R. 1969. The stylets of the green peach aphid, Myzus persicae (Homoptera: Aphididae).

Canad. Ent. 101 (1):31-41.

Forrest, J. M. S. 1971. The growth of Aphis fabae as an indicator of the nutritional advantage

of galling to the apple aphid Dysaphis devecta. Ent. exp. & appl. 14 (4): 477-483.

Gerhardt, K. 1922. Uber die Entwicklung der Spirallockengalle von Pemphigus spirothecae ander

Pyramidenpappel. Z. Pflkrankh. 32: 177-189. (Seen in Rev. appl. Ent. A10: 492 (1922)).

Mani, M.S. 1964. Ecology of plant galls. Monogr. Biol. 12. Junk (The Hague).

Miles, P. W. 1968. Insect secretions in plants. Ann. Rev. Phytopathol. 6: 137-164.

Toth, L. 1939. Uber die Biologie der Blattlaus Pemphigus spirothecae Pass. Z. angew. Ent. 26 (2): |

291-311.

J. ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), DEc. 31, 1975 31

THE STATUS OF CONOCEPHALUS FASCIATUS VICINUS

(MORSE, 1901) (ORTHOPTERA: CONOCEPHALIDAE)

JOHN E. R. STAINER'

ABSTRACT

It has been common practice to divide Conocephalus fasciatus (DeGeer,

1773) into two subspecies: C. f. fasciatus from eastern North America and

C. f. vicinus (Morse, 1901) from the west. The criteria for this division are

examined and evidence introduced to show that the name vicinus should

be suppressed and that the entire taxon should be called Conocephalus

fasciatus (DeGeer, 1773).

LITERATURE REVIEW

The name of this taxon has undergone many

changes since DeGeer (1773) described a tetti-

goniid from Pennsylvania which he called

Locusta fasciata. Thunberg (1815) set up the

genus Conocephalus which was intended to in-

clude, among others, the ‘‘cone-headed grass-

hoppers’ now placed in Neoconocephalus

Karny, 1907, and the ‘“‘meadow-grasshoppers’’

presently placed in the group. Audinet-Ser-

ville (1831) briefly described a_ genus,

Xiphidion, which included among its species

Xiphidion fasciatum (DeGeer). Burmeister

(1839) emended the suffix so that the name of

the genus became Xiphidium. These two names

were thereafter used more or less _inter-

changeably for the balance of the nineteenth

century.

Kirby (1890) listed four references to

Xiphidion and one to Xiphidium. A_ few

authors, including Kirby (1906), used the name

Anisoptera Latreille, 1829, for the same taxon.

Rehn (1907) re-examined the situation and

pronounced, as had Kirby (1906), that Cono-

cephalus hemipterus Thunberg was identical

with Gryllus conocephalus Linnaeus, 1758.

As no other specias had previously been desig-

nated as type of the genus, this made G. cono-

cephalus the type of the genus by tautonymy.

Kirby had not accepted the tautonymic nomen-

clature. When Rehn and Hebard (1915a, 1915b)

published their monograms on American

species of the genus, the name Conocephalus

became well established and it remains so to

the present day. DeGeer’s species is now known

as Conocephalus fasciatus (DeGeer).

Xiphidium vicinum was described by Morse

(1901) from the Pacific Southwest of the United

States of America, as a species similar to

X. fasciatum but with the ovipositor almost

constantly longer than in the latter species.

The ratio of hind femur to ovipositor was in-

dicated as being greater than in X. fasciatus.

Karny (1912) listed the two as separate species

of Conocephalus, but Kirby (1906) had already

'Present address: Dept. of Entomology, Macdonald Campus

of McGill University, Ste Anne de Bellevue, P.Q., Canada.

recognized the two as full species, placing them

in Anisoptera, presumably because of his lack

of acceptance of tautonymic names, as noted

above. The position of the “‘variety”’ productum

of Morse (1901) remained confused, probably

because of a lack of clarity in the original

description. Karny (1907, 1912) considered this

form to be a synonym of C. fasciatus, while

Kirby (1906) and Rehn and Hebard (1915)

both placed it under vicinus, which the latter

authors further considered to be but a sub-

species although he referred to Conocephalus

fasciatus (DeGeer). The next author to devote

much space to these members of Conocephalus

was Cantrall (1943, 1968) who used the full

trinomen of the eastern subspecies on both

occasions, thus implying acceptance of the

existence of another subspecies.

The ranges of the two groups were discussed

by Rehn and Hebard (1915). Subsequent papers

have made slight extensions in most possible

directions. C. f. fasciatus was said to range over

North America east of the Rockies and north

as far as southern Canada. C. f. vicinus was

considered to be restricted to the west: Califor-

nia, Oregon, Washington and the _ other

American states to the west of the Atlantic-

Pacific divide (except Alaska), and British

Columbia.

MATERIALS AND METHODS

Only dried insects were used in this study.

The measurements made were similar to those

used by Morse (1901) as criteria for separating

fasciatus from C. vicinus. Only females were

used because Morse was unable to separate the

males on morphological grounds. The measure-

ments of the males have been made as part of

another study but will not be discussed further

in this paper.

The lengths of the ovipositor and one hind

femur were recorded for each specimen. All

measurements were made with a ‘‘Wild M5”

stereo microscope equipped with a calibrated

ocular micrometer. Measurements for reason-

ably-sized series of specimens from various

individual localities were made and averaged

a2 J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

and the ratio of femur III to ovipositor-length

calculated. The ratios were then plotted on a

base map of North America.

A separate set of measurements was made

for all other available females (isolated speci-

mens and very short series). These were

grouped by state or province and averaged.

The averages were plotted on the same map to

provide an independent confirmation of the

results from data obtained from the longer

series.

RESULTS

The results are summarized in the accom-

panying map and table. The sample numbers

(which were quite randomly designated) and

localities follow: (1) Sainte Anne de Bellevue,

Quebec, (2) Antelope Springs, California,

(3) Eugene, Oregon, (4) Ames, Iowa, (5) Rock

Co., Minnesota, (6) Scott Co., Minnesota, (7)

Saint Anthony Park, near St. Paul, Minnesota,

(8) Ottertail Co., Minnesota, (9) Republic,

Anoka Co., Minnesota, (10) Rockaway Beach,

Long Island New York, (11) Juniper, Florida,

(14) South Ohio, Nova Scotia, (15) Avoca,

Quebec, (16) Evans, Washington, (17) Gaines-

ville, Florida, (18) Pequaming, Michigan, (19)

Thomasville, Georgia, (20) Jemez Hot Springs,

New Mexico, (21) Milford, Beaver Co., Utah,

(22) Klamath Falls, Oregon, (23) Castlegar,

British Columbia, (24) Malta, Montana, (25)

Lac Serpent, Quebec, (26) Morgan Arboretum,

Sainte Anne de Bellevue, Quebec, (28) Dorion,

Quebec, (29) Point Pelee National Park, On-

tario, (30) Sandbanks Provincial Park, Prince

Edward County, Ontario, (31) Salmon Arm,

British Columbia, (32) Saint Claude, Manitoba,

(33) Delorraine, Manitoba, (34) Alexandria,

Ontario.

DISCUSSION

An examination of the map (Fig. 1) reveals

that the ratio of femur III to ovipositor reaches

a maximum in California and a minimum in the

north-eastern part of the range. With minor

variations, which may probably be attributed

TABLE 1

Sample Ovipositor Femur III Ratio

number n length (mm) SD length (mm) SD ovipositor /femur III

ih 94 a 0.40 10.8 0.69 .66

1 94 aol 0.40 10.8 0.69 .66

2 9 10.7 0.37 11.6 0.56 92

3 11 8.6 0.30 11.4 0.51 £75

4 12 8.6 0.52 11.8 0.87 .73

9) 14 9.3 0.57 11.6 0.64 81

6 9 8.3 0.59 10.7 0.78 .78

7 10 8.6 0.49 11.4 0.35 75

7) T3 8,9 0,38 11,5 0,48 od,

10 Jia 7.4 0.55 8 0.74 .63

11 19 8.5 0.49 W272, 0.82 .70

14 13 7.6 0.36 11.6 0.39 .65

15 31 (es: 0.30 10.8 0.42 .68

16 7 9.4 0:99 T3 0.37 83

al 13 8.4 0.33 L238 Occ, .68

18 16 8.6 0.37 11.8 0.64 As

19 12 on 0.54 13.3 0.7 .68

20 8 9.0 0.44 PEZ 0.4 .80

>| 13 10.6 0.34 12.0 0.4 .88

22 8 10.3 0.27 11.4 0.56 .90

23 13 eh) 0.45 11.6 0.37 85

24 4 8.8 0.36 11.8 0.66 75

25 40 7.4 0.33 eZ 0.67 .66

26 24 el 0.28 NET 0.59 .66

28 10 8.1 0.28 1221 0.33 .67

29 24 7.8 0.55 12.2 0.71 .64

30 a, fies) 0.43 Use 0.60 .67

31 15 eZ 0.28 11.5 0.32 .80

32 19 8.6 0.37 10.8 0.71 .80

33 8 9.4 0.71 11.5 0.55 .82

34 25 7.9 0.84 11.5 0.42 .69

Conocephalus fasciatus: sample size; lengths of femur III and ovipositor and their ratios. Sample

numbers as in accompanying list of localities.

J ENTOMOL. Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975 30

Fig. 1. Conocephalus fasiatus: ratio of lengths, femur III to ovipositor. A single sample. © state

or provincial average.

34 J ENTOMOL.

to the small sample size, the ratio changes

steadily between the two regions. Similar

changes take place between California and

British Columbia and between California and

Mexico.

There were two independent sets of data

as described above. the same pattern was found

in the two separate sets of data, i.e., those from

the long series and those grouped by state or

province from individuals or short series. The

pattern that emerged may be described as indi-

cating a cline extending from a maximum

ratio in California-Utah to minimum at the

northern, eastern and, probably the southern

limits of the range. The lowest ratios were

found at the greatest distance from California;

that is, in the northeastern portion of the

range.

The existence of this cline calls into question

the utility of Morse’s name vicinus. Morse

had examined material only from New England

and California-Oregon and, apparently, no-

where between the two. he produced no usable

criteria for the separation of males and was

himself in many cases unable to distinguish

between vicinus and fasciatus males. It should

also be noted that, among other species of

Conocephalus, it is the males that are most

easily separated, the females often proving

difficult. Morse was able to separate his fe-

males by use of the femur III/ovipositor ratio,

but even this resulted in a “‘gray”’ area. A

ratio of 0.50 to 0.67 was supposed to indicate

C. fasciatus, while 069. to 0.95 was indicative

of vicinus. Specimens between 0.67 and 0.69

mightbe regarded as belonging to either. In

Soc. Brit. COLUMBIA 72 (1975), Dec. 31, 1975

practice, the ratios do not appear to have been

much used to separate the two taxa. Anything

from east of the continental (Atlantic-Pacific)

divide has been called C. fasciatus and that

from the west has been called vicinus, either

at the species or subspecies level. If one applies

Morse’s ratios to mid-western material, most

specimens from west of Illinois would have to

be called vicinus and there would be a very

wide band of overlap with fasciatus. Thus it

would be pointless to continue to recognize

eastern and western entities as meriting sepa-

rate names.

To end the confusion it is proposed to sup-

ress the name vicinus althogether and to refer

to the whole taxon as Conocephalus fasciatus

(DeGeer, 1773) regardless of geographical

differences.

ACKNOWLEDGEMENTS

A project of this type necessitates borrow-

ing specimens from many sources. In this case

thanks are due to the curators of about twenty

different institutions in North America who

lent material. In addition, the Entomology

Laboratories of the Academy of Natural

Sciences, Philidelphia, and of the Universities

of British Columbia and Idaho, and of the

Museum of Comparative Zoology, Harvard

University, kindly permitted the use of their

facilities. Financial assistance came in part

from a grant from the National Research Coun-

cil of Canada to Dr. D. K. McE. Kevan. Thanks

are also owed to Dr. Kevan for reading and

criticizing the manuscript and to Dr. T. J.

Walker for collecting a series of specimens from

Florida.

References

Audinet-Serville, J. G., 1831. Revue méthodique des insectes de l’ordre des Orthopteres; II. Anns.

Sci. nat. 22: 135-167.

Blatchley, w. S.,

1920. Orthoptera of Northeastern America with especial reference to the faunas

of Indiana and Florida; The Nature Publishing Company, Indianapolis.

Burmeister, H., 1839. Handb. der Ent., Berlin.

Cantrall, I. J., 1

943. The ecology of the Orthoptera and Dermaptera of the George Reserve,

Michigan; Mise. Publs. Mus. Zool. Univ. Mich., 54: 182 + X.

1968. An annotated list of the Dermaptera, Dictyoptera, Phasmatoptera and

Orthoptera. Mich. Ent. 1: 9.

Geer, C. de, 1773. Memoires pour servir a l’histoire des insectes, Stockholm.

Karny, H., 1907. Revisio Conocephalidarum. Abh. zool. bot. Ges. Wein IV (3): 1-114.

, 1912. Genera Insectorum 135: 7-13.

Kirby, W. F., 1890. On the employment of the names proposed for genera of Orthoptera, previous

to 1840. Scient. Proc. R. Dubl. Soc. 6: 556-597.

—_____, 1906. A synonymic catalogue of the Orthoptera. Brit. Mus. Longmans, London.

Morse, A. P., 1901. The Xiphidiini of the Pacific Coast. Can. Ent. XX XIII: 201 -205.

Rehn, J. A. G.,

1907. Orthoptera of the families Tettigoniidae and Gryllidae from Sapucay,

Paraguay. Proc. Acad. nat. Sci. Philad.: 370-395.

and Hebard, M.,

1915a. A synopsis of the species of the genus Conocephalus found in

North America north of Mexico. Trans Am. ent. Soc. XLI: 155-224.

___, 1915b. VI—A synopsis of the species of the genus Conocephalus found in

enCn south of the southern border of the United States. Trans. Am. Ent. Soc. XLI:

225-290.

Thunberg, C. P.,

1815. Hemiptorum maxillosum, Genera _ Illustrata,

Plurimusque novis

speciebus ditata ac descripta. Zap. imp. Akad. Nauk V: 218.

J. ENTOMOL. Soc. BRIT. COLUMBIA 72 (1975), Dec. 31, 1975

BOOK REVIEW

Lamb, K. P. 1974. Economic Entomology in

the Tropics. Academic Press, London, 195 pp.

£4.00.

In this brave and successful book the pub-

lisher presents something of a puzzle. Well

printed and illustrated on good quality paper,

it is elegantly hard-bound in AP livery; but it

is a small book which would fit into a paper-

back format no bigger than a thinnish Penguin.

Even as a reference and teaching text it must

surely soon be replaced by more detailed, re-

gional texts. Perhaps, hopefully, the present

hard-wearing library format means that it is a

trail breaker and the forerunner of a series for

graduate students and district agriculturists

based on crops or insect groups or major re-

gions. Any of these subdivisions is enough to

absorb several lifetimes of research and review,

but in a chauvinistic world, the last-named

may be the most promising.

The organization by chapters is as follows:

four pages on insects, good and bad; five pages

on classification based on the C.S.I.R.0.’s

Insects of Australia (1970); then short chap-

ters on primitive and some aquatic insects;

cockroaches and mantids; termites; Orthoptera

and Dermaptera; Hemiptera; Lepidoptera;

flies and fleas; beetles; Hymenoptera; the

ecology of pest control; insecticides; malaria;

and a summary of major pests of coffee, tea,

cotton, cocoa, sugar cane, rice and coconuts.

These, except for part of the rice crop, are cash

crops and export items. Missing, except for

passing mention, are pests of major local sub-

sistence crops: bananas, citrus, cassava,

pulses, millet, sorghum, mango, and maize.

The chapters on various orders include

tables of selected pests, with common names,

hosts, and distribution. Since keys are not pos-

sible, the tables exist in something of a

vacuum, and become almost unmanageably

long even when subdivided by hosts or groups

of crops attacked. For instance, there are tables

dealing with 50 Pyralids, 36 Noctuids, 31

scales, and 81 weevils; with distributions given

as e.g.: the Americas, Africa, India, or even

in desperation, pan-tropical. Prof. Lamb

assumes’ considerable familitarity with

scientific nomenclature. His English is clear

and scholarly and by no means condescending

or over-simplified. Mistakes, misspellings and

misprints are at an irreducible minimum. The

five to eight references with each chapter are

carefully chosen. Most are generalized works,

monographs and books rather than research

papers. Eleven of the 97 are in French, four in

German.

The dust jacket calls this: ‘‘A short, highly

condensed, immensely practical book . . . the

first broad review of economic insects in the

tropics.’’ As such it promises to be an invalu-

able starting point for problem solving, a teach-

ing text, and the basis for more detailed

successors.

H. R. MacCarthy

36 J. ENTOMOL. Soc. Brit. CoLuMBIA 72 (1975) Dec. 31, 1975

NOTICE TO CONTRIBUTORS

This society has no support except from subscriptions. It has become neces-

sary to institute a page charge. This has now been set at $20.00. The page charge

includes all extras except coloured illustrations, provided that such extras do not

comprise more than 40% of the published pages. Coloured illustrations will be

charged directly to the author. Authors, not attached to universities or official

institutions, who must pay these charges from their personal funds and are unable

to do so, may apply for assistance when submitting a manuscript.

Reprints are sold only in even hundreds and at the following prices:

Number of pages. 1-4 5-8 9-12 13-16 17-20 21-24 25-28

First 100 copies $33.00 46.50 63.00 82.50 105.00 130.50 159.00

Each extra 100 9.00” 12.00 15:00. 18-00 21.00 24.00 27.00:

Author’s discounts (up to 40%) may be granted to authors who certify

at the time of ordering that they are buying reprints at personal expense.

Authors ordering personal reprints in addition to those ordered by an institution

will be billed at the rate for extra hundreds.

Papers for the Journal need not have been presented at meetings of the

Entomological Society of British Columbia. nor is it mandatory, although pref-

erable, that authors be members of the society. The chief condition for publica-

tion is that the paper have some regional origin, interest, or application.

Contributions should be sent to:

H.R. MacCarthy,

6660 N.W. Marine Drive,

Vancouver, B.C. V6T 1X2

Manuscripts should be typed double-spaced on one side of white, line-

spaced numbered paper if possible, leaving generous margins. The original and

two copies, mailed flat, are required. Tables should be on separate, numbered

sheets, with the caption on the sheet. Captions for illustrations should also be on

separate numbered sheets, but more than one caption may be on a sheet. Photo-

graphs should be glossy prints of good size, clarity and contrast. Line drawings

should be in black ink on good quality white paper.

The style, abbreviations and citations should conform to the Style

Manual for Biological Journals published by the American Institute of Biological

Sciences.

BACK NUMBERS

Back numbers of this journal are available from the Secretary-—

Treasurer, from volume 45 (1949) to the present, at $4.00 per volume. Certain

earlier back numbers are also available, but only on special request to the

Secretary-Treasurer.

Address inquiries to:

N. V. Tonks, Secretary-Treasurer,

2819 Graham Street,

Victoria, B.C. V8T 3Z3

JOU RNAL_

_ ENTOMOLOGICAL

SOCIETY of

BRITISH COLUMBIA

Issued December 31, 1976

ECONOMIC

IL SON, k FINLAYSON & CAMPBELL—Controlling the European

Ww worm oot bagg obscurus L. in British Columbia..... agency we damien ke aut eats as

4 sean of adult ladybirds patie Ae Goccinellidael preying on field

| pe oo of pea aphids (Homoptera: Aphididae) ita She Steg nee aes

TAXONOMIC

BES & CHO-KAI CHAN—The aphids (Homoptera: Aphididae) of

ish Columbia 4. Further additions & corrections ..............000 eee eeee . 57

RTH & FRAZER—Compilation of taxonomic catalogues by

ea a te aa eRe ce Gite San pon Sig aU eldla ry Wig « Wie Wierkio wie sw biace ebro v.40 OO

REVIEW - 0000-0. e ese cece eee sees eee cee ee ete eee Pe pee UREN 67

JOURNAL

of the

ENTOMOLOGICAL

SOCIETY of

BRITISH COLUMBIA

Vol. 73 Issued December 31, 1976

ECONOMIC

WILKINSON, FINLAYSON & CAMPBELL—Controlling the European

Wireworm Agriotes obscurus L. in British Columbia.................0000000. 3

GENERAL

FRAZER & IVES—Homalotylus californicus (Hymenoptera: Encyrtidae),

a parasite of Coccinella californica (Coleoptera: Coccinellidae), in British

CUMIN Hae aes te eae eo oc oe Sos, curse ore Sa aia Ce aoe AS RNG Wig ee Ihe ea 6

MYERS & CAMPBELL—Predation by carpenter ants: a deterrent to the

Spread omeinnabar MOth “c. ccsicd ewe AAieu sews eS 0s ced be deals bua sae edie els 7

FINLAYSON & CAMPBELL—Carabid & Staphylinid beetles from agricultural

land in the lower Fraser Valley, British Columbia ....................0.00000- 10

SCHENK, MAHONEY, MOORE & ADAMS—Understory plants as indicators

of grand fir mortality due to the fir engraver ............ 0.0 ccc cece cee ence 21

KULHAVY, SCHENK & HUDSON—Cone & seed insects of subalpine fir during a

year of low cone production in Northern Idaho ........... 0.0.00 cece eee e ee eee OD

FORBES—The stylets of the large milkweed bug Oncopeltus fasciatus

(Hemiptera: Lygaeidae) & their innervation ........ 0.0... cece ee eee eee eens 29

FRAZER & GILBERT—Coccinellids & aphids: a quantitative study of the

impact of adult ladybirds (Coleoptera: Coccinellidae) preying on field

populations of pea aphids (Homoptera: Aphididae) .............. 220000 ees 38)

TAXONOMIC

FORBES & CHO-KAI CHAN—The aphids (Homoptera: Aphididae) of

British Columbia 4. Further additions & corrections ...............200000000 05070

RAWORTH & FRAZER—Compilation of taxonomic catalogues by

COCDITA) DY UIC H ae ae ga lee a aNd Ora YP ta aa Pe 63

Bo IMBEU LAY LIES Vn erroueucy cies e uic a tu arte, aie ee csc, sls iace ae’ 6 Gece wa laws wleenls aeans Oe eke aoe ete 67

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 |

Directors of the Entomological Society of

British Columbia for 1976-1977

President |

H. S. GERBER

B.C. Dept. of Agriculture,

Cloverdale

President-Elect

A. L. TURNBULL

Simon Fraser University,

Burnaby

Past President

J. R. CARROW

Pacific Forest Research Centre,

Victoria

Secretary-Treasurer

B. D. FRAZER

6660 N.W. Marine Drive, Vancouver, B.C. V6T 1X2

Honorary Auditor

D. G. FINLAYSON

Research Station, C.D.A., Vancouver

Editorial Committee

H. R. MacCARTHY

Vancouver

J. CORNER

Vernon

Directors

J. MYERS (2nd) R. CHORNEY (2nd) B. AINSCOUGH (2nd)

R. COSTELLO (1st) N. V. TONKS (1st)

Regional Director of National Society

J. P. M. MACKAUER

Simon Fraser University, Burnaby

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), DEc. 31, 1976 3

CONTROLLING THE EUROPEAN WIREWORM,

AGRIOTES OBSCURUS L., IN CORN IN BRITISH COLUMBIA

A. T. S. WILKINSON, D. G. FINLAYSON

AND C. J. CAMPBELL

Research Branch, Agriculture Canada

6660 N. W. Marine Drive, Vancouver, B.C.

ABSTRACT

Six insecticides at various rates and formulations, applied by three

methods over three seasons, were evaluated for controlling the European

wireworm, Agriotes obscurus L. in corn planted in silt loam. The insecticides

were in granular form, applied as a broadcast, in a band, or in the seed

furrow. Most of the materials, rates and methods gave good protection. In-

secticide applied in the furrow was placed either in contact with the seed, or

just ahead of it and mixed with soil. When it was in contact with the seed

the yield was slightly lower, indicating some phytotoxicity. The furrow

methods were the most economical in material and labour.

INTRODUCTION

Damage caused by wireworms to suscep-

tible crops such as corn and potatoes is in-

creasing in the lower Fraser Valley. The

problem is serious in corn grown for the fresh

market, canning and ensilage, especially near

Agassiz where the wireworm Agriotes obscurus

L. was accidently introduced from Europe

about 1900 and has become well established

(King et al. 1952; Wilkinson 1963). Much of the

infested land in this area has been treated with

the cyclodiene chlorinated hydrocarbons, aldrin

and heptachlor, which gave protection for at

least nine years following a single application

(Wilkinson et al. 1964). Later tests showed that

the small amounts of insecticide remaining in

the soil were still toxic to young wireworms

even 13 years after the soil was treated. In

many fields the wireworms were eradicated by

these chemicals but nearby headlands and road

allowances provided a continuing source of rein-

festation. Restoration of this wireworm to its

previous levels is slow because the adults do

not fly and the life cycle takes 3 to 4 years, so

that an infestation may take several years to

build up to economic levels. The worst problem

at present involves land that was not cleaned

up with the long-lasting chemicals of the late

1950s and early 1960s, but in time all the fields,

treated or not, will need treatment.

A series of tests of short-lived insecticides

and methods of application, were made during

several seasons to find an effective, economic

control. The most effective chemicals and the

initial rates were determined in the laboratory

and the field tests were done near Agassiz in

silt loam.

MATERIALS AND METHODS

1970 Experiment: The land was infested

with 80 A. obscurus per m? which destroyed

corn planted in May. On June 10, insecticides

were applied in randomized blocks replicated

four times. The granular insecticides were

broadcast evenly over the surface and worked

in to a depth of 10 cm. Oats, peas, and vetch

were planted since these crops can be grown

successfully on heavily infested land. The effect

of the treatment was determined in September

TABLE 1. Average numbers and percentage reduction of A. obscurus after broadcast soil treat-

ments with various insecticides, Agassiz, B. C., 1970.

Insecticide % granules Toxicant (Kg/ha) Wireworms/m? Control (/)

Fonofos 20 5.6 12.16 a** 84.8

Carbofuran 5 5.6 12.16 a 84.8

Carbofuran 10 5.6 14:53 4 81.8

Bux* 15 5.6 19.37 a 75.8

Check —_ 79.97 b _

* A 3:1 mixture of m-(1-methylbutyl)phenyl methylcarbamate and m-(l-ethylpropyl) phenyl

methylcarbamate.

** Values followed by the same letter are not significantly different (Duncan, 1955).

4 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 |

by counting the wireworms in 10 cylindrical soil

cores taken at random from each plot with an

augur. Each core was 103 cm? by 38 cm deep.

The results are shown in Table. 1.

1974 Experiment: The population was 75.3

A. obscurus per m’. Granular insecticides were

applied in a band, in the furrow and by the

broadcast method. The purpose of adding the

band and furrow treatments was to reduce the

amount of insecticide and thus the cost. Carbo-

furan was not included in the 1974 and 1975

experiments because of instability in some

soils. Bux was withdrawn by the manufacturer.

In the band method the insecticide was

applied in a strip 30 cm wide at 18.6 g toxicant |

per 100 m of row then worked into a depth of |

10 cm. The corn was seeded in the middle of |

the band. In the furrow method the insecticide

was applied with the seed at 9.3 g toxicant

per 100 m of row. The treating and planting ©

was done May 30. In September any differences |

in yield were shown by counting and weigh-

ing the corn stalks from 10 m of row. Wire-

worms were counted by sifting the soil and

examining the roots in five samples per plot,

each 15 cm square by 20 cm deep, dug with a

spade, with a corn root at the centre of the

sample. The results are shown in Table 2.

TABLE 2. Growth and yields of corn and average numbers of A obscurus per corn root after

various treatments with four granular insecticides at Agassiz, B.C., 1974.

Insecticide % Method of Toxicant

granules Application (Kg/ha)

Fonofos 10 Broadcast 5.6

Counter! 15 Broadcast 5.6

Fonofos 10 Band 2.0

N 2596? 10 Broadcast D6

Counter 1 Furrow 1.0

N 2596 10 Furrow 1.0

Bay 92114? 10 Furrow 1.0

Fonofos 10 Furrow 1.0

Bay 92114 10 Broadcast 5.6

Check — —

Avg. wt. Avg. no. Avg.no. Avg. wt./

plants wireworms/ stalks/ 10 m row

(Kg) corn root 10 m row (Kg)

1.04 a oa 47.5 a 44.3 a

1.03 a 50a 44.0 ab 40.1 ab

1.02 a 1.40 ab 41.7 ab 37.9 ab

1.0la 1.40 ab 41.2 ab 36.6 ab

.96 ab 1.85 ab 45.0 ab. 36.5 ab

.93 ab 1.40 ab 46.7 ab 35.5 ab

.92 ab 3.30 b 38.5 be 32.2 be

.89 ab 95a 40.7 ab 31.3 be

.87 ab 1.50 ab 31.5 cd 23.6 cd

.80 b 6.25 c Zieoa 19.2d

'AC 92100 S-([tert-butylthio] methyl) 0,0, diethyl phosphorodithioate

*S(p-chlorophenyl) o-ethyl ethane phosphorodithioate

*] methylethyl 2 [[ethoxy{ (1 methylethyl) amino] phosphinothioyl/oxy] benzoate

1975 Experiment: The methods of appli-

cation were the same as in 1974 except fora

modification of the furrow method. To deter-

mine if the insecticide applied with the seed

caused phytotoxicity and reduced the yield,

a second method was included whereby the in-

secticide was applied just ahead of the seed.

Rates of 9.3 and 13.9 g of toxicant per 100 m

were tested. The efficacy was determined by

differences in the number of stalks, weight of

the yield in 6 m of row and in wireworms count-

ed by the method used in 1974. The treatments

were made and the corn was planted May 138;

it was harvested September 26. The wireworm

counts were made September 30 and October 1.

The results are shown in Table 3. The data

were examined by analysis of variance and the

results compared with Duncan’s Multiple

Range Test (Duncan 1955).

RESULTS AND DISCUSSION

Based on population counts the broadcast

treatments of granules in 1970 all gave good

control of wireworms (Table 1). There were no

significant differences between the efficacy of

the chemicals even in the two granular formula-

tions of carbofuran.

In 1974 the results showed that in general

the broadcast treatments were slightly better

than the band or furrow treatments (Table 2).

With the exception of the Bay 92114 broadcast

treatment all the chemicals and methods gave

significantly better yields than the control and

all significantly reduced the number of wire-

worms. The furrow treatment of Bay 92114

was slightly, but not significantly, better than

the broadcast treatment.

In 1975 all the treatments gave significant

reductions in the number of wireworms over the

control but the differences in yield were less

clear, although significant differences were ob-

tained. The broadcast treatments generally

reduced the wireworm population more than

did the furrow treatments. There were differ-

ences between the two furrow methods; most of

the treatments in which the insecticide was

applied with the seed had low yields, which in-

dicated some phytotoxicity (Table 3). The

heavy rate used in the furrow seemed to have

little effect on yield but did give a greater re-

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Table 3. Growth and yields of corn and average number of A. obscurus per corn root after various

treatments with three granular insecticides, Agassiz, B.C., 1975.

Insecticide % Method of Toxicant Avg. no. Avg. no. Avg. wt./

granules Application (kg/ha) wireworms/ stalks/ (Kg/ 6 m

corn root 6m row row)

N 2596 10 Furrow* 1.8 .15 ab 30.5 abc 22 Ana

Counter 15 Furrowt LeZ — 33.2 ab 21.8 ab

Fonofos 10 Broadcast 5.6 0.0a ole2 ab 21.4 abc

Fonofos 10 Furrow* 1.8 .5 abc 31.0 abc 20.9 abcd

Fonofos 10 Furrow* 1.2 1.05 ¢ 29.7 abc 20.7 abcd

Counter 15 Furrow* 1.8 .15 ab 34.5 a 20.4 abcd

Fonofos 20 Furrow* Ly .55 abc 31.2 ab 20.4 abcd

N 2596 10 Broadcast 5.6 .1 ab 29.0 abcd 20.0 abcd

N 2596 10 Furrowt 1.8 o 27.5 abcde 19.9 abcd

Counter 15 Furrow* 12 .75 be 28.5 abcde 19.5 abcde

Fonofos 20 Furrowt 12 — 24.0 cde 18.8 abcde

N 2596 10 Furrow* 1.2 .5 abc 31.2 ab 18.6 abcde

Counter 15 Broadcast 5.6 .3 abc 28.2 abcde 18.2 abcde

N 2596 10 Furrowt 12 — 26.5 bede 18.2 abcde

Counter 15 Furrowt 1.8 — 28.0 abcde 17.6 bede

Fonofos 10 Furrowt 1.2 = 26.5 bede 17.2 cde

Fonofos 10 Furrowt 1.8 = 22.7 de 16.9 de

Untreated -— == — 225 0 22.0e 15.5e

*Insecticide applied ahead of the seed in the furrow.

tInsecticide applied with the seed.

duction in the number of wireworms than the

low rate. Four months after application, dead

and dying larvae were found in the plots treat-

ed by the furrow methods, which indicated that

there was some persistence in the chemicals.

Fonofos, N 2596 and Counter appeared to give

about equal control regardless of method of

application.

Over the years the broadcast treatments

have given the greatest reduction in the num-

ber of wireworms and generally the best pro-

tection to the corn crop. The differences in con-

trol are not great but the cost of insecticide

for the furow treatment is only % that of the

broadcast. Further savings are made because

it does not require extra passes over the land to

apply the insecticide or one or more additional

diskings or rototillings to work in the insecti-

cide. The band treatment requires about twice

as much insecticide as the furrow treatment

and does not have the advantage of easy appli-

cation. The fact that wireworms were still being

killed four months after the furrow treatments

were made indicates that all the chemicals

tested in 1975 remained toxic when in high con-

centrations in the soil. Thus, chemicals applied

by this method will give protection during a

growing season.

References

Duncan, D. B. 1955. Multiple range and multiple F tests. Biometrics 11:1-42.

King, K. M. R. Glendenning and A. T. S. Wilkinson. 1952. A wireworm (Agriotes obscurus L.) Can.

Insect Pest Rev. 30:269-270.

Wilkinson, A. T. S. 1963. Wireworms of cultivated land in British Columbia. Proc. Entomol.

Soc. Brit. Columbia. 60:3-17.

Wilkinson, A. T. S., D. G. Finlayson and H. V. Morley. 1964. Toxic residues in soil 9 years after

treatment with aldrin and heptachlor. Science 143:681-682.

6 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 |

HOMALOTYLUS CALIFORNICUS (HYMENOPTERA:

ENCYRTIDAE(, A PARASITE OF COCCINELLA CALIFORNICA

(COLEOPTERA: COCCINELLIDAE) IN BRITISH COLUMBIA

B. D. FRAZER! AND P. M. IVES?

ABSTRACT

We record the first occurrence in British Columbia of Homalotylus

californicus Girault, a parasite of Coccinella californica larvae. Parasitized

larvae are mummified and hardened with an abnormal bluish tint so they

are easily recognized in the field. The rate of parasitization in the field was

13%. The significance of this and related parasites of Coccinellids is

discussed.

In our study of the population dynamnics

of aphids on oats and alfalfa, we made daily

estimates of the abundance of coccinellids of

all stages in our field plots. The procedure for

estimating adult numbers will be reported else-

where. When a pupa was encountered its

species was recorded and a spot of paint was

placed beside it to avoid confusion later.

In 1975, first generation pupae of Coccinella

californica Mannerheim began to appear in

mid-july. On July 30 an unusual larva was seen.

It was moribund, hard, and mummified, but

attached to a leaf at its caudal end. It looked

like a larva about to pupate except for its dull

bluish colour. Such ‘blue’ larvae were also

identified with paint, and recorded separately.

The last blue larva was found on August 19

at the end of production of pupae in the field.

In all, 30 blue larvae were taken. From six

of these, emerged 5, 5, 5, 4, 3 and 3 adult

Homalotylus californicus Girault, but the re-

maining 24 mummified larvae failed to develop

further. When they were dissected, all con-

tained dead parasite larvae oriented longitudin-

ally more or less two abreast. Cocoons inside

those larvae from which H. californicus had

emerged were positioned similarly.

We recorded 201 normal pupae during the

time when the 30 parasitized larvae were found.

The rate of parasitization by H. californicus

was therefore estimated at 30/(201+30) or

13%. This value cannot easily by compared to

parasitization rates in the literature because of

apparent inconsistencies in the use of names.

The situation is similar to the confusion in use

of two species names of Homalotylus in Europe

(Hodek 1973); one species being solitary and

the other gregarious. Muesbeck et al. (1951)

and Peck (1963) refer to H. californicus as a

‘Research Scientist, Agriculture Canada, Research Station,

Vancouver, B.C. Canada, V6T 1X2.

“Post-Doctoral Fellow of the Institute of

Resource Ecology, University of B.C., Vancouver, B.C.

V6T 1E5.

Animal

subspecies of H. terminalis following Timber-

lake (1919) who did not find a constant diagnos-

tic character to separate the two. But Leonard

(1933) records that each pupa of Cycloneda

sanguinea L. had a single emergence hole cause

by H. terminalis, whereas our specimens had

many holes, one for each adult parasite.

Leonard recorded a parasitization rate for

C. sanguinea as 90%; Kulman (1971) found

that 26% of the Anatis quindecimpunctata

larvae he observed were parasitized, each pro-

ducing from 1 to 21 H. terminalis; and Kapur

(1942), and Miller and Thompson (1926, 1927),

recorded parasitization by H. t. californicus

as high as 42%, and by H. terminalis up to 50%,

respectively.

Yet in spite of the apparently low rate of

parasitization we observed, we believe the

H. californicus is potentially important. Pre-

liminary field experiments on the survival of

larval coccinellids show that less that 1% of

newly hatched, first instar larvae survive to the

fourth instar even when supplied with an

abundance of prey. the 13% mortality caused

by H. californicus is applied to those few sur-

viving fourth instar larvae. Since the parasite

is gregarious, the potential for increase and

detrimental impact on C. californica is great,

as shown by the high rates of parasitization

reported for other gregarious species.

Homalotylus spp. have been considered

by Hodek (1973) to be a very significant mor-

tality factor which may limit the entomopha-

gous efficiency of certain coccinellids in Europe,

India, the U.S.S.R. and Israel. However, most

species of Homalotylus are known to have

parasites of their own; perhaps this accounts

for their lack of more general and consistent

impact.

ACKNOWLEDGEMENTS

The specimens of Homalotylus californicus

were identified by Dr. C. M. Yoshimoto,

Biosystematics Research Institute, Ottawa.

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), Dec. 31, 1976 gk

Literature Cited

Hodek, I. 1973. Biology of Coccinellidae, Junk, The Hague, 260 p.

Kapur, A.D. 1942. Bionomics of some Coccinellidae, predaceous on aphids and coccids in

North India. Ind. J. Entomol. 4:49-56.

| Kulman, H. M. 1971. Parasitism of Anatis quindecimpunctata by Homalotylus terminalis. Ann.

Entomol. Soc. Amer. 64 (4):953-54.

26: 294

Florida Entomol. 10:40-46, 57-59.

aphid. Florida Entomol. 11:1-18.

Leonard, M. D. 1933. A braconid parasite of a Coccinellid new in Puerto Rico. J. Econ. Entomol.

| Miller, R. L. and W. L. Thompson, 1926. Life histories of Lady-beetle predators of the citrus aphid.

Miller, R. L. and W. L. Thompson, 1927. Life histories of Lady-beetle predators of the citrus

Muesbeck, C. F. W., K. V. Krombein and H. K. Townes, 1951. Hymenoptera of America North of

Mexico. U.S.D.A. agr. Monograph 2, 1420 p.

Peck, O. 1963. A catalogue of the Nearctic Chalcidoidae (Insecta: Hymenoptera). Can. Entomol.

Suppl. 30, 1092 p.

PREDATION BY CARPENTER ANTS: A DETERRENT TO

THE SPREAD OF CINNABAR MOTH

JUDITH H. MYERS AND BARBARA J. CAMPBELL

Institute of Animal Resource Ecology

and

Department of Plant Science

University of British Columbia, Vancouver

ABSTRACT

Cinnabar moth, an introduced biological control agent for tansy ragwort,

suffers heavy predation by carpenter ants in recently logged areas of

Oregon. We suggest that this mortality factor will reduce the spread of Cin-

nabar moth, thus preventing it from attacking a major seed source of tansy

ragwort and reducing its potential as a biological control agent. Single

larvae escape predation by ants more often than those in groups which

suggests that carpenter ant predation may select for larval dispersal.

The Cinnabar moth, Tria jacobaeae L.

(Arctiidae), has been widely spread from its

native Europe because of its potential as a

biological control agent against the weed Tansy

ragwort, Senecio jacobaea L. The success of

these introductions has ranged from ‘‘never

seen again’ to ‘‘abundant and thriving’’ after

15 years. At Abbotsford, B.C. the failure of the

first releases was attributed to heavy predation

by ground beetles (Wilkinson, 1965). In the

Gippsland vicinity of Victoria, Australia a

mecopteran, Harpobittacus nigriceps, heavily

predated a newly introduced Cinnabar popula-

tion and a nuclear polyhedral virus assured the

failure of the attempted introduction (Borne-

missza, 1966). The causes for the lack of

success of other introductions are not known

(Hawkes, 1968, Harris et al. 1975, Isaacson

1973).

Van der Meijden (1971) records an almost

perfect correlation between the log % mortality

of Cinnabar larvae and log density of Lasius

alienus, a predaceous ant. Further studies of

Lasius predation led Van der Meijden (1973) to

conclude that this ant may limit Cinnabar

numbers in some sand dune areas of the Neth-

erlands.

The following observations on predation by

ants were made as a by-product of experiments

designed to investigate larval dispersal in the

Cinnabar moth.

Study Area and Methods

The study was carried out in Linn County,

Oregon which lies between the western slope of

the Cascade Mountains and the eastern edge of

the Willamette Valley. Larvae were collected

from the Silbernagel population which was

studied by Isaacson (1973), and were trans-

ported to an area about 10 miles to the south on

Neal Creek Road. This area was logged within

the last 10 years so that stumps and fallen logs

were abundant on the steep hillsides. Tansy

ragwort is a common component of the herb-

8 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 |

TABLE 1. Survival after 2 days of 3rd and 4th instar Cinnabar larvae introduced to tansy ragwort |

plants in groups of approximately 20 individuals.

0-10%

Frequency

Total Survival = 98/329=30%

aceous vegetation which has invaded this area,

and moth populations occur sporadically along

the road.

We chose the particular site for the study

because while abundant, large ragwort plants

occurred there, Cinnabar moth larvae were

lacking. We placed third and fourth instar

larvae on plants in groups of approximately 20

individuals, and recorded their movement from

the central plant to surrounding plants.

Percent Survival

11-25% 40% 65% 80-90%

3 2 1 3

Results

The disappearance rate of larvae from tansy

ragwort plants was exceedingly high (Table 1).

Observations revealed that the reason for this

disappearance was the activity of carpenter

ants, Camponotus sp., which nested in sur-

rounding stumps. Ants were seen to attack and

carry off the Cinnabar moth caterpillars but

to verify that the high rate of disappearance

was due to ant predation we set up groups of

TABLE 2. A comparison of Cinnabar larval survival on tansy ragwort plants to which ants had

access and those which were ant-free. Larvae placed on plants in groups of 10.

Original Number

Number After 2 Days

Percent Survival

larvae on plants with the base coated with

“stickum’”’ which prevented ants from crawling

onto the plants. The comparative rates of dis-

appearance of larvae on ant-free plants and

those to which ants had access are compared in

Table 2.

We observed that those Cinnabar larvae

which dispersed from the original plant had

better short term survival than those which re-

mained behind (Table 3). The effect of group

size was further tested by comparing the sur-

vival of single larvae to those in groups of 10.

While the survival of these individual larvae

was not as high as that of the natural dis-

persers (Table 3), it was almost double that of

larvae in groups of 10 (Table 2) over a 2 day

observation period.

Plants Without Ants Plants With Ants

49 40

43 9

86 23

Discussion

The relationship of the carpenter ant to the

Cinnabar larvae is an interesting one. The

Cinnabar larvae feed preferentially at the tops

of the plants on the flower buds. Their feeding

activity releases sap and the carpenter ants

will feed beside the caterpillars taking the sap

from the freshly cut surface. The two species

have been observed to coexist in this way.

However, suddenly an ant may attack a cater-

pillar. The usual result is that the caterpillar

falls from the plant, sometimes taking its

attacker with it. If other ants are nearby they

too will join in the attack. On one occasion

eight larvae lived two days on a plant that was

occasionally visited by ants. Suddenly the

attack began, and within one hour only three

remained the others having been carried off

TABLE 3. Survival after 2 days of Cinnabar larvae which dispersed naturally from original tansy

ragwort plants or were placed individually on plants.

