The Pan-Pacific Entomologist

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OFFICERS FOR 1995

Curtis Y. Takahashi, President Vincent F. Lee, Managing Secretary

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THE PAN-PACIFIC ENTOMOLOGIST (ISSN 0031-0603) is published quarterly by the Pacific

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PAN-PACIFIC ENTOMOLOGIST

71(3): 137-141, (1995)

RECOVERY OF THE PARASITE

TRIARTHRIA SPINIPENNIS (MEIGEN)

(DIPTERA: TACHINIDAE) FROM AN INLAND

CALIFORNIA POPULATION OF THE

INTRODUCED EUROPEAN EARWIG*

JOHN F. BARTHELL! AND REBEKAH STONE?

Department of Environmental Science, Policy and Management,

University of California, Berkeley, California 94720

Abstract.—A tachinid parasite, Triarthria spinipennis (Meigen), introduced over 50 years ago to

control populations of the introduced European earwig in coastal California, is reported for the

first time in California’s Central Valley. Both the parasite and its host prefer cooler, more humid

environments near water. Parasites were found during two consecutive years and abundance

patterns within each year indicate they are multivoltine. The parasite has successfully accom-

panied its host’s inland invasion from the coastal region of California.

Key Words. —Insecta, Dermaptera, Diptera, Forficula auricularia, parasitism, Tachinidae, Triar-

thria spinipennis

Since its arrival in the western United States shortly after the turn of the century,

the European earwig, Forficula auricularia L., has extended its range throughout

much of California (Essig 1931, Langston & Powell 1975). European earwigs are

nocturnally and arboreally active foragers, giving them potential as biological

control agents of orchard pests (Carroll & Hoyt 1984, Mueller et al. 1988). They

are most noticeable in suburban environments where they commonly take diurnal

refuge in the cracks and crevices of man-made structures. Early reports about the

earwig suggested that its invasion might have a negative impact in California

because of its feeding on economically important plant species (Essig 1918, 1925).

In an effort to thwart the invasion of the earwig, two endoparasitic tachinids,

Triarthria spinipennis (Meigen) and Ocytata pallipes (Fallén), also referred to as

T. setipennis (Fallén), were introduced into Oregon during 1924 (Mote 1931).

Triarthria spinipennis was later released in the Bay Area of California (O’hara, in

press). By 1967 it had been recovered in Alameda, Contra Costa, Del Norte,

Humboldt, Marin, San Benito, San Francisco, San Mateo and Sonoma Counties

(Arnaud 1967, Schoeppner & Hagen 1963). Here we report the first record of the

parasite in the Central Valley of California, as well as information on the abun-

dance and distribution of the parasite and its host.

MATERIALS AND METHODS

Data were recorded from sampling units made from wooden trap-nests (Krom- |

bein 1967) during a study at the Cosumnes River Preserve (CRP), located 32 km

S of Sacramento, Sacramento County, California. A sampling unit (SU) consisted

' Current Address: Department of Biology, University of Central Oklahoma, Edmond, Oklahoma

73034.

2 Current Address: 940 Channing Way, Berkeley, California 94710.

* Authors page charges partially offset by a grant from the C. P. Alexander Fund, PCES.

138 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Figure 1. Tachinid puparia attached to the inner surface of tree bark where adult earwigs had

aggregated (puparia are between .25 and .50 cm in length).

of 12 trap-nests, each with dimensions of 12.0 x 2.5 x 2.0 cm and with a single

hole drilled to a 10 cm depth down its length. Four trap-nests for each of 3 hole

diameters (.50, .65 and .80 cm) were systematically arranged within a 5.0 x 12.0

x 12.0 cm unit and hung with wire from nails at 1.5 m heights on valley oak

trees (Quercus lobata Nee). Sampling units were spread approximately equidis-

tantly along a belt transect in each of three oak habitats: marsh, riparian and

grassland. During both years, each transect was of approximately equal length

and ran E-W, paralleling the Cosumnes River which bisects CRP along its south-

ern edge. During 1989 (5 May-—6 Oct), 10 SUs were monitored per habitat on a

biweekly basis. During 1990 (4 May-—5 Oct) 15 SUs were monitored per habitat

and sampled once a week to increase resolution of parasite/host abundance pat-

terns. Field replacements were made on the same day of the week Coe both

years so that sampling intervals would coincide.

After being removed from the field and replaced with a new SU, trap-nests

were dissected in the laboratory and the number of adult earwigs and tachinid fly

puparia counted. We were able to monitor puparia in trap-nests because earwigs

remain active until shortly before the endoparasitic larvae emerge for pupation

(Mote et al. 1931). Puparia are commonly found where adult earwigs normally

aggregate during the day, such as under the bark of dead tree limbs (Fig. 1).