Original Number

Number After 2 Days

Percent Survival

Larvae Larvae Placed

Dispersed On Individual

Naturally Plants

10 31

) 13

90 42

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 9

by the carpenter ants.

Tansy ragwort is common in Oregon on the

extensively logged slopes of the Cascades and

of the Coastal mountains to the West. Although

in many areas Cinnabar moths have become

established (Nagel and Isaacson, 1974) the

presence of carpenter ants in this environment

will undoubtedly influence the success of the

natural spread of the moth to tansy ragwort

areas. This will interfere with the attempt to

destroy the source for tansy ragwort seed

which these areas provide.

Predation by carpenter ants gives rise to

a situation in which dispersal of Cinnabar

larvae could be at a strong selective advantage.

The general interpretation has been that in

areas of high predation, survival of dispersing

larvae will be low (Green, 1974). However, al-

though larvae are exposed to predation while

traversing from one plant to another, aban-

donment of the usual clumped distribution of

Cinnabar moth larvae might make_ the

difference between success and failure of estab-

lishment. If there is a genetic component to

dispersal one might predict strong selection for

dispersal in these areas.

References

Bornemissza, G. F. 1966. An attempt to control ragwort in Australia with the Cinnabar Moth,

Callimorpha jacobaeae (L.) (Arctiidae: Lepidoptera). Australian J. of Zoology 14: 201-243.

Green, W. Q. 1974. An antagonistic insect/host-plant system: The problem of persistence.

Ph.D. thesis. University of British Columbia.

Hawkes, R. B. 1968. The Cinnabar moth, Tyria jacobaeae, for control of tansy ragwort. J. econ.

Ent. 61:499-501.

Harris, P., A. T. S. Wilkinson, M. E. Neary, L. S. Thompson, and D. Finnamore. 1975. Establish-

ment in Canada of the Cinnabar Moth, Tyria jacobaeae (Lepidoptera: Arctiidae) for con-

trolling the weed Senecio jacobaea. Can. Ent. 107:913-917.

Isaacson, D. L. 1973. A life table for the Cinnabar Moth, Tyria jacobaeae, in Oregon.

Entomophaga 18: 291-303.

Nagel, W. D. and D. L. Isaacson. 1974. Tyria jacobaeae and tansy ragwort in Western Oregon.

J. econ. Ent. 67: 494-496.

Van der Meijden, E. 1971. Senecio and Tyria (Callimorpha) in a Dutch dune area. A study on an

interaction between a monophagous consumer and its host plant. Dynamics of Popula-

tions (P. J. den Boer and G. R. Gradwell, eds) (Oosterbeek, 1970): 390-404.

. 1973. Experiments on dispersal, late-larval predation, and pupation in the

Cinnabar Moth (Tyria jacobaeae L.) with a radio-active label ('% Ir). Neth. J. Zool.

23: 403-445.

Wilkinson, A. T. S. 1965. Releases of Cinnabar Moth, Hypocrita jacobaeae (L.) (Lepidoptera:

Arctiidae) on tansy ragwort in British Columbia. Proc. Ent. Soc. Br. Columbia. 62: 10-13.

10 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

CARABID AND STAPHYLINID BEETLES FROM AGRICULTURAL

LAND IN THE LOWER FRASER VALLEY, BRITISH COLUMBIA

D. G. FINLAYSON AND C. J. CAMPBELL

Research Station, Agriculture Canada

Vancouver, British Columbia, V6T 1X2

ABSTRACT

Pit-traps were emptied every two or three days for two seasons in crop,

fallow, and grass plots to determine the species and population density of

Carabidae and Staphylinidae associated with agricultural land, and their

relationship with brassica crops. Half of the plots were enclosed by plastic

barriers and the beetles were trapped to extinction; half were not enclosed.

Thirty-three carabid and 16 staphylinid species were captured. The

dominant species was the small, generalized, European carabid predator,

Bembidion lampros, which had a population on crop and fallow land of about

29000/hectare. It was almost absent in grass. Other numerous carabids were

Harpalus aeneus, Calathus fuscipes, and Clivina fossor, all introduced

European spp., with populations of almost 2000, 5600, and 11000/hectare

respectively. The first and third of these were scarce in grassland but the

second was abundant. In plots of Brussels sprouts Aleochara bilineata, a

staphylinid, was effectively parasitic on root maggots, and averaged more

than 6000/hectare. Soil cores taken in October centred on a Brussels sprouts

plant averaged 26.4 Hylemya puparia per core of which 44% were parasitized

by A. bilineata.

INTRODUCTION

In 1916 Gibson and Treherne reported

several important parasites of root maggots.

They included several species of Carabidae,

which readily devoured eggs, larvae and

puparia of Hylemya brassicae (Bouche) in the

laboratory with other species of Staphylinidae

which they believed to be predacious. Included

also was the staphylinid Baryodma ontarionis

Csy. (= Aleochara bilineata Gyll.) a_ well-

documented parasite of the pupal stage of the

cabbage root maggot, H. brassicae. In-

vestigations of the biotic factors acting against

root maggots (Wilkes and Wishart 1953)

revealed a second staphylind parasite, A.

bipustulata (L) which parasitized considerably

fewer cabbage root maggots than A. bilineata,

but was four times as abundant on seed-corn

maggots H. platura (Meig.), a smaller host.

Wright (1956) and Wishart et al. (1956)

demonstrated the importance of carabid and

staphylinid beetles as predators of the im-

mature stages of the cabbage root fly,

especially of eggs. In 1960, Wright et al. ex-

posed untreated crops to the first generation of

the cabbage root fly and showed that predatory

beetles could greatly reduce the root maggots

and the crop damage. They discovered and

Coaker confirmed (1965) that the principal

predator in England was the small carabid,

Bembidion lampros (Hrbst.). To determine

which beetles were predators of eggs, Coaker

and Williams (1963) trapped beetles at

Wellesbourne, exposed them to cabbage root

fly eggs, and identified the egg-feeding species

by means of the precipitin test.

In 1972 and 1973, at Wellesbourne, England

and Agassiz, B.C., Finlayson et al. (1975)

examined the effects of several herbicides and

insecticides on carabid and staphylinid beetles

associated with minicauliflowers. The identity

and numbers of beetles present in the treated

and untreated plots were determined by pitfall

trapping, a method discussed at length by

Greenslade (1964). We investigated these

predator populations in the lower Fraser

Valley, mainly to determine their species and

population density in agricultural land, and

their relationship with cropping practices,

especially in brassicas.

METHODS

The work was done at the Agriculture

Canada Sub-station at Abbotsford. Three

agricultural conditions were sampled: crop,

fallow and grassland. In 1974 the plots were

400 m’. Three of the plots were open so that the

beetles could migrate freely, and three were en-

closed by 4 mil black polyethylene barriers 15

cm high. The barriers were made by folding a

strip of polyethylene, 60 cm wide, over a nylon

cord, stapling the cord and polyethylene to 15

cm stakes about 2.5 m apart, and anchoring the

bottom flaps by covering them with soil. In

1975, the plots were reduced to 100 m’. There

were 12 plots, two each of crop, fallow and

grass enclosed by the barrier and two each left

open.

The pitfall traps (pit-traps) were new tin

cans, 7 cm diam x 11 cm deep. A hole, 2 cm

diam, was cut in the bottom and covered with

40-mesh Lumite screen to allow rain water to

drain while retaining the beetles. The pit-traps

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 11

were sunk in the ground with their rims level

with the soil surface. After heavy rains the pit-

traps were wiped clean around the upper 5 cm

to remove accumulated dirt and ensure a

smooth surface and thus to prevent the beetles

from climbing out of the trap and escaping. In

1974 predation by birds, especially crows, Cor-

vus brachyrhynchos hesperis Ridgway, in the

pit-traps set in grass led us to insert a cone-

shaped wire barrier of 1 cm mesh chicken net-

ting, which allowed the beetles to enter but

kept out the birds.

In 1974 there were 45 pit-traps in each 10 x

40 m plot, three rows of 15 traps spaced 2.5 m

apart. Grass and fallow plots were sampled

from April 26, but the cropped plots only from

July 5 because barriers could not be erected un-

til the Brussels sprouts crop, seeded June 17,

was established. In 1975 each plot contained 16

pit-traps, evenly spaced throughout the plot,

four in each of four rows, 2 m apart. The pit-

traps and barriers were set in place in late Mar-

ch. Brussels sprouts plants were transplanted

on April 1, and collecting started immediately.

The beetles were removed from the pit-traps

usually on Monday, Wednesday and Friday of

each week, identified and recorded. The beetles

were identified in the field or if necessary sub-

mitted to the Biosystematic Unit in Ottawa for

identification or confirmation. Beetles captured

in the enclosed plots were released outside the

barrier, but those captured in the open area

were immediately released within the plot. Thus

the total numbers captured in the enclosed area

revealed the number per unit area, whereas

those taken in the open area revealed their

habitat preference and the cycle of the adult

stage. The numbers of beetles of each species

were recorded separately on each collecting

period during the week, then summed to give a

weekly total for each species.

Soil samples were taken from the Brussels

sprouts plots at harvest in 1975 to determine

the percentage parasitism of the overwintering

population of puparia of H. brassicae. Ten sam-

ples were taken from each of the four plots of

Brussels sprouts. Each sample, 15 cm diam x

12 cm deep, with the topped plant as the centre

of the sample, was cut with a core sampler on

October 7. The core was placed in a cardboard

tub, 18 cm diam x 13 cm deep, sealed with a lid,

placed in the greenhouse for 21 days to allow

immature larvae to complete development, then

stored at 3°C for 100 days to break diapause in

H. brassicae. The puparia were recovered from

the soil cores by floatation, placed in 30 ml bot-

tles, and held at room temperature till the

emergence of a fly or a parasite. Those puparia

which did not produce either were dissected to

determine if parasites were present but had

failed to emerge.

RESULTS AND DISCUSSION

Thirty-three species of Carabidae and 16

species of Staphylinidae were taken from the

pit-traps. They are listed alphabetically in ac-

cordance with Hatch (1953, 1957).

Carabidae

Amara apricaria (Payk.)

Amara californica De}.

Amara familiaris (Duft)*

Amara obesa Say

Amara sp. (lunicollis group)

Anisodactylus binotatus (F)*

Agonum mulleri (Hbst.)*

Agonum subsericeum LeC.

Bembidion lampros (Hrbst.)*

Bembidion obscurellum Mots.

Bembidion petrosum Gebl.

Bembidion sp.

Blethisa oregonensis LeC.

Bradycellus congener LeC.

Bradycellus nigrinus De}.

Calathus fuscipes (Goeze)*

Calasoma tepidum LeC.

Carabus granulatus L.*

* Carabus nemoralis Mill.*

Clivina fossor (L.)*

Harpalus aeneus (F.)*

Harpalus opacipennis Hald.

Harpalus somnulentus De}.

Leistus ferruginosus Mann.

Loricera decempunctata Esch.

Notiophilus nitens LeC.

Pterostichus adstrictus Esch.

Pterostichus lama Men.

Pterostichus vulgaris L.*

Scaphinotus marginatus Fisch.

Scaphinotus angusticollis Mannh.

Trachypachus holmbergi Mots.

Trechus obtusus Er.*

Staphylinidae

Aleochara bilineata Gyll.*

Aleochara montanica Cys.

Atheta sp.

Hyponygrus angustatus Steph.*

Lathrobium sp.

Megalinus linearis O1.*

Morychus oblongus LeC.

Ocypus aeneocephalus DeG.*

Oxytelus rugosus (F.)*

Philonthus concinnus Grav.*

Philonthus fuscipennis (Mann)*

Philonthus varius Grav.*

Quedius curtipennis Csy.

Rugilus oregonus Csy.

Tachyporus chrysomelinus L.*

Tachyporus n. sp. near chrysomelinus

*Introduced species

Of the species captured, six carabids, A. famili-

aris, B. lampros, C. fossor, H. aeneus, P. vul-

garis and T. obtusus, and two staphylinids,

A. bilineata and O. rugosus are listed as preda-

tors of eggs of the cabbage root fly by Coaker

12 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DrEc. 31, 1976

TABLE 1. Carabid and staphylinid beetles taken from pit-traps in crop, fallow and grass plots,

enclosed by barriers at Abbotsford, British Columbia in 1974 and 1975.

Number of beetles per hectare

Cropped Fallowed Grass

1974 1975 1974 1975 1974 1975

Aleochara bilineata* 0 6200 16) 25 0 0

Amara spp. 1550 5350 3225 4650 325 2400

Anisodactylus binotatus 25 550 700 400 100 400

Bembidion lampros 3825 31100 16100 38500 215 650

Bembidion obscurellum 475 1950 1100 1850 0 0

Bembidion sp 25 0 350 0 1525 50

Calathus fuscipes 5875 550 7900 2800 9775 6800

Carabus nemoralis 50 0 25 100 100 50

Clivina fossor 175 15500 6400 10850 25 450

Harpalus aeneus 525 2000 4300 1600 325 150

Megalinus linearis* 275 1000 2025 650 1650 = 15100

Ocypus aeneocephalus* 0) 50 0 150 1050 1450

Philonthus concinnus* 100 950 375 250 300 3850

Philonthus fuscipennis* 75 50 50 0 1275 1400

Philonthus varius* 25 450 250 250 375 500

Pterostichus vulgaris 2275 1950 4625 700 500 700

Trachypachus holmbergi 0 600 125 650 0 50

*Staphylinidae

and Williams (1963). Although the smaller

species feed on eggs and probably early instar

maggots, the larger species of Amara,

Calathus, Harpalus, Pterostichus and Philon-

thus are capable of feeding on third instar

maggots and even of cracking the puparia.

Some species were considerably more abun-

dant than others. At Abbotsford, 19 species

(13 carabids and 6 staphylinids) appeared most

frequently; the other 30 species were taken

only occasionally.

The numbers of 19 of the common species

trapped have been collated so that those from

the barrier plots afford a reasonable estimate

of the numbers of each species per hectare

(Table 1). The numbers of the same species

from the open plots show preferences for any of

three habitats (Table 2). Because of the diffi-

culty in separating the three common Amara

spp. in the field (apricaria, californica, and

familiaris), they have been grouped under

Amara spp. All three species appeared in crop,

fallow and grassland, and appeared to show

only a slight preference for the cropped area.

The populations of Carabidae tended to be

highest on cultivated land. B. lampros,

B. obscurellum, C. fossor, and H. aeneus on

crop and fallow land averaged approximately

35,000, 1,900, 13,000 and 1,800 respectively

per hectare in 1975. These are very high num-

bers. The large species, especially C. fuscipes

and P. vulgaris, were present in cultivated

and sod land in comparable numbers. Con-

versely, the Staphylinidae appeared in greatest

numbers in grass, with M. linearis the most

common followed by P. concinnus, O, aeneoce-

phalus and P. fuscipennis. A. _ bilineata

appeared almost exclusively in the cropped

area. Its numbers are directly dependent on the

available numbers of its host, Hylemya

puparia.

When the numbers of beetles from the

barrier plots (Table 1) are compared with those

from the open plots (Table 2), it is obvious that

the increase in numbers results from recapture

of the same beetle. The numbers of the larger

species of beetles tended to be more uniform

from year to year.

Of the 19 species most commonly captured,

six were examined in greater detail to establish

the period of greatest frequency, the number of

generations per year and the adult cycle in re-

lation to generations of root maggots. The data

tabulated as weekly totals were plotted to show

the numbers captured per week in _ barrier

(Fig. 1) and open (Fig. 2), plots.

B. lampros and C. fossor were collected in

early spring, i.e. late March and very early

April. The peak of the cycle for B. lampros in

both years (Fig. 2a, 2g) centered around the last

week of May and the first week of June. It co-

incided well with the heavy oviposition of the

first generation of the onion fly H. antiqua

(Meig.), and the cabbage root fly. C. fossor

(Fig. 2d, 2j) was present at an early date but in

much smaller numbers. This species is consider-

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 13

TABLE 2. Carabid and staphylinid beetles taken from pit-traps in crop, fallow and grass plots, not

enclosed by barriers at Abbotsford, British Columbia in 1974 and 1975.

Number of beetles per hectare

Cropped Fallowed Grass

1974 1975 1974 SMES 1974 1975

Aleochara bilineata* 300 4550 25 250 0 0

Amara spp. 11075 8500 4375 4500 350 2800

Anisodactylus binotatus 25 1800 400 1350 3795 950

Bembidion lampros 1500 108250 38950 73250 450 850

Bembidion obscurellum Sia 7650 2475 16300 0 0

Bembidion sp. 0 50 125 50 O75 300

Calathus fuscipes 47250 26800 18150 ~=—-13550 29750 29900

Carabus nemoralis 75 0 (3 0) EPs) 700

Clivina fossor 50 3400 3850 4500 250 500

Harpalus aeneus 3450 26000 28100 21100 350 750

Megalinus linearis* Sy AD) 1400 1900 900 3350 15650

Ocypus aeneocephalus* 125 50 375 0 1450 2400

Philonthus concinnus* 75 1100 100 500 625 6600

Philonthus fuscipennis* 75 150 175 200 1600 2950

Philonthus varius* 25 400 125 100 L75 800

Pterostichus vulgaris 7225 1050 2300 500 6550 3100

Trachypachus holmbergi 0 5850 ATES) 4300 0 50

*Staphylinidae

ed beneficial as a predator of eggs of root mag-

gots, but it is also listed as a minor pest, causing

damage to corn seed similar to that caused by

wireworms (Tsinovskii 1961). Some of the larger

species including H. aeneus, H. rufipes (found

in eastern Canada), and P. vulgaris, have also

been reported to feed on strawberry fruits

(Briggs 1957).

C. fuscipes (Fig. 1c,i and 2c,i) was much

more numerous in 1974 than it was in 1975.

It peaked late in the year. Specimens were

taken from April through October, but the

greatest number coincided with the oviposition

of the third generation of cabbage root fly.

Its ability to feed on mature maggots and

puparia could assist considerably in reducing

Over-wintering populations.

Amara spp., B. obscurellum and H. aeneus

were generally common at the beginning of the

growing season but were still present over the

full period of trapping. H. aeneus showed a

tendency towards a spring emergence period

(Fig. le,k) but the Amara spp. were most

numerous in late summer and fall (Fig. 2f,1).

From the soil cores taken in October 1975,

20 plants within the barrier plots yielded 432

puparia and 20 plants in the open plots yielded

623. Hylemya flies emerged from 52.5% and

50.6% of these respectively. From the puparia

from the barrier plots which did not produce

flies 193 A. billineata, 44.7%, and 12 (2.8%)

cynipid wasps, Trybliographa probably rapae,

were recovered. From the puparia from the

open plots which did not produce flies 267

(42.8%) A. bilineata and 41 (6.6%) Trvyblio-

grapha were recovered. It is important to note

that the 40 plants sampled averaged only 26.4

puparia each and that these plants, trans-

planted on April 1, withstood the attack of

three generations of root maggots without the

protection of pesticides. For that reason it is

essential that research be continued to develop

chemical controls for brassica crops which

are not detrimental to the parasites and preda-

tors of the root maggot complex.

ACKNOWLEDGEMENT

We thank Drs. D. E. Bright, J. M. Campbell,

A. Smetana, and C. M. Yoshimoto, Entomology

Research Institute, Agriculture Canada,

Ottawa for identifying the specimens; and Dr.

H. R. MacCarthy for his advice and review of

the manuscript.

Fig. 1. Population curves for six carabid beetles on crop, fallow and grass plots, enclosed by

barriers, at Abbotsford, B.C. in 1974 (a-f) and 1975 (g-1).

Fig. 2. Population curves for six carabid beetles on crop, fallow and grass plots, not enclosed by

barriers, at Abbotsford, B.C. in 1974 (a-f) and 1975 (g-1).

250

200

150

100

| ed

rei

ise)

fe)

fo)

)

ar)

NUMBER OF BEETEES

3 10 17 2431

3.10 17 2431

BEMBIDION LAMPROS

(BARRIER PLOTS)

BRUSSELS SPROUTS

FALLOW GROUND £4-------

GRASS) 0 9) Bese eeeee asses

14 2128 5 I2 19 26 2 9 16 2330 6 13 2027 4 Il 18 25 |

JUNE

7 |4 2) 28 5

JUNE

JULY AUGUST SEPTEMBER OCTOBER

BEMBIDION

OBSCURELLUM

l2 19 26 2 9 16 2330 6 13 2027 4 Ii 18 25 |

JULY AUGUST SEPTEMBER OCTOBER

WEEKLY

250

BEMBIDION LAMPROS

(BARRIER PLOTS)

I975

200

150

BRUSSELS SPROUTS

FALLOW GROUND -—-—------

GRASS

100

saceneng rece cessccecnccee

see aoe -—~.

4 fl 1825 2 9 1623306 1320274 It 1825 | 8&8 15 2229 5 12 19 26 3

APRIL MAY JUNE JULY AUGUST SEPTEMBER

in BEMBIDION OBSCURELLUM

4 {| 1825 2 9 1623306 1320274 Il 1825 ! 8 15 22295 12 19 26 3

APRIL MAY JUNE JULY AUGUST SEPTEMBER

COLLECTIONS

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

NUMBER? OF BEETLES

3 10 17 243)

MAY

CALATHUS FUSCIPES

7 14 21 28 5

JUNE

l2 19 26 2 9 16 2330 6 13 2027 4 fl 18 25 | 4 fl 18 25 2 9 16 23 30 6

JULY

AUGUST SEPTEMBER OCTOBER APRIL MAY

CLIVINA FOSSOR

\ / me ‘

V/ v

3 10 17 2431 7 14 21 28 5 12 19 262 9 6 23 30 6 13 2027 4 Il 18 25 |

MAY JUNE JULY AUGUST SEPTEMBER OC TOBER APRIL MAY

WEEKLY COLL EC TIONS

CALATHUS FUSCIPES

ia seise

Po erorecneece

Pee eeccenes

I3 2027 4 Il 18 25 1 8 15 2229 5 1l2 I9 26 3

JUNE JULY AUGUST SEPTEMBER

CLIVINA FOSSOR

JUNE JULY AUGUST SEPTEMBER

J. ENTOMOL. Soc. Brit. CoLuMBIA 73 (1976), DEc. 31, 1976

NUMBER OF BEETLES

25 e A

HARPALUS AENEUS

3.10 17 2431 7 14 21 28 5 12 1926 2 9 16 2330 6 13 2027 4 Ii 18 25 | 4 fl 825 2 9 1623306 13 2027 4 tl 1825 | 8 15 22295 12 I9 26 3

MAY JUNE JULY AUGUST SEPTEMBER OCTOBER APRIL MAY JUNE JULY AUGUST SEPTEMBER

ae /' AMARA SPECIES AMARA SPECIES

oete

10 17 2431 7 142128 5 12 1926 2 9 16 2330 6 13 2027 4 I) 18 25 | 4 {| 1825 2 9 1623306 1320274 li 1825 | 8 15 2229 5 12 19 26 3

MAY JUNE JULY AUGUST SEPTEMBER OCTOBER APRIL MAY JUNE JULY AUGUST SEPTEMBER

WEEKLY COLLECTIONS

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

BEMBIDION LAMPROS

a (OPEN PLOTS )

200 / \

- r A I9 74

BRUSSELS SPROUTS

I v \ j \ GRASS

-— ~

3 10 17 2431 7 14 2128 5 12 19 26 2 9 16 2330 6 13 2027 4 fi 18 25 |

MAY JUNE JULY AUGUST SEPTEMBER OCTOBER

«| b

BEMBIDION OBSCURELLUM

NUMBER OF BEETLES

3 10 17 2431 7 1421285 12 1926 2 9 16 2330 6 13 2027 4 fi_ 18 25 |

MAY JUNE JULY AUGUST SEPTEMBER OCTOBER

FALLOW GROUND ------

250 Gg

200

BEMBIDION LAMPROS

(OPEN PLOTS)

I975

150

100 BRUSSELS SPROUTS

FALLOW GROUND

GRASS

4 fl 1825 2 9 (623306 1320274 It 1825 1 8 15 22295 12 I9 26 3

APRIL MAY JUNE JULY AUGUST SEPTEMBER

' : ; BEMBIDION OBSCURELLUM

4 il 1625.2 9 1623306 !3 20274 || 18 25-1 8 15 22:29-5 (2

APRIL MAY JUNE JULY AUGUST

I9 26 3

SEPTEMBER

WE Eel GOL |b LIONS

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

NUMBER OF BEETLES

500 C :

CALATHUS FUSCIPES

300

200

! :. ~, =. se.

Sasseanet Se suse ors tacos eet a free” sees Batazrecerseres oo ote a 5

3 10 17 2431 7 42128 5 l2 19 26 2 9 16 2330 6 13 2027 4 fl 18 25 | 4 | 825 2 9 1623306 1320274 It 1825 1! 8 15 2229 5 12 |I9 26 3

MAY JUNE JULY AUGUST SEPTEMBER OC TOBER APRIL MAY JUNE JULY AUGUST SEPTEMBER

1 \

boo “i

20: | 20

' CLIVINA FOSSOR

CLIVINA FOSSOR

3 10 17 2431 7 421285 12 19 26 2 9 16 2330 6 13 2027 4 fi 18 25 | 4 f| 1825 2 9 1623306 1320274 Il 1825 | 8 15 2229 5 12 I9 26 3

MAY JUNE JULY AUGUST SEPTEMBER OCTOBER APRIL MAY

WEEKLY COLLECTIONS —it—~tS

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

NUMBER OF BEETLES

HARPALUS AENEUS

100

ease ten, \ a = a =

3 10 17 2431 7 421 285 12 19 26 2 9 16 2330 6 13 2027 4 I) 18 25 |

MAY JUNE JULY AUGUST SEPTEMBER OCTOBER

AMARA SPECIES

3 10 17 2431 7 421 285 12 19 26 2 9 16 2330 6 13 2027 4 Ii 18 25 |

MAY JUNE JULY AUGUST SEPTEMBER OCTOBER

HARPALUS AENEUS

4 {| 1825 2 9 |6 23306 132027 4 Il 1825 | 8 15 2229 l2 19 26 3

APRIL MAY JUNE JULY AUGUST SEPTEMBER

AMARA SPECIES

A 4 \ /

7 \ / a \ 7

5 7 \ SG \ /

\ i 7, i

; \ <7 ~ 4

‘ fF

aN ‘ 5 ‘i

4 {1 1825 2 9 623306 1320274 Il 1825 1 8 15 22295 12 I9 26 3

APRIL MAY JUNE JULY AUGUST SEPTEMBER

WEEKLY COLLECTIONS

20 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DrEc. 31, 1976

References

Briggs, J. B. 1957. Some experiments on control of ground beetle damage to strawberry. 44th Rep.

E. Malling Res. Sta. 1955-1956. 142-145.

Coaker, T. H. 1965. Further experiments on the effect of beetlé predators on the numbers of cab-

bage root fly, Erioischia brassicae (Bouché), attacking brassica crops. Ann. appl. Biol.

56: 7-20.

Coaker, T. H. and D. A. Williams. 1963. The importance of some Carabidae and Staphylinidae

as predators of the cabbage root fly, Erioischia brassicae (Bouché). Ent. exp. et appl.

6: 156-164.

Finlayson, D. G., C. J. Campbell and H. A. Roberts. 1975. Herbicides and insecticides: their

compatibility and effects on weeds, insects and earthworms in the minicauliflower crop.

Ann. appl. Biol. 79: 95-108.

Gibson, A and R. C. Treherne. 1916. The cabbage root maggot and its control in Canada with

notes on the imported onion maggot and seed-corn maggot. Canada Dep. Agr. Entomol.

Branch Bull 12. 58 pp.

Greenslade, P. J. M. 1964. Pitfall trapping as a method for studying populations of Carabidae

(Coleoptera). J. Anim. Ecol. 33:301-310.

Hatch, M. H. 1953. The beetles of the Pacific northwest. Part I: Introduction and Adephaga.

Univ. of Wash. Press, Seattle.

Hatch, M. H. 1957. The beetles of the Pacific northwest. Part I]: Staphyliniformia. Univ. of Wash.

Press, Seattle.

Tsinovskii, Ya. P. 1961. Clivina fossor L. a pest of corn in the environment of Latvian SSR.

Tr. Inst. Biol. Akad. Navk. Latviisk. SSR 20: 163-164 (#15685 Biol. Abs. 42: 1237, 1963).

Wilkes, A. and G. Wishart. 1953. Studies on parasites of root maggots (Hylemya spp.; Diptera:

Anthomyiidae) in the Netherlands in relation to their control in Canada. Tijdschr. PPziebt.

59: 185-188.

Wishart, G., J. F. Doane and G. E. Maybe. 1956. Notes on beetles as predators of eggs of

Hylemyia brassicae (Bouché). Canadian Entomol. 88: 634-639.

Wright, D. W. 1956. Entomology report. Rep. Nat. Veg. Res. Sta. Wellesbourne (1955) 47.

Wright, D. W., R. D. Hughes, and J. Worrall. 1960. The effect of certain predators on the numbers

of cabbage root fly (Erioischia brassicae (Bouché)) and on subsequent damage caused by

the pest. Ann. appl. biol. 48: 756-763.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 raat

UNDERSTORY PLANTS AS INDICATORS OF GRAND FIR

MORTALITY DUE TO THE FIR ENGRAVER:

J. A. SCHENK, R. L. MAHONEY, J. A. MOORE, AND D. L. ADAMS?

ABSTRACT

Mortality of grand fir trees, caused by the fir engraver, Scolytus

ventralis, was monitored during 3 years on ten 0.1 acre (0.04 ha) circular

plots in each of nine stands in northern Idaho. Understory vegetation

was sampled on each plot on the basis of circular subplots of 0.03 acre

(0.012 ha). Analyses showed four species to be strongly correlated with

high and two with low tree mortality. The interaction between these

groups of plant species provided a variable that increased as the pro-

portion of high to low hazard plants increased. Various linear and non-

linear expressions were tested between the two plant groups and their

interaction regressed against killed trees per acre. The plant group

interaction term accounted for the most variation (r’=0.914) and

produced the lowest standard error of the estimate (1.55). The equation

for this variable took the form Y=2.291 + 0O.1llex, where X=plant

group interaction. This equation provides an indication of the susceptibility

of grand fir stands to mortality caused by the fir engraver.

Grand fir, Abies grandis (Dougl.) Lindl., is

a major component of the grand fir - western

larch - Douglas-fir type in the northwestern

United States and southern British Columbia

(Fowells 1965). In Idaho, this species com-

prises half (874 M acres) (349.6 M ha) of the

total acreage occupied by the spruce-fir group

of types (Wilson 1962).

Numerous insect species attack grand fir,

but most of them cause little damage and are

of relatively minor economic importance. The

western balsam bark beetle, Dryocetes confusus

Sw., and the fir engraver, Scolytus ventralis

LeConte, are the principal bark beetle pests

(Fowells 1965). Epidemic infestations of the

fir engraver are sometimes severe, but rela-

tively localized and may be correlated with epi-

demics of the Douglas-fir tussock moth,

Orygia pseudotsugata (McD.) (Berryman 1973).

As an example of their severity, Stevens (1971)

reported that about 37,000 grand fir trees were

killed in 1954 on 6,000 acres (4800 ha) of the

Cibola National Forest in New Mexico.

Parasites and predators may help to con-

trol the fir engraver in some years (Massey

1966, Ashraf and Berryman 1970), but

generally are considered ineffective in prevent-

ing outbreaks (Stevens 1971). Chemical control

‘Published with the approval of the Director, Forest, Wild-

life, and Range Experiment Station, University of Idaho,

Moscow as contribution No. 18. Supported in part by McIntire-

Stennis funds and Potlatch Corporation, Lewiston, Idaho.

*Professor, Research Technician, Research Associate, and

Professor, respectively, College of Forestry, Wildlife and Range

Sciences, University of Idaho, Moscow, Idaho.

methods under forest conditions are considered

by most workers to be limited because of the

wide variation in the pattern of attack and

injury to the host tree. Little or no benefit is

gained by chemically destroying fir engraver

broods in trees under mass attack, unless those

broods in top-killed and ‘‘patch’’ attacked

trees (having the potential to sustain or re-

generate an epidemic) are also identified and

destroyed (Keen 1952, Struble 1957, Stevens

1971).

Silvicultural methods probably offer the

best possibility for minimizing losses. This

approach requires cultural practices that re-

move trees predisposed to attack, and the

maintenance of stand vigor and resistance

through regulation of density and composition.

Attainment of these objectives necessitates a

stand hazard rating system that will help forest

managers to assign treatment priorities. The

system should be based on data easily obtained

during the taking of standard timber inven-

tories.

It has been demonstrated that, in the

northern Rocky Mountains, the subordinate

plant unions reflect differences in site charac-

teristics (Daubenmire and Daubenmire 1968).

Thus, it seemed likely that the presence or

absence of certain understory plant species

or species groups could indicate site conditions

favorable or unfavorable to high mortality

caused by the fir engraver. A plant species

group as used here is a collection of plants with

similar relationships to a specified variable.

The study was conducted in three experi-

mental areas (replicates), each consisting of

three study sites, established on lands of the

22 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Potlatch Corporation in northern Idaho. Two

replicates (Gold Creek and Lost Creek) are

located in Abies grandis/Pachistima myrsinites

habitat types in Latah County and the third

replicate (Jaype) is located in a Thuja plicata/

Pachistima myrsinites habitat type in Clear-

water County. In each study grand fir com-

prises between 63% and 76% of the stems per

acre of more than 3 inches dbh.

Ten circular plots each of 0.1 acre (0.04 ha)

were systematically located with a random

start within each of the nine study sites. Grand

fir mortality attributable to the fir engraver

was monitored in each plot for 3 years (1972-

1974). The total mortality per acre caused by

the fir engraver in each study site was then

calculated.

Understory vegetation was sampled on each

0.1-acre plot during late summer of 1974, using

0.03-acre (0.012 ha) circular subplots with

witnessed and staked plot centers. These veg-

etation plots were offset 18 feet from the 0.1-

acre plot centers to avoid the disturbance

resulting from frequent visits to the main plot

centers. All perennial shrubs, forbs, and gram-

inoids on each plot were recorded. An ocular

estimate of percent cover with low and tall

shrub species also was recorded for each plot.

Within any given study site, the subord-

inate plant complex was not influenced by

topography. We calculated the frequency or

percentage of the total number of understory

vegetation plots occupied by each herbaceous

and shrub species at each study site, and also

the average percentage cover for each shrub

species.

The frequencies or average percentage cover

of about 50 plant species were evaluated by

means of correlation matrices, using killed trees

per acre during three years as one variable and,

as the other, frequency of a herb or shrub

species, or the average percentage cover of a

shrub... We assumed that the composition of the

subordinate plant complex and its relationship

to the site would remain unchanged during the

three years in the absence of outside disturbance

and considering only perennial plant species.

Based on this assumption, plant data collected

at the end of the mortality period were used to

indicate a relationship to mortality in stands

where fir engraver populations were likely to be

present. Those species showing direct or in-

verse correlation coefficients of 0.80 or more

were subjectively accepted as indicating high or

low mortality caused by the fir engraver. Six

species were thus selected for further analyses.

Results

Four of the six plant species had frequen-

cies that were directly correlated (group A),

and two had frequencies that were inversely

correlated (group B), with killed trees per acre

during the three years (Table 1). Additional ana-

lysis showed a high degree of correlation be-

tween the frequency of a given plant species and

the frequency of other species having a similar

(direct or inverse) correlation. The frequency

of each group was then calculated for each

study site, based on the percentage of the total

number of understory vegetation subplots

within each study site in which any single mem-

ber species of the plant group occurred.

The interaction between the frequencies of

the two plant species groups produced a var-

iable that increased with the proportion of

group A or high hazard to group B or low

hazard plants. This is expressed by:

PGI=fA/1 + fB

where:

PGI=plant group interaction

fA=frequency of occurrence of plant

species in group A.

fB=frequency of occurrence of plant

species in group B.

Table 1. Correlation coefficients for plant species correlated with grand fir trees killed

per acre by the fir engraver during 3 years, in northern Idaho, 1974.

Plant species variable

Common name

Usual habitat1/ r

Carex deweyana Schw.

Arenaria macrophylla Hook. Sandwort

Satureja douglasii (Benth.) Breq.

Holodiscus discolor (Pursh) Maxim.

Clintonia uniflora (Schult.) Kunth.

Chimaphila umbellata (L.) Bart.

Yerba buena

Oceanspray

Blue-bead lily

Pipsissewa

Dewey’s sedge Moist woodlands to forest openings 0.886

Moist to dry, shaded to open woods 0.812

Coniferous woods 0.825

Open dry to moist woods 0.946

Moist coniferous woods ~0.822

Under conifers in woods - 0.820

1/Scientific name, common name and usual habitat from Hitchcock and Cronquist 1973.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 23

To develop a mathematical expression that

would relate understory vegetation variables

to trees killed per acre by the fir engraver

during the three years, we tested various linear

and non-linear expressions of plant species

groups A and B, and plant group interaction, re-

gressed against trees killed per acre. The best

mathematical equations for these variables

took the following form:

Y=1.922 - 0.809X 1? + 1.713X 4 (1)

Y=15.045 - 0.136X » (2)

Y=2.291 + 0.11le%3 (3)

where:

Y=trees killed per acre by the fir engraver

during 3 years (KTA)

X, =frequency of occurrence of plant species

in group A

X»=frequency of occurrence of plant species

in group B

X3=plant species group interaction

(X;/1+ Xe)

The correlation coefficients for equations

1—3 are 0.954, -0.917 and 0.956, and their

standard error of the estimates are 1.634, 1.765,

and 1.550 respectively. The variable that ac-

counted for the most variation and also produc-

ed the lowest standard error of the estimate

was plant group interaction (equation 3) which

accounted for 92% of the variation in KTA, and

is significant at an oc |level of .01.

Discussion

It is noteworthy that the plant species in

group A are considered seral and those in group

B are considered climax species when the sub-

ordinate plant union is Pachistima myrsinites

(Daubenmire and Daubenmire 1968). Thus, the

presence of group A species indicates a site

presumably less conducive, and the presence

of group B species indicates a site more con-

ducive, to the maintenance of favorable mois-

ture conditions and vigor of grand fir.

The value of the relationship reported here

is its use as a means of ranking sites support-

ing grand fir according to their potential sus-

ceptibility. The level of mortality is depend-

ent upon stand variables, upon the intensity of

stress imposed on the site by adverse abiotic

factors, and upon the population levels of the

fir engraver. Other predisposing factors include

the presence of root disease (Partridge and

Miller 1972), and the reduced ability of trees

to produce traumatic resin canals (Berryman

1969, Berryman and Ashraf 1970).

In practice the subordinate plant union

would be sampled at each plot center during the

regular timber inventory, using 0.03-acre circu-

lar plots, and recording the presence of each

plant species group. At each plot, a plant

species group would be recorded as present if

any of the member species were present. The

plant group interaction term (PGI) would be

calculated and used as the independent variable

in equation 3 to indicate the susceptibility of

the stand of grand fir to mortality caused by

fir engraver.

Table 2. Correlation matrix between the frequencies of plant species in two groups,

northern Idaho, 1974.

y/x 1 2 3 4 5 6

1 1.000

2 0.796 1.000

3 0.898 0.767 1.000

4 0.887 0.738 0.905 1.000

4) -0.783 -0.702 -0.701 -0.833 1.000

6 -0.912 -0.775 -0.973 -0.885 0.613 1.000

Plant Group B

5. Clintonia uniflora (Schult.) Kunth.

6. Chimaphila umbellata (L.) Bart.

Plant Group A

1, Holodiscus discolor (Pursh) Maxim.

2. Carex deweyana Schw.

3. Arenaria macrophylla Hook.

4. Satureja douglasii (Benth.) Briq.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Acknowledgements and James E. Jewell, Professor, Assistant Pro-

The authors acknowledge the assistance of fessor, and Graduate Assistant, University of

Frederic D. Johnson, Douglass M. Henderson, Idaho, respectively, in plant species identifica-

tion.

Literature Cited

. Ashraf, M. and A. A. Berryman. 1970. Biology of Sulphuretylenchus elongatus (Nematoda:

Sphaerulariidae), and its effect on its host, Scolytus ventralis (Coleoptera: Scolytidae).

Can. Entomol. 102: 197-213.

. Berryman, A. A. 1969. Response of Abies grandis to attack by Scolytus ventralis (Coleoptera:

Scolytidae). Can. Entomol. 101: 1033-1041.

______i*d'Y73. Population dynamics of the fir engraver, Scolytus ventralis (Coleoptera:

Scolytidae), I. Analysis of population behaviour and survival from 1964 to 1971. Can.

Entomol. 105: 1465-1488.

and M. Ashraf. 1970. Effects of Abies grandis resin on the attack behaviour

and brood survival of Scolytus ventralis (Coleoptera: Scolytidae). Can. Entomo. 102:

1229-1236.

. Daubenmire, R. and J. B. Daubenmire. 1968. Forest vegetation of eastern Washington and

northern Idaho. Wash. State Univ., Agr. Exp. Sta. Tech. Bull. 60, 104 pp.

. Fowells, H. A. 1965. (ed.). Silvics of forest trees of the United States. U. S. Dept. Agr., Agr.

Handbk. 271, 762 pp.

. Hitchcock, C. L. and A. Cronquist. 1973. Flora of the Pacific Northwest. U. of Wash. Press.,

730 pp.

. Keen, F. P. 1952. Insect enemies of western forests. U.S. Dept. Agr., Misc. Publ. 273, 280 pp.

. Massey, C. L. 1966. The influence of nematode parasites and associates on bark beetles in the

United States, Bull. Entomol. Soc. Amer. 12: 384-386.

. Partridge, A. D. and D. L. Miller. 1972. Bark beetles and root rots related in Idaho conifers.

Plant Disease Reptr. 56: 498-500.

. Stevens, R. E. 1971. Fir engraver. U. S. Dept. Agr., Forest Service, Forest Pest Leafl. 13, 7 pp.

. Struble, G. R. 1957. The fir engraver, a serious enemy of western true firs. U.S. Dept. Agr.,

Prod. Res. Rept. 11, 18 pp.

. Wilson, A. K. 1962. Timber resources of Idaho. U.S. Dept. Agr., Forest Service, Intermt.

Forest and Range Exp. Sta., Forest Survey Release 3, 42 pp.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

CONE AND SEED INSECTS OF SUBALPINE FIR

DURING A YEAR OF LOW CONE PRODUCTION IN

NORTHERN IDAHO!

D. L. KULHAVY, J. A. SCHENK, AND T. J. HUDSON?

College of Forestry, Wildlife and Range Sciences

University of Idaho, Moscow, Idaho

ABSTRACT

Cone and seed insects destroyed 29 percent of the seed crop of subalpine

fir (Abies lasiocarpa) in the Freezeout Mountain area of northern Idaho

in 1972 during a year of low cone production. Larvae of a coneworm,

Dioryctria abietivorella destroyed 12 percent of the seed crop, accounting

for 42 percent of the total insect damage. A newly discovered midge pest,

a species of Dasineura, destroyed 11 percent of the seed crop, amounting to

40 percent of the total insect damage. The dipterans, Hylemya abietis,

Earoymia sp., and Asynapta keeni, and the chalcid wasp, Megastigmus

lasiocarpae, together destroyed 4 percent of the seed crop. Unknown causes

accounted for 1.5 percent of the total seed destruction. X-ray was used to

estimate seed lost to M. lasiocarpae and Dasineura sp. Regression equations

are given relating cone length (mm), and the seeds on the axial surface, to

total seeds. Sound and damaged seeds on the axial surface were highly

correlated with the totals of sound and damaged seeds, respectively, in the

cone.

INTRODUCTION

Insects inhabiting cones and seeds of sub-

alpine fir, Abies lasiocarpa (Hook.) Nutt., have

received little attention. Keen (1958) listed five

species of insects that cause damage to sub-

alpine fir cones: the fir coneworm, Dioryctria

abietella (Denis and _ Schiffermueller) (=

D. abietivorella (Grote)); a cone maggot,

Earomyia aquilonia McAlpine; two species of

seed chalcids in the genus Megastigmus; and a

cone midge, Asynapta keeni (Foote). Hedlin

(1974) states that E. aquilonia destroys most

of the seeds in infested cones in British

Columbia, and that the subalpine-fir chalcid,

Megastigmus lasiocarpae Crosby, is not a

serious pest. He constructed a key to the

insects damaging cones in British Columbia.

Moyer and Parker (1973), and Kulhavy, et al.

(1975) presented a list of insects reared from

these cones in Utah and Idaho. Kulhavy (1974)

also constructed keys to the damage and to the

insect pests of subalpine fir cones in Idaho.

Several methods are available to evaluate

the damage within a cone and the impact on

the seed crop. Cones can be halved longitudin-

ally and counts made of insect-damaged,

‘Published with the approval of the Director, Forest, Wild-

life and Range Experiment Station University of Idaho, Moscow

as contribution number 37. Supported in part by MclIntyre-

Stennis funds’’.

2Graduate assistant, Professor, and _ scientific aide,

respectively. This research is a portion of a Master’s thesis by

the senior author.

3An r” of 0.92 was obtained from a regression of seeds

from one-half of a cone to total seeds within a cone.

aborted, sound and the total seeds on the ex-

posed axial surface (Winjum and Johnson

1960, McLemore 1961, and Bramlett and

Hutchinson 1964). Seed-infesting insects may

be detected by x-ray and dissections (Speers

1968, Fedde 1973). This paper reports on

damage by cone and seed insects of subalpine

fir in a year of very low cone production in

northern Idaho, and on the reliability of estima-

ting the damaged, sound, and the total

numbers of seeds in cones.

Subalpine fir cones were collected from early

July through early September, 1972 from

a 1.0 x 0.3 km. area in the Freezeout Mountain

region of Shoshone County, Idaho. The collec-

tion area, primarily an Abies lasiocarpa/

Xerophyllum tenax habitat type (Daubenmire

and Daubenmire 1968), has a slope of less than

10 percent to the southwest with an average

elevation of 1800 m. From each of 15 cone

bearing trees in the study area, 15 to 20 cones

were collected for insect rearing and damage

evaluation. These cones represented about 15

to 20 percent of the production in the area. The

average height of the sampled trees was 9.3 m

(range 3.1 to 13.7 m). The ages, taken at 1.3m

height, averaged 27 years (range 20 to 40 years)

and diameters averaged 20.0 cm (range 4.5 to

34.8 cm). Cones collected were placed either in

one-gallon, single-light-source rearing cartons

at 24°C, or dissected for insect damage. In the

former case, the emerged adults were identi-

fied by specialists and included in a checklist

(Kulhavy, et al. 1975), and in a key to damage

(Kulhavy 1974).

26 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

From the 250 cone sample, 72 were com-

pletely disected within two weeks after collec-

tion for insect damage and seed estimation.

These cones were cut in half lengthwise using a

modified cone-knife cutter, and the numbers

of insect-damaged seeds were counted on the

exposed axial surface. Seeds were then hand

extracted from one-half of each cone’ (the half

selected at random by the toss of a coin),

counted and the seedwings removed. The seeds

were then placed in plastic petri dishes and

x-rayed for seed-infesting insects. The radio-

graphs were made in Faxitron® Model 804

self-contained X-ray system at 15 kVP for 8 to

10 seconds using Polaroid® Type 52 Land film.

The film was then developed for 10 to 15

seconds and coated with Polaroid print coater.

The number of seed-infesting insects was

counted and added to the damage caused by

other insects. This value was regressed against

the observed axial damage to estimate total

insect damage.

The cone length (mm), width (mm), and axial

seed count were regressed against the total

number of seeds within one-half of a cone to ob-

tain an estimate of the sound and total number

of seeds within a cone. Observations on life

history and behavior of the various species also

were recorded.

RESULTS

Dioryctria abietivorella (Grote), fir coneworm

Larvae of this pyralid infested 20 percent of

the examined cones and destroyed 45.7 percent

of the seeds in the infested cones. It was the

most destructive of all species, and caused

41.6 percent of the total insect damage,

destroying 12.0 percent of the seed crop.

Damage by D. abietivorella has been described

by Keen (1958) and their feeding in subalpine

fir cones is similar to that of related species in

other trees species. The larvae often bore from

one cone to another and through previously

infested cones, leaving large masses of granular

frass on the exterior of cones held together

by webbing. Damaged cones turn brown and

brittle by early August.

Larvae of D. abietivorella are behaviorally

distinct from other lepidopteran pests of cones.

When exposed, a mature larva immediately

begins sealing its tunnel by spinning silk across

the opeing, adding frass pellets to the lattice,

then more silk. The behavior observed was

similar to that seen in construction of pupal

cells although the latter are lined with addition-

al silk. A new species of parasitic Diptera in

the genus Lixophaga (Tachinidae) was reared

by us from larvae of D. abielivorella. The

impact of this parasite is not known.

Dasineura sp., seed midge

Estimates of damage by the newly-discov-

ered cecidomyiid pest of subalpine fir seeds

were obtained from radiographs and seed

dissections because the larvae feed internally

in the seeds or underneath the seed coat. They

destroyed 11.4 percent of the seed crop and

accounted for 39.2 percent of the total insect

damage. Mature larvae of this species are

readily distinguished on radiographs from

larvae of the seed chalcid, Megastigmus lasio-

carpae. Late instar M. lasiocarpae larvae are

distinclty ‘‘C’’ shaped and tapered at both

ends, whereas larvae of Dasineura are straight

or curved in the seeds, but not tapered.

This species overwinters as mature larvae

but no pupae or adults were recovered. About

10 percent of the larvae were parasitized by a

small, black, braconid wasp.

Asynapta keeni (Foote)

The larvae of this cecidomyiid were more

abundant (700) then those of any other species.

However, they accounted for only 1.2 percent of

the total insect damage and destroyed 0.4

percent of the seed crop by resin exudation.

The life cycle of the species in cones of sub-

alpine fir is the same as it is in cones of grand

fir, Abies grandis (Douglas) Lindley, (Kulhavy

1974). Adults emerge in late August or the

following spring.

Hylemya abietis (Huckett)

One larva of this anthomyiid infested one

subalpine fir cone and destroyed 32 seeds. This

amounted to one percent of the insect-caused

loss, or 0.3 percent of the seed crop. Larvae

when removed from cones collected later became

sluggish and constricted. They overwinter in

puparia in the soil and adults emerge the follow-

ing spring.

Earoymia sp.

Larvae of this lonchaeid caused 3.9 percent

of the insect damage and destroyed 1.3 per-

cent of the total seed crop in 1972. Seeds mined

by the larvae become flat, resinous and dark

brown. Only a very small amount of fine frass

is produced. After the mature larvae leave a

cone they move frantically until they find a

suitable pupation site in the litter or soil. The

larvae travel by three methods: (1) they wiggle

the entire body, causing a rolling, twisting

motion; (2) they alternately constrict and

lengthen the body segments, resulting in a

forward motion; and (3) they grasp fleshy areas

near the posterior spiracles with one or both

mouthhooks, which constricts the body into a

“C” shape with the midbody segments

flattened dorso-ventrally. When the mouth-

hooks are released, the larva is propelled for a

distance of 8 to 15 cm. This snapping motion

was stimulated in the laboratory and observed

in the field, and has been reported previously

for E. aquilonia by R. W. Reid as cited by

McAlpine (1956).

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEC.

ol, 1976 27

TABLE 1. Summary of regression analyses for predicting total, filled, and damaged seeds in

subalpine fir cones, northern Idaho, 1972 (n=72).

Dependent’ Independent

Variables Variables Intercept

1] Length (mm.) -50.4

Yy Width (mm.) -82.7

Yq Length, Width 62.2

«I Axial seeds (Total) -21.6

Yo Axial sound seeds 14.0

Y3 Axial damaged seeds 9.2

** Significantly different from zero at a=.01

Standard

error of

Regression estimate Coefficient of

Coefficient (Sy.x) Determination (r’)

2.09 19.6 .6055**

6.86 25.0 1313 a

1.96, 01.7 19.7 .6073**

4.88 23.9 .4120**

3.47 28.0 .4668**

2.55 15.5 .6777**

1 Yy =Total seed in one-half of a cone; Y2=total sound seeds in one-half of a cone;

Y3=total damaged seeds in one-half of a cone.

Megastigmus lasiocarpae Crosby

Larvae of this torymid destroyed 2.2 per-

cent of the seed crop, which has 7.4 percent of

the insect-caused seed loss. Damage by this

seed-infesting chalcid was estimated from

radiographs and_ seed_ dissections. Our

observations agree with those of Keen (1958)

who suggested that the species has a one year

life cycle snychronized with cone development.

The eggs are deposited in the seeds early in

cone devlopment and the larvae feed singly.

Only one larva develops if more than one egg

is deposited within a seed. Overwintering occurs

as mature larvae or pupae, and adults emerge

the following spring. An undetermined por-

tion of the population entered extended

diapause in 1972 and emerged in 1974.

Unknown causes

These accounted for 1.5 percent of the total

seed destruction.

Estimation of Seed Production and Damage

The number of seeds within subalpine fir

cones can be reliably estimated (r’=.6055,

a=.01) from the cone length (Table 1). Neither

cone width, nor the inclusion of both cone

length and width improved the fit. Similarly,

expressing the independent variables in

logarithms, or fitting a second degree poly-

nominal failed to significantly increase the fit.

The number of damaged seeds/cone also can

be reliably estimated (r’?=.6777, a=.01) from

counts of damaged seeds on an axial section

(Table 1). However, the axial slice technique

did not provide as good an estimate of the total

number of seeds/cone (r’=.4120), or the num-

ber of sound seeds/cone (r?=.4668). Means and

standard deviations for all variables are shown

in Table 2.

DISCUSSION

Every cone dissected from the Freezeout

Mountain area had at least one seed destroyed

by insects. Insects destroyed 29.1 percent of

the total seed crop during a year of very poor

cone reproduction. This loss is magnified by the

high percentage of aborted seeds, the naturally

low viability of subalpine fir seeds (USDA

TABLE 2. Means and standard deviations for all variables for subalpine fir cones,

northern Idaho, 1972.

Variable Mean Standard Deviation

Length (mm) 737 11.5

Width (mm) 28.7 yAE |

Axial seeds (Total) 27.8 4.1

Axial sound seeds fit Tel

Axial damaged seeds 9.1 On

Total sound seeds Ble 38.0

Total damaged seeds 32.6 27.1

Total seeds 114.2 31.0

28 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

1974) and the cyclic nature of cone crops.

Desiccation of the seeds adversely affects

survival and seedling establishment during

the first season of growth. In the Freezeout

Mountain area, the establishment of seedlings

was further hindered by the light intensity

(USDA 1965) which exceeded 50 percent full

sunlight. The similarity and proximity of the

insect pests of grand fir cones (Kulhavy 1974,

Kulhavy et al., 1975) indicate that the infesta-

tions probably were from overwintering or

emigrating insects. The most destructive insect

species, the coneworm, is an ubiquitous pest

of cones and was also the most destructive

pest of grand fir cones (Kulhavy 1974, Kulhavy

and Schenk in press).

To obtain a reliable estimate of loss to cone

and seed insects, damage by the insects feed-

ing internally must be taken into account.

Thus, a portion of the seeds should be

examined by radiography or dissected to esti-

mate the damage. Although reliable estimates

were obtained of the total damage from the

number of damaged seeds on the axial surface,

and of total seeds per cone from the cone

length, Kulhavy, (1974) has shown that there is

high variability over the range of grand fir.

Similar variability in subalpine fir is likely.

Thus, the equation for predicting seeds in sub-

alpine fir cones should be tested at different

levels of cone production and insect populations

and over a broader geographic range before

applying it indiscriminately.

The loss of seeds to insects, coupled with

the cyclic nature of cone crops and the

generally poor germination of subalpine fir,

are factors that should be considered before

planning a timber harvest where natural re-

generation is desired.

ACKNOWLEDGEMENTS

We thank Drs. R. W. Stark and E. R.

Canfield, University of Idaho, and P. J.

Gravelle, Potlatch Corporation, who reviewed

the manuscript, and Drs. R. J. Gagne’, G.

Steyskal, and B. D. Burks who provided insect

identifications.

LITERATURE CITED

Bramlett, D. L., and J. G. Hutchinson. 1964. Estimating sound seed per cone in shortleaf pine.

U.S. Dept. Agr. Forest Serv. Res. Note SE-18. 2 pp.

Daubenmire, R., and J. B. Daubenmire. 1968. Forest vegetation of eastern Washington and

northern Idaho. Wash. State Univ. Agr. Exp. Sta. Tech. Bull. No. 60. 104 pp.

Fedde, G. F. 1973. Impact of the balsam woolly aphid (Homoptera: Phylloxeridae) on cones and

seed produced by infested Fraser fir. Can. Entomol. 105:673-680.

Hedlin, A. F. 1974. Cone and seed insects of British Columbia. Pacific Forest Res. Cen.,

Victoria, Brit. Col. 63 pp.

Keen, F. P. 1958. Cone and seed insects of western forest trees. U.S. Dept. Agr. Misc. Bull.

No. 1169. 168 pp.

Kulhavy, D. L. 1974. Cone and seed insects of grand and subalpine firs in northern Idaho. College

of Forestry, Wildlife and Range Sciences, M.S. thesis, University of Idaho. 79 pp.

Kulhavy, D. L, J. W. Dale, and J. A. Schenk. 1975. A checklist of the cone and seed insects of

Idaho. Forest, Wildlife and Range Experiment Station, Univ. of Idaho, Info. Ser.

No. 6. 28 pp.

Kulhavy, D. L. and J. A. Schenk. 1976. An evaluation of damage by cone and seed insects of

grand fir in northern Idaho. Univ. of Idaho, Dept. of Entomol. 50th Anniversary Pub.

(in press).

McAlpine, J. F. 1956. Cone-infesting Lonchaeids of the genus Earomyia Zett, with descriptions of

five new species from western North America (Diptera: Lonchaeidae). Can. Entomol.

88: 178-196.

McLemore, B. F. 1961. Estimating pine seed yields. U.S. Dept. Agr. Forest Serv. SE Exp.

Sta. Rep. No. 134. 2 pp.

Moyer, M. M., and D. L. Parker. 1973. A revised list of seed and cone insects collected from native

conifers in the Intermountain Region. Branch of Forest Insect and Disease Prevention

and Control. U.S. Dept. Agr. Forest Serv., Ogden, Utah. 15 pp.

Speers, C. F. 1968. Insect infestation distorts Fraser Fir seed tests. U.S. Dept. Agr. Forest Serv.

Tree Planters’ Notes 18:19-21.

U.S. Dept. Agr. 1965. Silvics of forest trees of the United States. U.S. Dept. Agr. Forest Serv.

Handbook No. 271. 762 pp.

U.S. Dept. Agr. 1974. Seeds of woody plants in the United States. U.S. Dept. Agr. Handbook

No. 450. 883 pp.

Winjum, J. K., and N. E. Johnson. 1960. A modified knife-cone cutter for Douglas fir seed studies.

J. Forest. 58:487-488.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 29

THE STYLETS OF THE LARGE MILKWEED BUG, ONCOPELTUS

FASCIATUS (HEMIPTERA: LYGAEIDAE , AND THEIR

INNERVATION’

A. R. FORBES

Research Station, Agriculture Canada,

Vancouver, British Columbia

ABSTRACT

Sections of the stylets of the large milkweed bug were examined in the

electron microscope. They differ from those of 29 spp. of Homoptera studied

earlier, in having: flanges on the maxillary stylets that engage grooves in

the mandibular stylets; three large and three small dendrites in the central

duct within the mandibular stylets; and a large salivary canal.

INTRODUCTION

The large milkweed bug, Oncopeltus

fasciatus (Dallas), is a widely used research

animal since it is reasonably large and can be

reared easily in the laboratory throughout the

year. Its widespread usage prompted a review

of published information on its morphology,

physiology and behavior (Feir 1974). No in-

formation on the structure of its stylets is in-

cluded in this review, nor are there other repor-

ts on their fine structure. The present paper

describes the stylets of this bug and compares

them with the stylets of some Hemiptera

(Suborder Homoptera) studied previously.

MATERIALS AND METHODS

The large milkweed bugs were from colonies

maintained in the laboratory at the University

of British Columbia.

The stylets were dissected from the bugs

and immediately fixed simultaneously for 1 hr.

on ice in 2% osmium tetroxide and 4%

glutaraldehyde, both in 0.1 M cacodylate buf-

fer, washed in 0.1 M cacodylate buffer (pH 7),

post-fixed in 2% osmium tetroxide in the same

buffer for ’2 hr, dehydrated in ethanol, and em-

bedded in Epon 812 by the method of Luft

(1961). The sections were cut with glass knives

on a Reichert Om U2 ultramicrotome, mounted

on grids with carbon-collodion supporting films

and stained with uranyl acetate and lead

citrate. They were examined with Philips 200 or

300 electron microscopes.

RESULTS AND DISCUSSION

The piercing-sucking organs of the large

milkweed bug consist of a pair each of man-

dibular and maxillary stylets. Each stylet has

an enlarged base within the head capsule and

an elongated shaft mostly outside the head. Ex-

cept at the bases, the mandibular stylets en-

velop the maxillary stylets closely, so that in a

cross section of the stylet bundle (Fig. 1), the

‘Contribution No. 390, Research Station, 6660 N. W. Marine

Drive, Vancouver, British Columbia, V6T 1X2.

mandibular stylets are on the outside and the

maxillary stylets are on the inside. Except at

their bases, the maxillary stylets are in-

terlocked by a system of ridges and grooves.

On the inner surface of each maxillary stylet

there are two wide concavities which together

form the food and the salivary canals. The food

canal is anterior to and only slightly larger than

the salivary canal. The bug injects saliva into

the milkweed seed by way of the salivary canal

and sucks the food material into the gut by way

of the food canal.

More specific morphological details are as

follows:

The maxillary stylets are only slightly

longer (5%) than the mandibular stylets. The

length of the stylets, including the base is

about 6 mm. The tip of each mandibular stylet

has a series of transverse, barb-like teeth across

its outer face. A cross section of the whole

stylet bundle, about midway in the shafts (Fig.

1) shows the interlocked maxillary stylets with

the food and salivary canals between their ap-

posed inner surfaces. The stylet bundle is ap-

proximately 26 micrometers in diameter, the

food canal 9 micrometers in diameter and the

salivary canal 8 micrometers in diameter. The

salivary canal is thus only slightly smaller than

the food canal. The mechanism that interlocks

the maxillary stylets consists of three grooves in

the right maxillary stylet and two grooves and

three flanged ridges in the left. The maxillary

stylets are not bilaterally symmetrical. There is

a ridge with two flanges at the anterior margin

of the outer surface of each maxillary stylet

which fits into a groove on the inner surface of

each mandibular stylet. This produces a com-

pactly interlocked stylet bundle but the inter-

locking mechanism is such that independent

movement upon one another is possible for each

of the four stylets. The body of each maxillary

stylet also contains a narrow central cavity

which often appears in sections as two cavities

because of the apposition of parts of its walls.

Each mandibular stylet contains a central

duct running from the base to near the tip. The

30 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

half of the shafts. CC, cental cavity; CD, central duct; FdC, food canal;

MdS, mandibular stylet; MxS, maxillary stylet; SC, salivary canal.

Fig. 2 Electron micrograph of a section of the central duct in a mandibular stylet of O. fasciatus.

There are six dendrites in the central duct. k:ach dendrite (D) contains neurotubules (NT) and is

suirounded by a cuticular sheath (CS).

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 Sul

fasciatus. 3. midway, about three mm from the tip, showing five dendrites in the duct 4. about

two mm from the tip, showing four dendrites in the duct and one (arrow) in the wall of the

stylet. 5. at the stylet tip, after the central duct has bifurcated. The two

branches of the central duct are indicated by arrows.

central duct is approximately 2 by 6 micrometers

and contains six dendrites. All the dendrites

were traced from the base of the mandibular sty-

let to midway along the stylet:bundle.' The den-

drites are of two types: three large dendrites

which are usually near the centre of the duct

and away from the walls; and three smaller

dendrites usually placed peripherally and close

to the wall (Fig. 2). About midway along the

stylet bundle one of the small, peripheral den-

drites leaves the central duct and proceeds to

the outside of the stylet and a receptor site,

leaving five dendrites in the central duct (Fig.

3). About 1 mm closer to the tip, another of the

small, peripheral dendrites leaves the duct (Fig.

4), leaving only 4 dendrites in the duct (Fig. 4).

The last small peripheral dendrite leaves the

duct. about 1 mm further distad, leaving only

the three large dendrites in the duct. Close to

the tip of the stylet, the central duct bifurcates

(Fig. 5); one branch contains two dendrites, the

other branch contains one.

The stylets of the large milkweed bug differ

in some respects from those of the Hemiptera

(Suborder Homoptera) previously studied by

me (Forbes 1969 & 1972, Forbes & Mullick

1970, Forbes & Raine 1973, Chan & Forbes

1975). The salivary canal of the large milkweed

bug is almost as large as the food canal,

presumably because large amounts of saliva are

needed to soften the somewhat dry food before

it can be sucked up the food canal; aphids, the

six-spotted leafhopper, the greenhouse

whitefly, the pear psylla, and the balsam woolly

aphid all have a salivary canal which is much

smaller than the food canal. These all suck

liquid plant sap, so that presumably less saliva

is required when they feed. The body of each

maxillary stylet of the large milkweed bug con-

tains a large, narrow central cavity, which is

apparently empty; the maxillary stylets of the

six-spotted leafhopper also have cavities but

these contain dendrites. There are ridges and

grooves that interlock the maxillary with the

mandibular stylets of the large milkweed bug;

no such interlocking mechanism occurs in any

of the homopterous insects mentioned. The cen-

tral duct in the mandibular stylets of the large

milkweed bug contain six dentrites, three of

which are smaller and go to receptor sites

proximad to the tip of the stylet and three of

which are larger and reach the stylet tip; all of

more than 25 species of aphids examined have

mandibular stylets with two similar dendrites

running to their tips (Forbes 1969 & un-

published, Chan & Forbes 1975). The

greenhouse whitefly and the pear psylla also

have two dentrites running to the stylet tips

but the balsam woolly aphid has three. The six-

spotted leafhopper’s mandubular stylets have

three dendrites which run to their tips or very

close to them.

The structure and function of the stylets of

other Hemiptera and the probable significance

of the nerves in the stylets have been discussed

in my earlier papers already cited.

29 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

ACKNOWLEDGEMENTS Chan and Miss Bea Schroeder provided tech-

Dr. G. G. E. Scudder, Department of nical assistance and Mr. S. W. MacDiarmid

Zoology, University of British Columbia, sup- Prepared the figures for publication.

plied the large milkweed bugs. Mr. Cho-Kai

References

Chan, C-K, and A. R. Forbes. 1975. Life-cycle of a spiral gall aphid, Pemphigus spirothecae

(Homoptera: Aphididae) on poplar in British Columbia. J. Ent. Soc. Brit. Columbia.

72: 26-30.

Feir, D. 1974, Oncopeltus fasciatus: a research animal. Ann., Rev. Ent. 19:81-96.

Forbes, A. R. 1969. The stylets of the green peach aphid, Myzus persicae (Homoptera: Aphididae).

Can. Ent. 101:31-41.

. 1972. Innervation of the stylets of the pear psylla, Psylla pyricola (Homoptera:

Psyllidae), and the greenhouse whitefly, Trialeurodes vaporariorum (Homoptera: Aleyro-

didae). J. Ent. Soc. Brit. Columbia. 69:27-30.

Forbes, A. R., and D. B. Mullick. 1970. The stylets of the balsam woolly aphid, Adelges piceae

(Homoptera: Adelgidae). Can. Ent. 102:1074-1082.

Forbes, A. R., and J. Raine. 1973. The stylets of the six-spotted leafhopper, Macrosteles fascifrons

(Homoptera: Cicadellidae). Can. Ent. 105:559-567.

Luft, J. H. 1961. Improvements in epoxy resin embedding methods. J. Biophys. Biochem. Cytol.

9:409-414.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

COCCINELLIDS AND APHIDS:

A Quantitative Study of the Impact of Adult Ladybirds

(Coleoptera: Coccinellidae) preying on Field Populations

of Pea Aphids (Homoptera: Aphididae)

B. D. FRAZER

Agriculture Canada Research Station, 6660 N.W. Marine Drive,

Vancouver, B.C. Canada, V6T 1X2

N. GILBERT

Institute of Animal Ecology, University of

British Columbia, Vancouver, V6T 1W5

ABSTRACT

This paper examines the quantitative effect of predation by a ladybird

beetle, Coccinella trifasciata, on field populations of pea aphid, Acyrthosiphon

pisum. Field studies showed that no mathematical function, involving only

the current densities of predator and prey, can predict the true predation

rate. We studied the components of the predation process in detail, first

in the laboratory, and then in the field. We derived a new, empirical (not

theoretical) formula for predation rate, which includes predator and prey

densities, predator voracity, prey age-distribution, and temperature.

Temperature has a single effect on the rate of aphid development, but a

double effect on the predation rate, so that coccinellids are much more

effective predators at high temperatures, than at low. Field cage experi-

ments, with known numbers of beetles, revealed that all current methods

of counting adult coccinellids in the field greatly underestimate their true

numbers. When this fault is rectified, the new formula correctly predicts the

predation rate.

The study shows that it is possible to investigate a predator-prey.

relationship, in the field, in considerable detail, in order to predict the preda-

tion rate over a wide range of circumstances. The study reveals several

sharp, qualitative, differences between the predation relationship observed

in the laboratory, and the same relationship observed in the field. All

laboratory studies must therefore be suspect, until verified in the field. In

particular, arthropod predation studies must allow for effects of

temperature on both predation rate and prey population dynamics. The

coccinellid-aphid relationship permits no equilibrium, or steady state, so

that conventional definitions of stability do not apply. The coccinellid’s

functional response is inherently unstable: the relationship is stabilized

solely by a numerical response. Implications for biological control are

discussed.

Contents

1. Background

Sampling and field biology

Biological parameters

Population model

2. Predation in the laboratory

Method

Analysis

3. Predation in the field

Method

Analysis

4. Beetles and aphids combined —first attempt

Sampling and field biology

Effect of temperature on beetles

Synthesis

5. Beetles and aphids combined— second

attempt

Analysis of cage experiments

Discussion

34 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Drc. 31, 1976

6. Conclusions

Laboratory v. field studies

Stability

Some technical considerations

References

7. Acknowledgments

Appendix 1. Aphid population model

Appendix 2. Algorithm to compute physiologi-

cal time in the field

Appendix 3. Field predation model

Appendix 4. Derivation of the expression for

survival rate

Appendix 5. Algorithm to compute weighted

average temperature for beetle

activity

Appendix 6. Aphid population model

Introduction

Morris et al. (1963) pioneered the use of life

tables for insects which have more or less dis-

crete generations. Hughes (1963) and Hughes

and Gilbert (1968) produced a ‘variable life-

table’ model of the cabbage aphid, which has

overlapping generations. That model assessed

the impact of a parasite on the aphid (Gilbert

and Hughes 1971). The parasite had no serious

effect on aphid abundance, which is restricted

by competition and crowding. In_ similar

analyses of other insects (Hassell 1969,

Gutierrez et al. 1971, 1974a, b; Wratten 1973,

Gilbert and Gutierrez 1973), natural enemies

also had scant effect on prey numbers. Yet

many parasites and predators effectively

reduce the numbers of their prey (e.g. Frazer

and van den Bosch 1973, DeBach 1974).

In 1972 we began to study field popula-

tions of pea aphid, Acyrthosiphon pisum

(Harris) on alfalfa, Medicago sativa L. After

the first year it was obvious (§1) that coc-

cinellid predators significantly affect aphid

density in the field. This paper analyses the

predation process (§§ 4 & 5). This is the first

time that Holling’s (1964) ‘‘component

analysis”’ has been applied to predation in the

field, and tied into the life table approach of

Morris et al (1963).

1. BACKGROUND

This section describes the field biology, and

proves that the predation rate cannot be a

function of current predator and prey densities

alone.

Sampling and Field Biology

Alfalfa, Medicago sativa L., cv. Alfa was

sown in 1971 at the University of British

Columbia. The plot consisted of 18 rows each

25 m long and 1 m apart. The crop was cut

three times during the summer of 1972, when-

ever about 10% of the plants were in flower.

This approximated the commercial practice

in the region.

A population of pea aphids, Acyrthosiphon

pisum (Harris), became established on plants

in 1971, overwintered as eggs, and reappeared

in 1972. Pea aphids normally infest the actively

growing terminals of alfalfa. We began sampl-

ing aphids in April and took samples about

once weekly throughout the summer. A sample

comprised 20 plastic bags, each containing ten

terminals collected directly in the field. Pea

aphids readily drop off a plant when it is cut,

but care was taken to ensure that no aphids

were lost. The bags were taken to the labora-

tory, where the aphids were beaten off the

plants onto a sheet of paper, sorted under the

microscope into four juvenile instars and

adults, and counted. The fourth instar and

adult aphids were separated into winged and

wingless morphs.

Hymenopterous parasites, Aphidius ervi

ervi Haliday, A. smithi Sharma & Subba Rao,

and Praon pequodorum Viereck, attack the

aphids. The parasites are themselves attacked

by the hyperparasites Asaphes_ vulgaris

Walker, A. californicus Girault, and Dendro-

cernus near niger Howard. To estimate the

parasitization rate we dissected all aphids of

the third and later instars in every sample, and

recorded the numbers and sizes of parasite

larvae they contained.

Large numbers of adult coccinellids invaded

the alfalfa plot between May 9 and July 18.

The commonest species were Coccinella tri-

fasciata perplexa Mulsant, C. t. subversa

Leconte, C. undecimpunctata undecimpunctata

“L., C. johnsoni Casey, C. californica Manner-

heim, and Cycloneda munda Say. To sample

for coccinellids, observers walked on either side

of each row of alfalfa counting all visible

beetles. At the same time we counted the para-

site mummies. Aphidiid parasites pupate in-

side or below the dead, eviscerated host aphid,

which is transformed into a shell, or ‘‘“mummy’”’.

This gives a second estimate of the para-

sitization rate.

At the start of the season, aphid numbers

began to increase (Fig. 1, May 9-25). After

the beetles had arrived (May 25-31), the aphid

population declined to a low level, which it

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 35

180

=!140

100

(a)

die

= (A) COCCINELLIDS

yy 20

_,40 ; ’

< (B) APHIDS

= e

lJ 3.0

a y APHIDS PER

rf INFESTED

o A TERMINAL >

y 2.0 : rs

2 / <

xr P =

: :

z 1.0

= §

Lad APHIDS PER

= TERMINAL

20 40 60 80 120

PHYSIOLOGICAL TIME (QUIPS)

RS aaa) RPE) OE aaa ay TT

MAY JUNE JULY

FIGURE 1A. Coccinellids of all species in the whole plot; 1B, aphids per terminal, both in 1972.

Each aphid sample contained at least 160 plants. The fall in ‘aphids per infested terminal’

beginning at q 84 is probably due to an inaccurate estimate of: p (see text). Curves

A and B (1B) are computed by Appendix 1 in the absence and presence of coccinellids.

36 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

maintained throughout the period of maximal

coccinellid numbers (May 31-June 21). There-

after, coccinellid numbers fell sharply, and the

aphids again increased (June 21-July 18) until

the alfalfa was cut. We shall concentrate on

the early period shown in Fig. 1. Later in the

season, the aphids were attacked by many

other natural enemies of aphids, eg. Chryso-

pids, Nabids, Mirids, Spiders, Syrphids, and

Coccinellid larvae. At the same time, the alfalfa

plants grew so big that the aphid samples be-

came unreliable.Nevertheless, the aphid popu-

lation dynamics during the first half of the

season are sufficiently simple to permit some

understanding of the underlying processes.

Our task is to explain the course of aphid num-

bers shown in Fig. 1.

Biological parameters

An aphid goes through four instars before

becoming adult. We estimated the duration of

each instar, and the pattern of adult fecundity,

by rearing aphids in the laboratory at each of

four constant temperatures (10°, 15°, 20°, 25°).

The development rate increased linearly with

temperature in this range, so that a given in-

star required a constant amount of ‘physio-

logical time’, measured in day-degrees above a

threshold temperature of 4°C (Campbell et al.

1974). Since this physiological time-scale is

the aphid’s own time-scale, we adopted it for

this study. The first three instars each took

about the same amount of physiological time,

which we adopted as the aphid’s basic time-

unit, one ‘instar-period’. The fourth instar

took longer; 1% instar-periods for wingless

aphids, and 1% for winged. To accommodate

these varying periods, we adopted one quarter-

instar-period, or ‘quip’ (q), as the unit of

physiological time. For the pea aphid at

Vancouver, one quip equals 6.56 day-degrees C

above the threshold temperature of 4°C.

Parthenogenetic wingless aphids mature

after 18 q, begin to reproduce at 19 q and can

survive to 90 q. The physiological time-scale

compensates for the effects of temperature,

not only on development, but also on re-

production. For reproduction, the compensa-

tion is not quite perfect, but on the physiologi-

cal time-scale, the time pattern of reproduction

was nearly the same for the four temperatures.

In other words, on this scale, both the total

fecundity and the reproductive pattern are

effectively independent of temperature.

Population Model

These development times and fecundities

allowed us to predict the rate of aphid increase,

assuming that all individuals survive to age

90 q. This we did by a simple simulation model

(Appendix 1). We first converted calendar

time in the field to physiological time, using a

computer program (Appendix 2) which fitted

sine curves to daily maximum and minimum

air temperatures, and integrated them above

the developmental temperature threshold

(Morris & Bennett 1967). Each day in the field

calendar was converted to its equivalent in

physiological time, beginning arbitrarily on

May 1, 1972.

There was a large discrepancy between the

aphid model (curve A, Fig. 1) and observed

aphid densities. The data indicated heavy

mortality while the coccinellids were present.

The age distributions (not shown) agreed.

From 0-22 q, the aphids increased in numbers

(fig. 1) at the rate predicted by the simulation

model. No beetles were seen until 20 q. During

20-40 q, there was an influx of beetles, and the

aphid population began to decline. The beetles

remained in large numbers during 40-70 q,

and the aphid population remained low. Most

of the beetles left the plot between 70-120 q,

whereupon the aphid population resumed its

exponential increase.

The beetles had some direct effect on the

aphids, as indicated by changes in the average

number of aphids per infested terminal. The

probability p that a sample unit of n terminals

contains no aphids is f™ where f is the frequency

of uninfested terminals. From the values of p ob-

served in the samples we estimate the corres-

ponding f and p!,, . The average number of

aphids per terminal is then divided by (1-f), to

estimate the average number of aphids per

infested terminal. During the period May 9-19

(9-22 q, Fig. 1), that number increased from 1.9

to 4.2, since the population consisted of adults

and their progeny, living on the same plants.

The frequency f of unoccupied terminals was

considerably greater than would be predicted by

a random, i.e. Poisson, distribution with the ob-

served mean number of aphids per terminal.

When the beetles arrived during 20-40 q, the

average number of aphids per infested terminal

fell to its minimum level of one, a probable result

of the activity of the beetles. When beetles

search plants, they catch only a small propor-

tion of the aphids and scatter the rest on the

plants. When the beetles left, the aphids became

aggregated again as the mean density increased.

At first the simulation model used the

simplest possible predation function. The

beetle’s voracity was measured by feeding

average-sized aphids to adult C. trifasciata in

the laboratory. It was recorded as a number of

aphids; later, we used biomass. If there are 6

beetles per terminal, and each eats k aphids per

q, the demand for aphids will be kb per q. If

there are a aphids per terminal, each aphid

must expect to be eaten kb/a times per q. If

the beetles search at random, the aphids will

escape predation with a frequency equal to the

zero term of the Poisson distribution, which in

this case equals exp (-kb/a), a crude expression

that worked well in previous cases (Hughes &

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 3d

Gilbert 1968, Gilbert & Gutierrez 1973). When

this survival rate, calculated in the model for

every q, was applied in the population model,

the aphid numbers rapidly decreased to zero

(curve B, Fig. 1). But the field counts of beetles

probably underestimated the true numbers,

since some beetles escape notice. We therefore

concluded that:

(1) The beetles were sufficient in timing and

numbers, to explain the early season re-

duction in the aphid population.

(2) The success of the beetles in finding aphids

at low density was considerably less than

that predicted by random search.

(3) No. conceivable mathematical function

which includes only the current average

numbers of predators and prey, can predict

the survival rate of the prey: aphid and

beetle numbers were much the same at 30 q

and 90 q, yet at 30 q aphid numbers de-

clined, and at 90 q they increased (Fig. 1).

The true predation rate must therefore be

affected by some other factor, which might

be some characteristic of the predator or

prey populations, e.g. age distribution or

aggregation (cf Hassell & May 1973), or

some environmental factor. We decided to

study the predation process in detail.

2. PREDATION IN THE LABORATORY

Holling (1966) has shown how to study the

actual process of predation with great realism.

Rather than invoke theoretical functions and

assumptions, Holling studied the detailed be-

haviour of the predators and prey, to determine

the important biological parameters which pre-

dict the ‘functional response’. But his approach

is too complex for application in the field. We

needed a simpler model of predation, at once

realistic but simple enough for field use. We

decided to study predation in an artificial

arena to identify those essential components

which must unavoidably be measured in the

field. To avoid duplication of symbols, we shall

freely mix algebraic and FORTRAN notations.

Methods

The tests were made in standard greenhouse

flats each containing 12 small alfalfa plants

arranged in a 3 x 4 grid. Each plant had a single

stem with many of its leaves removed, so that

the aphids could easily be seen. To make the

aphids visible when on the ground, the soil

was covered with white sand. The sand was kept

wet because the beetles made poor traction on

dry sand. The aphids and beetles were confined

by a transparent plastic cage 29 cm x 45 cm

and 21 cm high. To prevent the insects from

walking up the walls of the cage, its lower rim,

which rested on the sand at the edge of the flat,

was coated with Fluon (a brand of polytetra-

fluoroethylene dispersion supplied by Imperial

Chemical Industries Ltd.). All the coccinellid

species found in the field, except one, readily

flew off the plants and landed on the cage, so

nullifying the test. The exception was C.u.

undecimpunctata, which we adopted for the

laboratory work.

We re-defined ‘hunger’ as that weight of

aphids which a beetle will voluntarily eat until

satiated. We established the hunger curve

by feeding forty beetles until they refused to

eat aphids presented directly to them, then

starving them for various time periods at

24 + 1°C, and weighing them. Each was again

fed to repletion, and its increase in weight re-

corded. After 24 hours’ starvation, males of

C. u. undecimpunctata will eat a maximum of

2.0 mg. of aphid on average, and females about

3.0 mg. We therefore write HGR = 2.0xH for

males, and 3.0xH for females. The curve for

H (Fig. 2A) is of the type H = 1 - exp/(-kt)

(Holling 1966). Thus we shall use H for the

relative hunger, the same for both sexes, and

HGR for the absolute hunger.

The laboratory tests were done in a con-

trolled room at 24.0 + 1°. We placed aphids in

known numbers and instars on the 12 plants,

and left them to settle. Then we chose a beetle

of known sex, which had been starved for a

predetermined time at constant temperature,

so that its initial hunger HGR could be esti-

mated (Fig. 2A). Dixon (1959) has shown that a

coccinellid changes its search pattern when it

makes contact with an aphid, even if it does

not capture the aphid. Therefore, each time the

beetle climbed onto a plant, we recorded its

hunger HGR and the time TLC since the beetle

last contacted an aphid. At the start of each

test we allowed the beetle to make contact with

an aphid but not to capture it. Both HGR

and TLC were thus established at the start of

each test.

The beetle was placed on the sand inside the

cage, where it began to search the plants for

aphids. For every visit to a plant, we recorded

the following: plant height; the number of

trifoliate leaves; numbers and instars of the

aphids on the plant at the start of the visit;

numbers and instars of aphids which were

eaten, which fell from the plant but returned to

it, and which fell and left the plant for another;

whether or not the beetle made contact with

an aphid on the plant; and the lengths of time

which the beetle spent in searching the plant,

stationary on the plant, moving on the ground

after it had left the plant, and stationary on

the ground.

A beetle is stationary when it is eating,

cleaning its appendages or resting, usually

when it is not hungry. A beetle detects aphids

only when it contacts them with its maxillary

or labial palps. After contacting an aphid, the

beetle scours the locality very thoroughly,

making frequent turning movements. When a

beetle searches a plant, many of the aphids on

38 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DrEc. 31, 1976

@ MALE °

Oo FEMALE @

y=3(1-e 9 !4T)

Ls)

yo 2tiae 2147)

WEIGHT OF APHIDS EATEN (Mg)

8 12 16

HOURS OF STARVATION

@® MALE

Oo FEMALE

y= 3.8(1-e 9-08T)

fw ou >

WEIGHT OF APHIDS EATEN (Mg)

10 60 70

20 30 40 50

HOURS OF STARVATION

FIGURE 2A. Hunger, HGR, curves of Coccinella undecimpunctata at 24°C; B, C. trifasciata at 20°C.

Each point is a mean value from about 40 beetles. The physiology underlying the variability

in hunger has not been explored, but females tend to vary more in weight than males

because captive females may lay eggs, and may or may not eat them.

that plant fall off, and so avoid predation. The

aphids rarely left plants unless disturbed. We

tallied the aphids as they moved from plant to

plant, by means of counters which were moved

correspondingly from square to square of a

checkerboard. In this way, the current popula-

tion of any plant was known whenever a beetle

climbed onto it. A beetle can capture and eat

aphids of all sizes, and the average time taken

to consume an aphid is directly proportional

to the aphid’s weight (Fig. 3). But not all pea

aphids are equally at risk. The older and larger

aphids drop from plants much more readily

than the young ones, so that first and second

instar nymphs are those most vulnerable to

predation. Large aphids which have fallen off

a plant can find their way onto a new plant

much more readily than can small aphids. In

particular, a winged adult is largely immune

from predation, partly because it readily falls

off the plant, and partly because the beetle

usually seizes the aphid by its wings and so

400

fe}

°o

200

CONSUMPTION TIME (SECS)

0.2

0.4 0.6 08

APHID WEIGHT (Mg)

cannot eat it without first letting go, where-

upon the aphid usually escapes.

We made fifty such laboratory tests, each

lasting an hour or more. Altogether, 2,020

plant visits were recorded, with varying num-

bers and distributions of aphids. When two

beetles were placed in the cage together, they

searched independently.

Analysis

The next step is to determine, from the data

collected in the laboratory tests, the ‘com-

ponents’ of the predation process (Holling

1966). The measurements taken were very

variable, but regression analysis revealed the

following relationships, which were similar for

both sexes. The probability, PC (Table 1) that

a beetle would make contact with an aphid on

a given plant was proportional to the beetles’

hunger, HGR, and to the number of aphids on

the plant. That probability was never very

1.0 1.2 1.4

FIGURE 3. Times taken by adult C. undecimpunctata to eat various instars of aphid at 24°C. Each

point is a mean of between 9 (adult) and 70 (1st instar) aphids.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 39

TABLE 1. Variable Names and Their Meaning

AWT—weight (mg) of one aphid; which varies with instar (Table 2).

HGR—hunger (mg) of aphid (Fig. 2).

H—hunger, on a relative scale from 0 (replete) to 1 (fully hungry).

PC—probability that a beetle will make contact with an aphid.

PE—probability that a beetle will eat an aphid.

PL—probability that an aphid will leave a plant.

TLC—time (sec) since a beetle last contacted or ate an aphid.

TS—time (sec) spent searching a plant.

great. If no contact was made, the time, TS,

which the beetle spent on the plant, increased

with plant size and decreased with TLC, the

time since last contact. According to the re-

gression analyses, ‘plant size’ is best expressed

as the simple product of plant height and the

number of leaves. The probability, PL, that any

given aphid shall leave a plant increases with

TS. If contact was made, the probability, PE,

that the beetle ate any given aphid was propor-

tional to HGR. Since older aphids fell off and

escaped predation more easily than younger

ones, the probabilities PL and PE had to be

corrected by factors appropriate to the

different aphid instars (Table 2) present on the

plant.

When no aphids were eaten, TS increased

with plant size: when some were eaten, TS in-

creased with the total number of aphids on the

plant, and additional time elapsed while the

beetle ate its prey and cleaned its mouth parts.

Time spent in eating was proportinal to the bio-

mass of the aphid eaten (Fig. 3). Whether or

not any aphid was contacted, PL increased

with TS: but PL (with contact) exceeded PL

(no contact), because the beetle searched the

plant more thoroughly after it had made con-

tact. The beetle also spent time on the ground,

while moving between plants. If the beetle was

hungry (HGR was large) or if it had recently

contacted an aphid (TLC was small), it spent

a relatively short time on the ground.