RESULTS AND DISCUSSION

Numbers of earwigs were not evenly distributed among habitats during 1989

(x? = 1007.90; df = 2; P = .0001) or 1990 (x? = 7004.85; df = 2; P = .0001) with

most appearing in the marsh and/or riparian habitats (Table 1). Parasite numbers

were also significantly different among habitats during both 1989 (x? = 15.00; df

= 2; P= .0006) and 1990 (x? = 47.14; df = 2; P= .0001). During 1990, however,

1995 BARTHELL & STONE: EARWIG PARASITES 139

A. 1989 (Biweekly)

50 19 May 16 Jun 14 Jul 11 Aug 8 Sep 6 Oct

18 B. 1990 (Weekly)

Total Number of Puparia

11 May 8 Jun 6 Jul 3 Aug 31 Aug 28 Sep

Sampling Intervals

Figure 2. Abundance of tachinid puparia found at biweekly intervals during 1989 (a) and at weekly

intervals during 1990 (b).

the number of puparia in habitats differed significantly from those levels expected

based upon host numbers per habitat (x? = 11.47; df = 2; P = .0032), with all

but one puparium occurring in the marsh and riparian habitats (Table 1). No

puparia were recovered from the grassland during 1989, suggesting that the par-

asite, like its host, may avoid the exposed and drier conditions of this habitat

type.

Overall numbers of puparia relative to adult earwigs were low during both 1989

(n = 30) and 1990 (n = 68) with parasitization levels =1%. However, these were

140 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Table 1. Total numbers of earwigs and tachinid puparia (parentheses) found in each of three

habitats.

Year Marsh River _ Grass =

1989 1327 (15) 1246 (15) 123 (O) 2696 (30)

1990 7784 (47) 1929 (20) 1280 (1) 10,993 (68)

undoubtedly low estimates of parasitization in the population because the parasites

potentially contained within the earwigs counted from SUs had not necessarily

completed their development. The exact contribution to earwig mortality therefore

remains unknown at CRP, although 18% parasitization was recorded for a pop-

ulation in Danville, California (Schoeppner & Hagen 1963).

Both 1989 and 1990 data show temporal abundance patterns that are consistent

with multivoltine parasite populations (Fig. 2). During 1989, there were two

periods when tachinid puparia were continuously observed: 2 Jun—28 Jul and 8

Sep—6 Oct, with an intervening period of four weeks (two sampling periods) when

no parasites were detected. In 1990 puparia were observed during three continuous

periods: 11 May—8 Jun, 6 Jul—27 Jul and 31 Aug—7 Sep with intervening periods

of three and four weeks, respectively, when no puparia were observed in trap-

nests. Variation in host numbers between sampling periods may partially explain

the uneven distribution of tachinid puparia during both years. However, the long

periods (18-20 weeks) over which the parasites were noted during each year suggest

that multiple generations of parasites must have developed since the develop-

mental time of larvae ranges from 21-90 days (Mote et al. 1931), less than the

period over which puparia were observed in either year.

Our data indicate a well-established population of the introduced tachinid, T.

spinipennis in the Central Valley of California. The occurrence of puparia in

sampling units during two consecutive years demonstrates that the parasite sur-

vived at least one overwintering period. The parasite appears to be able to follow

its host (though less commonly) into more exposed and drier habitats such as the

oak grassland in our study. The extended period over which puparia were observed

during each year suggests the parasite is producing more than one generation per

year as previously described for this species (Mote et al. 1931).

The presence of 7. spinipennis in the Central Valley of California is an important

finding because it demonstrates that the parasite can survive in both the coastal

and Central Valley regions of California, two climatically distinct areas of the

state. The majority of earwigs and tachinid puparia were found near cooler and

more humid riparian habitats which is consistent with findings of other studies

(Chant & McLeod 1952, Crumb et al. 1941). The riparian habitats in our study

surround the Cosumnes River which eventually flows to the San Francisco Bay,

where the European earwig was first noted in California (Essig 1923). It is, there-

fore, likely that the earwig and its parasite have used this river and other waterways

as inland invasion corridors throughout the state.

Material Examined. —USA. CALIFORNIA. SACRAMENTO Co.: Cosumnes River Preserve, 6 Jul

1990, 2 males & 4 females; 13 Jul 1990, 1 male & 1 female. Specimens deposited in the California

Academy of Sciences.