These relationships were built into a simula-

tion model of the predation process. Since the

relationships are all linear, the model uses aver-

age values; for example, TS is actually very

variable, even allowing for plant size, etc., but

the model uses the average value appropriate

to the particular circumstances. Since the

model represents events in the laboratory only,

we shall not describe it in detail: but later we

shall present a similar, but simpler, model of

predation in the field (Appendix 3). The labora-

tory model was checked, and the values of PE

and TS were altered in order to reproduce the

timing and frequencies of eating and leaving

observed in all the various experimental con-

ditions.

We then analysed the laboratory model to

see which features could safely be omitted—

especially those difficult to measure in the field.

The most important conclusion was_ that

although contact certainly influenced the be-

haviour of individual beetles, its effect could

be absorbed into the values of PE and PL,

and so the whole mechanism of contact could

be omitted, provided the PE and PL were modi-

fied appropriately. This was fortunate, since it

would be almost impossible to observe TLC in

the field. However, the contact mechanism

might cause PE to increase with the number of

aphids on the plant. But an analysis of the

numbers of aphids eaten on plants with varying

initial numbers of aphids, showed no tendency

TABLE 2. Values of AWT, FACTE and FACTL

Average weights (mg) of aphids in the field (AWT) in 1973 and 1974. Aphids in the laboratory

were generally lighter (cf. Appendix 3). When a beetle visits a plant, each aphid on that plant is

eaten or leaves the plant, with relative frequencies FACTE and FACTL respectively. The fre-

quencies were estimated during the laboratory tests. They must be multiplied by appropriate

constants to give absolute frequencies PE or PL.

Aphid

Instar 1

Instar 2

Instar 3

Instar 4

Adult wingless

Adult winged

Mummy

AWT FACTE FACTL

0.17 1.68 0.64

0.33 1.28 0.68

0.91 0.75 1.05

1.88 0.52 1.13

3.82 0.46 1.29

2.15 0.36 lots IF

1.88 0.57 —

40 J. ENTOMOL. Soc. BrIT. COLUMBIA 73 (1976), DEc. 31, 1976

for PE to vary; except that once one aphid had

been eaten, other aphids on the same plant

were slightly more likely to be eaten. The effect

could be ignored, leaving hunger as the sole

driving mechanism.

3. PREDATION IN THE FIELD

This section converts the laboratory preda-

tion model to represent the same process in the

field, and uses it to predict the survival rate of

aphids in the field. As far as possible, we

measured all the model’s parameters again, by

watching and timing beetles in the field.

Timing

In the first series of field observations,

we watched beetles searching at a low aphid

density of about 0.2 per terminal. One observer

followed the beetle’s progress over the vegeta-

tion, while another timed and recorded each

visit to a new plant. In this way, we estimated

the average time, TS, which a beetle spends on

a plant when no aphid is eaten. The estimate of

TS, i.e. 51.3 sec (Appendix 3), is the average

of 504 plant visits.

It was not necessary to measure the sizes

of the alfalfa plants in the field. They were

generally larger than those in the laboratory,

with more leaves and branches. But the beetles

did not search the entire plant; instead, they

primarily searched the sunlit canopy of con-

tiguous leaves and stems, where most of the

aphids were. Most importantly, neighbouring

plants touch, and so both aphids and beetles

walked or flew freely from plant to plant. The

beetles spent no time on the ground while

searching for aphids, and the time spent on

any plant did not depend on that plant’s overall

size.

Probability of Capture

In another series of field observations, we

seeded lengths of row with high densities of

aphids, and watched the beetles search for

them. The average density of aphids on these

plants was determined afterwards by sampling.

That density, multiplied by the total number

of plants visited (286), gave the total number

of aphids at risk, 1746. Of those, 32 were

actually eaten, giving a frequency PE of

capture of 0.018. In the model, PE equals a

constant times the relative hunger H. This

constant is tentatively deduced as follows:

since the beetles flew in from other parts of the

field where aphids were scarce, we assumed

that the beetles were very hungry, with

H=0.88, corresponding to 15 h starvation as

set initially in the model (Appendix 3). The

constant must therefore be 0.018+0.88, so that

PE=0.0205 x H. This equation is re-examined

in Appendix 4. The value of PE is much lower

in the field than in the laboratory, because in

the field a beetle makes only a cursory search

of each plant, but searches many more plants in

a given time. The same series of field observa-

tions gave the average time spent on one plant

when aphids were eaten. In the laboratory

model, PE was a function of time searching,

which in turn was a function of plant size. In

the field model, PE is no longer affected by

plant size, and therefore the distinction

between time searching and not searching is

no longer required. Regression analysis of the

field data shows that the time spent on a plant

increases with the number of aphids eaten;

so in the model, it appears as a linear function

of the total weight of aphids eaten (Fig. 3).

Probability of prey movement

We could not directly measure PL, the prob-

ability of an aphid leaving a plant, because

it was impossible to see how many aphids

left during a visit by a beetle. However, PL

must depend on the beetles’ searching be-

haviour in much the same way as PE. There-

fore, to estimate PL in the field, we took the

frequency with which aphids fell off the plants

in the laboratory, and changed it in the same

proportion as the observed change in PE. The

resulting value of PL must clearly be suspect;

fortunately, analysis of the model showed that

within reasonable limits, the value of PL had

little effect on the predation rate. This does

not, of course, imply that the aphids’ be-

haviour in leaving the plant did not affect the

predation rate, for that behaviour affected PE

as well as PL. Having thus obtained overall

values for PE and PL, we used the same factors

(Table 2) as were observed in the laboratory,

to compute the probabilities for each aphid in-

star. This was unavoidable, since it was im-

possible to count all the aphids of each instar

on a plant in the field without disturbing them.

However, these corrections were reasonable,

because the relative frequencies depended

more on the behaviour of the aphids than of

the beetles. Most of the aphids captured by

beetles in the field, were the youngest, as in

the laboratory.

We now use these rules to develop the field

model for predation (Appendix 3). It is im-

possible to determine the sex of each beetle

encountered in the field without unduly distur-

bing it, and so the field model assumes a 1:1

sex ratio.

Effects of Temperature

The model describes events during one q at

18.5°C, the average temperature during the

field observations. But the times spent on each

plant are related to the speed at which beetles

move and thus to temperature. We placed

beetles of the three species on vertical poles

in the laboratory, and timed their walking

speeds at different temperatures. The result

(Fig. 4) shows that the beetles’ walking and

searching speed has about the same temper-

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 4]

ature threshold as the aphids’ rate of develop-

ment, and so we may use the same physiolo-

gical time-scale for both predators and prey.

The field predation model therefore describes

the predation process during one q at any

ambient temperature.

Temperature has an additional effect on

coccinellids. At low temperatures, many of

the field beetles are inactive (Fig. 7), even

though they are capable of motion (Fig. 4).

The physiological time-scale thus allows for the

effect of temperature on the beetles’ speed of

search when active, but not for the variable

amount of activity. Therefore, the number of

beetles actually present at any given time

must be multiplied by an activity coefficient,

to give the effective number of active beetles.

At first, we used the data in Fig. 7 to estimate

the activity/temperature relation, with a tem-

perature threshold of 8.7°C. But later we found

(§ 5) that the counts in Fig. 7 are still biassed.

The field cage experiments in § 5 demand that

the temperature threshold be reduced to 4°C,

the same value as for beetle movement. The

algorithm used to calculate the approximate

average temperature, for each q in the field,

appears in appendix 5. Despite several

attempts, we have not obtained a direct estim-

ate of the activity/temperature relation, which

is complicated by effects of sunshine and by

some kind of circadian rhythm. But the fact

that temperature has a double effect on the

beetles, and a single effect on the aphids, has

important consequences for the predator-prey

relationship (§ 6).

3.0

(A) C trifasciata

2.0

fo)

RATE OF TRAVEL (CM/SEC)

° fo)

10 15

TEMPERATURE (C°)

C. californica

Analysis

The aphid survival rates, predicted by the

field predation model, will now be applied to

the aphid population model. It would be

possible to build the predation simulation

model directly into the aphid population model,

by calculating the survival rate de novo when-

ever it is needed. To do so would take im-

practicable amounts of computer time. The

results of the predation model are best ex-

pressed as empirical functions which can be

used directly in the population model.

The predation rate must depend on beetle

density, and on aphid age-distribution, den-

sity and possibly aggregation. All these para-

meters must therefore appear in the empirical

function. The problem is not really so complex.

For the model shows that the overall survival

of a mixture of aphids of different ages is

about equal to the weighted average of the

predicted survival rates of the individual age

groups. For example, it shows that the survival

of 0.2 adult + 0.6 instar I aphids/plant (total

density = 0.8) is, very nearly, % of the survival

of 0.8 adults/plant + % the survival of 0.8

first instar/plant. Moreover, the survival rate

must. be squared when the beetle density is

doubled, since the beetles search independently

of each other. The model shows just that effect,

which incidentally proves that the model’s

time-step of one q is short enough, as far as the

beetles are concerned: that is, within one gq,

no beetle can destroy so many aphids that it

seriously reduces the number of prey available

y=-0.17 +0.043X

y=-0.25 +0.049x

20 25

FIGURE 4. Effect of temperature on coccinellid walking speeds. Each point is a mean of

about 40 observations.

42 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DrEc. 31, 1976

APHID DENSITY

4 6

0.954

{eo}

°o

APHID SURVIVAL RATE

o Oo

9 a

0.707

FIGURE 5. Survival rates per q, computed by Appendix 3, of second-instar aphids attacked by

C. trifasciata. Coccinellid density=1/60 plants. Curves A, B, C are fitted in Appendix 4.

to other beetles. These circumstances permit

us to analyse the predation model, using beetles

at a fixed density, and aphids of one instar

only. We used second instar aphids, and beetles

at the highest density observed in the field,

viz. 1 per 60 plants. We chose this case because

it gives high aphid mortality, and therefore

accurate estimates of survival rates. For each

aphid density, the model (Appendix 3) was

run many times, using different random num-

bers: the average survival rates predicted for

varying aphid densities are shown in Fig. 5.

They do not lie precisely on a smooth curve

because they are estimated by this ‘Monte

Carlo’ method, which estimates the survival

rate from a finite number of trials.

The effects of aphid distribution or aggre-

gation on predation rate are slight according to

the field predation model. At average densities

PREDATION RATE /HOUR

,o) ro) (

oO “

ro)

2 3

APHID DENSITY

of less than one per plant, the survival rate is

slightly lower when the aphids are highly

aggregated on few plants, than when well

spread out on isolated plants. That is because,

having found one aphid, a beetle easily finds

the others on the same plant. There is no such

effect at high aphid densities, when a beetle can

find enough aphids irrespective of their distri-

bution.

By contrast, the laboratory predation model

showed a great effect of aphid distribution

(Fig. 6): the predation rate might be three

times greater when the aphids were clumped,

than when they were well spread out. This was

an effect of timing, which persisted after the

contact mechanism was eliminated from the

model. It arose because, in the laboratory, the

beetles could not climb directly from one plant

onto another, and therefore spent a long time

FIGURE 6. Predation rates per beetle-hour at 24°C, computed by the laboratory predation model,

of second instar aphids when attacked by C. undecimpunctata. Coccinellid density = 1/100

plants. Different lines refer to different initial proportions of uninfested plants, as marked.

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), DEc. 31, 1976 43

on each plant. In the field, however, the beetles

moved directly from plant to plant, and thus

visited many more plants for each aphid

caught.

A predator-prey relationship might indeed

be stabilized by predators scattering their prey

(cf. Huffaker, Shea & Herman 1963), but not in

our alfalfa plot, where the predators ranged

freely and quickly over the area. We therefore

ignored the slight effect of aphid distribution

found in the field predation model, because it

was equivalent at most to a 5% increase in

beetle density, which is well within the ac-

curacy of our field counts.

The next task was to fit an empirical func-

tion for survival from predation. We already

knew how to deal with varying beetle densities

and mixtures of aphid instars, so we needed

only to fit a curve to the predicted points in

Fig. 5. This was done (Appendix 4) and the

resultant expression for the survival rate of

aphids of instar I is

s=exp (Saar = pee (1 - ex (-ka)) )

= AWT(I)~ a pat

where k=2.6 x AWT (I) x FACTE (I) x (0.654 +

0.026/a+0.075)). This expression for s gives

the fitted curve C in Fig. 5. By contrast, curve

A is the random search curve, discarded in§1.

During the period 1 - 121 q of 1972 (Fig. 1),

field densities of aphids were always less than

one per plant. At these densities, the survival

rate predicted by the model is very much higher

than the random rate (Fig. 5), for the following

reason: random search implies that the beetles

can find aphids immediately, whereas the model

imposes a time restriction. At low aphid den-

sities, there is far too little time within a single

q for a beetle to visit enough plants to find all

the aphids it needs. Little wonder that random

search in § 1 incorrectly predicted the demise of

the aphid population.

4. BEETLES AND APHIDS COMBINED

—FIRST ATTEMPT—

This section tries to reconcile the predicted

predation rate with the observed survival rate

of aphids in the field. By the time we had com-

pleted the field predation model, we had ob-

tained population records from a new season

which showed that the 1972 beetle counts were

inaccurate. We therefore shall not use the 1972

data further, but instead describe the field

methods used in 1973.

Sampling and field biology

Two plots of Alfa alfalfa were sampled

0.8 km apart on the grounds of the University of

British Columbia. Plot 1 was that sampled in

1972. Plot 2, sown in 1972, consisted of 26 rows’

each 15 m long and 1 m apart. When the alfalfa

was cut infrequently, the plants produced

numerous lateral branches which made our

sampling units of plant terminals ambiguous

and ill-defined. We therefore departed from

standard commercial practice in 1973 by cut-

ting more often, whenever the plants reached

about 1 m in height. All the rows were cut

simultaneously on plot 1, but even- and odd-

numbered rows of plot 2 were cut alternately,

so that half the rows always contained tall plan-

ts bearing aphids. We sampled the even and

odd rows of plot 2 separately, whereas plot 1

was sampled as a unit. Aphid samples were

taken by cutting individual plant terminals and

beating aphids off. The small-scale distribution

of aphids over the plants does not seriously af-

fect the predation rate in the field (§ 3). We

looked for consistent large-scale patchiness, by

taking samples from a regular grid pattern over

the whole alfalfa plot. There was none. The

number of terminals per sample varied between

40 and 400, according to the aphid density.

Aphid samples were taken from each plot at

least once a week, but 2-3 times a week during

warm periods, when aphids were developing

quickly.

The 1972 method of counting coccinellids

and parasite mummies gave reproducible

results; but we later found it to be inaccurate

because mummies are easily overlooked and

beetles are most easily seen when temperatures

are high. Instead, we randomly chose between

40 and 70 short (30 cm) lengths of row, and

searched them thoroughly for beetles. Beetle

numbers changed rapidly (Fig. 8), and so we

sampled almost daily during the main period of

attack. Each beetle was classified by species,

and according to whether it was moving or

stationary when first sighted (Fig. 7). The am-

bient temperature inside a Stevenson screen

placed on the ground in the plot was also recor-

ded. The same species of coccinellids were

found as in the previous year, but since C. john-

soni was observed freely mating in the field

with C. californica, we counted them as one

species. The dominant species was again C.

trifasciata, which was three to five times as

common as C. californica. The other species

were comparatively rare.

We counted mummies at least twice weekly

by the same method used for beetles. The mum-

mies were classified as unemerged, emerged or

preyed upon. The latter are easily recognized

because the edges of the irregular holes made

by coccinellids or the punctures made by

chrysopids and nabids are darkly stained; the

circular emergence holes of primary parasites

and the irregular emergence holes of hyper-

parasites are not stained. We took samples of

unemerged mummies from time to time and

reared them at constant temperature, to

estimate the sex-ratio of the parasites, their

age-distribution, and rates of hyper-

parasitization.

The numbers of plants per foot of row were

counted at various times through the season, to

44 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

0.8

y= -0.39 +0.045 xX

PROPORTION MOVING

12 16 20

TEMPERATURE (C°)

FIGURE 7. Effect of ambient temperature on proportion of C. trifasciata observed moving in

field counts. For absolute numbers, see Fig. 10.

reconcile the two methods of sampling, viz.

aphids/terminal, and beetles/length of row. We

made checks by enclosing all the plants in one-

foot lengths of row in plastic bags, cutting the

plants at the base, and counting all the aphids

and mummies found in the bags. Consistently,

the average number of mummies/ft. was about

twice that observed in the regular counts,

mainly because mummies on the underside of

the leaves or low on the plant, had been

overlooked. The regular counts therefore are

multiplied by the appropriate factor to correct

for this under-estimate. Equally consistently,

and irrespective of average plant height, total

numbers of aphids/ft. were only half those

predicted by multiplying the number of plan-

ts/ft. of row by the average number of

aphids/plant derived from aphid samples. This

is not unreasonable, since tall plants are much

more heavily infested than the short ones. We

therefore divided the counts of plants per foot

by the appropriate correction factor to give the

number of effective plants per foot.

Synthesis

Next we insert into the population model

the aphids’ rate of survival from predation,

calculated by the field predation model, and

using the new beetle density b. We make no

distinction between the different species of coc-

cinellids, but equate them all to C. trifasciata,

which was always in the majority.

On plot 2 (1973), a generation of parasites

matured during the period of coccinellid attack

(Fig. 8). The mortality due to parasitism must

therefore be inserted into the aphid population

model. The best estimate comes from the field

counts of mummies, and we therefore include in

the model an amount of parasitization which

reproduces the observed pattern of parasite

mummies, both in time and numbers. We used

the following method: the developmental

threshold for the parasite Aphidius ervi is 4.2°;

thus the two physiological time-scales are in

proportion throughout the period of beetle at-

tack. The length of time spent by a parasite in

the mummy can therefore be equated to a fixed

amount of the aphid’s physiological time,

namely 15 q.

It is the juvenile aphids between ages 4 q

and 17 q which bear the brunt of the parasite

attack (A. Campbell, pers. comm.). Laboratory

tests showed that parasitized aphids, collected

in the field in their fourth instar, can produce

up to 26 progeny before the parasite pupates

and kills the aphid. We therefore represent

parasitism in the following way: parasitized

aphids are not distinguished from unparasitized

aphids in the model until the time comes for the

parasite larvae to pupate. Then a proportion of

aphids in the appropriate age-range is con-

verted into parasite mummies. The correct

proportion of parasitized aphids will thus

produce their appropriate number of progeny

before they die. The proportion of aphids con-

verted into mummies, varies with time. The

proportions were chosen by trial-and-error, to

give the observed numbers and time-pattern of

mummies in the field.

The parasite mummies are themselves sub-

ject to coccinellid attack, and therefore form a

distinct class of prey in the predation model.

The model gives the observed proportion of

preyed-upon mummies, only when the

predation rate on mummies is reduced to one-

third the predation rate of first instar aphids

(Table 2). Unlike healthy aphids, parasitized

aphids often move to the upper surfaces of

leaves, where beetles rarely search. The mum-

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), DEc. 31, 1976 45

Wor

- 10

Zao

>a °

<I=m

sii 5.015

q =

waz CUT

= W005

1s eae eee MR Ieee

= 25

_ 2.0 ---B

a A

7 ,

oO 861.5

w”

a C

= ‘

= 40

<q ;

t o5 - RAIN CUT :

= > és 7

ev 130

5O 70 90 110

PHYSIOLOGICAL TIME (QUIPS)

i ee ae eT ae PN Se Le i en eee rape ha a naee

MAY JUNE JULY

FIGURE 8. Numbers of beetles and aphids in 1973, plot 2, even-numbered rows. The upper section

shows the weighted average temperature/q. TEMP, above the activity threshold 8.7°C. It is

computed by Appendix 5 and used in Appendix 6. The middle section shows the field counts,

COCC, of beetles/plant. The temporary increase in beetle numbers during gq 60-q 65 occurred when

the odd-numbered rows of alfalfa were cut, and the beetles moved to the uncut even-numbered

rows. The lower section shows the observed numbers of aphid/plant, together with three curves

computed by Appendix 6. The population model reproduces the effect of heavy rain at q 62 by

imposing the appropriate survival rate on the aphids; similarly when the alfalfa was cut at q 80.

These survival rates were found empirically by comparing aphid densities before and after the

event. Precisely the same survival rates were observed on plot 1 and on the odd-numbered rows of

plot 2.

46 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

mies therefore suffer an unexpectedly low rate

of predation.

Fig. 8 shows the population dynamics of

aphids and beetles on the even-numbered rows

of plot 2, during and immediately after the

period of beetle attack in May and June, 1978.

The physiological time-scale starts on March 1,

1973. The pattern of events was very similar on

the odd-numbered rows of plot 2, and on plot 1,

i.e., the coccinellids arrived when the aphids

were increasing in numbers, and the aphid

population then declined, the beetles left, and

the aphids again resumed their exponential in-

crease. The same thing had happened in 1972

(Fig. 1).

Aphid numbers never exceeded an average

of 0.7 per terminal during the period shown in

Fig. 8, and so no density-dependent com-

petition for food can be invoked. The

population model simply combines fecundity

rates for the aphids with the predicted survival

rates from coccinellid and parasite attack. To

explain the observed changes in aphid numbers

the model must predict rates of survival from

parasitization and predation, equal to those

which the aphids actually experienced in the

field. The predicted effects of parasitization and

predation are too low to prevent a steady in-

crease in simulated aphid numbers (curve B,

Fig. 8). If the number of beetles is arbitrarily

quadrupled, the model simulates the observed

aphid numbers well enough for the period 15-79

q during the beetle attack (curve C, Fig. 8). We

are out by a factor of four.

The curves in Fig. 8 were computed (Ap-

pendix 6) using the laboratory estimate of

aphid fecundity. Much later we found (§ 5) that

fecundity in the field is consistently only 30% of

the laboratory estimate. This largely explains

why curve C (Fig. 8) rises too fast during the

period 80-130 q, when few coccinellids were

seen. But it does not explain the discrepancy

during the period of beetle attack. Using the

true aphid fecundity, the observed number of

beetles must be doubled, if the population

model is to reproduce the field data. Fig. 9

~ ol

AVERAGE FECUNDITY PER QUIP

25 30

TEMPERATURE (C°)

shows the results of laboratory experiments to

test the effect of high temperatures on aphid

fecundity. There was no effect until the tem-

perature exceeded 27°C, which was the highest

temperature observed in the field. Thus the new

population model gives a better approximation

of the true mortality, than the ‘random search’

of § 1; but it now seems to underestimate the

beetles’ destructiveness.

5. BEETLES AND APHIDS COMBINED

—SECOND ATTEMPT—

This section reconciles the predicted

predation rate with the prey population

dynamics.

In 1974, we erected four cages on plot 1.

Each cage was 5 x 6 x 2 m high, and contained

three rows of alfalfa each 6 m long. The cages

were covered with translucent plastic and

screening, which together admitted light, fresh

air and rain. The temperatures recorded in the

cages were sometimes a few degrees higher,

during the day, than those in the field outside.

We used the cages to compare aphid population

dynamics in the presence and absence of known

numbers of coccinellids. These were irst-

generation beetles bred in the laboratory, par-

tly to eliminate parasitism, but mainly because

we could not rely on collecting enough beetles

from the field, early in the season. Figs. 11-13

show the results of three successive ex-

periments, made for different purposes and in

different conditions. The first was to determine

the number of ladybirds needed to make an ob-

vious reduction in aphid numbers, without

driving them down too low. It also examined

the possibility that the aphids might suffer

mortality, over and above the direct predation,

when beetles drive them off the plant; for

example, when the youngest aphids fall off a

plant in the laboratory, they have difficulty in

finding a new plant. This explains why they fall

off so much less readily than the older aphids

(Table 2), even though they suffer a greater

rate of predation in consequence. The weather

during this first experiment was cool and wet.

FIGURE 9. Effect of temperature on fecundity of aphids collected in the field andkept at constant

temperature in the laboratory. Each point is a mean of about 20 adult aphids.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 47

The second experiment, in warmer weather,

was done in duplicate to see how much

variation might occur between replicates. The

third experiment, during a period of cloudy,

warm weather, was started at variable aphid

densities, partly to check for density-dependent

restrictions on the rate of aphid increase, and

partly to compare the predation rate at dif-

ferent prey densities. Each experiment ran until

the alfalfa plants were too large for accurate

sampling (§ 4), or until an incipient fungal

epidemic threatened the aphids. After each ex-

periment, the surviving coccinellids were

removed and counted, the cages were sprayed

with a short-lived insecticide, and the alfalfa

was cut and allowed to grow for two weeks

1.0

0.87 NOT MOVING

SS)

MOVING

COCCINELLIDS PER FOOT - ROW

0.2

12 14 16 18

TEMPERATURE (C°)

before the next experiment began.

Standard counts, as described in § 4, never

revealed more than 25% of the true beetle num-

bers, even at high temperatures up to 28° and

at low aphid densities. The ladybirds spent

most of their time in the stubble at the base of

the alfalfa. This observation itself can explain

the remaining discrepancy: the beetle counts in

the field (Fig 8) almost certainly un-

derestimated the actual numbers present. The

number of moving beetles (Fig. 10) increased

steadily with temperature, but there was no

corresponding decrease in the observed number

of stationary beetles, which might be sa

if all beetles had been visible.

20 22

FIGURE 10. Effect of ambient temperature on numbers of C. trifasciata observed moving (10B),

and not moving (10A), in field counts (cf. Fig. 7). Each point is the mean of counts from about

60 row-feet.

Analysis of cage experiments

Details of the individual experiments appear

in the legends to Figs. 11-13. Each figure shows

the means of successive aphid samples,

together with the simulation curves generated

by the computer. All broken curves refer to

control cages without beetles. These curves all

show the same rate of aphid increase, or, in

other words different sections of the same

curve of exponential population increase. They

are not exponential at the start of the ex-

periment, because of the initial, non-

equilibrium, age-distributions. The relative rate

of increase is the same at all aphid densities,

but it is far less than would be expected from

the aphids’ fecundity, estimated in the

laboratory. In fact, the broken curves are

generated by imposing a 70% reduction in

fecundity. We do not know the cause of this

discrepancy, which has occurred consistently

throughout the whole study, and in later work.

Probably it means that fecundity in the field

(which cannot be measured directly) is only

30% of that in ideal laboratory conditions. The

discrepancy might alternatively be due to

predation, at a constant rate of 70% throughout

the season, acting on newly-born aphids only

(to give the right age-distributions). In the con-

trol cages, we had to impose extra mortality of

1.3%/q on aphids of all ages. This ‘background’

mortality is ascribed to the numerous hunting

spiders Erigone metlakatla Crosby & Bishop,

observed in the cages. There was also a certain

amount of parasitization, which we estimated

48 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

from counts of mummies (§ 4), and which in-

creased from 0.3%/q in the first experiment to

1.0% in the third.

The ‘disturbed’ curve in Fig. 11 refers to a

cage which contained no coccinellids, but in

which the alfalfa was disturbed by hand four

times/q, causing some aphids to fall off the

plants, as they do when approached by a

ladybird. If such aphids do not climb back onto

a new plant, the rate of population increase will

be reduced. There evidently is some reduction,

but not much. The disturbance caused by a

beetle is much less than that which we made by

hand.

The unbroken curves in Figs. 11-13 were

generated by imposing the additional mortality

attributed to beetle attack. They assume that

the predation occurs independently of the

background mortality, i.e. that the overall sur-

vival rate is the product of the two separate

survival rates. This is a very reasonable assum-

ption, because each coccinellid searches in-

dependently of other predators and parasites.

The ladybirds also suffered mortality,

mostly from predation by a _ web-spinning

spider, Enoplognatha ovata (Clerck). We could

not spray to control the spiders, for fear of

provoking an outbreak of mites. Therefore,

although we introduced known numbers of male

and female beetles during each experiment, we

do not know the exact numbers alive at any

given time. After the end of each experiment,

we collected ladybirds from the cages until few,

if any, remained. We then computed the sur-

vival rate needed to reduce the initial numbers

of beetles introduced to the final numbers

recovered. The mortality proved to be rather

more than 2%/q in all three experiments. The

numbers of beetles shown in Figs. 11-13,

although accurate at start and finish, thus

depend on the assumption of constant survival

rates. Our subsequent conclusions are not

seriously affected by reasonable deviations

from that assumption. At the end of each ex-

periment we took bag samples (§ 4) to convert

the numbers of beetles and mummies to a per-

terminal basis.

Figs. 11-13 cover a _ range of field

temperatures and aphid densities. We used

more than twice as many beetles per cage in

cool (Fig. 11), as in warm conditions (Fig. 13).

If our understanding of coccinellid predation is

reasonably complete, we should be able to ap-

ply a single formula (with appropriate tem-

peratures, beetle numbers and initial aphid den-

sities) to all three experiments. It is possible to

do so. Every curve in Figs. 11-13 is computed

by the same program; and all the parameters in

that program, except three, have been

estimated from other sources. Two parameters,

viz. aphid fecundity and background mortality,

were dictated by the aphid numbers observed

in the control cages. The third parameter is the

coefficient which specifies how beetle activity

increases with temperature (§ 3). The curves

require that beetle activity be, on average,

0.018 times the temperature above 4°C. This is

merely an overall parameter chosen to reconcile

the unbroken curves with the observations. The

computer program, not listed here, is very

similar to Appendix 6. We think that the

agreement is good, bearing in mind the dif-

ferences between replicates in Fig. 12. It could

easily be improved by minor adjustments. The

only serious discrepancy is in Fig. 11, where the

computer predicts that increased temperatures,

towards the end of the experiment, should have

prevented the final increase in aphid density. In

fact the weather remained continuously cloudy,

which may have depressed beetle activity; we

certainly need further information about the ef-

fect of weather on beetle activity. Otherwise,

the agreement between observation and predic-

tion is acceptable, and so we have a single for-

mula, given in § 3 and used in Appendix 6,

which satisfactorily predicts the predation rate

over a wide range of temperatures and prey

densities.

DISCUSSION

It does not follow that the components of

the formula necessarily reproduce the biological

details correctly. For example, we have ignored

the fact that the hunger curve, used in the field

predation model of § 3, refers to C. un-

decimpunctata (Fig. 2A), not to C. trifasciata.

The hunger curve for C. trifasciata (Fig. 2B)

was estimated at the end of the investigation,

using beetles taken from the field cages. The

observations in Fig. 2B were taken at 20°C. The

curves in Fig. 2B predict a maximal con-

sumption/q of 5.5 mg/beetle, as compared with

the 5.7 mg for C. undecimpunctata, used in § 3.

Thus the two species agree very closely in this

respect, and there is no need to change the for-

mula of § 3. But P.M. Ives informs us that

female C. trifasciata, kept in the laboratory and

fed ad libitum, ate only 4.4 mg per q on

average. The reason is undoubtedly that given

in § 3, that the initial hunger level of 0.88, used

in our calculations, is too high for a well-fed

beetle. There is therefore some residual ignoran-

ce about the voracity of coccinellids in the field,

but it is unimportant here: for the computer

program generates the same unbroken curves

in Figs. 11-18, whatever the maximal con-

sumption (within reasonable limits), provided

that the temperature coefficient for beetle ac-

tivity is altered accordingly. Thus the residual

errors in beetle activity cancel the remaining

errors in beetle voracity, to give identical

predictions of the predation rate.

Whatever the true average level of coc-

cinellid activity may be, it is certainly very low.

Watching the predation process in the

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 49

ee IS

okr

a <

ao &wio

w W>

iu< 5

800

600

BEETLES

PER CAGE

ve)

re)

24 A BEETLES /

O CONTROL - UNDISTURBED UNDISTURBED re

ae O CONTROL- DISTURBED i

MEAN APHIDS PER TERMINAL

20 30

PHYSIOLOGICAL TIME (QUIPS)

FIGURE 11. First cage experiment. In the lower section the points represent observed sample

means but the curves were computed. Each sample in Figs. 11-13 contained about 27 plants,

except at the start and end of each experiment, when each sample contained about 36 plants. The

curves are largely independent of the observations—see text. The ‘undisturbed’ curve shows the

exponential increase in the absence of ladybird predation. The ‘disturbed’ curve is computed on

the assumption that mechanical disturbance of the plants, causing some aphids to fall off, causes

no mortality. The solid line curve predicts the effect of predation by the numbers of beetles shown

in the middle section, at the weighted average temperatures shown in the upper section. Compared

with Figs. 12 and 13, temperatures were low and the number of beetles needed to show any

obvious effect was consequently large. There was a fourth cage containing half the number of

beetles shown here, which gave results intermediate between the ‘undisturbed’ and unbroken

curves. To avoid confusion, those results are not shown.

50 20 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

ac ©

Or 15

wu >

atmo

= x

300

<I 200

wit

Mn 100

4 BEETLES - CAGE | /

A BEETLES — CAGE 2 x /

® CONTROL - CAGE 3 ; eg

MEAN APHIDS PER TERMINAL

10 20 30 40

PHYSIOLOGICAL TIME (QUIPS)

FIGURE 12. Second cage experiment. There were two replicate cages containing coccinellids, and

two controls. Only one curve has been computed for each pair of cages. The differences between

cages 1 and 2, and between 3 and 4, measure the variation experienced between replicates. These

differences must be borne in mind during any examination of Figs. 11-13. Beetle numbers were

the same at the start, but declined more in cage 1 than in cage 2, which partly explains the

difference in aphid numbers. The number of beetles shown in the middle section is the

average for the two cages.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 51

Ww 20

wo?

aav

ar 15

wa>

<=9

Ll <x

250

wm Wl

3S 150

uw) &

a0 a

6 4 BEETLES - CAGE | of

4S BEETLES - CAGE 2 y ‘

® CONTROL — CAGE 3 /

F © CONTROL —- CAGE 4 /

MEAN APHIDS PER TERMINAL

10 20 30

PHYSIOLOGICAL TIME (QUIPS)

FIGURE 13. Third cage experiment. Different cages were deliberately started at different aphid

densities, to examine the effects of aphid density on predation rate and rate of aphid increase.

The curves predicted for cages 2 and 3 disagree with the data, but only within the limits of varia-

tion revealed in Fig. 12 (see text). The curve for cage 2 remains level from q 11 to q 25, but then

begins to rise as temperatures and beetle numbers decline. This illustrates the principle that no

equilibrium between aphid and coccinellid numbers can be permanent. Figs. 11-13 have different

scales for aphid density. The number of beetles shown in the middle section is the average for the

two cages: More survived in cage 1 than in cage 2, and the curves are computed accordingly.

52 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

laboratory, we saw a hungry predator

anxiously scouring its universe for prey. Wat-

ching a population of beetles in a field cage in

conditions almost identical with those of the

open field, we saw the ladybirds spending a

good three-quarters of their time motionless in

the stubble. In the laboratory, there was

nowhere to hide. The contrast between

laboratory and field could not be greater.

The cage experiments give some _in-

formation about possible interactions between

predation and parasitization rates. If

parasitized aphids suffer a higher predation

rate than unparasitized, there will accordingly

be a relative shortage of parasite mummies in

the cages containing beetles. No large or con-

sistent difference was seen: such heterogeneity

as did occur was restricted to the first ex-

periment, where the parasitization was begun

by emerging overwintered adults.

The new formula for predation rate still does

not resolve the discrepancy between observa-

tion and prediction in Fig. 8. In fact, it makes it

worse, because beetle activity is less than we

previously supposed (§ 4). We now need four

times as many beetles as were actually observ-

ed, to produce the decline in aphid numbers

shown in Fig. 8, 35-79 q. We can readily believe

that, as in the field cages, there were four times

as many beetles present as appeared in the

samples. Although we have a good estimate of

the predation rate, we still have no sure way of

sampling beetle numbers in the field. Stan-

dard methods using sweep nets, walking

counts, or suction machines, are hopelessly

inaccurate. Our intensive counts find only a

fraction of the numbers actually present, and

that fraction must vary with aphid density,

temperature, and probably the time of day.

The adult coccinellid, at first sight so conspicu-

ous an animal, is in fact very cryptic.

6. CONCLUSIONS

Laboratory v. field studies

The coccinellid-aphid relationship, observed

in the field, differs from that in the laboratory

in three major respects. The distribution of

prey affects the predation rate in the labora-

tory but not in the field (§ 3). Predators observ-

ed in the laboratory were more active than

those in the field (§ 5). Temperature has an

overriding effect in both laboratory and field —

a fact which would not be noticed at constant

temperature in the laboratory. Moreover, it

has a differential effect on predation rate, and

on population dynamics of the prey. This

means that predation and population studies

on insects must include temperature as an

essential component, and that studies of preda-

tion alone, unlinked to population dynamics

can be meretricious. It also means that labora-

tory studies alone are unreliable, because some

vital aspect of the true, i.e. the field relation-

ship may be completely overlooked in the

laboratory.

Holling (1966) pioneered the detailed behav-

ioural and physiological approach to the study

of predation and discussed the advantages of

his approach, over more superficial methods

(Holling 1964). Holling’s work was so detailed

that it could be done only in the laboratory:

but the method can be simplified and applied in

the field, to predict predation rates which can

be reconciled with the population dynamics of

the prey. Thus Holling’s approach, offering

precise predictions over a wide range of contin-

gencies, may be combined with the broader

realism of quantitative field studies, as first

attempted by Morris (1963). Two major con-

clusions are therefore that (1) laboratory

studies of ecological relationships must not

be trusted until verified in the field, and (2)

it is in fact possible to make detailed predator-

prey studies in the field, to explain the obser-

ved impact of predation on the prey population.

Stability

The coccinellid-pea aphid _ relationship

sharply contradicts existing theories on insect

predators and prey, and of ecological stability.

It permits no steady-state, or equilibrium, be-

tween predators and prey. It is true that, for

any given aphid density and temperature, there

is some number of coccinellids which could keep

aphid numbers constant, once the aphid age-

distribution had settled to a steady-state: but

the ladybirds rarely approach the necessary

predator prey ratio, even at high temperatures.

Moreover, the relationship would be unstable.

Curve C (Fig. 5) shows a monotonic increase

of survival rate with aphid density, so that

any chance increase in aphid numbers will allow

the aphids to gain, and the beetles could not

thereafter restore the balance. Conversely,

the slightest decrease in aphid numbers would

allow the beetles to drive the aphids towards

extinction. Moreover, the required number of

beetles depends critically on temperature, so

that even a slight change in temperature would

upset the equilibrium. There is nothing in the

coccinellid-aphid functional relationship to

prevent either a continual increase in aphid

numbers, or a continual decline towards extinc-

tion. We have twice observed such a decline in

the field (Figs. 1 and 8), which was arrested

because the predator left the field when the

prey density became very low. The con-

ventional definition of stability (Hassell & May

1973), as a tendency to return towards some

steady-state or equilibrium (which need never

be actually reached), does not apply here, where

the relationship is completely unstable, but

extremely resilient (Holling 1973). The

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 De

functional response is unstable, and the rela-

tionship is stabilized only by the predator’s

numerical response.

Some technical considerations

To assess the impact of predators on their

prey populations, we must compare the num-

bers of prey actually observed, with the num-

bers that would be observed, in identical field

conditions, but in the absence of the predators.

This is very difficult to do, especially if the

comparison is to cover all conditions normally

encountered in the field. The method used here,

of dissecting the predation process and tying

it into the population dynamics of the prey,

is perhaps the only fully reliable method used

so far. The chief technical difficulty in the

field was not to observe the process of preda-

tion but to estimate the density of predators,

for which we still have no satisfactory method.

Several theories of predation embody the

concept of a predator’s, or parasite’s, area of

search. Our predator is limited at low prey

densities, not by its capacity for prey, but by

the time available to search for them. This is

equivalent to a limited area of search, since the

predator cannot search the whole area within

the time available. We believe it is better to

think in terms of timing, rather than of area of

search, partly because it emphasizes the

dynamic nature of the predator-prey relation-

ship, and partly because the aphids play hide-

and-seek with the beetles. Even if a ladybird

could search the whole area, it still would not

find all the aphids.

This study offers cold comfort for biological

control workers. Since the coccinellid-aphid

relationship is unstable and incapable of a

steady-state, we cannot expect the coccinellids

to keep aphid numbers low for any length of

time. Usually the beetles merely slow the in-

crease in aphid numbers. At high temperatures,

the beetles can certainly depress aphid numbers

(Figs. 1 and 8); but we have seen this happen

only during unusually warm periods early in

the season; and even then, the beetles quickly

left the field in search of other prey. The

coccinellids’ double temperature requirement,

and their mobility, make them _ ineffective

predators, in that they rarely restrict the

density of their prey. To use ladybirds as

effective and permanent agents for biological

control, we must direct their natural behaviour

to a quite unnatural end.

7. ACKNOWLEDGEMENTS

We are deeply indebted to Mrs. Anthea

Bryan and Mr. David Raworth for their very

skilled and painstaking work. We thank Mr.

Rick Chorney, Mrs. Catherine Fockler, Mr.

Murray Isman, Miss Katherine White, Miss

Shiona Whyte, and Mr. Donald Wood for their

help: Dr. A. P. Gutierrez and Dr. C.S. Holling

for technical advice: Dr. Holling and Dr. H. R.

MacCarthy for carefully reviewing the manu-

script: Mr. J. H. Severson for drawing the

Figures: and Mr. Don Pearce and his staff for

agricultural operations. The National Research

Council of Canada paid part of the bill with

Operating and Development Grants. The

spiders were identified by Dr. C. D. Dondale.

References

Campbell, A., Frazer, B. D., Gilbert, N., Gutierrez, A. P. and M. Mackauer. 1974. Temperature

requirements of some aphids and their parasites. J. Appl. Ecol. 11, 431-438.

DeBach, P. 1974. Biological control by natural enemies. Cambridge University Press, Cambridge.

Dixon, A. F. G. 1959. An experimental study of the searching behaviour of the predatory

coccinellid beetle Adalia bipunctata (L.) J. Anim. Ecol. 28, 259-281.

Frazer, B. D. and R. van den Bosch. 1973. Biological control of the walnut aphid in California:

The interrelationship of the aphid and its parasite. Environ Ent. 2,561-568.

Gilbert, N. and A. P. Gutierrez. 1973. A plant-aphid-parasite relationship. J. Anim. Ecol. 42,

323-340.

Gilbert, N. and R. D. Hughes. 1971. A model of an aphid population—three adventures. J. Anim.

Ecol. 40, 525-534.

Gutierrez, A. P., Morgan, D. J. and D. E. Havenstein. 1971. The ecology of Aphis craccivora Koch

and subterranean clover stunt virus. I. the phenology of aphid populations and the epi-

demiology of virus in pastures in south-east Australia. J. Appl. Ecol. 8, 699-721.

Gutierrez, A. P., Havenstein, D. E., Nix, H. A. and P. A. Moore. 1974a. The ecology of Aphis

craccivora Koch and subterranean clover stunt virus II. A model of cowpea aphid popu-

lations in temperate pastures. J. Appl. Ecol. 11, 1-20.

Gutierrez, A. P., Havenstein, D. E., Nix, H. A. and P. A. Moore. 1974b. The ecology of Aphis

craccivora Koch and subterranean clover stunt virus III. A regional perspective of the

phenology and migration of the cowpea aphid. J. Appl. Ecol. 11, 21-35.

54 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

Hassell, M.P. 1969. A population model for the interaction between Cyzenis albicans (Fall.)

(Tachinidae) and Operophtera brumata (1.) (Geometridae) at Wytham, Berkshire. J. Anim.

Ecol. 38, 567-576.

Hassell, M. P. and R.M. May. 1973. Stability in insect host-parasite models. J. Anim. Ecol. 42,

693-726.

Holling, C. S. 1964. The analysis of complex population processes. Can. Ent. 96., 335-347.

Holling, C. S. 1966. The functional response of invertebrate predators to prey density. Mem. ent.

Soc. Can. No. 48.

Holling, C. S.'1973. Resilience and stability of ecological systems. Ann. rev. Ecol. & systematics 4,

1-23:

Huffaker, C. B., Shea, K. P. and S. G. Herman. 1963. Experimental studies on predation: complex

dispersion and levels of food in a acarine predator-prey interaction. Hilgardia 34, 305-330.

Hughes, R. D. 1963. Population dynamics of the cabbage aphid Brevicoryne brassicae (L.)

J. Anim. Ecol. 32, 393-424.

Hughes, R. D. and N. Gilbert. 1968. A model of an aphid population—a general statement.

J. Anim. Ecol. 37, 553-563.

Morris, R. R. et al. 1963. The dynamics of epidemic spruce budworm populations. Mem. ent. Soc.

Can. No. 31.

Morris, R. F. and C. W. Bennett. 1967. Seasonal population trends and extensive census methods

for Hyphantria cunea. Can. Ent. 99, 9-17.

Wratten,S.D. 1973. The effectiveness of the coccinellid beetle, Adalia bipunctata (L.), as a preda-

tor of the lime aphid, Eucallipterus tiliae L. J. Anim. Ecol. 42, 785-802.

Appendices 1, 3, 5 and 6 will be sent upon

request to either author.

Appendix 2

Algorithm to compute physiological time in

the field

This method was devised by Morris &

Bennett (1967), but the algorithm has not been

published. Successive daily maximum and mini-

mum field temperatures are stored in an array

X. The algorithm fits a sine curve between two

successive values of X, and integrates it above

the threshold temperature thresh. It there-

fore calculates two increments (from min to

max and from max to min) for each calendar

day. Each increment, B, is calculated in day-

degree units if the original temperatures

are Fahrenheit, B will be in a day-°F., and

similarly for Celsius. The algorithm is applied

to successive pairs of values X(I), X(I+1),

where I =1, 2,3...

IF(X(1I).LE.X(I+1))GO TO 2

XMAX=X(I)

XMIN=X(I+1)

GO TO 4

2 XMAX=X(I+1)

XMIN=X(I)

4 Y=XMAX+XMIN-2.* THRESH

IF(XMIN.LT.THRESH)GO TO 6

B=.25*Y

GO TO 10

6 IF(XMAX.GT.THRESH)GO TO 8

B=0.

GO TO 10

8 T=ARCSIN(Y/(XMIN-XMAX))

B=.125*Y*(1.-.63661977*T)+

.079577472/(XMAX-XMIN)*COS(T)

10 CONTINUE

Appendix 4

Derivation of the expression for

survival rate

The problem is to fit a curve to the data

points in Fig. 5. At high aphid densities, when

the beetles have no trouble in finding aphids,

the survival rate s must approach the ‘random

search’ survival rate exp (-kb/a), for the

appropriate value of k, which is deduced as

follows: In the model, each beetle starts with

hunger H=0.88, corresponding to a starvation

time of 15 hours. If such a beetle were suddenly

presented with all the aphids it needed, it would

eat an average of 5.7 mg. of aphids in the first

q. This quantity is deduced from the hunger

curve when an average beetle eats its fill, and

thereafter eats a whole aphid whenever it be-

comes hungry enough to do so. Therefore,

the beetle will eat 5.7/AWT aphids, each of

weight AWT (Table 1), so that the appropriate

value of & is 5.7/AWT. Curve A (Fig. 5) is the

random search survival s =exp(-5.7b/(AWT-

xa)), or for mathematical convenience

-log s=5.7 b/(AWT x a)

This defines the required curve at the top end

of the scale in Fig. 5. We shall now derive a

theoretical value for -log s at the other end of

the scale, when aphid density is very low. In the

model, a beetle takes 51.3 seconds to visit one

plant, provided that no aphid is found and

eaten. At 18.5°C, 1 q lasts 40,000 seconds, in

which time each beetle can visit 780 plants.

Since there are 6 beetles per plant, each plant

will receive an average of m=780 b visits/q.

Any given plant will actually be visited r times,

where r follows the Poisson distribution with

mean, i.e. the probability of exactly r visits

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 55

is e’"mT/r!. We shall suppose that the aphid

density is almost zero, so that most plants

carry no aphids, but a few plants have a single

aphid. In such circumstances, the beetles will

be completely hungry (H=1). The probability

of an aphid being eaten, when a beetle visits

its plant, is PE, estimated from field observa-

tion to be 0.0205, which is the value of PE

used in the field predation model of Appendix

3 to compute the data points of Fig. 5. The

probability that one aphid survives one visit

by the beetle is therefore (1-0.0205), and so

the probability that it survives r successive

visits is (1-0.0205)". The average survival rate

s will therefore be the average value of this

expression ffor _ all

¥(1-0.0205)"e"™m"/r!, which reduces’ to

s=exp (-0.0205 m). Since m=780 b, it follows

that, at near-zero aphid density,

-log s =0.0205 x 780 b. (2)

The required survival curve must therefore

agree with expression (1) at high aphid densi-

ties, and with (2) when the aphid density a

approaches zero. There are many such curves,

but an obvious one (mathematically speaking)

to try is:

-log s = 5.7b [1 - exp (-ka)]/(AWT xa) (8).

This expression approaches (1) for large values

of a, and it also satisfies the requirement stated

in §3, that if the beetle density 6 is doubled,

the survival rate s is squared. Expression (3)

agrees with (2) as a tends to zero if the appro-

priate value, namely

0.0205 x 780 x AWT / 5.7 (4).

is chosen for the parameter k. When the value

1.0

0.9

values of jy, i.e.

of AWT for second-instar aphids is substituted

in (3), we get curve B of Fig. 5.

It is obvious from Fig. 5 that curve B still

does not fit the data points very well. Although

there are many other curves which satisfy

the requirements of (1) and (2), it is unlikely

that any equally simple formula will give a

better fit than curve B. Rather than try one

formula after another, it is better to tailor (3)

to fit the data points. In expression (3), the

term (-5.75/AWT x a) represents the random

search of expression (1), while the term

[1-exp(-ka)] reflects the fact that, at low aphid

densities, the beetle has insufficient time to

catch all the aphids it wants. Indeed, when ex-

pression (4) is substituted for k, the value of

ka turns out to be the number of aphids which a

beetle can expect to catch in a given time, divi-

ded by the number of aphids required to

keep the beetle satiated during that time.

Mathematically speaking, we could alter the

terms for either random search or insufficient

time; but since curve B gives a poor fit

only at small aphid densities, it makes better

biological sense to modify [1 - exp(ka)]. The

value of k is evidently not constant, but must

vary with the aphid density a. Its value ko,

when a=O, must still be given by (4). From

each survival rate computed by the predation

model (Fig. 5), we deduce the appropriate value

of k in (3). Fig. 14 shows the values of k/ko

for varying aphid densities. When a ‘greater

than’ 4, the value of k/ko is of no concern be-

cause the insufficient time factor (1 -exp/-ka))

then has little effect on the survival rate.

us K/K,= 0.654 + 0.026/(a+ 0.075)

APHID DENSITY

FIGURE 14. Values of k/ko deduced from Fig. 5 and the curvilinear regression, weighted according

to the accuracy of each point.

56 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

In Fig. 14, a rectangular hyperbola has been

fitted to the values of k/ko by non-linear re-

gression, weighted according to the accuracy

of each point, giving the formula k/ko=0.654

+0.026/(a+0.75). This formula contains two in-

dependent empirical parameters, because

k/ko must equal unity when a=O. We call

k/ko the ‘hunger correction’, for the following

reason: the curve for k/ko remains unchanged

when we alter PE, PL, TS, or the instar of the

aphids concerned. Such changes (with the ex-

ception of PL) will, of course, alter the sur-

vival rate s directly from the formula for ko.

However, an acceleration of the _ beetle’s

digestion (i.e. of the rate at which its hunger

H increases with time) does increase the value

of k/ko somewhat, whenever the aphid density,

a, exceeds one per plant, but has little effect

at lower densities, when the beetle is con-

tinuously very hungry. For example, accord-

ing to the predation model, the beetle’s average

relative hunger H is 0.64 at aphid density

a=1, but 0.91 at a=0.1. It appears, then, that

the shape of the k/ko curve in Fig. 14 is largely

due to the fact that, the fewer aphids there are,

the hungrier the beetle remains, and the more

anxiously it searches. It must be remembered

that changes in hunger level affect not only

k/ko, but the random search term as well.

We thus end up with expression (3), but

with

k=0.0205 X780 x AWT [0.654 + 0.026/(a +0.075) |

/5.7 (5).

We then get curve C in Fig. 5, which fits the

computed data points well. Finally we must

reconsider the value of PE, since it varies

according to the aphid instar. In face, PE

equals some _ constant times FACTE

(Table 2). We recorded the instar of every aphid

which we saw captured in the field, and the

average value of FACTE for those aphids

is 1.07. To reproduce the _ estimated

overall value of PE (0.0205), we _ write

PE=0.019 x FACTE, since 0.019 x 1.07=0.0205.

The figure 0.0205 in (5) must therefore be re-

placed by 0.019 x FACTE, and we then have the

formula for survival rate used in Appendix 5.

This means, incidentally, that the estimated

overall value 0.0205 should not be used in

Appendix 3, since FACTE=1.28 for second-

instar aphids (Table 2), giving a corresponding

PE=0.019 x 1.28=0.024. This error does not

affect the analysis in this Appendix, since the

k/ko curve is unaffected by changes in PE.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

THE APHIDS (HOMOPTERA: APHIDIDAE)

OF BRITISH COLUMBIA

4. FURTHER ADDITIONS AND CORRECTIONS!

A. R. FORBES AND CHO-KAI CHAN

Research Station, Agriculture Canada

Vancouver, British Columbia

ABSTRACT

Twenty-five species of aphids are added to the taxonomic list of the

aphids of British Columbia. New host records, a few corrections, and

some name changes are also included.

INTRODUCTION

Two previous lists of the aphids of British

Columbia recorded 261 species collected from

294 hosts or in traps (Forbes, Frazer, and

MacCarthy 1973; Forbes, Frazer and Chan

1974).

The present list adds 25 species of aphids

(indicated with an asterisk in the list) and 213

aphid-host plant associations to the previous

lists. One hundred and twenty-nine of the new

aphid-host plant associations are _ plant

species not in the previous lists. The additions

bring the number of known aphid species in

British Columbia to 286. Aphids have now been

collected from 423 different host plants.

The present paper includes a few corrections

to the previous lists and some name changes

in conformity with current usage in aphid

taxonomy. The aphids are arranged alpha-

betically by species. The location of each

collection site can be determined from Table 1

or from the tables of localities in the previous

papers.

The complete data for all collections have

now been computerized, so that up-to-date

aphid or host lists are easily available. The

computer programming is described in detail

elsewhere in this Journal (Raworth, and

Frazer 1976).

‘Contribution No. 387, Research Station, 6660 N. W. Marine

Drive, Vancouver, British Columbia, V6T 1X2.

LIST OF SPECIES

ABIETINUM (Walker), ELATOBIUM

Picea sp: Vancouver, May 3/74, May 7/75.

AEGOPODII (Scopoli), CAVARIELLA

Petroselinum crispum: Vancouver,

Apr. 29/75.

ALBIPES Richards, THELAXES

Quercus prinus: Vancouver (UBC), Jun 6/75,

sti 1/75.

ALNI (DeGeer), PTEROCALLIS

Alnus rubra: Vancouver, Sep 26,75.

ALNIFOLIAE ALNIFOLIAE — (Williams),

PROCIPHILUS Previously listed as

PROCIPHILUS ALNIFOLIAE Williams.

Amelanchier canadensis: Vancouver (UBC),

Jun L1/ 75,

ANNULATUS (Hartig), TUBERCULOIDES

Quercus garryana: Vancouver (UBC),

Jum dy 75,

Quercus robur: Vancouver, Sep 26/75; Van-

couver (UBC), Jun 12/74.

Quercus robur var fastigiata:

(UBC), Jun 18/75.

Quercus sp: Vancouver, Jun 2/73.

ASCALONICUS Doncaster, MYZUS

Arctostaphylos uva-ursi: Vanncouver (UBC),

May 5/75.

Fragaria Sp: Vancouver (UBC), May 15/74.

Lactuca sp: Vancouver, Apr 5/58.

Ranunculus occidentalis: Vancouver,

May 20/75.

Rheum rhaponticum: Vancouver, May 20/75.

Viola sp: North Vancouver, May 25/75.

Vancouver

TABLE 1. Localities where aphids were collected, with airline distances from reference points.

Locality Reference

Point

Bridesville Kelowna

Delta Vancouver

Lac La Hache Williams Lake

Laidlaw Vancouver

Robson Creston

Salmon Arm Kamloops

West Vancouver Vancouver

Dir. Distance

km mi

S 94 59

S 24 1

SE 58 36

E 104 65

NW 93 58

E 72 45

W 13 8

58 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

*AUREUS Richards, BETULAPHIS

Betula sp: Terrace, Jul 12/60 (Richards

1961a).

AVENAE (Fabricius), MACROSIPHUM

Avena sativa: Agassiz, Jul 28/69.

Juncus articulatus: Vancouver (UBC),

Aug 7/74.

Juncus bufonius: Vancouver (UBC),

Aug 7/74.

Scirpus validus: Vancouver (UBC), Aug 9/74.

Triglochin maritimum: Vancouver (UBC),

Aug 9/74.

Zea mays: Agassiz, Jul 28/69.

BAKERI (Cowen), ROEPKEA

Crataegus douglasii: Vancouver (UBC)

Jun 5/75.

Prunus avium: Summerland, Oct 25/74.

Prunus domestica: Summerland, Oct 25/74.

BERBERIDIS (Kaltenbach), LIOSOMAPHIS

Berberis aquifolium: Vancouver, May 15/73;

Vancouver (UBC), Jul 8/74.

Berberis hybrido-gagnepaini:

(UBC), Jun 19/75.

BICOLOR BICOLOR (Oestlund),

PTE ROCOMMA

Populus nigra var italica: Vancouver (UBC),

Apr 24/74, Apr 26/74, Apr 30/74, May 9/73.

Populus sp: Vancouver (UBC), May 21/73.

Populus trichocarpa: Vancouver (UBC),

May 21/73.

Salix sp: North Vancouver, May 20/73.

BURSARIUS (Linnaeus), PEMPHIGUS

Populs nigra var italica: Vancouver (UBC),

Jun 28/73.

CALIFORNICUM (Clarke), MACROSIPHUM

Salix scouleriana: Vancouver (UBC),

Jun 25/74.

Salix sp: Vancouver (UBC), Jun 8/73.

*CALLUNAE Theobald, APHIS

Calluna vulgaris: Vancouver (UBC),

Jul 18/74, Jul 19/74.

CARAGANAE (Cholodkovsky),

ACYRTHOSIPHON

Caragana arborescens:

Aug 14/75.

CARDUI (Linnaeus), BRACHYCAUDUS

Prunus domestica: Summerland, Oct 25/74.

CASTANICOLA Baker, MYZOCALLIS

Castanea dentata: Vancouver (UBC),

Sep 4/75.

CERASI (Fabricius), MYZUS

Prunus avium: Summerland, Oct. 25/74.

Prunus cerasus: Vancouver (CDA), Apr 18/75

(In Rearing Room).

Prunus emarginata: Creston, May 30/75,

Jun 28/75; Robson, Jun 29/75.

Prunus serrulata var shirofugen: Vancouver,

May 13/75.

Prunus sp: Creston, Jun 28/75; Summerland,

Jun 3/75.

Vancouver

Vancouver (UBC),

CERASIFOLIAE (Fitch),

RHOPALOSIPHUM

Prunus virginiana: Summerland, May 28/75,

Jun 19/75.

Prunus viginiana var demissa: Bridesville,

Jun 4/75: Robson, Jun 29/75.

CIRCUMFLEXUS (Buckton),

AULACORTHUM

Campanula persicifolia: Vancouver,

Aug 19/75.

Oxalis corniculata:

Aug 19/75.

CIRSII (Linnaeus), DACTYNOTUS

Cirsium arvense: Ladner, Jul 17/74.

CLAVICORNIS Richards, AULACORTHUM

Rosa sp: Williams Lake, Jun 15/56.

CORNI (Fabricius), ANOECIA

Cornus obliqua: Vancouver (UBC), Oct 24/75.

CORNIELLA Hille Ris Lambers, APHIS

Cornus ‘Eddie’s White Wonder’: Vancouver

(UBC), Sep 9/75.

Cornus florida: Vancouver (UBC), Sep 9/75.

Cornus florida var pluribracteata: Vancouver

(UBC), Sep 9/75.

Cornus kousa: Vancouver (UBC), Sep 9/75.

Cornus mas: Vancouver (UBC), Sep 11/75.

Cornus obliqua: Vancouver (UBC), Sep 11/75.

Cornus racemosa: Vancouver (UBC),

Sep 9/75.

CORYLI (Goeze), MYZOCALLIS

Corylus cornuta: Vancouver (UBC), Aug

27/14, Oct. 2/775.

*COWENI (Cockerell), TAMALIA

Arctostaphylos uva-ursi: Vancouver (UBC),

Sep 12/75.

CRACCIVORA Koch, APHIS

Holodiscus discolor: Brentwood, Jul 5/59.

CYPERI (Walker), TRICHOCALLIS

Carex sitchensis: Vancouver (UBC),

Aug 9/74.

DIRHODUM (Walker), ACYRTHOSIPHON

Crataegus oxyacantha ‘Paul’s Scarlet’:

Vancouver (UBC), Jun 5/75.

DORSATUM Richards, AULACORTHUM

Gaultheria shallon: Vancouver (UBC),

Sep 2/75.

ELAEAGNI (Del Guercio), CAPITOPHORUS

Previously listed as ELAEGNI (del Guercio)

due to a typographical error.

*ENIGMAE Hottes & Frison,

RHOPALOSIPHUM

Typha latifolia: Vancouver (UBC), Aug 9/74.

*EPILOBII Kaltenbach, APHIS

Epilobium watsonii: Vancouver, Jun 11/73.

ERIOPHORI (Walker), CERURAPHIS

Carex sitchensis: Vancouver (UBC), Aug

9/74.

Scirpus microcarpus: Vancouver (UBC),

Aug 9/74.

Viburnum opulus: Vancouver, Apr 22/73.

Vancouver, Jul 23/75,

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976 59

EUPHORBIAE (Thomas), MACROSIPHUM

Chaenomeles japonica: Vancouver, Jun 13/75.

Cornus stolonifera: Vancouver (UBC),

Jul 15/75, Aug 5/75, Aug 27/74.

Dahlia sp: Vancouver, Aug 1/74.

Deutzia gracilis: Vancouver (UBC),

Jun 19/75.

Deutzia x rosea var carminea: Vancouver

(WBC), Jun 18/75.

Dicentra formosa: Vancouver (UBC),

Jun 10/74.

Escallonia x edinensis: Vancouver (UBC),

Sep 4/75.

Forsythia sp: Vancouver (UBC), Jun 27/75.

Fragaria sp: Victoria, May 30/57.

Fuchsia hybrida: Vancouver, Aug 27/75.

Gynura aurantiaca: Richmond, Nov 4/75.

Halesia carolina: Vancouver (UBC),

Jun 26/75, Jul 22/75.

Hypochaeris radicata: Vancouver (UBC),

gun 13/75.

Ilex aquifolium var aureo-marginata: Van-

couver (UBC), Jun 18/75.

Iris kaempferi: Vancouver (UBC), Aug 28/74.

Lapsana communis: Vancouver, Jun 13/75.

Liriodendron tulipifera: Vancouver (UBC),

Jun 9/75, Aug 14/75.

Montia sibirica: Vancouver (UBC), Jun 13/75.

Philadelphus lewisii: Vancouver (UBC),

Jul 15/75.

Philadelphus lewisii var gordonianus: Van-

couver, Apr 20/73; Vancouver (UBC),

Jun 22/59, Aug 8/59.

Philadelphus x virginalis: Vancouver (UBC),

May 16/75, Jun 17/75, Jun 18/75, Jun 26/75,

Jun 27/75.

Rosa sp: Vancouver, May 16/73, May 16/74.

Salix sp: Vancouver, Jun 13/73.

Spiraea douglasii: Vancouver (UBC),

Jun 25/74, Jul 15/75.

Verbena x hybrida: Trout Creek, Sep 3/65.

Vinca minor: Vancouver (UBC), Jun 19/75.

FABAE Scopoli, APHIS

Amelanchier canadensis: Vancouver (UBC),

Jun 11/75.

Callistephus chinensis: Vancouver (CDA),

Aug 7/75 (In Greenhouse).

Chenopodium album: Vancouver (UBC),

Aug 11/75.

Cuscuta subinclusa: Vancouver (CDA),

Aug 7/75 (In Greenhouse).

Deutzia gracilis: Vancouver (UBC), Jun

19/75.

Euonymus alatus: Vancouver (UBC),

Sep 4/75.

Euonymus europaea: Vancouver (UBC),

May 23/75, Sept 9/75, Sep 22/75.

Euonymus latifolius: Vancouver (UBC),

Sep 9/75.

Fatsia japonica: Vancouver, Jul 13/75.

Ficus carica: Vancouver (UBC), Jun 23/75.

Hedera helix: North Vancouver, May 16/73.

Liriodendron tulipifera: Vancouver (UBC),

Aug 14/75.

Matricaria matricarioides: Vancouver (UBC),

oul 217 75:

Philadelphus lewisiti var gordonianus: Van-

couver, Apr 20/73.

Philadelphus sp: Vancouver, Jun 29/71.

Philadelphus x virginalis: Vancouver (UBC),

May 16/75, Jun 18/75.

Sassafras albidum: Vancouver (UBC),

Sep 9/75.

Viburnum _ trilobum:

Jul 3/75, Sep 3/75.

FAGI (Linnaeus), PHYLLAPHIS

Fagus sylvatica var purpurea: Vancouver,

May 14/73.

FARINOSA Gmelin, APHIS

Salix sp: West Vancouver, May 25/73.

FIMBRIATA Richards, FIMBRIAPHIS

Arctostaphylos uva-ursi: Vancouver (UBC),

Jun 2/75.

Fragaria sp: Agassiz,

Island, May 23/57.

FRAGAEFOLII (Cockerell),

CHAETOSIPHON

Fragaria sp: Lulu Island, Jul 17/57; Van-

couver, Apr 24/59; Vancouver (UBC),

May 15/74.

Rosa sp: Summerland, Jun 19/75.

FRAGARIAE (Walker), MACROSIPHUM

Juncus bufonius: Vancouver (UBC),

Aug 7/74.

Rubus discolor: Vancouver (UBC), Jun 12/74.

Scirpus validus: Vancouver (UBC),

Aug 9/74.

*GALEOPSIDIS ( Kaltenbach)

CRY PTOMYZUS

Ribes laxiflorum: Vancouver, Aug 3/60. |

*GENTNERI (Mason), FIMBRIAPHIS

Amelanchier laevis: Vancouver (UBC),

Jun 5/75.

Crataegus douglasii: Vancouver (UBC),

Jun 5/75.

Mespilus germanica: Vancouver (UBC),

Apr 28/75, Jun 11/75.

*GLYCERIAE (Kaltenbach), SIPHA

Agrostis alba var palustris: Vancouver

(UBC), Jul 28/74.

GRAVICORNIS (Patch), PARATHECABIUS

Previously listed as THECABIUS GRAVI-

CORNIS (Patch).

HEDERAE (Kaltenbach), APHIS

Previously listed as APHIS PSEUDOHED-

ERAE Theobald.

Hedera helix: North Vancouver, May 16/73.

HELICHRYSI (Kaltenbach),

BRACHYCAUDUS

Chaenomeles japonica: Vancouver, Jun 13/75.

Philadelphus sp: Vancouver, Jun 8/59.

Philadelphus x virginalis: Vancouver (UBC),

Jun 20/75.

Vancouver (UBC),

May 15/75; Lulu

60 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Prunus domestica: Robson, May 30/75;

Summerland, Oct 25/74.

Prunus sp: Surrey, May 20/73.

Verbena x hybrida: Trout Creek, Sep 3/65.

HERACLELLA Davis, APHIS

Heracleum lanatum: Vancouver (UBC),

Aug 7/75.

HIPPOPHAES (Walker) CAPITOPHORUS

Polygonum lapathifolium: Vancouver (UBC),

Aug 26/74.

Polygonum persicaria: Pemberton,

Aug 25/75.

*HUMBOLDTI (Essig), SITOMYZUS

Physocarpus malvaceus: Vancouver (UBC),

May 28/75.

*HYDRANGEAE (Matsumura),

RHOPALOSIPHONINUS

Deutzia gracilis: Vancouver (UBC),Jun 19/75.

J UGLANDICOLA (Kaltenbach),

CHROMAPHIS

Juglans sp: Vancouver, May 29/73.

*KNOWLTONI Robinson, MYZODIUM

Callitriche stagnalis: Vancouver

Aug 26/74.

LACTUCAE (Linnaeus), HYPEROMYZUS

Ribes laxiflorum: Burnaby, Jun 6/75.

LACTUCAE (Passerini), ACYRTHOSIPHON

Lactuca sp: Penticton, Jul 27/67.

(UBC),

LAMBERSI MacGillivray, _MASONAPHIS

Gaultheria shallon: Vancouver (UBC),

Jun 17/75.

Ilex altaclarensis: Vancouver (UBC),

Jun 18/75.

Ilex aquifolium: Vancouver (UBC),

Jun 18/75.

Ilex aquifolium var aureo-marginata: Van-

couver (UBC), Jun 18/75.

Rhododendron ‘Directeur Moerlands’:

couver (UBC), Jun 9/75.

Rhododendron ‘Glacier”’:

Sep 3/75.

Van-

Vancouver (UBC),

Rhododendron luteum: Vancouver (UBC),

Jun 6/75, Jun 9/75.

Rhododendron ‘Princess Elizabeth’: Van-

couver (UBC), Jun 6/75, Jun 9/75.

Rhododendron sp: Burnaby, Jun 9/75: Van-

couver, Jun _ 6/75; Vancouver (UBC),

Jun 16/75, Jun 17/75.

LANIGERUM (Hausmann), ERIOSOMA

Pyrus fusca: Delta, May 7/78.

LONGICAUDA Richards, ASPIDAPHIS

Spiraea douglasii: Vancouver (UBC),

Jul 15/75.

LYTHRI (Schrank), MYZUS

Prunus domestica: Vancouver, Jun 2/73.

MACROSIPHUM (Wilson),

ACYRTHOSIPHON

Amelanchier alnifolia: Summerland,

May 28/75.

Amelanchier canadensis: Vancouver (UBC),

Jun 11/75:

Amelanchier laevis: Vancouver (UBC),

Jun 5/75.

*MAGNA Hille Ris Lambers, MASONAPHIS

Composites: Lac La Hache, Jul 6/66

(Hille Ris Lambers 1974).

*MANITOBENSIS Robinson,

MACROSIPHUM

Cornus stolonifera: Vancouver (UBC),

Jun 12/74.

MAXIMA (Mason), MASONAPHIS

Rubus parviflorus: Vancouver (UBC),

Apr 3/74, Apr 18/74, Apr 22/74, Jun 18/74,

Aug 27/74.

*MODESTUM (Hottes), MYZODIUM

Pogonatum urnigerum: Vancouver (UBC),

Aug 26/74.

Polytrichum commune: Vancouver (UBC),

Aug 6/74, Aug 7/74, Aug 14/74.

Polytrichum juniperinum: Vancouver (UBC),

Mar 6/75, Jul 3/74, Jul 8/74, Jul 16/74,

Jul 23/74, Aug 2/74, Aug 7/74, Aug 9/74.

MORRISONI (Swain), MASONAPHIS

Chamaecyparis pisifera: Vancouver (UBC),

Aug 15/74.

Chamaecyparis pisifera

couver (UBC), Jul 30/74.

Chamaecyparis pisifera ‘Filifera’: Vancouver

(UBC), Aug 15/74.

‘Boulevard’: Van-

Chamaecyparis pisifera ‘Plumosa’: Van-

couver (UBC), Jul 30/74, Aug 15/74,

Aug 27/75.

Chamaecyparis pisifera ‘Squarrosa’: Van-

couver (UBC), Jul 30/74.

Cupressocyparis leylandii: Vancouver (UBC),

Aug 15/74.

Juniperus chinensis ‘Pfitzeriana’: Van-

couver (UBC), Aug 15/74.

Sequoiadendron _ giganteum: Vancouver

(UBC), Sep 4/75, Sep 11/75.

Thuja plicata: Vancouver (UBC), Aug 29/74.

NEOMEXICANA (Cockerell), APHIS

Ribes laxiflorum: Agassiz, May 11/59.

Ribes sanguineum: Vancouver (UBC),

May 16/75.

NERVATA (Gillette), WAHLGRENIELLA

Arbutus menziesii: Vancouver (UBC),

Apr 7/75, Apr 28/75.

NYMPHAEAE (Linnaeus), RHOPALOSI-

PHUM

Alisma plantago-aquatica: Vancouver

(UBC), Aug 28/74.

Elodea canadensis: Vancouver, Sep 22/74.

Prunus avium: Summerland, Oct 25/74.

Prunus domestica: Summerland, Oct 25/74.

Prunus persica: Summerland, Oct 25/74.

Prunus sp: Surrey, May 20/73.

Saururus cernuus: Vancouver (UBC),

Aug 28/74.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976 61

OCCIDENTALIS (Davidson), CINARA

Abies siberica: Vancouver (UBC), Jul 10/75.

ORNATUS Laing, MYZUS

Abelia ‘Edward Goucher’: Vancouver (UBC),

Jun 24/75, Oct 24/75.

Campanula persicifolia: Vancouver, Jul

15/75, Aug 19/75.

Deutzia x rosea var carminea: Vancouver

(UBC), Jun 18/75.

Forsythia x intermedia: Vancouver (UBC),

Jun 18/75.

Gynura aurantiaca: Richmond, Nov 5/75.

Lactuca sp: Vancouver, Apr 5/58.

Lapsana communis: Vancouver, Jun 13/75.

Mentha spicata: Vancouver, Jul 23/75.

Oxalis corniculata: Vancouver, Jul 23/75.

Philadelphus lewisii var gordonianus: Van-

couver (UBC), May 22/58.

Philadelphus x virginalis: Vancouver (UBC),

Jun 18/75.

Primula alpicola ssp luna: Vancouver (UBC),

Sep 12/75.

Ranunculus occidentalis: Vancouver,

May 20/75.

Rheum rhaponticum: Vancouver, May 20/75.

Trifolium pratense: Vancouver, Sep 26/75.

Weigela ‘Eva Rathke’: Vancouver (UBC),

Jul 3/75, Sep 3/75.

OSMARONIAE (Wilson), MACROSIPHUM

Osmaronia cerasiformis: Vancouver (UBC),

Apr 30/75, Aug 29/74.

PADI (Linnaeus), RHOPALOSIPHUM

Prunus virginiana: Summerland, May 28/75.

*PALUSTRIS (Theobald), EUSCHIZAPHIS

Juncus articulatus: Vancouver (UBC),

Aug 6/74, Aug 7/74.

Juncus tenuis: Vancouver (UBC), Aug 6/74.

PARVIFLORI Hill, AMPHOROPHORA

Rubus discolor: Vancouver (UBC), Jun

12/74, Jun 25/74.

PASTINACAE (Linnaeus), CAVARIELLA

Heracleum lanatum: Vancouver, May 24/73;

Vancouver (UBC), Aug 7/75.

Salix lasiandra: Vancouver, Sep 26/75.

Salix sp: Vancouver, Jun 5/73.

PERSICAE (Sulzer), MYZUS

Callistephus chinensis: Vancouver (CDA),

Nov 3/75 (In Greenhouse).

Capsicum sp: Chilliwack, Aug 27/74.

Convolvulus sepium: Vancouver, May 15/75.

Daucus carota: Vancouver (CDA), May

23/74 (In Greenhouse).

Epilobium watsonii: Vancouver (UBC),

Aug 18/75.

Philadelphus x virginalis: Vancouver (UBC),

Jul 22/75.

Pisum sativum: Vancouver (CDA), Nov

17/75 (In Greenhouse).

Plantago major: Vancouver (UBC),

Sep 11/74.

Portulaca oleracea: Vancouver (UBC),

Sep 11/74.

Prunus persica: Summerland, Oct 25/74.

Vicia faba: Agassiz, Jul/65.

*PILICORNIS (Hartig), CINARA

In flight: Vancouver (UBC), Jun 11/75.

Tsuga heterophylla: Vancouver, Jul 14/75.

PINEA (Mordvilko), CINARA

Pinus nigra: Vancouver (UBC), Jun 23/75.

Pinus sylvestris: Vancouver (UBC),

Sep 4/75.

PINETI (Fabricius), SCHIZOLACHNUS

Pinus sylvestris: Vancouver (UBC), Sep 4/75.

*PISUM SPARTII (Koch),

ACYRTHOSIPHON

Cytisus scoparius: Vancouver (UBC),

Aug 29/74.

PLANTAGINEA (Passerini), DYSAPHIS

Malus sp: Vancouver (UBC), Jun 13/75.

POMI DeGeer, APHIS

Amelanchier canadensis: Vancouver (UBC),

Jun 11/75:

Cotoneaster bullata: Vancouver (UBC),

Jun 20/75.

Cotoneaster dammeri: Vancouver (UBC),

Jun 5/75.

Cotoneaster horizontalis: Vancouver (UBC),

Jun o/s 1d:

Cotoneaster salicifolia ‘Repens’: Vancouver

(UBC), Jun 5/75.

Crataegus douglasii: Vancouver (UBC),

Jun 5/75.

Malus ionensis: Vancouver (UBC), Jun 17/75.

Pyracantha crenulata ‘Flava’: Vancouver

(UBC), Sep 11/75.

Sorbus aucuparia: Vancouver (UBC),

Jun 18/75.

POPULIMONILIS (Riley),

PARATHECABIUS

Previously listed as THECABIUS POPULI-

MONILIS (Riley).

POPULIVENAE Fitch, PEMPHIGUS

Rumex acetosella: Richmond, Oct 6/75.

*PRAETERITA Walker, APHIS

Epilobium angustifolium: Lulu Island,

Jul 14/70.

*PRUNI Wilson & Davis, ASIPHONAPHIS

Prunus virginiana: Summerland, May 28/75.

PRUNI (Geoffroy), HYALOPTERUS

Prunus avium: Summerland, Oct 25/74.

Prunus domestica: Summerland, Oct 25/74.

Typha latifolia: Salmon Arm, Aug 18/74;

Vancouver (UBC), Aug 9/74.

*PSEUDOMORRISONI MacGillivray,

MASONAPHIS

Juniperus squamata ‘Meyeri’: Vancouver

(UBC), Sep 11/75.

62 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

PSEUDOTAXIFOLIAE Palmer, CINARA

Moericke yellow pan water trap: Chilliwack,

Aug 2/67.

*PUNCTATA (Monell), MYZOCALLIS

Quercus macrocarpa: Vancouver

Jul 10/75.

Quercus prinus: Vancouver (UBC), Jun 11/75.

PUNCTIPENNIS Zetterstedt, EUCERAPHIS

Betula papyrifera var commutata: Vancouver

(UBC), Apr 18/74.

RHAMNI Clarke, MACROSIPHUM

Rhamnus_ purshiana: Vancouver

Nov 4/75.

ROSAE (Linnaeus), MACROSIPHUM

Ilex altaclarensis: Vancouver (UBC),

Jun 18/75.

Ilex glabra: Vancouver (UBC), Jun 19/75.

Ilex integra: Burnaby, Jun 9/75.

RUSSELLAE Hille Ris Lambers,

DACTYNOTUS

Anaphalis margaritacea: Vancouver (UBC),

Sep 12/75, Sep 23/75.

SAMBUCIFOLIAE Fitch, APHIS

Sambucus racemosa var arborescens:

couver (UBC), Apr 19/75, Apr 30/75,

Aug 27/74.

SANGUICEPS Richards, PTEROCOMMA

Salix scouleriana: Vancouver (UBC),

Apr 18/74, Apr 30/74, May 10/74.

Salix sp: Vancouver (UBC), Oct 23/48.

SCABROSUM Richards, AULACORTHUM

Rubus spectabilis: Vancouver (UBC),

Jun 25/74.

SCLEROSA Richards, ROEPKEA

Crataegus douglasii: Duncan, Aug 4/65

(Richards 1969).

Lathyrus nevadensis ssp lanceolatus:

Victoria, Aug 5/65 (Richards 1969).

SENSORIATA (Gillette & Bragg), ROEPKEA

Previously listed as SENSORIATA (Gillette

& Palmer) due to a typographical error.

SIPHUNCULATA Richards, PLACOAPHIS

In flight: Vancouver (UBC), Sep 23/75.

Rosa sp: Creston, Jun/55 (Richards 1961b).

SOLANI (Kaltenbach), AULACORTHUM

Aucuba japonica: Vancouver, Jun 4/74.

Clematis ‘Nelly Moser’: North Vancouver,

May 20/74.

Digitalis purpurea: Vancouver, Sep 26/75.

Heracleum lanatum: Vancouver (UBC),

Jun 9/75.

Lapsana communis: Vancouver, Jun 13/73.

Philadelphus lewisii var gordonianus:

Vancouver, Apr 20/73.

Primula juliae ‘Wanda’: Victoria, May 18/73.

Primula sp: Vancouver (CDA), Mar 9/75

(In Greenhouse).

Tilia americana: Vancouver (UBC),

Jun 11/75.

(UBC),

Van-

Tropaeolum majus: North Vancouver,

Jun 18/74.

Tulipa gesneriana: North Vancouver,

May 25/75.

SPIRAEAE MacGillivray, MASONAPHIS

Previously listed as SPIRAEAE (MacGilliv-

ray) due to a typographical error.

Corylus cornuta: Vancouver (UBC),

Jun 10/74, Jun 12/74.

Spiraea douglasii: Vancouver (UBC),

Jul 15/75.

*SPIRAECOLA (Patch), MASONAPHIS

Spiraea thunbergii: Vancouver (UBC),

Jun 18/75.

*SPIROTHECAE Passerini, PEMPHIGUS

Populus nigra var italica: Vancouver (UBC),

Apr 24/74, Apr 25/74, Apr 26/74, Apr 30/74,

May 24/74, Jun 13/74, Jul 5/74, Aug 13/74,

Sep 6/74, Sep 27/74, Oct 15/73, Oct 15/74,

Oct 16/74, Nov 1/74, Nov 4/74.

STANLEYI Wilson, MACROSIPHUM

Previously listed as STANLEYI (Wilson) due

to a typographical error.

Sambucus racemosa var arborescens: Van-

couver (UBC), Apr 19/75, Apr 30/75, Jun

25/74, Aug 27/74.

STAPHYLEAE (Koch), RHOPALOSIPHON-

INUS

Vinca minor: Vancouver (UBC), Jun 19/75.

TANACETARIA (Kaltenbach), MACROSI-

PHONIELLA

Tanacetum vulgare: Texas Lake, Jul 24/67.

TESTUDINACEA (Fernie), PERIPHYLLUS

Acer ginala: Vancouver (UBC), Jun 5/75.

Acer glabrum var douglasii: Vancouver

(UBC), Jun 5/75.

TILIAE (Linnaeus), EUCALLIPTERUS

Tilia americana: Vancouver (UBC),

29/75, May 16/75, Jun 11/75, Oct 3/75.

Tilia petiolaris: Vancouver (UBC), Jun 5/75,

Oct 6/75.

ULMISACCULI (Patch), COLOPHA

Agropyron repens: Laidlaw, Apr 17/74.

*VIBURNICOLA (Gillette), NEOCERUR-

APHIS

Viburnum opulus: Vancouver, Apr 22/73.

*WAHNAGA Hottes, MASONAPHIS

In flight: Vancouver (UBC), Sep 23/75.

WALSHII (Monell), MYZOCALLIS

Quercus rubra: Vancouver, Aug 30/74; Van-

couver (UBC), Aug 29/74.

XYLOSTEI (DeGeer), STAGONA

Previously listed as PROCIPHILUS

XYLOSTEI (DeGeer).

Apr

*Aphid species not in the previous lists.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 63

References

Forbes, A. R., B. D. Frazer, and H. R. MacCarthy. 1973. The aphids (Homoptera: Aphididae) of

British Columbia. 1. A basic taxonomic list. J. ent. Soc. Brit. Columbia 70: 43-57.

Forbes, A. R., B. D. Frazer, and Cho-Kai Chan. 1974. The aphids (Homoptera: Aphididae) of

British Columbia. 3. Additions and corrections. J. ent. Soc. Brit. Columbia 71: 43-49.

Hille Ris Lambers, D. 1974. On American aphids, with descriptions of a new genus and some new.

species (Homoptera, Aphididae). Tijdschrift voor Entomologie 117: 103-155.

Raworth, D. A., and B. D. Frazer. 1976. Compilation of taxonomic catalogues by computer.

J. ent. Soc. Brit. Columbia 73:

Richards, W. R. 1961la. North American Bornerina Bramstedt and Betulaphis Glendenning

(Homoptera: Aphididae). Canad. Ent. 93(6):486-494.

1961b. New genera and species of rose-infesting aphids (Homoptera:

Aphididae). Canad. Ent. 93(8): 622-625.

. 1969. A review of the holarctic genus Roepkea with descriptions of four new

nearctic species (Homoptera: Aphididae). Canad. Ent. 101 (11): 1121-1162.

COMPILATION OF TAXONOMIC CATALOGUES BY COMPUTER

D. A. RAWORTH ANDB. D. FRAZER

Research Station, Agriculture Canada

Vancouver, British Columbia V6T 1X2

ABSTRACT

The advantages of using a computer are examined for storing, updating,

and cross indexing taxonomic collection data in working and published lists.

Records of collections of animals and plants

for taxonomic purposes or for compilations of

more general lists of fauna and flora are

typically and unavoidably voluminous. Dif-

ficulty occurs in manually updating, cross in-

dexing and listing data about each collection

easily and quickly. However, the data are

usually regular, in that information for every

collection may be split into several logical and

uniform divisions. For example, collection data

consistently include taxonomic identification,

location of the sample, date, collector, and

sometimes a description of the sample and

habitat. This regularity suits the data ad-

mirably to computer storage and manipulation.

The advantage of using a computer is mainly in

the speed with which it can extract, arrange

and print information. The time saved is ap-

preciable as the data base becomes larger. This

paper discusses the use of the computer for

maintaining and updating the various lists

associated with a collection of aphids from

British Columbia.

The aphidologists of our research group

have accumulated a data base of more than

1500 collections during the past 20 years. In-

formation is recorded on cards (Fig. 1) at the

time a collection is made and these cards are in-

dexed by plant host species. When an aphid is

identified these data are also indexed

alphabetically by aphid species. About 150

collections are added each year. The task of

identifying aphids is made easier by using lists

of previously collected aphids and host plants

ordered in various ways (1, 2, 3), so that much

time has been spent maintaining cross indices

by hand.

Computer programming is a time con-

suming and often costly procedure. Most com-

puting centers, however, maintain a library of

those ‘canned’ programs most often needed by

computer users. One such program called “The

UBC Report Generator’ (RG), (4) was suited to

our needs. The following is a brief description of

how RG was used.

RG requires that all collections have the

same divisions or fields of data, and that these

fields be in a constant order. We ordered our

data on three data cards per collection: by

aphid genus, species and authority on the first;

by host plant family, common name, genus,

species and class code on the second; and by

location of sample, month number, month, day,

year, collector’s name and lot number on the

third. These fields are separated by commas.

Since RG is extremely flexible this is only one

of a number of ways in which the data can be

organized. The data were then punched on com-

puter cards (Fig. 2) and the card images were

stored on magnetic tape for economical com-

puter operations.

64 J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

Aids

V/,

gis

Fig. 1. A completed collection card.

In order to obtain lists, we ‘ran’ RG with

the data, a description of how the data were set

up and a series of commands describing what

items to extract and how to order and print

them (Fig. 3). Many other possibilities exist.

In many instances, field contents may be

duplicated from collection to collection and

when ordered, appear redundant (Fig. 3a).

Although RG does not have the facility to

reduce redundancy, it does allow the use of

computer language subroutines which can be

written to handle the problem. Subroutines

were written in FORTRAN IV, to eliminate

redundancy (Fig 4) and to provide appropriate

punctuation.

The printing capability of the computer is

far greater than that indicated by figures 3 and

4 because it has all the necessary typewriter

characters and is much faster. Since

publishable manuscripts were desirable in ad-

dition to working lists, a computer program

was written to convert the normal upper case

computer card characters to appropriate upper

and lower case characters (Fig. 5).

Although RG is a complex program capable

of many tasks it is remarkably easy to use,

even for those not familiar with computers.

Costs are minimal, but of course vary with the

quantity and complexity of the lists.

Preparation of a list of 1500 collections

organized as illustrated (Fig. 3-5) cost between

$5.00 and $15.00. The time required is as little

as three minutes for the finished product. By

far the most difficult and time consuming task

is keypunching the original data, but this is

done only once.

In conclusion, computer capabilities in

taxonomy are limited only by need, time,

money and imagination. We hope that greater

use will be made of computers for facilitating

the manipulation of animal and plant collection

data. Their use for this purpose promotes bet-

ter and more efficient use of the data and frees

research and support staff for more interesting

duties.