1995 BARTHELL & STONE: EARWIG PARASITES 141

ACKNOWLEDGMENT

We thank P. H. Arnaud, California Academy of Sciences, for identifying the

flies and comments on the manuscript, and K. S. Hagen, University of California

Division of Biological Control, for encouraging this work.

LITERATURE CITED

Arnaud, P. H. 1967. Occurrence of Bigonicheta spinipennis (Meigen) in California (Diptera: Ta-

chinidae). Pan-Pac. Entomol., 43: 39-41.

Carroll, D. P. & S. C. Hoyt. 1984. Augmentation of European earwigs (Dermaptera: Forficulidae)

for biological control of apple aphid (Homoptera: Aphididae) in an apple orchard. J. Econ.

Entomol., 77: 738-740.

Chant, D. A. & J. H. McLeod. 1952. Effects of certain climatic factors on the daily abundance of

the European earwig, Forficula auricularia L. (Dermaptera: Forficulidae), in Vancouver British

Columbia. Can. Entomol., 84: 174-180.

Crumb, S. E., P. M. Eide & A. E. Bonn. 1941. The European earwig. USDA Tech. Bull., 766.

Essig, E.O. 1918. The European earwig, Forficula auricularia Linn. J. Econ. Entomol., 11: 338-

339.

Essig, E.O. 1923. The European earwig in California. J. Econ. Entomol., 16: 458-459.

Essig, E.O. 1925. Economic notes. Pan-Pac. Entomol., 2: 45-46.

Essig, E.O. 1931. A history of entomology. The Macmillan Co., New York.

Krombein, K. V. 1967. Trap-nesting wasps and bees: life histories, nests, and associates. Smithsonian

Press, Washington, D.C.

Langston, R. L. & J. A. Powell. 1975. The earwigs of California (Order Dermaptera). Bull. Cal.

Insect Surv., 20: 1-25.

Mote, D. C. 1931. The introduction of the tachinid parasites of the European earwig in Oregon. J.

Econ. Entomol., 24: 948-964.

Mote, D. C., H. C. Stearns & R. E. Dimick. 1931. The biology of Digonichaeta setipennis Fall., a

tachinid parasite of the European earwig, as observed primarily under western Oregon condi-

tions. J. Econ. Entomol., 24: 957-961.

Mueller, T. F., L. H. M. Blommers & P. J. M. Mols. 1988. Earwig (Forficula auricularia) predation

on the woolly apple aphid, Eriosoma lanigerum. Entomol. Exp. App., 47: 145-152.

O’hara, J. E. (in press). Earwig parasitoids of the genus Triarthria Stephens (Diptera: Tachinidae)

in the New World. Can. Entomol.

Schoeppner, R. & K. S. Hagen. 1963. Biological control of the European earwig. Univ. Calif. Agric.

Exp. Stn. Rep.

PAN-PACIFIC ENTOMOLOGIST

71(3): 142-148, (1995)

ADULT FLIGHT DYNAMICS OF WALNUT HUSK FLY

(DIPTERA: TEPHRITIDAE) IN THE

WILLAMETTE VALLEY OF OREGON

ABDULMAJID KASANA AND M. T. ALINIAZEE

Department of Entomology, Oregon State University,

Corvallis, Oregon 97331

Abstract.—Seasonal flight of the walnut husk fly (WHF), Rhagoletis completa Cresson, was

investigated using Pherocon AM traps in unsprayed trees, and commercial walnut orchards for

a 4-year period (1990-1993). The adult emergence of WHF varied from year to year. The first

flies in untreated trees were detected from July 1 through July 17; with an average of July 9.

Seasonal peaks were observed between August 10 and September 4, and the last flies were trapped

on September 11 through October 9. In commercial orchards, the first flies were trapped July

13 through August 5, seasonal peaks occurred around August 31 through September 9, and the

last flies were trapped between September 14 through 30. Adult emergence occurred approxi-

mately two weeks later in commercial orchards. Only one generation per year was recorded.

Dissections of females indicated that under field conditions, WHF was capable of egg laying 7

days after emergence, and females with mature eggs were found throughout the walnut growing

season.