ACKNOWLEDGEMENTS

We thank Dr. A. R. Forbes and Mr. Cho-Kai

Chan who provided the data, the staff of the

UBC Computing Centre, in particular Rita

Cockle, who gave information and advice and

Mr. S. W. MacDiarmid for the photography.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976 65

Dea SHEE»

SABA FRLEECYPR RESS: CHAMRECYP AR. [3sPis TFERG *PLUBOS n"

Mois CSHALTO »

Ya his UG. Os F450, ee aN? A~SS3Ni+

SCORAON CAaT- Tatls TYPHA>LATIFOL IA» OBs

FRUSSPRUNT + (GEOFFRDY > s

sSe lites (Sa: 74s 0. Kes CHAM: >

TYPHACEREs COMMON CAT-TAIL» TYPHAsLATIFOL TAs 9

HYALDPTERUS» PRUNTs» CGEQFFROY3.

725) 74:80. sMCMULLEN: 5

iii

es IRBs. t+ Ayr PRIUGUS « DOMESTIC: Oe.

a Yael aPTERD iSyPRUBISCGEDFFROY), =

CUBIC 329s SERPs 3. 78K, SPHEN: thats

“EAPRIFDL TACERE HIGHBORE CREMEBLERY sv BURMOMs TRILOBUMs Ofis

APHIS» FSESE, SCOPELI, ee

“ & % %.

CUBED? SUL ELA a Het, 7? Fey

aeaaeeeteiome-oonpropaccgrsorgs me

brat oe ASL oH OCR AMPERR Ys YI EBUPHUM, TRILOBUH, OG:

DAG2G00099902Ab IAG 690090000808

tBELERGEOAAG BEBRBBULUBBUYYUULBGUGUUOBR?

FULPIELLULIENN ELIA $447744444

42222277222222242222277722222327427 £92277472727 7

$2%

{

224227272

FEAL TIANA AALAN ALGAE RAE A LS PANAEANGYGALI44144444444444445444444544445

44444444

42337 G44

%%&S

999535455555555545449555554555554545

PEiT1T7 aL

a4 Z4 ;

4, 44308344 a”

Fig. 2. The collection data on computer cards.

Cle PINOPSIDA (CONIFERS)

Fe CUPRESSACEAE CHAMAECYPARIS PISTFERA *PLUMOSA®

MASONAPHIS MORRISONT

Cle MAGNOLIOPSIDA (FLOWERING PLANTS =~ DICOTYLEDONS)

F. CAPRIFOLIACEAF VIBURNUM TRILOBUM

APHIS FABAE

Cle MAGNOLIOPSIDA (FLOWERING PLANTS - DICOTYLEDONS)

Fe CAPRIFOLIACEAE VIBURNUM TRILOBUM

APHTS FABAE

Cle MAGNOLIOPSIDA (FLOWERING PLANTS - DICOTYLFEDONS)

Fe ROSACEAE PRUNUS DOMESTICA

HYALCPTERUS PRUNT

Cle LILIOPSIOA (FLOWERING PLANTS -— MONOCOTYLEDONS)

Fe TYPHACEAE TYPHA LATIFOLIA

HYALCPTERUS PRUNT

Cle LILIGPOSIDA (FLOWERING PLANTS - MONOCOTYLEDONS)

Fe TYPHACEAE TYPHA LATIFOLIA

HYALCPTERUS PRUNI

Fig. 3a. All collections of figure 2 extracted and ordered by plant class, family, genus, and species;

aphid genus, and species.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEC. 31, 1976

FABAE SCOPOLI APHIS

VIBURNUM TRILOBUM VANCOUVER (UBC) JUL3/75

FABAE SCOPOLI APHIS

VIBURNUM TRILOBUM VANCOUVER (UBC) SEP3/75

MORRISONI (SWAIN) MASONAPHIS

CHAMAEC YPARIS PISIFERA *PLUMOSA® VANCOUVER (UBC) JUL30/74

PRUNI {(GEQFFROY) HYALOPTERUS

PRUNUS DOMESTICA SUMMERLAND OCT25/74

PRUNI {GEOFFROY) HYALOPTERUS

TYPHA LATIFOLIA SALMON ARM AUGLB/74

PRUNI (GEOFFROY) HYALOPTERUS

TYPHA LATIFOLIA VANCOUVER (UBC) AUG9/74

Fig. 3b. All collections of figure 2 extracted and ordered by aphid species, authority, and genus;

plant genus, and species; location, month number, day, and year.

APHIS FABAE SCOPOLI

VIBURNUM TRILOBUM JUL3/75

HYALOPTERUS PRUNI (GEOFFROY)

TYPHA LATIFCLIA AUG9S/74&

. All collections of figure 2 extracted where plant class code was ‘QA’ or ‘QB’, location

contained ‘Vancouver’, and month number was less than 9.

Cle PINOPSIDA (CONIFERS)

Fe CUPRESSACEAS |

CHAMAECYPARIS PISTFERA *PLUMOSAS

MASONAPHIS MORRISONI

Cle MAGNOLIOPSIDA (FLOWERING PLANTS — DICOTYLEDONS)

Fe CAPRIFOLIACEAE

VIBURNUM TRILOBUM

APHIS FABAE

Fe ROSACEAF

PRUNUS DOMESTICA

HYALOPTERUS PRUNT

Cle LILIOPSIDA (FLOWERING PLANTS - MONOCOTYLENONS) -

Fe. TYPHACEAF

TYPHA LATTFOLIA -

HYALOPTERUS PUNT

Fig. 4. Redundancy of figure 3a eliminated.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 67

FABAE Scopoli, APHIS

¢ Viburnum trilobum: Vancouver (UBC), Jul3/75, Sep3/75.

MORRISONI (Swain), MASONAPHIS

¥ Chamaecyparis pisifera 'Plumgsa': Vancouver (UBC), Ju130/74.

PRUNI (Geoffroy), HYALOPTERUS

@ Prunus domestica: Summerland, Oct25/74.

Typha latifolia: Salmon Arm, Aug18/74; Vancouver (UBC), Aug9/74,

Fig. 5. Figure 3b in publishable form.

References

Forbes, A. R., B. D. Frazer and H. R. MacCarthy. 1973. The Aphids (Homoptera: Aphididae) of

British Columbia. 1. A Basic Taxonomic List. J. Ent. Soc. Brit. Col. 70:43-57.

Forbes, A. R. and B. D. Frazer. 1973. The Aphids (Homoptera: Aphididae) of British Columbia.

2. A Host Plant Catalogue. J. Ent. Soc. Brit. Col. 70:58-68.

Forbes, A. R., B. D. Frazer and Cho-Kai Chan. 1974. The Aphids (Homoptera: Aphididae) of

British Columbia. 3. Additions and Corrections. J. Ent. Soc. Brit. Col. 71:43-49.

Miller, A.

1975. The UBC Report Generator. Computing Center, the University of British

Columbia, Vancouver, B.C., Canada V6T 1W5.

BOOK REVIEW

Mamaev, B. M. 1974. Evolution of gall forming

insects—gall midges (English Edition). Trans-

lated by A. Crozy, edited by K. M. Harris.

Published by The British Library, Lending

Division, printed by W. S. Maney Ltd., Leeds,

England, 317 pp. 79 figs. Size 6’ x 812" (15.5¢ x

22c). Paper cover. Price L 8.50, + $15.00.

(Translation of Russian Edition, published by

‘Nauka’’, Leningrad, 1968).

This book is a monograph of the family

Cecidomyiidae that focuses on the origins, the

lines and the patterns of evolution. It defines

the family, the subfamilies, the tribes and sub-

tribes in terms of the morphology, anatomy and

ecology of all stages, but it contains no taxo-

nomic keys. The author’s primary purpose is

to outline the evolutionary development of gall

midges, and from this, to construct a logical

classification. Thus, the classification adopted

in the first chapter is, in effect, the practical

outcome of the contents of the remaining seven

chapters. The book is the culmination of 15

years work, beginning in 1951, on the native

gall midge fauna of the European U.S.S.R.,

the Caucasus, Central Asia and the Far East.

The collation of collections from different habi-

tats (soil, litter, wood and living plant tissues)

from these geographically distant and ecologi-

cally distinct areas (forests, steppes, deserts

and mountains) provide the factual bases for

the theoretical constructions developed.

Dr. Mamaev is well qualified to undertake

such a project. He obtained his Ph.D under

Prof. E. S. Smirnov, Head, Department of

Entomology, Moscow State University, about

1951, and then went to work at the Institute

of Evolutionary Morphology and Ecology of

Animals, (Laboratory of Soil Zoology) Soviet

Academy of Sciences in Moscow. Since then

he has been a prolific researcher (author or co-

author of 38 papers cited in the book),

especially on Cecidomyiidae. All his work has

been based on a multidisciplinary approach

and most of his findings reflect a thorough-

ness and a soundness rarely encountered. His

book is based largely on his own findings,

coupled with first-hand information from col-

leagues with similar interests. Thus his book

is built on a solid foundation of personal inves-

tigations and knowledge, and is much more

than a synthesis of previously published data.

Part one, consisting of four chapters, deals

primarily with the morphological aspects of the

evolution of gall midges. Chapter one consists

of diagnoses of the family, subfamilies, tribes

and the subtribes; it also provides a modern

classification of the family breaking it into two

subfamilies: the Lestremiinae with three tribes,

Lestremiini, Moehniini (since eliminated be-

cause the only known species belongs to the

Sciaridae), and Micromyiini, and the Cedico-

myiinae with six tribes, Heteropezini, Por-

ricondylini, Oligotrophini, Lasiopterini, Ceci-

domyiini and Asphondyliini. Chapter two

describes the evolution of the larvae from the

standpoints of morpho-ecological types, adapt-

ive changes in the integument, the head struct-

ures and the digestive systems. Chapter three

deals with the evolution of the adults in a

similar manner but with special emphasis on

development of winglessness, changes in sense

organs, and the form of the male and female

terminalia. Chapter four is an analysis of the

occurrence patterns of morphological charac-

ters in larvae and adults, ending in a dendro-

gram showing the ‘phylogenetic links of the

major taxonomic groups of gall midges.” Of

special interest is a discussion on the exchange

of secondary sexual characters between males

and females, e.g., feminization of antennae in

males, and the significance of such phenomena

in classification. Unfortunately the dendrogram

(Fig. 45) summarizing the ideas of this chapter

is poorly organized. It shows the subfamily

Cecidomyiidae as a monophyletic group arising

from a single subtribe (Catochina) of the Lest-

remiinae. This, in effect, makes the Cecido-

myiinae a sister-group of the subtribe Cato-

china and makes the subfamily Lestremiinae

a paraphyletic group. In the text, however,

and in a subsequent phylogenetic chart (Fig.

79) the Cecidomyiinae are correctly treated as

a sister-group of the Lestremiinae, i.e., arising

from the common ancestor of all Cecidomyiidae.

The second half of the book also contains

four chapters and deals mainly with the ecologi-

cal aspects of the evolution of the gall midges.

Chapter five considers the ecological pre-

requisites for proliferation of gall midges—

adaptations for expansion into different hosts

and geographic areas, and adaptations for in-

tensifying the multiplication and_ survival

of species. Chapter six deals with the ecological

pathways leading to mycetophagy, phyto-

phagy and gall formation; it also includes

discussions on gall midges as plant parasites

and on the importance of flowers in their evo-

lution. Chapter seven treats special aspects of

gall fly speciation and gall formation in plants;

one of the main points made is that host data

and the forms of the galls are not always reli-

able criteria for species identification. Chapter

eight reviews the paleontological data relating

to gall midges, and discusses the main stages

of evolution of the family in relation to geo-

logical ages, ecological backgrounds and the

evolution of plants. The author concludes that

the Cecidomyiidae are a sister-group of the

Mycetophilidae and he provides a phylogenetic

chart showing the evolution of all the tribes

within the family. The final pages include an

appendix outlining techniques for collecting and

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976

studying gall midges, lists of references in

Roman and Cyrillic alphabets and an index

of the Latin names of insects referred to in the

text.

The book fulfills a real need for this large

and difficult group, possibly the largest family

of Diptera. The author has managed success-

fully to analyse and synthesize an immense

amount of information from the whole spec-

trum of biosystematics and to construct a

classification that appears to be both practical

and in harmony with the evolutionary patterns

of the group. He has introduced a wealth of new

facts and ideas and has provided a very real

addition to our knowledge on almost all

aspects of the biology and systematics of these

flies. No other book covers the subject so

thoroughly or so well. As the author himself

states, however, refinements and improvements

will appear as further progress is made on this

and related families. For example, the genus

Moehnia (known from females only of one

species) is now known to be an aberrant mem-

ber of the Sciaridae, thereby eliminating one

of the tribes of the Lestrimiinae. Such develop-

ments are to be expected and do not reduce the

overall value of the book.

This edition is a translation, and the trans-

lator and the editor have wisely adhered to a

policy of exactly portraying the thoughts of the

author rather than producing smooth, beautiful

English. This results in a style that is some-

times heavy and awkward, but in general

Messrs. Crozy and Harris are to be compli-

mented for an easily readable rendition. The

author’s method of providing separate conclu-

sions at the end of each chapter has resulted

in a certain amount of repetition, but this is

not a bad fault. The book itself was printed by

photographic means from typewritten pages,

and it has the general appearance of a xeroxed

thesis. The right margin of each page is very

uneven and in a few instances (pp. 22, 134)

the reproduction is poor; the half tone photo-

graphs (about half the figures) also suffered

as a result of this type of reproduction. The

paper is of good quality, but the bindng is

extremely poor; many pages of my copy have

become detached from the spine of the book.

There can be no doublt that his work repre-

sents a very significant step forward in our

knowledge of gall midges, and that it will be a

basic reference for many years. Anyone who

has any interest in the family should have a

copy.

J. F. McAlpine,

Biosystematics Research Institute,

Agriculture Canada,

Ottawa, Ontario, K1A OC6.

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), DEc. 31, 1976 69

NOTICE TO CONTRIBUTORS

This society has no support except from subscriptions. It has become neces-

sary to institute a page charge. This has now been set at $20.00. The page

charge includes all extras except coloured illustrations, provided that such

extras do not comprise more than 40% of the published pages. Coloured illustra-

tions will be charged directly to the author. Authors, not attached to universi-

ties or official institutions, who must pay these charges from their personal

funds and are unable to do so, may apply for assistance when submitting a

manuscript.

Reprints are sold only in even hundreds and at the following prices:

Number of pages 1-4 5-8 9-12 13-16 17-20 21-24 25-28

First 100 copies $33.00 46.50 63.00 82.50 105.00 130.50 159.00

Each extra 100 9.00 12.00 15.00 18.00 21.00 24.00 27.00

Author’s discounts (up to 40%) may be granted to authors who certify at

the time of ordering that they are buying reprints at personal expense. Authors

ordering personal reprints in addition to those ordered by an institution will

be billed at the rate for extra hundreds.

Membership is open to anyone with an interest in entomology. Dues are

$5.00 per year; for students $2.00.

Papers for the Journal need not have been presented at meetings of the

Entomological Society of British Columbia, nor is it mandatory, although pref-

erable, that authors be members of the society. The chief condition for publica-

tion is that the paper have some regional origin, interest, or application.

Contributions should be sent to:

H. R. MacCarthy,

6660 N.W. Marine Drive,

Vancouver, B.C. V6T 1X2

Manuscripts should be typed double-spaced on one side of white, line-spaced

numbered paper if possible, leaving generous margins. The original and two

copies, mailed flat, are required. Tables should be on separate, numbered

sheets, with the caption on the sheet. Captions for illustrations should also be

on separate numbered sheets, but more than one caption may be on a sheet.

Photographs should be glossy prints of good size, clarity and contrast. Line

drawings should be in black ink on good quality white paper.

The style, abbreviations and citations should conform to the Style Manual

for Biological Journals published by the American Institute of Biological

Sciences.

BACK NUMBERS

Back numbers of this journal are available from the Secretary-Treasurer,

from volume 45 (1949) to the present, at $8.00 per volume. Certain earlier

back numbers are also available, but only on special request to the Secretary-

Treasurer.

Address inquiries to:

B. D. Frazer, Secretary-Treasurer,

6660 N.W. Marine Drive,

Vancouver, B.C. V6T 1X2

J. ENTOMOL. Soc. Brit. COLUMBIA 73 (1976), DEc. 31, 1976

J. ENTOMOL. Soc. BRIT. COLUMBIA 73 (1976), Dec. 31, 1976

' ENTOMOLOGICAL

_ ~SOCIETY of

Issued December 31, 1977

ae ECONOMIC

; CARTY—Pest management: four years experience in a

BOMPMIEEM ANG oe ee ete eee etree teeter eeseesee

& EVERSON—Phytoseiulus persimilis (Acarina: Phytoseiidae) for

of two-spotted mites in a commercial greenhouse ...............2...225 7

& TONKS—A method for rearing the predaceous mite,

Jseiulus persimilis (Acarina: Phytoseiidae) .............0. cece cece e sees 8

GENERAL

Pe cue BO es te a ee Ee eee 10

R & FINLAYSON—Parasites of the larch casebearer, Coleophora

(Lepidoptera: Coleophoridae) in the West Kootenay area,

Sh e's Srey dia alta Wie ab eicsiw bd cye k ce eee vee 1G

& OLSEN—Feeding potential of predators of Myzus persicae ............23

AKRE—Morphology of alimentary and reproductive tracts of the

ent bot fly, Cuterebra tenebrosa (Diptera: Cuterebridae) ...................27

ve , SNYDER & COLETTI—Insects collected from an alpine-subalpine

TE Ae Na fate a ee

TAXONOMIC

LTON—A new Clastoptera from sagebrush

Seeuota, Homoptera: Cercopidac) 6... .0 06. ee ee ee we le eee oe BS

I ea tee ya We Gaus y fin Seek a dice yn s vie oo su bw ee 9, 26, 31,41

Re a coke eco e s 42

JOURNAL

of the

ENTOMOLOGICAL

SOCIETY of

BRITISH COLUMBIA

Issued December 31, 1977

ECONOMIC

MADSEN & CARTY—Pest management: four years experience in a

commercial orchard

TONKS & EVERSON—Phytoseiulus persimilis (Acarina: Phytoseiidae) for

control of two-spotted mites in a commercial greenhouse

THEAKER & TONKS—A method for rearing the predaceous mite,

Phytoseiulus persimilis (Acarina: Phytoseiidae)

GENERAL

MILLER & FINLAYSON—Distribution of Coleophora laricella (Lepidoptera:

Coleophoridae) and its major parasites in the crowns of western larch

in British Columbia

MILLER & FINLAYSON—Parasites of the larch casebearer, Coleophora

laricella (Lepidoptera: Coleophoridae) in the West Kootenay area,

British Columbia

TAMAKI & OLSEN—Feeding potential of predators of Myzus persicae ............ 23

BAIRD & AKRE—Morphology of alimentary and reproductive tracts of the

rodent bot fly, Cuterebra tenebrosa (Diptera: Cuterebridae)

DYER & HALL—Effect of anti-aggregative pheremones 3,2-MCH and

trans-verbenol on Dendroctonus rufipennis attacks on spruce stumps ...........32

HARLING, SNYDER & COLETTI—Insects collected from an alpine-subalpine

region in S. BH. British Columbia... 0... 00 cc ccc cece cece ct cence ccc c sc cense D4

VANDERSAR—Overwintering survival of Pissodes strobi (Peck)

(Coleoptera: Curculionidae) in sitka spruce leaders .............0 ccc cece eeeee od

TAXONOMIC

HAMILTON—A new Clastoptera from sagebrush

(Rhynchota: Homoptera: Cercopidae)

SCIENTIFIC NOTES

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

Directors of the Entomological Society of

British Columbia for 1977-1978

President

A. L. TURNBULL

Simon Fraser University

Burnaby

President-Elect

P. BELTON

Simon Fraser University

Burnaby

Past-President

H. S. GERBER

B.C. Min. of Agriculture

Cloverdale

Secretary-Treasurer

B. W. FRASER

6660 N. W. Marine Drive,

Vancouver, B.C. V6T 1X2

Editorial Committee

H. R. MacCARTHY

Vancouver

J. CORNER

Vernon

Directors

R. COSTELLO (2nd) N. V. TONKS (2nd) _ G. Gillespie (1st)

A. R. FORBES (1st) R. ELLIOTT (1st)

Regional Director of National Society

J.P. M. MACKAUER

Simon Fraser University, Burnaby

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 3

PEST MANAGEMENT: FOUR YEARS EXPERIENCE

IN A COMMERCIAL APPLE ORCHARD

H. F. MADSEN AND B. E. CARTY:

Research Station, Agriculture Canada,

Summerland, British Columbia

ABSTRACT

Pest management in a 12 ha apple orchard from 1973 to 1976 resulted in

a 50 percent reduction in the number of sprays that are normally applied to

control insects and mites. Codling moth, Laspeyresia pomonella (L.), popula-

tions were monitored by sex pheromone traps and populations of other

insects and mites were assessed by specific sampling techniques. Leafrollers

were the most difficult pests to control and fruit injury was 1.5 to 2.0 per-

cent in 3 of the 4 years. Mites were held below treatment levels by the

predator, Typhlodromus occidentalis Nesbitt, except for the apple rust mite,

Aculus schlechtendali (Nalepa) which required chemical control.

INTRODUCTION

Six commercial apple orchards were pest

managed from 1973 to 1976 in order to validate

sampling techniques and economic injury levels

for major apple pests. This paper examines

the data from one of these orchards over a 4-

year period. Pest intensity varies from orchard

to orchard, and date from one site is not

completely representative of all areas.

However, it does illustrate the efficiency of

procedures and the value of pest management

as a method of pest control.

METHODS

The pest managed orchard was located in

East Kelowna, B.C. in the heart of an apple

and cherry growing area. It was 12 ha in size

and planted to 4 apple cultivars, McIntosh,

Spartan, Red Delicious and Golden Delicious.

The McIntosh and Spartan trees were in solid

blocks and the Red Delicious were interplanted

with Golden Delicious. All trees were standard

plantings with variable planting distances.

Previous to 1973, the orchard was sprayed

routinely following recommendations in the

B.C. Tree Fruit Production Guide and received

ca. 7 applications each season.

The following pests were monitored during

the 4-year study: European fruit scale, Quadra-

spidiotus ostreaeformis (Curtis); San Jose

scale, Quadraspidiotus perniciosus (Comstock):

fruittree leafroller, Archips argyrospilus

(Walker); European leafroller, Archips rosanus

(Linnaeus); codling moth, Laspeyresia

pomonella (Linnaeus); western flower thrips,

Frankliniella occidentalis (Pergande); the

mirid Campylomma verbasci (Meyer): white

apple leafhopper, Typhlocyba pomaria McAtee;

eyespotted budmoth, Spilonota ocellana (Denis

& Schiffermuller); apple aphid, Aphis pomi

DeGeer; European red mite, Panonychus ulmi

(Koch); McDaniel spider mite, Tetranychus

‘Contribution No. 458, Research Station, Summerland.

mcdanieli McGregor; and apple rust mite,

Aculus schlenchtendali (Nalepa).

Sampling methods and economic injury

thresholds for the above pests have been

described by Madsen et al. (1975). A few

modifications in sampling methods and a few

changes in economic injury thresholds were

made after the above paper was prepared. The

treatment level for fruittree leafroller was

reduced from 10 larvae per 100 leaf clusters to

5 because injury was 1 to 2 percent when the

treatment level was 10.

We devised a new method of assessing

thrips populations. A sample of blossom

clusters was placed in a Berlese funnel and left

there for 6 hours. As the blossoms wilted, the

thrips moved down and were captured in a jar

of alcohol at the base of the funnel. This

method was quicker and more accurate than

the previously used extractor.

The treatment level for Campylomma ver-

basci was reduced from 5 nymphs per limb

tap sample to 2. Although C. verbasci was not

a problem in the orchard described in this

paper, evidence from other orchards indicated

that a level of 5 per limb tap resulted in ca.

3 to 4 percent fruit injury.

Although 2 species of leafrollers were

present in the orchard, their seasonal history

and behavior is similar and they cause the same

type of damage to apples (Madsen et al. 1976).

Therefore, all fruit with leafroller injury was

placed in a single category.

The effectiveness of the program was

assessed by harvest samples for insects that

attack fruit directly. A total of 250 apples per

bin were examined while the fruit was being

picked and fruit injury by the various pests

was recorded. We sampled a minimum of 3 of

the total bins picked for each apple cultivar.

Pests that attack leaves and do not directly

affect fruit were assessed by rating leaf injury

if populations exceeded the treatment level.

4 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

RESULTS AND DISCUSSION

Codling moth is the key pest in an apple

management program because chemical control

directed against this insect affects other pests

as well as natural enemies. The data on codling

moth monitoring in this orchard during 1973

and 1974 have been discussed by Vakenti and

Madsen (1976). In 1973, sex pheromone traps

indicated low codling moth populations within

the orchard, but high numbers in neighboring

orchards. No sprays were applied and the per-

cent injured fruit at harvest was only 0.1 (Table

1). We have calculated that a codling moth

infestation of 0.5 can be tolerated by orchard-

ists and does not justify the cost of a spray

application (Vakenti and Madsen 1976). In

1974, trap captures indicated a need for treat-

ment on 3 occasions, but the moth numbers

were only slightly above the treatment level of

2 per trap. We suggested chemical control but

the orchardist chose not to apply a spray. The

codling moth injury at harvest was 0.7 percent

which indicated at least one spray would have

been justified.

Fig. 1 illustrates the codling moth captures

for 1975 and 1976. The traps captured an

average of over 4 per trap in early June of 1975

and a codling moth spray was applied a week

later. No further sprays were applied although

the moth capture was slightly above treatment

level the first week of July. In 1976, the treat-

ment level was exceeded during the week of

July 12, but over 70 percent of the moths were

captured in a single block of Red and Golden

Delicious trees. We suggested that treatment

be limited to this area which was ca. 3 of the

total orchard. A single application was applied

to this block and was the only codling moth

spray the orchard received. Fruit injury by

codling moth was well below the acceptable

level of 0.5 percent in both years. During the

4-year period, only 13 sprays were applied for

codling moth control in contrast to a calendar

based program which would have required a

minimum of 8 treatments.

Leafrollers required treatment in all 4 years,

but control from 1973 to 1975 was not as effec-

tive as expected. Diazinon was used until 1975

when there was evidence of tolerance by leaf-

rollers to this pesticide from orchards in the

same general area (Madsen and Carty 1977). In

1976, azinphosmethyl was used instead of

diazinon, and fruit injury was reduced by ca.

90 percent from the previous year.

Injury by eyespotted budmoth was negli-

gible and noted only in 1975 and 1976. Thrips

injury, represented by pansy spot on McIntosh

and Spartan cultivars, was variable and our

earlier sampling method did not detect popula-

tions that caused 2 percent injury in 1973. The

population when sampled by the Berlese funnel

method indicated a treatment level in 1975,

but the grower chose not to spray. It is doubt-

ful if a spray would have been justified since

fruit injury was less than 1 percent.

Campylomma verbasci was not present in

sufficient numbers to be of concern in this

orchard. White apple leafhopper populations

Table 1. Summary of pest management — Fitzgerald Orchard, Kelowna, 1973-1976.

Number of sprays applied, percent fruit injury

and degree of foliage injury

mee 1973 1974 1975 1976

S S I S I S I

Codling moth! 0 0 07 1 0.2 4 Onl

Fruittree leafroller and 1 2.0 1 5 iL 1.6 1, 02

European leafroller'

Eyespotted budmoth! 0 0.0 0 0.0 0 0.1 0 0.1

Thrips! 0 ZA 0 0.0 0 0.8 0 0.0

Campylomma verbasci’ 0 0.0 0 0.1 0 0.0 0 0.1

San Jose scale! 0 0.0 0 0.0 0 0.0 0 0.0

European fruit scale’ 0 0.0 0 0.0 0 0.0 0 0.0

White apple leafhopper? 0 0 nil 0 nil 1 nil

Apple aphid? 0 O nil 0 nil 0 nil

European red mite’ 1 1 nil Vp nil 1 nil

McDaniel spider mite? 0 0 nil 0 nil 0 nil

Apple rust mite? 1 i nil VY, nil 0 nil

‘damage assessed by fruit injury.

*damage assessed by leaf injury.

3+= slight damage, no effect on Apple quality.

Abbreviations: S=sprays, I=injury.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 5

CODLING MOTH PHEROMONE TRAP CAPTURES

FITZGERALD ORCHARD EAST KELOWNA

1975

30 co «OINSIDE

mm OUTSIDE

: TH il

7 = = ; Ba = i | i fi] | _

= pO. | Ge SO) 14, 8. oe Ge

a MAY JUNE JULY AUG. SEPT.

ee 1976

5 [= _ INSIDE

= mmm =OUTSIDE

: |

3 Ty, oa 14 28 12 26 9 23 6 20

MAY JUNE SEY AUG. SEPT:

Fig. 1. Codling moth pheromone trap captures 1975-1976.

Arrows indicate date of spraying. Unbroken arrow=entire orchard sprayed, broken arrow="

of orchard sprayed.

6 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

were below treatment levels from 1973 to 1975,

but a spray was required in 1976. Apple aphid

was present on young trees in all 4 years, but

colonies were restricted to terminal growth and

populations did not reach treatment level.

Mites were not a problem in the orchard

during the 4-year experiment except for apple

rust mite. The principal mite predator in

British Columbia orchards, Typhlodromus

occidentalis Nesbitt, increased during the first

year of pest management and there was an

excellent ratio of predators to phytophagous

mites during the subsequent 3 years. The

sprays in Table 1 for European red mite control

were delayed dormant oil treatments directed

against overwintered eggs. Downing and

Arrand (1976) stated that a delayed dormant

oil spray is often necessary to ensure that

integrated mite control programs will be

successful. Apple rust mite increased to treat-

ment level in 1973 and 1974 and light foliage

injury occurred in 1973 although a spray was

applied. In 1975, one block of Red Delicious

trees required a spray for apple rust mite

control and no leaf injury was detected.

No San Jose scale or European fruit scale

was encountered in any of the harvest samples.

European fruit scale is prevalent in other

orchards in this area and packinghouses have

advised growers to spray routinely. Our

management techniques did not indicate a need

to spray for this pest, but the dormant oil

spray used for European red mite eggs

probably had an effect on any scales that were

present.

Over the 4-year period, 14 applications were

made for pest control which is a 50 percent

reduction over a calendar based spray program.

On the whole, results in other pest managed

orchards were similar and the number of sprays

necessary to obtain control was reduced by 35

to 50 percent. The cost of an advisory program

has been calculated as $50 per ha (Haley 1976).

To apply a single spray of azinphosmethyl

for codling moth or leafroller control costs ca.

$25 per ha for the material alone. It is evident

that the cost of an advisory program would be

realized if the yearly spray program were

reduced by 2 applications. Another advantage

of pest management which has seldom been

mentioned is improved control when it is

necessary to spray. Timing of sprays is more

accurately based upon samples rather than on

calendar dates or phenological data used in

production guides.

References

Downing, R. S. and J. C. Arrand. 1976. Integrated control of orchard mites on apple in British

Columbia. Can. Ent. 108. 77-81.

Haley, Sue. 1976. Apple pest management in the North Okanagan Valley, British Columbia: A

feasibility study. M.A. Thesis, Simon Fraser University, Burnaby, B.C. 1-48.

Madsen, H. F., F. E. Peters and J. M. Vakenti. 1975. Pest management: Experience in six British

Columbia apple orchards. Can. Ent. 107: 873-877.

Madsen, H. F., and F. E. Peters. 1976. Pest management: Monitoring populations of Archips

argyrospilus and Archips rosanus (Lepidoptera: Tortricidae) with sex pheromone traps.

Ibid 108: 1281-1284.

Madsen, H. F. and B. E. Carty. 1977. Fruittree leafroller (Lepidoptera: Tortricidae): Control of a

population tolerant to diazinon. J. Econ. Ent. (in press).

Vakenti, J. M. and H. F. Madsen. 1976. Codling moth (Lepidoptera: Olethreutidae): Monitoring

populations in apple orchards with sex pheromone traps. Can. Ent. 108: 433-438.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 7

PHYTOSEIULUS PERSIMILIS (ACARINA: PHYTOSEIIDAE)

FOR CONTROL OF TWO-SPOTTED MITES

IN A COMMERCIAL GREENHOUSE?

N. V. TONKS AND P. EVERSON?

Research Station, Agriculture Canada

Sidney, British Columbia

ABSTRACT

Natural infestations of the twospotted spider mite were controlled on

greenhouse cucumber by early releases of the predatory mite, Phytoseiulus

persimilis Athias-Henriot. Later sporadic mite outbreaks severely damaged

some plants and required frequent surveys and repeated predator releases

in the greenhouse. However, no mite sprays were required and crop yield

was Satisfactory.

INTRODUCTION

Chemical control of the twospotted spider

mite, Tetranychus urticae Koch, on greenhouse

cucumbers is becoming increasingly difficult

in British Columbia. A number of reports have

been published on the use of the predaceous

mite, Phytoseiulus persimilis Athias-Henriot,

for control of spider mites on greenhouse

cucumbers (Chant 1961; Gould 1970, 1971;

Scopes and Parr 1971; Anonymous 1972). This

paper reports the results of a preliminary trial

in British Columbia using P. persimilis for

control of the twospotted spider mite on

cucumber in a commercial greenhouse.

METHODS

A commercial greenhouse containing 1300

parthenocarpic cucumber plants on 12,500

sq. ft. (0.12 hectare) was examined on March 24

for infestations of twospotted spider mites.

Fifty-nine infested plants were tagged and 400

predator mites released among them. Predators

were distributed by tapping 2 to 5 specimens

from a glass vial onto a cucumber leaf on each

infested plant. Five leaves, on each tagged,

infested plant were then examined periodically

for host and predator mites.

‘Contribution No.

Canada, Stidney, B.C.

236, Research Station, Agriculture

*Present address: Department of Biology, University of

Victoria, B.C.

TABLE 1. Percentage of leaves with T. urticae,

Tagged plants received no further preda-

tors, but 2200 were distributed throughout the

remainder of the planting on April 1, and 2400

on June 11. An additional 1600 predators were

used to combat localized outbreaks of mites

during April and May.

RESULTS AND DISCUSSION

Table 1 shows that twospotted spider mites

on tagged, infested plants were eliminated

by mid-May, about 55 days after predator mites

were released. However, sporadic localized out-

breaks of mites occurred in the planting during

May and part of June. Some plants were

severely damaged, but losses were not serious

in relation to the total planting. Predators

were abundant throughout the planting by

June 21, and no further mite outbreaks

occurred. Both host and predator mites had

disappeared from all plants by mid-July. There

was no recurrence of twospotted spider mites

before the plants were removed in early

August.

The introduction of red spider mites in a

planting before releasing predators has been

recommended in England to establish a

predictable predator-prey interaction

(Anonymous 1972). In our trials, predators

were released in naturally occurring mite

infestations. Plants with well-established

infestations almost invariably suffered severe

damage before the predators achieved control.

and T. urticae plus P. persimilis, following the

release of predatory mites. A total of 295 leaves were examined on each sampling date.

Days after

Predator Mite Release

% Leaves

with T. urticae

% Leaves

with T. urticae

and P. persimilis

22 38

43 ig

55 1

fel

100

nil

8 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

In addition, sporadic outbreaks of mites

required frequent monitoring of the planting

and repeated releases of predators. Neverthe-

less, we feel that the trial was successful.

Economic control of mites was achieved when

predators were released early in the develop-

ment of mite infestations. No mite sprays were

required in the test planting, and cucumber

yields were satisfactory throughout a normal

cropping period. This contrasted with condi-

tions in the same greenhouse during the

previous season, when plant damage from

mites and frequent acaricide applications

shortened the cropping period by 3 to 4 weeks.

References

Anonymous. 1972. The biological control of cucumber pests. Growers Bull. No. 1, Glasshouse

Crops Research Institute, Littlehampton, Sussex.

Chant, D. A. 1961. An experiment on the biological control of Tetranychus telarius L. in a green-

house using Phytoseiulus persimilis A.H. Canad. Ent. 93: 437-443.

Gould, H. J. 1970. Preliminary studies of an integrated control program for cucumber pests and

an evaluation of methods of introducing Phytoseiulus persimilis Athias-Henriot for the

control of Tetranychus urticae Koch. Ann. appl. Biol. 66: 503-513.

Gould, H. J. 1971. Large scale trial of an integrated control programme for cucumber pests on

commercial nurseries. P1. Path. 20: 149-156.

Scopes, N. E. A. and W. J. Parr. 1971. Big decision on predator control must be made. Grower

75 (13): 794-798.

A METHOD FOR REARING THE PREDACEOUS MITE,

PHYTOSEIULUS PERSIMILIS (ACARINA: PHYTOSEIIDAE)

T. L. THEAKER AND N. V. TONKS

Research Station, Agriculture Canada

Sidney, British Columbia

ABSTRACT

The predaceous mite, Phytoseiulus persimilis Athias-Henriot, was reared

successfully in a darkened growth chamber on blotting paper on a freezer

carton lid floated on water in a plastic saucer. Predators were fed with

twospotted spider mites collected from infested bean leaves with a mite

brushing machine.

INTRODUCTION

During studies initiated on the biological

control of the twospotted spider mite,

Tetranychus urticae Koch on_ greenhouse

cucumbers, we needed a simple method for

rearing the predaceous mite, Phytoseiulus

persimilis Athias-Henriot. Techniques -for

mass-rearing both host and predaceous mites

have been published (McMurtry and Scriven

1965, Scopes 1968, Scriven and McMurtry

1971, Anonymous 1975). This report describes

adaptations and innovations developed for our

own conditions and facilities.

METHODS AND DISCUSSION

We reared twospotted spider mites on bush

beans (Phaseolus vulgaris L. cv. Stringless

Greenpod) grown in 3:2:1 soil-peat-sand mix,

Contribution No. 237,

Canada, Sidney, B.C.

Research Station, Agriculture

'J. W. Gates, personal communication

planting 4 seeds in each 15 cm diameter plastic

pot. When the plants are about 30 cm high,

they are transferred to a growth chamber

maintained at 251°C with 16 hours of light.

Predaceous mites are reared in darkness

at 2541°C. Each culture is started by trans-

ferring 30 predaceous mites to a 9 cm disc of

blotting paper. This paper is placed on an inver-

ted 12 cm diameter lid from a freezer carton

(Plasti-Pak Containers, Toronto, Canada).

Wandering by the mites is minimized by

floating the lid on water in a plastic saucer

25 cm in diameter and 4.5 cm deep. The lid is

centred in the saucer by attaching one small

magnet to the bottom of the lid and a second

magnet in the bottom of the saucer. Another

25 cm plastic saucer is inverted over the culture

as a cover to maintain a high relative humidity

within the container.

Each predaceous mite culture is fed with

twospotted spider mites removed from infested

bean leaves with a mite brushing machine

(Henderson and McBurnie, 1943). We found

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 9

that many mites were injured when leaves were

passed between both brushes of the machine,

so we removed one brush. The leaf can be

then pressed and moved gently against the

remaining brush with the hand until all the

mites are removed. Apparently the same effect

can be achieved on some machines by reversing

the belt drive so that the brushes rotate

outwards'. The mites are collected on a 12 cm

blotting paper disc and tapped off or brushed

from the paper onto the predator culture.

Cultures develop satisfactorily if fed three

times a week. Rate of increase varies among

cultures, but we have obtained 400 to 1000

predators from single cultures after 3 to 4

weeks. One culture will remain productive for

many weeks, but after about 6 weeks debris

accumulation interferes with collecting.

Collections are made with a small suction

aspirator. One person can collect at least 1000

mites an hour from vigorous cultures. Although

predators survive only a few hours when they

are collected in vials without any host mites,

they survive about 7 days in vials containing

mite-infested bean leaf sections.

Our relatively small demand for predaceous

mites required the services of one person for

_about 3 hours per week. This includes planting

about 20 pots of beans per week, maintaining

established plants and feeding 6 to 10 cultures.

The whole rearing procedure can be readily

expanded or reduced according to demand.

References

Anonymous. 1975. Biological pest control - rearing parasites and predators. Bull. No. 2, Glass-

house Crops Research Institute, Littlehampton, Sussex.

Henderson, C. F. and H. Y. McBurnie. 1943. Sampling techniques for determining populations of

citrus red mite and its predators. U.S. Dep. Agric. Circ. 671.

McMurtry, J. A. and G. T. Scriven. 1965. Insectary production of Phytoseiid mites. J. Econ.

Ent. 58: 282-284.

Scopes, N. E. A. 1968. Mass rearing of Phytoseiulus riegeli Dosse for use in commercial horticul-

_ture. Pl. Path. 17: 123-126.

Scriven, G. T. and J. A. McMurtry. 1971. Quantitive production and processing of Tetranychid

mites for large-scale testing or predator production. J. Econ. Ent. 64: 1255-1257.

THE FIRST RECORD OF CULISETA SIL VESTRIS MINNESOTAE

BARR IN BRITISH COLUMBIA (DIPTERA: CULICIDAE).

Curtis (1967) speculated that Culiseta

silvestris minnesotae likely occurred in British

Columbia since it has been taken near the

southern boundaries of the province. During

a routine light-trap survey in the municipality

of Port Coquitlam, a suburb of Vancouver,

British Columbia, two C.s. minnesotae females

were collected on July 12 and August 14, 1974.

The larvae of this species have not yet been

found in British Columbia.

Originally described by Barr (1957) as

Culiseta minnesotae, Stone (1967) assigned it

as a subspecies of Culiseta silvestris Shenga-

rev.

This finding brings the total number of

mosquito species recorded in British Columbia

to 41, and extends the known Canadian range

of this species from Ontario to the West Coast.

I wish to thank Dr. D. M. Wood of the

Biosystematics Research Institute, Agricul-

ture Canada, Ottawa, for confirming my

tentative determination of these specimens.

References

Barr, A. R. 1957. A new species of Culiseta (Diptera: Culicidae) from North America. Proc. Ent.

Soc. Wash. 59: 163-167.

Curtis, C. L. 1967. Mosquitoes of British Columbia. Occasional Papers, B.C. Provincial Museum,

No. 15, 90 pp.

Stone, A. 1967. A synoptic catalogue of the mosquitoes of the world, Supplement III (Diptera:

Culicidae). Proc. Ent. Soc. Wash. 69: 197-224.

R. A. Costello

British Columbia Ministry of Agriculture,

Cloverdale, B.C.

AND ITS MAJOR PARASITES IN THE CROWNS OF WESTERN

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

DISTRIBUTION OF COLEOPHORA LARICELLA

(LEPIDOPTERA: COLEOPHORIDAE)

LARCH IN BRITISH COLUMBIA?!

By GORDON E. MILLER? AND THELMA FINLAYSON?

ABSTRACT

The distribution of Coleophora laricella (Hbn.) and its parasites Dicla-

docerus spp. (D nearcticus Yosh. and D. pacificus Yosh. (Yoshimoto 1976))

and Spilochalcis albifrons (Walsh) in the crowns of western larch were

determined for five classes of trees. In open-grown trees more than 7.6 m

high, C. laricella densities were greater at 1.5-3.1 m than at 6.1-7.6 m above

the ground, on the sunny side of a tree than on the shaded side, and on the

outer half than on the inner half of a branch. In open-grown trees 3.0-4.6 m

high and in trees forming a closed canopy, only the outer branch halves had

significantly greater densities. The only significant variation in parasitism

by Dicladocerus spp. occurred between branch halves in open-grown, non-

roadside trees more than 7.6 m high, with more parasitism on the inner

halves than the outer. Parasitism by S. albifrons was significantly greater

at the lower crown level than at the higher in open-grown, closed-canopy,

non-roadside trees that were more than 7.6 m high, and on the outer branch

half than on the inner half in the same category of tree.

INTRODUCTION

Little is known about the within-tree

distribution of the larch casebearer, Coleophora

laricella (Hbn.) (Lepidoptera: Coleophoridae),

an introduced pest, and its major parasites in

British Columbia, in trees growing in different

situations, It is thus difficult to develop

adequate sampling procedures. Dicladocerus

spp. (D. nearcticus Yosh. and D. pacificus

Yosh. (Yoshimoto 1976) (Hymenoptera: Eulo-

phidae) andSpilochalcis albifrons (Walsh)

(Hymenoptera: Chalcididae) were by far the

most abundant species in a two-year survey of

parasites of C. laricella (Miller and Finlayson

1974, 1977).

METHODS

Crowns of 40 western larch trees in five

classes were sampled on 13 June 1974 at Shore-

acres, British Columbia. The five classes of

trees and the number in each class were:

Webb (1953) examined the distribution of

C. laricella on American larch, Larix laricina

(Du Roi) K. Koch, but only on large, open-

grown trees. There have been no published

reports of within-tree distribution of C. laricella

in western larch, Larix occidentalis Nutt.