Key Words.—Insecta, Rhagoletis completa, walnut husk fly, flight activity, seasonal flight

The walnut husk fly (WHF), Rhagoletis completa Cresson, is a pest of walnuts

throughout western North America. Like other tephritids, WHF flight activity is

dependent on the availability of food, shelter and oviposition sites. Gibson &

Kearby (1978) in Missouri and Riedl & Hoying (1980) in California studied WHF

flight activity using Pherocon AM traps and reported that WHF was active from

July through October. Other Rhagoletis sp. are reported to be active during this

time period, although slight differences were found due to host type and envi-

ronmental conditions (Frick 1952; Oatman 1964; Dean & Chapman 1973;

AliNiazee 1976, 1978; Trottier et al. 1975; AliNiazee & Westcott 1987; Jones et

al. 1989, 1991). Although WHF is a serious walnut pest in the Pacific Northwest,

few studies have been conducted on its biology in this region. This study inves-

tigated the seasonal flight pattern of WHF from western Oregon, analyzed seasonal

maturity of ovipositing females in the field, and determined the impact of envi-

ronmental conditions such as temperature and rainfall on the flight pattern.

MATERIALS AND METHODS

Adult Flight Dynamics in Unsprayed Trees.—Unsprayed, mature backyard

‘Franquette’ walnut trees with a history of high WHF infestation were selected

for this study. Commercially available standard Pherocon AM yellow sticky traps

(Trece, Salinas, Calif.) without additional ammonium carbonate lure, were hung

at a height of 2 m above the ground on bearing trees (Anonymous 1982) at the

four compass directions to trap flies. A total of 5 different sites were used and a

minimum of two traps placed at each site. Traps were hung at the outside of the

tree canopy, and small branches and leaves were cleared away to increase visibility

and prevent leaves from touching the trap surfaces. From mid June until the end

1995 KASANA & ALINIAZEE: WALNUT HUSK FLY FLIGHT IN OREGON _ 143

Table 1. Four year pattern of adult catches of Rhagoletis completa in Pherocon AM traps in

unsprayed walnut trees, Willamette Valley, Oregon.

Date flies caught : . ;

First mature Lastimmature Total flight Average no. of

Year ~ First Peak Last female emale duration (days) flies/trap/season

1990 7/11 8/27 10/1 7/23 9/10 82 456

1991 7/17 9/4 10/9 7/29 9/16 86 488

1992 7/1 8/10 9/11 7/13 8/17 75 451

1993 7/9 8/30 10/1 1423 _ Me 690

Mean 7/9 8/19 9/28 22 9/4 80 521

of October, traps were replaced every 4 weeks (AliNiazee & Fisher 1985). The

trap catches were monitored three times a week, and each time a count was taken

the traps were cleaned. The flies were removed from traps, sexed (Moffitt 1958),

washed in kerosene oil and females were stored in a 70% ethanol-glycerol solution

by date for ovarian development studies.

Adult Flight Dynamics in Commercial Walnut Orchards.—Two commercial

walnut orchards in Junction City, Oregon were selected for this study. Orchard

No. 1 was a 3 hectare planting of ‘Franquette’ which had been sprayed annually

for WHF control. Orchard No. 2 was a 5 hectare block of mixed varieties, ‘Fran-

quette,’ ‘Manregian,’ ‘Mayette,’ ‘Spurgeon,’ and ‘Hartley,’ which was not treated

for WHF or other pests during the study period. Irrigation, nitrogen fertilizer use

and other cultural practices including sheep grazing were practiced in both or-

chards. Two Pherocon AM traps were evenly spaced on south side of two trees

2 m above ground in each orchard. The trap catch was monitored weekly during

1991 and 1992 seasons. Trapped flies were sexed and counted. The females

removed from the traps were washed in kerosene oil and stored in 70% ethanol-

glycerol by date for laboratory dissections.

Female Ovarian Development Under Field Conditions. —The females collected

from Pherocon AM traps were dissected in the laboratory to determine presence

of eggs and egg development. Egg development in the ovaries was used to group

the flies into two categories: undeveloped (mature oocytes absent), and developed

(with varying degree of ovarian development but a minimum of full sized terminal

oocytes). The latter category included females capable of laying eggs.

RESULTS AND DISCUSSION

Adult Flight Dynamics in Unsprayed Trees.—Initial trap catch in unsprayed

trees occurred on Jul 11, 17, 1 and 9, respectively for 1990, 1991, 1992, and 1993

study years (Table 1). The peak catches for these same years were Aug 27, Sep 4,

Aug 10 and Aug 30. Fly capture terminated on Oct 1, 9, Sep 11 and Sep 24,

respectively for 1990 through 1993. The total number of days flies were trapped

varied from 75 in 1992 to 86 in 1991 (Table 1). A sex ratio of close to 1:1 was

noticed during the entire study period. In general females outnumbered males

during the early season with males more abundant after mid-season (Figure 1).