Distributions of Dicladocerus spp. and S. albi-

frons on western larch have been reported by

Tunnock et al. (1972), but again only on large,

open-grown trees.

The objective of this study was to determine

the within-tree distributions of C. laricella,

Dicladocerus spp. and S. albifrons in western

larch trees growing in various situations, to

provide data that could improve sampling

techniques.

Class Description Number of trees

1 Open-grown trees at least 91.4 m 10

(100 yd.) from road and over 12.2 m

(40 ft.) high

Z Same as Class 1 except 7.6-10.7 m 10

(25-35 ft.) high

3 Same as Class 1 except 3.1-4.6 m 5

(10-15 ft.) high

4 Same as Class 1 except trees were 5

roadside

5 Same as Class 1 except trees formed 10

closed canopy. Trees sampled were at

least twice height of trees from the

edge of stand

‘Based on a thesis submitted by the senior author in partial

fulfillment of an M.Sc. degree

University, Burnaby, B.C. V5A 1S6

*Graduate student and Professor, respectively, Simon Fraser

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 i

Samples from Class 1 trees were also taken

on 15 May 1974 but were analyzed for distri-

bution of C. laricella only.

Samples were taken at two crown levels:

1.5-3.1 m (5-10 ft.) and 6.1-7.6 m (20-25 ft.)

above the ground. Two primary branches were

taken from both the sunny and shaded sides of

each tree from each crown level and cut in half.

The branch halves were mass-reared in pairs

according to tree, crown level, side of tree, and

branch half. Rearing was done in 30.5x61.0x

30.5 cm (1x2x1 ft.) cages constructed from

corrugated paper cartons, the tops of which

were replaced with 0.2 mm mesh.

Parasites were collected daily and placed

directly into 70% ethanol. After parasite

emergence was completed, host cases were

removed manually and the number of fascicles

counted.

For statistical analyses, log; x transfor-

mations were done on C. laricella densities

(number per 100 fascicles) and arcsine trans-

formations were calculated for percentage

parasitism data. In analyses of variance (Dixon

1973) of the intra-tree distributions of each

class, trees were allowed to go random, result-

ing in conservative F values. The data are

presented in the untransformed form.

RESULTS

There were no_ significant differences

between the tree classes in mean density of

C. laricella or mean percentage parasitism by

Dicladocerus spp. or by S. albifrons in the

crown levels (Table 1). C. laricella densities

varied significantly between crown levels,

between sides of the tree, and between branch

halves in Classes 1, 2 and 4; and between

branch halves only in Classes 3 and 5 (Figure

1). The densities were significantly higher

on the outer branch halves than on the inner

in all classes. Significantly higher densities

occurred at the lower crown level than at the

higher in Classes 1, 2 and 4 but no significant

differences occurred between crown levels in

Class 5. Densities were also significantly higher

on the sunny sides of trees than on the shaded

sides in Classes 1, 2 and 4 but no significant

differences between sides of trees occurred in

Classes 3 and 5. The distributions did not differ

in Class 1 trees between the two collections.

The only significant variation in parasitism

by Dicladocerus spp. occurred between branch

halves, with more parasitism on the inner than

on the outer halves, in Classes 1 and 2 (Fig. 2).

No significant variations occurred between

crown levels or sides of trees in any of the

classes, or between branch halves in Classes

3, 4 and 5.

Parasitism by S. albifrons was significantly

greater at the lower crown level than at the

higher in Classes 1, 2 and 5; and on the outer

branch halves than on the inner in Classes 1

and 2 (Fig. 3). No significant differences

occurred between branch halves in Classes 3,

4 and 5, or between crown levels in Class 4.

DISCUSSION

Webb (1953) found distributions of C. lari-

cella similar to those in the crown levels and

branch portion in open-grown tree classes 1

to 4 of this study, i.e., higher casebearer

densities at the bottom of the crown than at the

top and on the terminal part of the branch than

at the base. The abundance of C. laricella

larvae and pupae on the sunny side of the tree

and the outer half of the branch may reflect the

oviposition site preferences of the female moths

TABLE 1. Density of Coleophora laricella and percentage parasitism by Dicladocerus spp., and by

Spilochalcis albifrons in five classes of trees on 13 June 1974 at Shoreacres, British Columbia.

(X = mean, SD = standard deviation)

Crown C. laricella density

% Parasitism

Class Level (no./100 fascicles) Dicladocerus spp. S. albifrons

(ft.) x SD X SD x SD

1 5-10 Tort 5.7 6.5 2.6 oa 4.1

20-25 eel 2.6 8.4 2e9 4.2 3.1

2 5-10 174 4.5 ed 2.3 10.3 4.7

20-25 Sai eg OTs 2 5.8 3.8

3 5-10 13.2 2.8 ss 1.6 7 2.0

20-25 11.0 22 9.4 5.0 3.1 3.4

4 5-10 23.1 3.2 5.0 1.6 10 3.0

20-25 10.8 2.3 6.9 3.4 2.8 ye)

5 5-10 Piz 2.8 6.6 4.3 js 5.8

12 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

Shaded

Sunny /\ Shaded

May 15. 1974 collection June 13. 1974 collection

50 Sunny /{ Shaded Sunny Shaded

June 13, 1974 collection

Fig. 1. Schematic representation of within-tree distributions of Coleophora laricella in one class of

tree on 15 May 1974 and five classes of trees on 13 June 1974 at Shoreacres, British

Columbia. (Numbers represent number of casebearers per 100 fascicles, the outer being

those of the outer branch half and the inner those of the inner branch half)

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEC. 31, 1977 1S}

30 Sunny / Shaded

= 30

= OG

Sunny /A Shaded

10 wy K +

90 Sunny /\ Shaded

= 30

Fig. 2. Schematic representation of within-tree distributions of Dicladocerus spp. in five classes of

trees on 13 June 1974 at Shoreacres, British Columbia. (Numbers represent percentage

parasitism, the outer being those of the outer branch half and the inner those of inner

branch half)

14 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

90 Shaded

ale

aie

Shaded

10 120

Fig. 3. Schematic representation of within-tree distributions of Spilochalcis albifrons in five classes

of trees on 13 June 1974 at Shoreacres, British Columbia. (Numbers represent percentage

parasitism, the outer being those of the outer branch half and the inner those of the inner

branch half)

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 15

(Sloan and Coppel 1965; Webb 1953).

The distribution of Dicladocerus spp. could

be affected by movements of C. laricella after

parasitization. The amount of spring movement

by casebearer larvae is influenced by casebearer

density, greater movements occurring at higher

densities (Webb 1953). At the densities

observed in this study, casebearer movement

was not great enough to cause a difference in

the distribution of the host between the two

collections, the apparent period of parasitiza-

tion (Miller and Finlayson 1977) in Class 1

trees. Host movement probably is not a factor

in the distribution of S. albifrons as this species

apparently attacks the sessile pupae of the host

(Bousfield and Lood 1971).

The within-tree distributions of Diclado-

cerus spp. and S. albifrons in Classes 1 and 2

are similar to those in 9.1-12.2 m (30-40 ft.)

trees in the western United States (Tunnock

et al. 1972). The distributions of Dicladocerus

spp. and S. albifrons within trees probably

reduces competition for casebearers between

these species on open-grown trees (Tunnock

et al. 1972).

When measuring the degree of parasitism

of C. laricella, Bousfield and Lood (1971) took

their samples from the terminal 45.7 cm (18’’)

of branches rather than whole branches. In

open-grown trees more than 7.6 m (25 ft.) high,

such a sampling technique would overestimate

parasitism by S. albifrons and underestimate

parasitism by Dicladocerus spp.

The differences in distributions of both

C. laricella and its parasites between classes

must be considered when measuring casebearer

populations or parasitism, especially if less

than whole-branch samples are taken, and when

sampling trees of differing types.

ACKNOWLEDGMENTS

We thank Drs. A. L. Turnbull and J. A.

McLean, Department of Biological Sciences,

Simon Fraser University, for advice on the

statistical analyses. We are grateful for

financial support for this work from National

Research Council Grant No. A4657 and in 1973

from Contract OSP3-0228 from the Pacific

Forest Research Centre, Canadian Forestry

Service, Department of the Environment,

Victoria, B.C.

References

Bousfield, W. E. and R. C. Lood. 1971. Impact of parasites on the larch casebearer in the Northern

Region 1970. U.S.D.A. For. Serv. Rept. 71-4, Northern Region, Missoula, Mont.

Dixon, W. J. 1973. BMD Biomedical Computer Programs. Univ. of Calif. Press, Los Angeles.

Miller, G. E. and T. Finlayson. 1974. Native parasites of the larch casebearer, Coleophora laricella

(Lepidoptera: Coleophoridae), in the west Kootenay area of British Columbia. J. entomol.

Soc. Brit. Colomb. 71: 14-21.

Miller, G. E. and T. Finlayson. 1977. Parasites of the larch casebearer, Coleophora laricella (Lepi-

doptera: Coleophoridae), in the West Kootenay area, British Columbia. J. entomol. Soc.

Brit. Columb. (in press).

Sloan, N. F. and H. C. Coppel. 1965. Oviposition patterns and egg predation of the larch case-

bearer, Coleophora laricella Hbn. in Wisconsin. Univ. of Wisconsin For. Res. Note. No.

124.

Tunnock, S., M. McGregor and W. E. Bousfield. 1972. Distribution of larch casebearer parasites

in the crowns of western larch trees in the Northern Region. U.S.D.A. For. Serv. Rept.

72-4, Northern Region, Missoula, Mont.

Webb, F. E. 1953. An ecological study of the larch casebearer, Coleophora laricella Hbn. (Lepidop-

tera: Coleophoridae). Ph.D. Thesis, Univ. of Michigan, Ann Arbor, Mich.

Yoshimoto, C. M. 1976. Revision of the genus Dicladocerus (Eulophidae: Chalcidoidea) of America

north of Mexico, with particular reference to species attacking larch casebearer (Lepidop-

tera: Coleophoridae). Can. Ent. 108: 1173-1206.

16 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

PARASITES OF THE LARCH CASEBEARER,

COLEOPHORA LARICELLA (LEPIDOPTERA: COLEOPHORIDAE).

IN THE WEST KOOTENAY AREA, BRITISH COLUMBIA?

GORDON E. MILLER? AND THELMA FINLAYSON:?

ABSTRACT

The parasite complex of the larch casebearer, Coleophora laricella (Hbn.),

was investigated in the Kootenay area of British Columbia in 1973 and 1974.

Forty-one species of hymenopterous parasites were obtained from rearings

of almost 153,000 final-instar host larvae and pupae. In 1973 and 1974, 31

and 24 species, respectively, were reared, with 14 common to both years.

Twenty-nine of these, in 24 genera, were confirmed as larch casebearer

parasites by individual rearings and by reports in the literature. No

parasites were obtained from eggs, needle-mining larvae, or third-instar

case-bearing larvae. The highest total percentage parasitism was 17.7%

in 1973 and 24.5% in 1974, both at Rossland. In Collection II the

Dicladocerus spp. complex comprised 46.0% of the total parasitism in 1973,

and 63.8% of the total in 1974; it was the most abundant at four of the

eight collecting sites in 1973 and 13 of the 14 sites in 1974. Spilochalcis

albifrons (Walsh) comprised 32.8% and 23.5% of the total parasitism in the

years 1973 and 1974 respectively; it was most abundant at three collection

sites in 1973 and at two in 1974. Mesopolobus sp. constituted 4.9% of the

total in 1973 and 9.9% in 1974. Larch casebearer densities in the first

collection in 1973 were highest at Fruitvale and Shoreacres with 150 and

130 cases per 100 fascicles respectively; in 1974, the highest host densities

in the first collection were at Kootenay Bay and Fruitvale with 48 and 41

cases per 100 fascicles respectively.

INTRODUCTION

The larch casebearer, Coleophora laricella

(Hbn.) (Lepidoptera: Coleophoridae), a

European species introduced into western

North America, is currently a target of

biological control efforts. Releases of exotic

parasites have been in progress for about 17

years (Denton 1972; Morris and Monts 1972;

Ryan and Denton 1973; Ryan et al. 1975, 1977).

Turnbull and Chant (1961) argued ‘that the

ecology of a pest being considered for a

biological control programme should be studied

in the area of proposed release prior to the

introduction of natural enemies. To determine

the identities of parasites and degree of parasi-

tism of C. laricella in British Columbia, surveys

were carried out in 1973 and 1974. Results of

the 1973 survey were reported by Miller and

Finlayson (1974).

METHODS

Procedures in 1974 were similar to those

used in the 1973 survey and were described by

Miller and Finlayson. Samples were taken in

1973 at eight sites: Anarchist Summit, Arrow

Creek, Cascade (=Christina Lake), Fruitvale,

Rossland, Sheep’s Creek, Shoreacres, and

'Based on a thesis submitted by the senior author in partial

fulfillment of an M.Sc. degree.

*Graduate student and Professor, respectively, Simon Fraser

University, Burnaby, B.C. V5A 1S6

Yahk. In 1974 these eight were again investi-

gated plus the following additional six sites:

Cranbrook, Johnstone Creek Park, Kootenay

Bay, Roosville, Rykerts and Winlaw (Fig. 1).

Collection I on May 14-15, 1974, consisted

mainly of final-instar larvae and Collection II

on June 12-13, mainly of pupae.

Ten trees were sampled in each collection at

1.5 - 3.0 m (5-10 ft.) and at 6.1 - 7.6 m (20-25 ft.)

Five primary branches were taken from the full

circumference of each tree at each height.

Mass-rearing was done in 30.5x61.0x30.5 cm

(1x2x1 ft.) cardboard boxes in which the tops

had been replaced by 0.2 mm mesh. Individual

rearing of larvae and pupae collected at

Cascade, Rossland, Sheep’s Creek and Shore-

acres in 1974 was done in % dram vials to

which fresh larch needles were supplied as

required by the feeding larvae.

Eggs were collected both years from 10

trees at each site and mass-reared in petri

dishes. Early larval instars were collected at

Rossland and Shoreacres in August and

October, 1973. These were mass-reared in

approximately the same way as the later

instars.

RESULTS

A total of 134,511 C. laricella were mass-

reared: 102,947 in 1973 and 31,564 in 1974;

and 18,300 were reared individually in 1974.

In 1974 there were 20,168 casebearers in

Collection I and 11,396 in Collection II, whereas

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

Sanu

\ a Scale : miles

0 30

ee ae es caren

p N i SN) Range of Larix

J Ng

aa WN occidentalis

— Range of

SS Coleophora

laricella

ors \\ \

7 CAW SK \

é S e

KC lw \\e

\ \ \ ) \\\ YN \

N \ W IN . \ 6

AK \\ INN

WS NW NS AX

\ ¢ Ni »~ \

K Ni \ |

N N WN «

\X KRY S\\\ \

\ XS CRANBROOK \\

ANY Gv

A NR NS ~~

\NN AAS 10% ~ 12S UNS |

ee ENA ASA 6 RS

COLEECTION SIMES

1 ANARCHIST SUMMIT 8 WINLAW

2 JOHNSTONE CREEK PARK 9 KOOTENAY BAY

3. CASCADE 10 ARROW CREEK

4 ROSSLAND 11 RYKERTS

5 FRUITVALE WZ YAHK

6 SHEEP'S CREEK 13. CRANBROOK

7 SHOREACRES 14 ROOSVILLE

Fig. 1. Distribution of Coleophora laricella in British Columbia in 1972 and location of the collection

sites in 1973 and 1974. (Adapted from R. F. Shepherd and D. A. Ross, ‘‘Problem analysis: larch

casebearer in B.C.’’ Unpublished Internal Report BC-37, Pac. For. Res. Cent., Victoria, B.C. 1973).

18 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977

the comparable collections in 1973 amounted to

40,695 and 62,242. As more samples were taken

in 1974 than in 1973, the figures indicate a con-

siderable reduction in populations over the

range of this species in British Columbia

between the two years.

In 1974, a total of 1,989 specimens of 24

species of hymenopterous parasites and hyper-

parasites were reared as compared with 4,459

specimens of 31 species in 1973 (Miller and

Finlayson 1974). The total number of species

obtained in the two years was 41, with 14

common to both.

Table 1. Confirmed parasites from mass-rearings of Coleophora laricella in British,

Columbia in 1973 and 1974

1973

May 8-9

No. No.

Hymenopterous Parasites

Abundance

1974

May 23-25 May 14-15 June 12-13

No. No. No. No. No. No.

Obtained Sites? Obtained Sites? Obtained Sitesb Obtained Sites?

Braconidae

Bracon pygmaeus Prov.',’,®

Ichneumonidae

Campoplex rufipes Prov.’

Diadegma sp.',?

Gelis tenellus (Say)', ’,

Gelis sp. ', ’, °

Itoplectis vesca Townes !

Pristomerus sp. ', ”

Scambus decorus Walley !

Eulophidae

Achrysocharella sp. ', ?

Chrysocharis laricinellae

( Ratz.) 7;°

Cirrospilus pictus (Nees)

Dicladocerus spp. (2) ', ”, °

Elachertus proteoteratis

(How.) *

Euderus cushmani (Crawford) 3

Eulophus sp. ** 2 i

Tetrastichus dolosus (Gahan) ?

Tetrastichus ecus Wlkr. ', ”

Zagrammosoma americanum

Gir. ?

Encyrtidae

Copidosoma sp.’

Pteromalidae

Catolaccus aeneoviridis (Gir.) ?,

Habrocytus phycidis Ashm. ”, * Ll

Mesopolobus sp. ', ” 15 2

Chalcididae

Spilochalcis albifrons (Walsh) ', ?, *

32 5

325 8

—_

Eurytomidae

Eurytoma sp. 3*

Diapriidae

Telenomus spp. (3) **

Trissolcus sp. **

273 8 9 5 6 4

2 i

3 2 1 1

2 2 2 2

) 4 3 2

1 1 2, i

2 1 4 4 4 3

10 2 4 2 2 1

30 3 7 2 3 1

5 2 1 1

1 1

1,480 8 693 14 669 14

1 1

2 1

2) 2

142 5 1 1

10 1 2 it

1 1

2 1

5 2

158 6 ail 9 104 wy)

1,054 6 247 7

1 1

6 2

10 2

a-out of 8 b-out of 14

1 confirmed by individual rearings in this study

2 confirmed by Bousfield and Lood (1973)

3 confirmed by Webb (1953)

* confirmed to genus only.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977

Table 2. Relative abundance of the confirmed Coleophora laricella parasite species obtained from

mass-rearings of C. laricella in British Columbia in 1973 and 1974 (in per cent)

1973 1974

Species May 8-9 May 23-25 May 14-15 June 12-13

Dicladocerus spp. 86.7 46.0 83.2 63.8

Spilochalcis albifrons 52:5 20.0

Bracon pygmaeus 8.5 8.5 0.6

Mesopolobus sp. 4.9 13.3 9.9

Tetrastichus ecus ° 4.4 0.1

Other (no. of species) 4.8 (3) 30 (19) B00) 2 N12)

Some of the parasites that emerged from

mass-reared samples could have come from

hosts other than C. laricella that were

accidentally included in the collections. A mass-

reared parasite was considered to have come

from C. laricella only if it had been obtained

from the individual rearings in this work, or

had been verified previously (Bousfield and

Lood 1973; Denton 1972; Sloan 1965; Webb

1953).

Twenty-nine species have been confirmed as

parasites of C. laricella (Table 1). The 12

species not considered to be casebearer para-

sites are: Aphidius sp. (Aphidiidae); Acrolyta

sp., Hyposoter sp. (Ichneumonidae);

Aprostocetus spp. (2), Diglyphus _ sp.,

Melittobia sp. (Eulophidae); Thysanus sp.

(Thysanidae); Cyrtogaster vulgaris Whlkr.

(Pteromalidae); Aphanogmus sp. (Ceraphroni-

dae); and Aclista sp. (Diapriidae).

Most of the confirmed species represent new

host records for British Columbia. Gelis

tenellus (Say), Scambus decorus Wly., Tetrasti-

chus ecus Wlkr. [=xanthops(Ratz.) | and Spi-

lochalcis albifrons (Walsh) were previously

recorded by Andrews and Geistlinger (1969).

These workers also obtained Bracon sp. which

may well have been B. pygmaeus Prov;

Amblymerus sp. which probably is the same as

the Mesopolobus sp. found in this study; and a

species reported as Dicladocerus westwoodii

Westw. which may be either of the two new

species found in this study, D. nearcticus

Yosh. or D. pacificus Yosh. (Yoshimoto 1976).

Two species not taken in the study but which

have been reported previously as parasites of

C. laricella in British Columbia are Scambus

transgressus (Holmg.) and _ Sceptrothelys

deione (Wlkr.) (Andrews and Geistlinger 1969).

Although many parasite species were ob-

tained, only a few predominated, with

Dicladocerus spp. and S. albifrons being by far

the most abundant (Table 2). The most abun-

dant species were also the most widespread

(Table 1). Dicladocerus spp. and Mesopolobus

sp. increased in relative abundance in 1974

when compared with 1973, while the other

species that were relatively abundant in 1973

Table 3. Summary of confirmed parasites from mass-rearings of Coleophora laricella collected at

14 locations in British Columbia on May 14-15, 1974 .

Parasitism

C.laricella |Dicladocerus spp. Mesopolobus sp. Other Total

No. of Cases/100 No. of No. No. No. No. of

Location Cases Fascicles|Emerged “ | Emerged Reared % Reared Taxa h

Anarchist Summit 95 1.2 1 jal 1 ioe

Arrow Creek 2,126 29.8 36 17. 9 0.4 3 0.1 48 2aced

Cascade 1,488 17.7 61 4.1 g 0.6 8 (0.5 78 7 Fo-2

Cranbrook 53 0.6 3 Del 33 1 ek

Fruitvale 2,774 40.8 86 oul 11 0.4 11 0.4 108 Sitord

Johnstone Creek Park 169 8.5 2 12 2 LZ

Kootenay Bay A275 47.8 9 O02 4 0.1 S01 @ 1s 2 0.4

Roosville 61 0.7 3 4.9 3 1 4.9

Rossland 832 8.0 54 6.5 3 04 9 11 66 4 7.9

Rykerts 4,619 21.9 162 3.5 HAGE 0.6 3 O.1 192 2 4.2

Sheep’s Creek 1,873 19.7 121 6.5 31 eye. 19! «710: ala 5 9.1

Shoreacres 1,604 25.4 150 9.4 18 L243. 70:8) Sl 6 11.3

Winlaw 94 G2 4 4.3 1 en 5 2 5.3

Yahk 105 0.8 1 0 1 1.0 2 1 1.9

J. ENTOMOL, Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

UL I & VG I i G €°0 éV qe

08 [ 9 eT I L9 | 80 GL MBTULM

991 8 L8G L’0 él GL vol 9 LG GL Za UST PSL'T Se1OB810YS

EST 9 LST LT LT 6'T 61 ST SI L’6 L6 v6 100°T Yee1D s,deeyg

L’6 & LOT £0 9 80 al VT VG GL €S1 Ust OZL'T sqroy Ay

G'¥S G 9€ VE S UP 9 VT G 9ST £3 66 al Pue[ssoy

ST I I ST I L‘0 9S o[Asoo"

oe G g9 v0 € ES 29 09 30°C Aeg Avusj00y

Ge I v Ge Vv O'S SIT Wed Yee1D suojsuyor

T9 g 86 £0 S L‘0 él L’0 IT vv IL 1'9% GT9'T oTeAN IY

og I G eG G v0 8& AEM MLE)

9OT 8 L&I v0 S OS 09 8°0 6 vv €S SOI 661'T SPpese)

€'8 € 861 a0 8 80 él L'0 at €°9 L6 U's1 9bG'T Wests Bory

Weg G 9 ae I eg . 60 v6 PWUUING YTYyIeUy

o exe, jo peasy % peresy % pesi0uiy | 3 pes10wy F posiauiy | sepoioseyq saseg uolqyeI0'T

‘ON ‘ON ‘ON ‘ON Yo ‘ON Yo ‘ON OOL/Seseg jJo'oN

[210 I9yIO SUOAJIQ[e ‘ds snqojodosay | ‘dds snaad0pepaiqg V]feotse] “Oo

slojeyooyids

UIST}ISVIEg

PLOL ‘ET-ZI PUNE UO BIQuINjOD Ysipag Ul SUOT}BIO] FT

Je pezoa[[O9 e]jeaAe] e1oydoa[oy Jo Ssulieei-ssewW WoJJ soeyisered pourmjuod Jo AreuluIns ‘fp ajqey,

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 21

decreased, relatively. In 1974, Dicladocerus

spp. were the most abundant at all locations in

the first collection (Table 3) and at 13 in the

second (Table 4). In 1973, Dicladocerus spp.

were the most abundant at six of the eight

locations in the first collection and at five in the

second collection; B. pygmaeus was the most

abundant at two in the first collection and one

in the second; and S. albifrons was the most

abundant at two in the second (Miller and

Finlayson 1974).

Greater parasitism, in terms of both number

of taxa and percentage parasitism, occurred

in the second collection than in the first in both

1973 (Miller and Finlayson) and 1974 (Tables 1,

oe 4).

The greatest casebearer densities per 100

fascicles in 1974 were at Kootenay Bay and

Fruitvale where there were, respectively, 47.8

and 40.8 in the first collection and 36.0 and 26.1

in the second (Tables 3, 4). The greatest total

percentage parasitism of 24.5% occurred at

Rossland where host density was 3.9 case-

bearers per 100 fascicles. Percentages of para-

sitism at the various locations were not related

to host densities, as was also the case in 1973

(Miller and Finlayson 1974).

Achrysocharella sp. was the only gregarious

parasite species indicated by individual

rearings. The mean number of adults produced

from four cases was 3.25. Bousfield and Lood

(1971) also found a very low incidence of

gregariousness. However, they found three

species, Achrysocharella silvia Gir., T. ecus

and Mesopolobus sp., that occasionally pro-

duced more than one adult per case.

No parasites emerged from mass-rearings

of 2,427 eggs, 19,279 needlemining larvae, or

6,890 fall-collected, casebearing, third-instar

larvae.

DISCUSSION

The parasite complex and incidence of para-

sitism on C. laricella in British Columbia were

comparable to those in other areas of North

America (Bousfield and Lood 1971, 1973;

Denton 1972; Sloan 1965; Webb 1953). The

parasite complex also resembles the complexes

in the Alps region of Europe (Jasch 1973),

although more major species, in terms of rela-

tive abundance and constancy, occurred in the

Alps. There was a low incidence of three species

of parasites in needle-mining larvae and case-

bearing, third-instar larvae in the Alps,

whereas no parasites were taken from these

stages in British Columbia. There are no

reports of parasites that emerge from C. lari-

cella eggs.

Miller and Finlayson (1974) reported two

European species that had been released

against C. laricella in eastern North America

in the 1930’s: Chrysocharis laricinellae (Ratz.)

and Cirrospilus pictus (Nees). C. laricinellae

was found again in 1974. Ryan et al. (1974)

give possible explanations for the presence

of these species.

Agathis pumila (Ratz.) (Braconidae) is

conspicuous by its absence in this survey. It

was released against C. laricella in British

Columbia in 1969 and has since become estab-

lished (Morris and Monts 1972). One of the

release sites was less than one mile from the

Arrow Creek location in this study.

The increase in parasitism between the two

collections in both 1973 and 1974 indicates that

adult parasites are active during this period

and/or that C. laricella reaches a more suscep-

tible stage. Sweep-net collections of adults of

B. pygmaeus, I. vesca, Dicladocerus spp. and

Mesopolobus sp. during the first 1974 collection

confirmed their presence in the field during this

period. The increase in parasitism by S. albi-

frons between collections was probably correla-

ted with the increase in host pupal populations

between collections, as pupae are thought to be

the stage attacked by this species (Bousfield

and Lood 1971). Similar increases in parasitism

of C. laricella and other coleophorids during the

spring-feeding period have been _ reported

(Beacher 1947; Bousfield and Lood 1971;

Doner 1934).

Mortality of C. laricella caused by the native

parasites may be limited by the number of

alternate hosts available to the parasites in the

absence of suitable instars of C. laricella as

these, or related species, are known to have

more than one generation per year (Clausen

1962; Dowden 1941; Jasch 1973) and not all of

them can be spent on C. laricella. S. albifrons is

more dependent on alternate hosts than other

species as very few females (2.5% of the species

total in 1973 and 0.0% in 1974) emerged from

C. laricella in this study.

A positive trend was noted between total

percentage parasitism and the total number of

lepidopteran and sawfly larvae (which may or

may not be alternate hosts of the parasites

taken) at five of the sites. In eastern Canada

the introduced species C. laricinellae, is much

more effective against C. laricella in the

presence of A. pumila or in the presence of

alternate hosts due to improved synchroni-

zation (Quednau 1970). The lack of alternate

hosts has been suggested as a limiting factor of

parasitism in other coleophorids (Beacher

1947; Doner 1934, 1936).

Species of exotic parasites that have been

recently released, or that are contemplated for

release, against C. laricella in western North

America are taxonomically related to the native

species reared in this study. They also are non-

specific and non-synchronized with C. laricella

(with the exception of A. pumila) and have a

minor role in reducing larch casebearer popula-

tions in Europe (Jasch 1973). For these

22 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

reasons, the probability that they will be effec- Agriculture, Ottawa, Ont., for identifying the

tive biological control agents in western North parasites. The work was supported by National

America is questionable. Research Council Grant No. A4657 and in

ACKNOWLEDGMENTS 1973 by Contract OSP3-0228 from the Pacific

We thank Drs. J. R. Barron, L. Masner, Forest Research Centre, Canadian Forestry

W. R. M. Mason, C. M. Yoshimoto, and Messrs. Service, Department of the Environment,

H. E. Bisdee and M. Ivanochko, Entomology Victoria, B.C., for both of which we express our

Research Institute, Canada Department of appreciation.

References

Andrews, R. J. and N. J. Geistlinger. 1969. Parasites of the larch casebearer, Coleophora laricella

(Hbn.), in British Columbia (Lepidoptera: Coleophoridae). J. entomol. Soc. Brit. Columb.

66: 50-51.

Beacher, J. H. 1947. Studies of pistol case-bearer parasites. Ann. ent. Soc. Am. 40: 530-544.

Bousfield, W. E. and R. C. Lood. 1971. Impact of parasites on the larch casebearer in the Northern

Region 1970. U.S.D.A. For. Serv. Rept. 71-4, Northern Region, Missoula, Mont.

Bousfield, W. E. and R. C. Lood. 1973. Parasites of the larch casebearer in Montana, Idaho, and

Washington. Environ. Ent. 2: 212-213.

Clausen, C. P. 1962. Entomophagous Insects. Hafner Publ. Co., New York.

Denton, R. E. 1972. Establishment of Agathis pumila (Ratz.) for control of larch casebearer, and

notes on native parasitism and predation in Idaho. U.S.D.A. For. Serv. Res. Note

INT-164, Intermt. For. and Range Exp. Stn.

Doner, M. H. 1934. Observations on the biology of Microbracon pygmaeus (Prov.), an important

parasite of Coleophora pruniella Cl. Ann. ent. Soc. Am. 27: 435-442.

Doner, M. H. 1936. Hymenopterous parasites of Coleophora pruniella CL., and parasites recorded

from other species of Coleophora. Ann. ent. Soc. Am. 29: 224-244.

Dowden, P. B. 1941. Parasites of the birch leaf-mining sawfly (Phyllotoma nemorata). U.S.D.A.

Tech. Bull. 757.

Jasch, A. 1973. Populationsdynamik und Parasitenkomplex der Larchenminiermotte, Coleophora

laricella Hbn., im natiirlichen Verbreitungsgebiet der Europdischen Larche, Larix decidua

Mill. Z. angew. Ent. 73: 1-42.

Miller, G. E. and T. Finlayson. 1974. Native parasites of the larch casebearer, Coleophora laricella

(Lepidoptera: Coleophoridae), in the west Kootenay area of British Columbia. J. entomol.

Soc. Brit. Columb. 71: 14-21.

Morris, E. and J. Monts. 1972. Larch casebearer infestations in Nelson Forest District, 1972. Can.

For. Serv., Forest Insect & Disease Surv. Pest Rept., Pacific Forest Research Centre,

Victoria, B.C.

Quednau, F. W. 1970. Competition and cooperation between C. laricinellae and A. pumila on larch

casebearer in Quebec. Can. Ent. 102: 602-612.

Ryan, R. B., W. E. Bousfield, R. E. Denton, R. L. Johnsey, L. F. Pettinger and R. F. Schmitz.

1975. Additional releases of larch casebearer parasites for biological control in the

western United States. U.S.D.A. For. Serv. Res. Note PNW-242.

Ryan, R. B., W. E. Bousfield, C. W. Johanningmeier, G. B. Parsons, R. F. Schmitz and L. J.

Theroux. 1977. Releases of recently imported larch casebearer parasites for biological

control in the western United States, including relocations of Agathis pumila. U.S.D.A.

For. Serv. Res. Note PNW-290.

Ryan, R. B., W. E. Bousfield, G. E. Miller and T. Finlayson. 1974. Presence of Chrysocharis lari-

cinellae, a parasite of the larch casebearer, in the Pacific Northwest. J. econ. Ent. 67: 805.

Ryan, R. B. and R. E. Denton. 1973. Initial releases of Chrysocharis laricinellae and Dicladocerus

westwoodii for biological control of the larch casebearer in the western United States.

U.S.D.A. For Serv. Res. Note PNW-200.

Sloan, N. F. 1965. Biotic factors affecting populations of the larch casebearer Coleophora laricella

Hbn. in Wisconsin. Ph.D. Thesis, Univ. of Wisconsin, Madison, Wisc.

Turnbull, A. L. and D. A. Chant. 1961. The practice and theory of biological control of insects in

Canada. Can. J. Zool. 39: 697-753.

Webb, F. E. 1953. An ecological study of the larch casebearer, Coleophora laricella Hbn. (Lepidop-

tera: Coleophoridae). Ph.D. Thesis, Univ. of Michigan, Ann Arbor, Mich.

Yoshimoto, C. M. 1976. Revision of the genus Dicladocerus (Eulophidae: Chalcidoidea) of America

north of Mexico, with particular reference to species attacking larch casebearer (Lepidop-

tera: Coleophoridae). Can. Ent. 108: 1173-1206.

_ J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 23

FEEDING POTENTIAL OF PREDATORS OF

MYZUS PERSICAE'/

GEORGE TAMAKI AND DARRYLL OLSEN

Yakima Agricultural Research Laboratory,

Agric. Res. Serv., USDA, Yakima, WA 98902

ABSTRACT

A rate of feeding for predator insects on th green peach aphid, Myzus

persicae (Sulzer), was determined based on the number of aphids consumed

from a more natural environment corrected for reproduction and natural

death. Of the predator species studied, the largest, Coccinella transverso-

guttata Falderman, consumed about 10 times more aphids than the

smallest, Orius tristicolor (White), and about 7 times more than the average

for all other predator species combined.

INTRODUCTION

Pest management specialists working in

the Yakima Valley of central Washington have

needed a method of relating the abundance of

certain predator insects to their potential effect

on populations of the green peach aphid (GPA),

Myzus persicae (Sulzer). A predictive model

was therefore developed whereby the numerical

census of a predator species is converted to

factors that reflect the reductive impact of the

predator complex against the GPA (Tamaki

et al. 1974). Thus, one component of this model

separates the predator complex into discrete

groups, each with gross similarities in feeding

capacity. Then each group is assigned a

numerical factor related to its rate of consump-

tion of aphids. The feasibility of the model was

demonstrated by using factors drawn from date

provided by Goodarzy and Davis (1958) and

Simpson and Burkhardt (1960), concerning the

predators of the spotted alfalfa aphid, Therioa-

phis maculata (Buckton), for demonstrating

the feasibility of the model, but we now needed

factors applicable to the predators of the

GPA found in the Yakima Valley. However,

workers studying aphidophagous predators in

the past have usually introduced known

number of prey into cage with a predator and

then counted the number dead, partially eaten,

or missing. Such a procedure cannot provide

an accurate estimate of the impact of predators

on a viable population of aphids. We therefore

altered the procedure by providing a host plant

for the aphids when we exposed them to preda-

tors so as to incorporate the effects of repro-

duction of the aphids and natural mortality

on the prey searching of the predators. We-also

examined the apparent role and abundance of

predator species in the field.

MATERIALS AND METHODS

In 1973, single adult predators were placed

on a bouquet of sugarbeet leaves in 1-pint ice

cream carton cages located at random on a

laboratory bench under daylight-fluorescent

'/ Hemiptera: Aphididae.

lighting, which provided a 16 h photophase.

Then 100 GPA from the laboratory colony

(3rd and 4th instars and adults) were placed

in each cage. The cages were examined each

morning for 3 days (days 2, 3, and 4) after the

predators were introduced and the number of

aphids was counted. Also, on days 2 and 3,

sufficient aphids were added to bring the total

in each cage to 100. The smaller species of

predators were found to consume only ca. 10 of

the aphids/day; the larger species consumed

ca. 50. The resulting differences between cages

in the age distribution and reproduction of

the aphids then produced inconsistent numbers

of prey consumed. Therefore, in 1974, we used

sugarbeet leaf bouquets and ice cream carton

cages as before but reduced the number of

aphids available to the smaller predators to

20/day. In this way all species of predators

actually consumed about 50% of the prey

available. Also, in 1973 and 1974, we noted that

reproduction and natural mortality of the

aphids began to be affected by the deteriora-

tion of the bouquets by the 4th day of the test.

Therefore, in 1975, the aphids were placed on

small sugarbeet plants in large plastic cages

(Fig. 1). Otherwise (numbers of aphids per cage

per day), the procedure was like that in 1974.

The insect predators used in the test were

collected in the field from sugarbeet, clover, or

alfalfa. Three species (determined by availabili-

ty) were tested each week through the growing

season.

Temperatures during the test period avera-

ged 24°C (range of 19-33°C); the RH averaged

46% (range 44-48%). Rate of predation was

determined as the average of the difference

between the number of aphids available at the

beginning of each day minus the number

remaining after each day for 4 days. Each

treatment was replicated 10 times on each of

the 4 days.

RESULTS AND DISCUSSION

Although the difference in the test proce-

dures in 1974 and 1975 resulted in differences

spryde pue 10}epeid a4e[OSI 07 posn aed *T “SIq

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

in aphid reproduction and natural death, the

feeding rate for a given species of predator

was similar both years; therefore, these data

were combined in Table 1. Also, the data for the

2 Bembidion spp. were combined because only

small numbers were tested and the feeding

rates were very similar. Plainly, the size of the

predator was of major importance. Thus, the

daily consumption of GPA by Coccinella

transversoguttata, the largest of the predators

studied, was 10 times that of the smallest

predator, Orius tristicolor, 5 times that of the

combined average of all the other predator

species listed in Table 1.

In the field, C. transversoguttata, one of the

large coccinellid species, was more common

than Hippodamia convergens Guérin-Meéneville.

Nabis alternatus was more common sugar-

beets, alfalfa, and clover than N. americoferus

Carayon though the latter was found frequent-

ly in these crops. Geocoris bullatus, which is

larger than G. pallens, consumed ca. 2 more

aphids/day. However, G. pallens was the most

abundant in sugarbeets and potatoes; G.

bullatus generally inhabits more permanent

grass covers such as floors of orchards and

also many perennial forage crops (Tamaki

1972). Little is known of Scymnus margini-

Table 1. Average rate of predation of green peach aphid by selected adult predators.

Mean (+ se)

No. of

Species predators predation/day per predator

Coccinella

transveroguttata Falderman 70 52.10+ 3.438

Nabis

alternatus Parshley 100 10.37 = .62

Anthocoris

melanocerus Reuter 50 8.46 + .74

Geocoris

bullatus (Say) 80 8:30 = 57

Scymnus

marginicollis Mann 90 7.99 + .43

Bembidion

spp. 40 6.66 + .67

Geocoris

pallens Stal 80 6.47 + .52

Orius

tristicolor (White) 90 hole A3

collis except that we have frequently observed

the larvae and adults of this small coccinellid

feeding on GPA on sugarbeets.

The two small carabids, Bembidion

obscurellum Mots. and B. rupicola Kby., were

ajbundant in some fields of sugarbeets and

potatoes. In the laboratory, these species will

feed on larval scab gnat, Pnyxia_ scabiei

(Hopkins), and GPA. Mitchell (1963) reported

that the crop contents of Bembidion lampros

(Herbst) consisted of parts of collembolans,

small mites, and earthworm material and that

in the laboratory, the adults and larvae would

feed on most types of invertebrate animal prey

found in soil samples.

Anthocoris melanocerus Reuter and Orius

tristicolor are in the same family, Anthocoridae,

but A. melanocerus is ca. 4-5 times larger than

O. tristicolor and consumed nearly twice as

many GPA. A. melanocerus is primarily known

as a predator of psyllids on deciduous fruit

trees (Madsen 1961 and Watson and Wilde

1963); however, it has also been reported

feeding on aphids on many vegetable and

forage crops (Tamaki and Weeks 1968). Orius

tristicolor was rarely observed to feed on

aphids in the field; in fact, it was seen to run

between aphids in attempts to capture a thrip.

Smith and Hagen (1956) also reported that O.

tristicolor preferentially fed upon mites and

thrips, rarely aphids. In the _ laboratory,

however, O. tristicolor will feed on aphids if no

other prey is available.

Although the feeding rates of the predators

that we report are based on laboratory studies,

most of these predators (except O. tristicolor

and Bembidion spp.) would probably feed at

the same rates in the field if aphids were

abundant. However, when aphid numbers are

minimum, searching time and prey preference

would probably lower the rates.

26 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977

Geocoris pallens

insect predators

Myzus persicae - green peach aphid

Nabis alternatus

Orius tristicolor

Scymnus marginicollis

Predators of Myzus persicae

Anthocoris melanocerus

Bembidion spp.

biological control

Coccinella transversoguttata

Geocoris bullatus

References

Goodarzy, K., and D. W. Davis. 1958. Natural enemies of the spotted alfalfa aphid in Utah. J.:

Econ. Entomol. 51: 612-6.

Madsen, H. F. 1961. Notes on Anthocorus melanocerus Reuter (Hemiptera: Anthocoridae) as a

predator of the pear psylla in British Columbia. Can. Entomol. 93: 660-2.

Mitchell, B. 1963. Ecology of the two carabic beetles, Bembedion lampros (Herbst) and Trechus

quadristriatus (Shrank). I. Life cycles and feeding behavior. J. Anim. Ecol. 32: 289-99.

Simpson, R. G., and C. C. Burkhardt. 1960. Biology and evaluation of certain predators of Therio-

aphis maculata (Buckton). J. Econ. Entomol. 53: 89-94.

Smith, R. F., and K. S. Hagen. 1956. Enemies of spotted alfalfa aphid. Calif. Agric. 10: 8-10.

Tamaki, G. 1972. The biology of Geocoris buttalus inhabiting orchard floors and its impact on

Myzus persicae on peaches. Environ. Entomol. 1: 559-65.

Tamaki, G., J. U. McGuire, and J. E. Turner. 1974. Predator power and efficacy: A model to

evaluate their impact. Environ. Entomol. 3: 625-30.

Tamaki, G., and R. E. Weeks. 1968. Anthocoris melanocerus as a predator of the green peach aphid

on sugarbeets and broccoli. Ann. Entomol. Soc. Am. 61: 579-84.

Watson, T. K., and W. H. A. Wilde. 1963. Laboratory and field observations of two predators of

pear psylla in British Columbia. Can. Entomol. 95:435-8.

THE SYSTEMATIC POSITION OF THE

APPLE-AND-THORN SKELETONIZER:

This moth, also known as squeletteuse du

pomier et du cenellier (Benoit 1975), has been

referred to in North America as Anthophila

pariana (Cl.) since the 1930’s and usually as

Hemerophila pariana (Cl.) before then. To

check its identity in Western Canada the

genitalia and the external morphology of

specimens from the Vancouver, B.C., area were

compared with data in European studies on the

taxonomy and systematics. It was confirmed

that the species found in the Vancouver

district, where it was usually abundant in

1976, is a single species rather than a complex

and is the same species found in Europe and

the USSR; but that, in line with the con-

clusions of Danilevsky (1963) and Danilevsky

and Kuznetzov (1973), it is of the genus

Hemerophila Hubn. rather than of Anthophila

Haw. The correct name of the species found in

the Vancouver district, and presumably

elsewhere in North America, is_ therefore

Hemerophila pariana (Cl.). - M. Doganlar,

Pestology Centre, Simon Fraser University,

Burnaby, B.C.

References

Benoit, P. 1974. Noms Francais d’Insectes au Canada. Agric. Que. publ. QA38-R4-30.

Danilevsky, A. S. 1963. [new species of Glyphipterygidae (Lepidoptera) in the USSR] Ent. Rev.

48: 585-593.

Danilevsky, A. S., and V. I. Kuznetzov. 1973. [A review of the Glyphipterygid moths of the genus

Hemerophila Hb. (Lepidoptera, Glyphipterygidae) of the fauna of the USSR]. Tr.

Vsesoyuz. Entomol. Obshch. 56: 8-17.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 27.

MORPHOLOGY OF ALIMENTARY AND REPRODUCTIVE

TRACTS OF THE RODENT BOT FLY, CUTEREBRA TENEBROSA

(DIPTERA: CUTEREBRIDAE)'

CRAIG R. BAIRD?

and

ROGER D. AKRE?

ABSTRACT

The internal reproductive and alimentary structures of Cuterebra

tenebrosa Coquillett were studied and compared to other calypterate flies.

Well defined mouth parts are present. Paired lingual salivary glands extend

horizontally almost to the abdomen; however, labial salivary glands were

not found. The alimentary canal is complete in female flies, whereas males

lack a crop. Females have three spherical spermathecae opening into the

upper portion of the genital chamber. Male reproductive structures are

similar to those in other flies. Tracheal air sacs fill one-third to one-half of

the abdomen.

INTRODUCTION

Little is known concerning the internal

structure of Cuterebra bot flies. Townsend

(1935) provided the earliest descriptions of

Cuterebra alimentary and reproductive tracts

but did not include illustrations.

In 1963, Catts described and illustrated the

alimentary and_ reproductive’ tracts of

Cuterebra latifrons Coquillett. A comparative

study of the alimentary canal of several flies

including C. latifrons was made by Singh and

Judd in 1966. Various authors have described

and illustrated the external genitalia of

Cuterebra (Bennett 1955; Haas & Dicke 1958;

Catts 1963; Graham and Capelle 1970; and

Baird and Graham 1973). The purpose of the

present paper is to report findings from

dissections of Cuterebra tenebrosa Coquillett

specimens and to provide illustrations of the

structures.

METHODS AND MATERIALS

Adult flies were obtained by rearing larvae

in captive bushytailed wood rats (Neotoma

cinerea Ord.). Within five days after emergence,

flies were injected with Kahle’s solution to kill

and fix them in an extended position. They

were stored in the same preservative for several

days and then transferred to 70% alcohol for

permanent storage. Dissections were performed

with standard insect dissection tools under a

binocular microscope.

‘Scientific Paper No. 4489, College of Agriculture Research

Center, Washington State University, Pullman. Project 994.3.

*Department of Entomology, University of Idaho, Moscow,

Idaho Address: P. O. Box 1058 Caldwell, Idaho 83605

*Department of Entomology, Washington State University,

Pullman, Washington 99163

OBSERVATIONS AND DISCUSSION

The use of Kahle’s solution to kill adult flies

proved a very useful technique since the

solution perpeated all body areas and preserved

the internal organs very well.

Alimentary Tract

No attempt was made to describe the mouth

parts of C. tenebrosa. The mouth parts are

typically muscoid in both sexes as described for

C. emasculator (Bennett 1955) and C. latifrons

(Catts 1963).

The paired racemose salivary glands are

connected anteriorly by a common salivary

duct which extends to the oral structures

(Figure 1). Posteriorly, the glands are situated

horizontally in the lower thorax and extend

almost to the abdomen. Catts (1963) reported

the salivary glands extending only into the

prothorax of C. latifrons. Singh and Judd

(1966), also working with C. latifrons found

salivary glands extending into the abdomen.

Townsend (1935) described salivary glands of

Cuterebra as being atrophied or absent. These

discrepancies may be due to age or to preser-

vation method.

Lowne (1890) and Hewitt (1914) indicated

that paired lingual salivary glands of Calliphora

and Musca, respectively, were of a simple

tubular type which ultimately terminated in the

posterior of the abdomen. Hori (1972) also

found tubular salivary glands extending into

the abdomen of flies belonging to eight

calypterate muscoid families. An additional

difference between Cuterebra and_ other

muscoid flies was that the labial salivary

glands present in Calliphora and Musca (Lowne

1890; Hewitt 1914) were absent in Cuterebra.

The alimentary canal in C. tenebrosa is

complete and basically similar to that in other

muscoid families. An important difference is

the apparent absence of a crop in male C.

J. ENTOMOL. Soc. Brit. CoLuMBIA 74 (1977), Dec. 31, 1977

He) dod [eIs1}S0A ‘AQ ‘yONp dois ‘QO ‘oes DeIPABd ‘SD ‘OBS DVIPID IO MOTA posiepUT °Z “By

winqoed ‘Y :se—nqny ueiysiydiey ‘LI :Snpnowquea ‘A ‘puets Arearpes ‘nS

‘a81}Ss0A dois ‘AQ ‘oes DVIPIeD ‘Gg :snseydose ‘Wy -esoiqoua} BIga19IND JO 49e1} ATeQUOUITY “[ “SI

G “SI

wil O°S

A 5S

N ee Oe

T 8d 4, &. Pe \

“SF

Fig. 3. Female reproductive organs. O, ovary; AG, accessory gland; S, spermatheca; GC, genital

chamber

Fig. 4. Male reproductive organs. T, testis; VD, vas deferens; AG, accessory glands; ED, ejacula-

tory duct; A, aedeagus

c="

met

an)

iS)

or)

é~

jo)

30 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977:

tenebrosa specimens. Only one of five males

had a crop, whereas all four females had small

crops (Figure 1, Figure 2). Studies with

C. latifrons present conflicting results: Catts

(1963) reported a vestigal crop, whereas Singh

and Judd (1966) described a crop proportional

in size to that of other muscoid Diptera.

The ventriculus begins with a_ typical

cardiac sac. This organ is termed the proventri-

culus by Lowne (1890), Hewitt (1914),

Hori (1972), and the cardia by Singh and

Judd (1966). The remainder of the C. tenebrosa

ventriculus is tubular and of the same diameter

throughout. This agrees with findings for

C. latifrons by Catts (1963) and Singh and

Judd (1966). Food remnants were found in the

ventriculus and intestines of three male C.

tenebrosa specimens. This must certainly be

material held over from larval feeding since the

flies had no opportunity to feed as adults. At

the ventriculus-intestine junction, two

Malpighian ducts are present. Each duct gives

rise to two moniliform Malpighian tubules

which extend among the organs of the

abdomen. The rectum is similar in shape to that

of other flies; four rectal pads are present on

the anterior portion. Catts (1963) and Singh

Judd (1966) reported similar observations for

C. latifrons. Large tracheal air sacs extend from

one-third to one-half of the length of the

abdomen of C. tenebrosa. Townsend (1935)

made no mention of air sacs in his studies of

Cuterebra specimens.

Reproductive Tract

Figures 3 and 4 illustrate the internal

reproductive system of female and male

C. tenebrosa, respectively. They are similar to

descriptions of other Cuterebra provided by

Townsend (1935) and Catts (1963), although

C. tenebrosa females have spherical sperma-

thecae in contrast to the sausage-shaped

spermathecae of C. latifrons.

According to Hori (1972), the majority of

calypterate muscoid flies have three sperma-

thecae, although several genera’ within

Stomoxydinae (Muscidae) have but two. In the

lower flies, the number of spermathecae ranges

from zero to four. C. tenebrosa specimens have

spermathecae arranged one on the upper left

side of the genital chamber, one on top, and one

on the upper right side of the chamber (1:1:1).

In contrast, most other muscoid genera have

two left and one right (2:1) or one left and two

right (1:2) (Lowne 1890; Hewitt 1914; Hori

1972). A variety of spermathecal shapes were

illustrated by Hori (1972) for muscoid flies;

however, within genera the shapes were fairly

consistent.

C. tenebrosa males are basically similar to

other muscoid flies in the internal reproductive

structures. One difference between C. tenebrosa

and C. latifrons (Catts 1963) is that the

accessory glands are smaller in relation to the

testes in C. tenebrosa. This may be a function

of the age of the fly, however, as Hori (1972)

stated the shape of the testes of male muscoid

flies correlated closely to the age.

CONCLUSIONS

The alimentary tract of Cuterebra tenebrosa

is basically similar to other muscoid Diptera.

The two main differences are the reduced or

absent crop in males and the racemose salivary

glands in C. tenebrosa.

In early Cuterebra literature, these bot flies

were described as being without mouth parts.

Although more recent work has shown the true

nature of their mouth parts and alimentary

system, no one has reported Cuterebra flies

feeding or drinking. Apparently there is no food

requirement for oviposition. In rearing several

hundred Cuterebra flies in recent years, we have

maintained them from eclosion to oviposition

(usually five days) with no opportunity to feed.

In most cases the resulting eggs have had a

high fertility, although most females laid only

50-75% of their complement of eggs before

dying.

ACKNOWLEDGEMENTS

We wish to thank Mr. Al Greene, Washing-

ton State University for the figures. Dr. M. T.

James, Washington State University and

Dr. K. J. Capelle, Brigham City, Utah reviewed

the manuscript.

References

Baird, C. R. & C. L. Graham. 1973. Cuterebra tenebrosa: Description of immature stages and a

redescription of the adult (Diptera:

Cuterebridae) Can. Ent. 105:1281-1293.

Bennett, G. F. 1955. Studies on Cuterebra emasculator Fitch 1856 (Diptera: Cuterebridae) and a

discussion of the status of the genus Cephenemyia Ltr. 1818. Can. J. Zool. 33: 75-98.

Catts, E. P. 1963. The biology of Cuterebra latifrons Coquillett (Diptera:

Cuterebridae). Ph.D.

Dissertation, University of California, Berkeley. 174 pp. (unpub.)

Graham, C. L. & K. J. Capelle. 1970. Redescription of Cuterebra polita (Diptera:

Cuterebridae)

with notes on its taxonomy and biology. Ann. Entomol. Soc. Amer. 63: 1569-1573.

Haas, G. E. & R. J. Dicke. 1958. On Cuterebra horripilum Clark (Diptera:

Cuterebridae) parasiti-

zing cottontail rabbits in Wisconsin. J. Parasitol. 44:527-540.

Hewitt, C. G. 1914. The House Fly, Cambridge University Press, London. 195 pp.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 31

- Hori, K. 1972. The works of the late Dr. Katshushige Hori. Comparative anatomy of the internal

organs of the calypterate muscoid flies and the other works. Kanazawa, Japan. 306 pp.

Lowne, B. T. 1890. The anatomy, morphology, and development of the blowfly (Calliphora

erythrocephala) I. Porter, London.

Singh, S. B. & W. W. Judd. 1966. A comparative study of the alimentary canal of adult calypterate

Diptera. Proc. Entomol. Soc. Ont. 96:29-80.

Townsend, C. H. T. 1935. Manual of myiology, Part II Muscoid classification and habits.

Townsend Pub., Sao Paulo, Brazil.

EURRHYPARA HORTULATA L. (URTICATA L.) ON THE

PACIFIC COAST (LEPIDOPTERA: PYRALIDAE)

This attractive little moth, which can hardly

be confused with anything else in the North

American fauna, is native to Europe and

temperate east Asia. It ranges from Ireland to

the Amur-Ussuri region and Manchuria. It

was established in Nova Scotia by 1907 at

MacNab’s Island and Truro. At present it has

a wide range in the Northeast, extending from

Newfoundland to Ontario and southward. The

moth flies mainly in July, at night, is attracted

to light and in the daytime is easily flushed.

The main food-plant in Europe is _ nettle,

Urtica dioica L., and other plants such as

Marrubium vulgare L., Stachys sp., Mentha

sp., Calystegia sepium Br. and Ribes sp.

Probably it has other plant hosts also. Little

is known about its food plants in North

America.

Until now there were no records of E.

hortulata having been collected on the Pacific

coast. There are no specimens from this area in

local collections or in the Canadian National

Collection at Ottawa.

On 18 June, 1977 a perfect female specimen

was seen resting on the ceiling of a living room

in East Vancouver. It was in such immaculate

condition that it was obvious that it was

freshly emerged. Unfortunately, in my excite-

ment, the specimen was somewhat damaged

during capture. Four days later, another

perfect specimen, a male, was flushed in the

garden and collected. Another was observed

in the garden on 23, 26 and 27 June but no

further specimens were collected in order to

give the species a chance to survive and become

established in Vancouver. How the moth

arrived in Vancouvr will remain a mystery.

Most likely the first specimens were introduced

last year, deposited eggs and produced moths

this year. The host-plant here remains

unknown. There are no nettles growing in the

vicinity and the nearest place known to me

where nettles grow in Vancouver is near the

seawall in Stanley Park. There are other

possible plant hosts, however, cultivated in our

garden, such as Stachys recta, at least three

different species of Mentha, Calystegia sepium

and Ribes sp. The moth may have selected one

of those plants on which to lay eggs.

In Europe the larva rolls the leaves or spins

them together. The cocoon is spun in a

sheltered place, usually under the bark, in

autumn. Hibernation takes place as a prepupal

larva which pupates in the spring. There is one

generation per year. Next June or July should

show whether the moth will establish itself in

Vancouver or not. Unlike horticulturists and

the Plant Protection Division, I hope it will.

References

Beirne, B.P. 1952. British Pyralid and Plume moths. London & New York.

Forbes, W. T. M. 1923. Lepidoptera of New York and neighbouring States. Part I, Ithaca.

Meyrick, E. 1968. A Revised Handbook of British Lepidoptera.

Munroe, E. 1976. Pyralidae. Pyraustinae. Pyraustini. The Moths of America North of Mexico.

fasc. 13.2A.

W. Lazorko

o2 J. ENTOMOL. Soc. BRIT. COLUMPIA 74 (1977), DEc. 31, 1977

EFFECT OF ANTI-AGGREGATIVE PHEROMONES 3,2-MCH

AND TRANS-VERBENOL ON DENDROCTONUS RUFIPENNIS

ATTACKS ON SPRUCE STUMPS |

E. D. A. DYER AND P. M. HALL

Canadian Forestry Service

Pacific Forest Research Centre

Victoria, B.C.

Department of Fisheries and the Environment

ABSTRACT

Anti-aggregative pheromones 3,2-MCH and 3,2-MCH with trans-

verbenol were released from open vials enclosed in perforated cans attached

to both sides of 50 winter-cut spruce stumps which normally attract spruce

beetles (Dendroctonus rufipennis). Although significantly fewer attacks

occurred on treated than on untreated stumps, the attack density was not

sufficiently reduced to be of practical value in controlling spruce beetle

reproduction in this host material. There was no significant difference in

reduction of beetle attacks between the 3,2-MCH and the 3,2-MCH with

trans-verbenol treatments.

RESUME

On a libere a partir de fioles ouvertes placées a |’intérieur de canettes

perforées, attachées aux ‘‘deux cOtés” de 50 souches d’Epinette coupees en

hiver, des pherormones anti-agglomerantes 3, 2-MCH et 3, 2-MCH avec

trans-verbenol et qui normalement, attirent de Dendroctone de |’Epinette

(Dendroctonus rufipenns). Malgré un nombre significativement reduit

d’attaques contres les souches traitees, comparativement aux autres

souches, la densité de |’infestation ne fut pas suffisamment diminuee pour

constituter un moyen pratique d’enrayer la reproduction du Dendroctone

de l’'Epinette dans cet arbre hote. I] n’y eut pas de differénce significative

dans la baisse des attaques du Dendroctone entre les traitements 3, 2-MCH

et 3, 2-MCH avec trans-verbenol.

INTRODUCTION

The spruce beetle, Dendroctonus rufipennis

(Kirby), occurs throughout the range of spruce

in Canada and the United States (Wood, 1963).

At epidemic levels, it attacks and kills large

volumes of mature standing spruce (Picea

engelmannii Parry, P. glauca (Moench) Voss),

and at endemic levels, it breeds principally in

fresh spruce windfall, stumps and slash.

3,2-MCH (°-methyl-2-cyclohexen-1-one),

an anti-aggregative pheromone produced by

the Douglas-fir beetle, Dendroctonus pseudotsu-

gae Hopk., has been shown to mask the effect of

the aggregative pheromones of this beetle

(Rudinsky et al., 1972). Other experiments with

this pheromone applied to spruce logs have

shown a similar anti-aggregative effect to

spruce beetles (Rudinsky et al., 1974; Kline

et al., 1974). A second pheromone, trans-

verbenol (trans- 4, 6, 6-trimethylbicyclo -

(3-1-1) -3-hepten-2-ol), is the principal aggrega-

tive pheromone of the mountain pine beetle,

Dendroctonus ponderosae Hopk. (Pitman and

Vité, 1969), but is an _ anti-aggregative

pheromone component of the western pine

beetle, Dendroctonus brevicomis Lec. (Wood,

1972). Results of experiments on the effect of

trans-verbenol on Douglas-fir beetle are

unclear; comparable experiments have given

both aggregative and anti-aggregative results

(Rudinsky et al., 1972). Furniss et al. (1976)

stated that trans-verbenol repressed attraction

of spruce bettle to logs with and without the

synthetic attractants frontalin and seudenol,

but that its effect was less than that of 3,

2-MCH.

An experiment to determine the anti-

agegregative effect of 3,2-MCH and 3,2-MCH

with trans-verbenol on spruce beetle was

carried out during the spring and summer of

1975, using attractive spruce stumps in a

winter clearcut area in central British

Columbia.

METHODS

Twenty 5-stump groups, in 10 pairs with

approximately 50 m between groups in each

pair, were selected throughout a large clear-

cut area and treated as follows: 10 groups, one

of each pair, were designated as controls and

left untreated; the other 10 groups were

alternately treated with 3, 2-MCH alone or with

3, 2-MCH and trans-verbenol. Closed perfora-

ted film cans, each containing an open 0.5 dr

vial with 0.1 ml 3, 2-MCH (Rudinsky et al.,

CE TTT IIE

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 33

1972), were placed on the centers of the north

and south sides of each treated stump. For

each stump treated with both 3, 2-MCH and

trans-verbenol, a second open 0.5 dr. vial con-

taining 0.15 ml of trans-verbenol was put in

each can with the 3, 2-MCH. Vials were checked

for evaporation throughout the flight period to

ensure the presence of the two chemicals.

Stumps were treated by May 29 and left

throughout June, the beetle flight period.

After flight, six 10.16-cm-diameter bark

samples were cut randomly from the north

lower side of each stump. The number of

entrance holes was counted on each sample

and totalled for all samples in all stumps of

each group. A randomization test for matched

pairs (Siegel, 1956) was used to compare the

3,2-MCH-treated stumps to their respective

controls, and 3,2-MCH_ + _ trans-verbenol

treated stumps to their respective controls.

Differences between treated and control pairs

were calculated for each of the 3,2-MCH and

3,2-MCH - trans-verbenol groups, and the two

treatments were compared to each other, using

a randomization test for two independent

samples (Siegel, 1956).

RESULTS AND DISCUSSION

The emission of 3,2-MCH alone and that of

3,2-MCH_ and/trans-verbenol at attractive

spruce stumps resulted in a reduction in the

number of beetle attacks compared to attacks

on untreated stumps, although only two of the

10 treated replicates were not attacked

(Table 1). The addition of trans-verbenol to

3, 2-MCH made no significant difference to the

degree of reduction in the number of attacks.

The emission of 3, 2-MCH at spruce stumps

produced a 50% reduction in attack density,

with a spacing of less than 1 m between 3,

2-MCH containers on _ individual stumps.

Rudinsky et al. (1974) used a 1.8 m spacing

between 3, 2-MCH containers on downed spruce

trees and achieved complete protection from

attacks. Since the north aspects of the spruce

stump bases are the most productive areas

for spruce beetle brood in logging slash (Dyer

and Taylor, 1971), the reduced attack density

on 3, 2-MCH-treated stumps is not low enough

to ensure population reduction in the next

generation. The lower density broods would

reduce competition and _ thereby possibly

increase survival to maturity under suitable

TABLE 1. Spruce beetle attacks/m? from 600 samples on north sides of 100 stumps with two

treatments and paired controls.

3, 2-MCH

TREATMENT

CONTROL

3,2-MCH + trans verbenol

TREATMENT CONTROL

‘differs from paired control @ 0.125 level of significance.

*differs from paired control@0.05 level of significance. No difference between MCH and

MCH + trans-verbenol @ 0.05 level of significance.

environmental conditions. The _ difference

between the reduction of attack on spruce

stumps and that on downed trees may be due

to the difference in environmental exposure

around the treated material. Open logging

slash, with greater air movement and higher

temperatures, would tend to disperse the

3, 2-MCH faster than in a more sheltered stand

environment, thereby producing a lower con-

centration of 3, 2-MCH at the source.

Therefore, 3,2-MCH apparently cannot be

applied by this method as a practical means of

reducing spruce beetle populations breeding in

suitable logging slash.

References

Dyer, E. D. A. and D. W. Taylor. 1971. Spruce beetle brood production in logging slash and wind-

thrown trees in British Columbia. Information Rept. BC-X-62. Can. Dept. Env., Pac. For.

Res. Centre, Victoria, B.C.

Furniss, M. M., B. H. Baker and B. C. Hostetler. 1976. Aggregation of spruce beetles (Coleoptera)

to seudenol and repression of attraction by methylcyclohexenone in Alaska. Can. Ent.

108: 1297-1302.

Kline, L. N., R. F. Schmitz, J. A. Rudinsky and M. M. Furniss. 1974. Repression of spruce

beetle (Coleoptera) attraction by methylcyclohexenone in Idaho. Can. Ent. 106: 485-491.

Pitman, G. B. and J. P. Vité. 1969. Aggregation behavior of Dendroctonus ponderosae (Coleoptera:

Scolytidae) in response to chemical messengers. Can. Ent. 101: 143-149.

34 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 |

Rudinsky, J. A., M. M. Furniss, L. N. Kline and R. F. Schmitz. 1972. Attraction and repression of |

Dendroctonus pseudotsugae (Coleoptera: Scolytidae) by three synthetic oo |

traps in Oregon and Idaho. Can. Ent. 104: 815-822.

Rudinsky, J. A., C. Sartwell, Jr.,

T. M. Graves and M. E. Morgan. 1974. Granular formulation of |

methylcyclohexenone: an antiaggregative pheromone of the Douglas-fir and spruce bark |

beetles (Col., Scolytidae). Z. ang. Ent. 75: 254-263.

Siegel, S. 1956. Non parametric statistics. McGraw-Hill Book Co. Inc., New York. 312 pp.

Wood, D. L. 1972. Selection and colonization of ponderosa pine by bark beetles. In: Insect/ Plant

Relationships; ed: H. F. van Emden. Symp. Roy. Entomol. Soc. (London) 6, 101-117.

Wood, S. L. 1963. A revision of the bark beetle genus Dendroctonus Erichson (Coleoptera:

Scolytidae). Gt. Basin Nat. 23: 117 pp.

INSECTS COLLECTED FROM AN ALPINE-SUBALPINE REGION

IN SE BRITISH COLUMBIA

J. HARLING', J. M. SNYDER? AND D. M. COLETTI?

Department of Biological Sciences

Notre Dame University

Nelson, B.C.

ABSTRACT

Insects were caught in a subalpine area of southeastern British Colum-

bia. The list consists of 23 spp. and 37 genera, in families of five orders. The

insects were collected during July and August, 1975 as part of a larger

study of the ecology of mountain caribou in the Poplar Creek area, north of

Nelson, B.C.

INTRODUCTION

There are few identified collections of

insects in the alpine-subalpine environment of

British Columbia. This is a report on insects

collected in the central Selkirk Mountains of

British Columbia during July and August 1975.

The paper by Allan (1969) is most similar to the

present report, although his collections were

mainly from lower elevations and limited to the

family Syrphidae. Other related studies, but

not from British Columbia, include those of

Chapman (1954), Dodge and Seago (1954) and

Mani (1955).

The insects reported here were obtained

during a survey for potential pests of mountain

caribou (Rangifer tarandus montanus) inhabi-

ting the alpine-subalpine environment at the

same time of the year. The caribou is the

subject of a study by Harling and Snyder

(unpublished).

METHODS AND STUDY AREA

The insects were sampled between 10 July

and 27 August, 1975 with pieces of wire screen

‘Present address:

Okanagan College

1000 KLO Road

Kelowna, B.C.

*Selkirk College

Castlegar, B.C.

‘Department of Biological Sciences

Simon Fraser University

Burnaby, B.C.

(40x50 cm), smeared with grease and placed

on supports about 0.9 m above ground level.

Additional collections were made with hand

nets and a Malaise trap. The insects were first |

identified in the laboratory and the identifica- —

tions verified by the Biosystematics Research ©

Institute, Canada Department of Agriculture,

Ottawa, Ontario.

General meteorological data were obtained |

from maximum and minimum thermometers, a

sling psychrometer, and a simple rain gauge;

wind speed and direction were estimated at the

time when samples were collected from the

traps.

The collection was mainly from the extreme |

north fork at the west end of the headwaters

of Poplar Creek (50° 21’ N, 117° 21’ W) in ©

southeastern British Columbia. The area com- ©

prised alpine meadows, talus slopes, receding |

snow patches and the upper fringe of climax ©

stands of englemann spruce (Picea englemanni)

and subalpine fir (Abies lasiocarpa). The collec- —

tions were made between 1500 and 1650 m >

elevation.

RESULTS

Table I lists the insects collected during the

study. Only those taxa verified by the Bio-

systematics Research Institute have been

included. Dipterans alone made up about 78%

of the catch. The families Bibionidae, Syrphi-

dae, Tabanidae and Tipulidae comprised more

than 50% of all the Dipterans caught. Hemip-

_J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 ao

Table 1. Insects collected from the Poplar Creek area of SE

British Columbia, July and August, 1975.

COLEOPTERA

DIPTERA

HEMIPTERA

HYMENOPTERA

Buprestidae Agrilus sp.

Melanophila drummondi(Kby.)

Cantharidae Podabrus scaber (LeC.)

Carabidae Phloeopterus sp.

Cerambycidae Anoplodera aspera (LeC.)

Xylotrechus longitarsis (Csy.)

Chrysomelidae Chryomela sp.

Syneta subalpina (Edwards)

Coccinellidae

Elateridae Ctenicera hoppingi (Van Dyke)

Ctenicera sylvatica (Van Dyke)

Lycidae Dictyopterus sp.

Scarabeidae Aphodius sp.

Scolytidae Orthotomicus sp.

Trypodendron lineatum (Oliv.)

Cryphalini

Scraptiidae Anaspis sp.

Staphylinidae Ptomaphagus sp.

Omaliinae

Anthomyiidae Hylemya sp.

Hylemya (Pegohylemia) fugax (Meigen)

Hylemya (Botanophila) spinidens (Malloch)

Bibionidae Bibio sp.

Calliphoridae Phormia regina ( Mg.)

Drosophilidae Clastopteromyia inversa (Walker)

Empididae Drapteris sp.

Empis brachysoma (Coquillett)

Tachydrominae

Muscidae Lasiops medius (Stein) “

Rhagionidae Symphoromyia atripes (Bigot)

Syrphidae Chrysotoxum sp. o

Melangyna sp. &

Syrphus torvus (O.S.) 3

Tabanidae Hybomitra osburni ( Hine)

Tachinidae Nowickia pilosa

Tipulidae

Limoniinae

Tipulinae

Miridae Irbisia nigripes (Kgnt)

Lygus varius (Kgnt)

Bombidae Pyrobombus (Pryrobambus) flavifrons flavifrons (Cresson)

Colletidae Hylaeus sp.

Siricidae Urocerus gigas flavicornis (F.)

Tenthredinidae Tenthredo sp. ,

Dolerus (Dolerus) sp.

Pamphiliidae Pamphilius sp.

LEPIDOPTERA

Nymphalidae

Boloria epithore (Edwards)

36 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 |

terans and Lepidopterans each comprised less

than 2% of the total; Coleopterans and

Hymenopterans represented the rest.

The temperature during the study ranged

from 3.4°C to 23.9°C with humidity from

43-88%. The maximum precipitation recorded

on a sampling day was 0.48 cm and on other

days was often zero. Wind speed varied from

force 0 to force 2 and was usually from the

south.

Catches were largest during periods of high

temperature, low precipitation, and _ low

humidity. No clear trend was noted with refer-

ence to wind speed or direction. Other authors

(Chapman, 1954; Mani, 1962) have confirmed

that the meteorological factors recorded here

do have a marked effect on insect activity

at high elevations.

DISCUSSION

At least an additional 25 species were

caught but were not identified by the Bio-

systematics Research Institute because they

were damaged in transit.

The methods employed in this investigation

were relatively simple, so that the analysis of

relative abundance could not be sophisticated.

However, the predominance of Dipterans in

relation to other groups was significant and

consistent with other surveys of alpine insect

fauna (Chapman, 1954; Dodge and Seago,

1954; Mani, 1955, 1962). Among families, the

Syrphidae and Tabanidae were abundant as_

also reported by Chapman (1954) but the

Tachinidae which he found to be abundant were |

represented here by a single specimen.

A number of the Dipteran species listed in

Table I may be associated with the caribou |

population of the area. In particular, the blow-

fly (Phormia regina (Mg.) ) and the tabanid

(Hybomitra osburni (Hine) ) could be potential |

caribou pests because related genera have been

confirmed as large mammal pests (Prior, 1968).

Bot and warble flies parasitize caribou

(Bergerud, 1961; Low, 1964; Layser, 1974)

and although no such species were recorded in

our samples, a close relative (the tachinid

Nowickia pilosa) was caught. The mountain

caribou continue to be studied in the area and

it is hoped that some confirmation of their |

insect pests will be forthcoming.

ACKNOWLEDGEMENTS

The authors thank the National Research |

Council of Canada for grants to J. Harling and

J. M. Snyder for their study on the ecology of

the mountain caribou of which the work repor-

ted here was a small part. We are also grateful ©

to the Professions for Tomorrow Programme of |

the B.C. Department of Labour for funding to |

employ student assistants during the summer

of 1975. Finally, we thank the staff of the Bio-

systematics Research Institute, Ottawa,

Ontario for verifying the identifications.

References

Allan, D. A. 1969. Syrphidae collected mostly in southern areas of the Okanagan Valley, British

Columbia. J. Entomol. Soc. Brit. Columbia 66: 19-21.

Bergerud, A. T. 1961. The reproductive season of Newfoundland caribou. (Unpublished) 31 pp.

Chapman, J. A. 1954. Studies on summit frequenting insects in western Montana. Ecology 35: |

41-49.

Dodge, H. R. and J. M. Seago. 1954. Sarcophagidae and other Diptera taken by trap and net on

Georgia mountain summits in 1952. Ecology 35: 50-59.

Layser, E. F. 1974. A review of the mountain caribou of northeastern Washington and adjacent

northern Idaho. J. Idaho Acad. of Science, Special Res. Issue. No. 3. 63 pp.

Low, W. A. 1964. A general ecological study of mountain caribou in Tweedsmuir Provincial Park |

(Unpublished report of work supported by the University of British Columbia and the

B.C. Fish and Wildlife Branch). 4 pp.

Mani, M. S. 1955. Entomological survey of the Himalaya, Pt. IV - Expedition to the Upper Chenab

Valley, 1954. Agra Univ. J. Res. (Sci.) 4: 157-170.

Mani, M. S. 1962. Introduction to high altitude entomology. Methuen, London. 302 pp.

Prior, R. 1968. The Roe Deer of Cranbourne Chase. Oxford University Press. 222 pp.

_ J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 37

OVERWINTERING SURVIVAL OF PISSODES STROBI (PECK)

(COLEOPTERA: CURCULIONIDAE) IN SITKA SPRUCE

LEADERS?

T. J. D. VANDERSAR?

Pestology Centre

Department of Biological Sciences

Simon Fraser University

Burnaby, B.C. V5A 1S6

Across most of its range, Pissodes strobi

Peck’ overwinters as an adult in the duff at the

base of brood hosts from which it emerged in

autumn (Belyea and Sullivan 1956; Stevenson

1967). On the west coast of British Columbia,

mild winters apparently permit adult P. strobi

to overwinter on the bole and laterals of Sitka

spruce (Gara, Carlson, and Hrutfiord 1971;

McMullen and Condrashoff 1973). Silver (1968)

suggested that although some P. strobi in

coastal B.C. overwinter as larvae in_ host

leaders, they may be unable to complete their

development the following spring.

On June 8, 1976, I collected 26 Sitka spruce

leaders attacked in 1975 from two plantations

near Port Renfrew, Vancouver Island. These

terminals were maintained in the laboratory at

‘Research supported by a Canadian Forestry Service Science

Subvention Grant, The National Science Foundation, U.S.A.

(Grant No. GB-15959), and the National Research Council,

Canada (Grant No. A3881).

*Graduate student.

Smith and Sugden (1969) designated the former Sitka

spruce weevil, Pissodes sitchensis Hopkins and the Engelmann

spruce weevil, P. engelmanni Hopkins, as ecotypes of P. strobi

Peck on the basis of morphological and cytogenetic similarities

(Manna and Smith 1959; Smith 1962).

approximately 20°C. Sixteen adult P. strobi

(9¢¢ and 7292) emerged during a 2-week

period in late June. Five additional male

weevils emerged in late July, from Sitka spruce

leaders collected at the same sites on July 7,

1976.

After a count of weevil emergence holes

chewed through the intact outer bark, the

leaders from the June 8, 1976 collection were

dissected. A total of 737 chip cocoons in the

xylem and pith contained 36 dead adults

(4.9%) that had failed to emerge. An additional

75.3% had apparently died in chip cocoons prior

to completing pupation. The count of

weathered emergence holes indicated that 130

adults (17.6%) had emerged in late summer to

fall, 1975. The 16 P. strobi that emerged in

early summer, 1976 constituted 2.2% of the

total chip cocoon population or 11.0% of the

total emergent population.

These results indicate that P. strobi can

successfully overwinter in the larval stage in

Sitka spruce leaders in coastal B.C.

Acknowledgements

I thank W. Coombs for allowing me to

collect weevils on plantations managed by

B.C. Forest Products Ltd., N. Yalpani for

assistance with field work, and Dr. J. H.

Borden for review of the manuscript.

References

Belyea, R. M. and C. R. Sullivan. 1956. The white pine weevil; a review of current knowledge. For.

Chron. 32: 58-67.

Gara, R. I., R. L. Carlson, and B. F. Hrutfiord. 1971. Influence of some physical and host factors

on the behaviour of the Sitka spruce weevil, Pissodes sitchensis, in southwestern

Washington. Ann. Ent. Soc. Am. 64: 467-471.

Manna, G. K. and S. G. Smith. 1959. Chromosomal polymorphism and inter-relationships among

bark beetles of the genus Pissodes Germar. The Nucleus 2: 179-208.

McMullen, L. H. and S. F. Condrashoff. 1973. Notes on dispersal, longevity, and overwintering

of adult Pissodes strobi (Peck) (Coleoptera: Curculionidae) on Vancouver Island. J. Ent.

Soc. B.C. 70: 22-26.

Silver, G. T. 1968. Studies on the Sitka spruce weevil, Pissodes sitchensis, in British Columbia.

Can. Ent. 100: 93-110.

Smith, S. G. 1962. Cytogenetic pathways in beetle speciation. Can. Ent. 94: 941-955.

Smith, S. G. and B. A. Sugden. 1969. Host trees and breeding sites of native North American

Pissodes bark weevils, with a note on synonymy. Ann. Ent. Soc. Am. 62: 146-148.

Stevenson, R. E. 1967. Notes on the biology of the Engelmann spruce weevil, Pissodes engelmanni

(Curculionidae: Coleoptera) and its parasites and predators. Can. Ent. 99: 201-213.

38 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977 |

A NEW CLASTOPTERA FROM SAGEBRUSH (RHYNCHOTA:

HOMOPTERA: CERCOPIDAE)

K. G. A. HAMILTON

Biosystematics Research Institute

Agriculture Canada, Research Branch

Ottawa, Ontario

ABSTRACT

J. Ent. Soc. B.C.

Clastoptera atrapicata n. sp. (Homoptera: Cercopidae) is described from

sagebrush (Artemisia tridentata Nutt) in central British Columbia and

Oregon. This species is closely allied to C. brunnea Ball, and, like it, exhibits

considerable variation in colour pattern of the face. The ovipositor and

colour varieties are illustrated and compared with those of its related

species.

The genus Clastoptera in America north of

Mexico was revised by Doering (1928) to

include 29 species. Of these, six were distinc-

tive in having fewer pronotal striae (10 or

fewer on midline) than the other species, and in

having ~~ arid-adapted _hosts: sagebrush

(Artemisia tridentata Nutt) and rabbit brush

(Chrysothamnus spp.). Two of these six, sierra

Doering and binotata Ball, are wholly black in

both sexes; one, delicata Uhler, is yellow with

black pronotal bars in both sexes; and in the

remaining three, the males are black and the

females are yellow with black pronotal bars. To

the latter group I now add a fourth previously

unrecognized species.

Clastoptera atrapicata n. sp.

(Figs. 7-10, 12, 16, 17)

Body form as in other Clastoptera, but with

frons considerably inflated, tylus longer than

median length of vertex in both sexes, in dorsal

aspect with tylus appearing about as long as

median length of vertex (Fig. 12). Length:

male, 2.9-3.5 mm; female, 3.2-4.2 mm.

Male. Colour blackish-brown except for pale

areas on tegmina around bullae, yellow spot at

centre of costa, and yellow spots on lora;

similar to C. brunnea Ball in colour. Male

genitalia as in brunnea (Doering 1928, pl. XXV,

fig. 3).

Female. Colour pale yellow, overlaid with

two heavy black bars across fore margin of

pronotum and between eyes, and finer brown

lines (6-9 in number) across pronotum; face

variously marked with fuscous and_ black

(Figs. 7-10); tegmina mottled with fuscous,

paler on apical cells and along edge of trans-

verse creases; legs pale, banded with fuscous;

similar to brunnea in colour.

Inner rami of ovipositor parallel-margined

on basal half, strongly tapered apically, ventral

margin curved dorsad, dorsal margin straight,

armed with two close-set teeth near midlength

(Figs. 16, 17); similar to ovipositor of C. lugu-

bris Ball.

Types. Holotype? , Seton L., Lillooet, B.C.,

ie a

—S

30 June 1926 (J. McDunnough) on sagebrush. |

Paratypes: 14¢4¢, 629, same data as holotype;

5336, 1392, 17 mi SE Spences Bridge, B.C., |

8 Aug. 1976 (K. G. A. Hamilton) on sagebrush;

13, SE slope Glass Butte, 12 mi E Hampton,

Lake Co., Ore., 12 July 1968 (J. D. Lattin)

68-27; 12 , 14 mi N Burns, Harney Co., Ore., 14

Aug. 1971 (P. W. Oman). Holotype and 38

paratypes no. 14073 in the Canadian National

Collection, Ottawa; 2 paratypes in the collec-

tion of Oregon State University, Corvallis.

Remarks. C. atrapicata is closely allied to

brunnea Ball, lugubris Ball and lineatocollis

Stl. Males of atrapicata may be distinguished

from all three by the more strongly inflated

frons and longer tylus (Fig. 12). In dorsal

aspect the tylus appears to be as long as the

vertex, while in the three allied species the

tylus appears half as long (Fig. 11). Males of

lugubris and lineatocollis also have more exten-

sive pale markings on the face (Doering 1928,

pl. IV, fig. 2a).

Females of lugubris differ from those of

atrapicata, brunnea and lineatocollis in their

larger size (3.6-4.6), in having the tylus very

strongly produced, in dorsal aspect longer than

the vertex, and in having the pronotal bars of

equal width and darkness with the interocular

bar.

Females of atrapicata can be distinguished

from those of all its other relatives by the shape

of the apex of the inner rami of the ovipositor,

and by the placement of the ovipositor teeth

near the centre of the blade (Figs. 16, 17). The

facial markings of atrapicata are also distinct:

the base of the clypellus always has a pale

transverse band (Figs. 7-10) not found in

brunnea and lineatocollis (Figs. 1-6); further-

more, the majority of specimens have the upper

half of the frons black (Figs. 7-8), a condition

not found in related species. The variability

of the facial markings show the close relation-

ship between brunnea and atrapicata.

| J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977

M4 ™

Seats

Gece

seatees

Ant

Me eats

oO wote.®,

4 Fj 4 ~

r A ara «

ee Wr a)

LPs e

Figs. 1-10. Facial patterns in Clasptoptera species. 1-5, C. brunnea Ball; 6, C. lineatocollis Stal;

7-10, C. atrapicata n. sp.

40 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), Dec. 31, 1977

aun, ai

ear

ote Se)

Figs. 11-12. Profile of head and pronotum of Clastoptera species with apparent extent of frons and |

vertex from dorsal aspect indicated by arrows. 11, C. brunnea; 12, C. atrapicata. |

Figs. 13-18. Ovipositor blades of Clastoptera species, lateral aspect. 13, 14, C. brunnea; 15, C. |

lineatocollis; 16, 17, C. atrapicata; 18, C. delicata Uhler.

J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 41

ACKNOWLEDGEMENTS

I wish to thank Dr. P. W. Oman of Oregon

State University, Corvallis for loan of speci-

mens of Clastoptera for comparison with those

deposited in the Canadian National Collection.

Reference

Doering, K. C. 1928. The genus Clastoptera in America North of Mexico. Kans. Univ. Sci. Bull.

18 (1): 5-153.

PTEROSTICHUS STRENUUS PANZ,

A NEWLY-DISCOVERED PALAEARCTIC SPECIES IN THE

VANCOUVER AREA (COLEOPTERA: CARABIDAE)

There are about 17 species of palaearctic

Carabids known to be introduced from Europe

into British Columbia, largely to the Vancouver

area. Most were known for some time but some

were discovered only recently. Lindroth (1957),

in his excellent treatise on faunal connections

between Europe and North America, postulated

that practially all of those species were intro-

duced with ship’s ballast (Scudder 1958). An

attempt is being made by the Entomological

Society of Canada in its Biological Survey Pro-

ject to collect all the available data on the distri-

bution of introduced Carabidae in this province.

I hope to compile a detailed list of the species

with their known places of occurrence in the

near future. Thus, this note may be of interest.

To the list of introduced species compiled

from Lindroth’s monograph (1963-1969) and

supplemented by my own collecting and obser-

vation during the past 29 years I am able to

add Pterostichus strenuus Panz., which has

been taken recently in Vancouver.

The first specimen, a female, was collected

on 8 June, 1968 on the marshy edge of a ditch,

close to Beaconsfield Park in East Vancouver.

All attempts to collect more specimens at the

time were unsuccessful. Three more specimens,

a male and two females, were collected by Prof.

G. G. E. Scudder of UBC on 21 August, 1973

in a marshy area at the foot of Olympic Street

in Vancouver (UBC Coll.). These specimens are

at present the only records from the Pacific

Coast of North America.

Pterostichus strenuus is distributed through

the whole northern Palaearctic. In North

America it has been known since 1937, restric-

ted to a small area of southeastern Newfound-

land, where it is a species of open, moderately

moist grassland, often close to the sea

(Lindroth, 1955). In Vancouver it appears to be

more hygrophilous and less common.

References

Lindroth, G. H. 1955. The Carabid beetles of Newfoundland. Lund.

Lindroth, C. H. 1957. The faunal Connections between Europe and North America. New-York-

Stockholm.

Lindroth, C. H. 1963-1969. The ground-beetles (Carabidae, excl. Cicindelinae) of Canada and

Alaska. Lund.

Scudder, G. G. E. 1958. A new aspect on the faunal connections between Europe and the Pacific

Northwest. Proc. Ent. Soc. of B.C. Vol. 55 p. 36. .

W. Lazorko

42 J. ENTOMOL. Soc. BRIT. COLUMBIA 74 (1977), DEc. 31, 1977 |

NOTICE TO CONTRIBUTORS

This society has no support except from subscriptions. It has become neces- |

sary to institute a page charge. This has now been set at $20.00. The page |

charge includes all extras except coloured illustrations, provided that such |

extras do not comprise more than 40% of the published pages. Coloured illustra- |

tions will be charged directly to the author. Authors, not attached to universi-

ties or official institutions, who must pay these charges from their personal |

funds and are unable to do so, may apply for assistance when submitting a |

manuscript.

Reprints are sold only in even hundreds and at the following prices:

Number of pages 1-4 5-8 9-12 13-16 17-20 21-24 25-28) |

First 100 copies $33.00 46.50 63.00 82.50 105.00 130.50 159.00 |

Each extra 100 9.00 12.00 15.00 18.00 21.00 24.00 27.00 |

Author’s discounts (up to 40%) may be granted to authors who certify at |

the time of ordering that they are buying reprints at personal expense. Authors |