The average date of first fly catch for the 4-year study period was Jul 9, the

peak Aug 19, and last catch Sep 28. There was a remarkable degree of consistency

in the time of first fly catch during the study period (mean Jul 9 + 7 SD day).

144 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

FUES / TRAP / COUNT

o-™ 7 ; 0-Seaee

O7/11 08/08 09/03 10/01 O7/17 08/14 09/11 10/09

DATES DATES

FUES / TRAP / COUNT

ar r 7 0 ' <

87/01 07/24 08/19 09/11 07/09 08/04 09/03 10/01

DATES DATES

Figure 1. Seasonal patterns of flight activity of Rhagoletis completa in the Willamette Valley of

Oregon for a four year period, 1990-93 (unsprayed walnut trees).

The number of flies trapped varied over the years but consistently high (range

451-690/trap) indicating the presence of a high adult population in the field.

Effect of Quadrants on Trap Catches. —There were no significant differences in

trap catches among quadrants during any year except for the capture of first fly

and last fly. In 1990, the first fly was captured on Jul 11 in the south quadrant,

in 1991, on Jul 17 in the south quadrant, in 1992, on Jul 1 in the west quadrant,

and in 1993 on Jul 9 in the east quadrant (Figure 2). The last flies of the season

were trapped on 11 Sep 1990 in north quadrant, 30 Oct 1991 in the south and

the west quadrants, 11 Sep 1992 in north and south quadrants, and Sep 24 in the

west quadrant (Figure 2).

Table 2. Seasonal pattern of Rhagoletis completa catches in Pherocon AM traps in commercial

walnut orchards.

Date flies caught

a Cé‘First mature Last immature Total flight Average no. of

Year First Peak Last female female duration (days) _ flies/trap/season

Orchard no. 1

1991 8/05 9/09 9/23 8/12 8/26 49 111

1992 7/13 8/31 9/14 7/27 8/24 63 342

Orchard no. 2

1991 8/05 9/02 9/30 8/19 9/02 56 207

1992 7/13 8/31 9/14 Tad 8/17 63 305

1995 KASANA & ALINIAZEE: WALNUT HUSK FLY FLIGHT IN OREGON | 145

FLIES / TRAP / WEEK

07/01 07/14 07/28 O8/11 08/25 09/08 09/22 10/06

DATES DATES

FLIES / TRAP / WEEK

ae :

ol wee =

07/01 07/14 07/28 08/11 08/25 09/08 09/22 10/06

DATES DATES

Figure 2. Quadrant-wise seasonal patterns of flight activity of R. completa under unsprayed walnut

trees.

In general, the earliest activity was seen in the south and east sides, with the

north side last. Fly catch varied by quadrant from 23 to 26% of total flies captured

suggesting an even distribution of flies throughout the trees. Similarly, Oatman

(1964) found no significant difference in Rhagoletis pomonella (Walsh), activity

among tree quadrants in Wisconsin.

Adult Flight Dynamics in Commercial Walnut Orchards.—During 1991, in

commercial walnut orchards, the first fly was trapped on Aug 5 (Figure 3), fly

catches generally increased with a seasonal peak on Sep 9 (Orchard 1) and Sep 2

(Orchard 2), and catches terminated on Sep 23 (Orchard 1) and Sep 30 (Orchard

2). A synthetic pyrethroid insecticide (Asana) was applied on Aug 26 in Orchard

1 while Orchard 2 was left untreated. Total flight activity in Orchard 1 lasted for

49 days and in Orchard 2 for 56 days.

During 1992, the fly activity was earlier than 1991; the first fly was trapped on

Jul 13 in both orchards, with a seasonal peak on Aug 31, and no flies were caught

after Sep 14 (Figure 3). The Orchard 1 was again sprayed with Asana on Aug 26,

while Orchard 2 was left untreated. The total flight period during 1992 was 63

days in both orchards and the sex ratio was approximately 1:1.

A comparison of flight patterns from commercial orchards and unsprayed trees

showed a 15 day difference in emergence in 1992, and 19 day in 1991 with

146 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Orchard # 1, 1991

Orchard # 2, 1991

—=- MALE -—+— FEMALE —=— TOTAL

—= MALE —— FEMALE —* TOTAL

FLIES / TRAP / WEEK

DATES

150 150

Orchard # 1, 1992

4254|@- MALE —— FEMALE —- TOTAL 1254 [= MALE —— FEMALE = TOTAL

100

Orchard # 2, 1992

FLIES / TRAP / WEEK

Oona 08/03 08/24 09/14

0 == :

07/13 08/03 08/24 09/14 DATES

DATES

Figure 3. Seasonal patterns of flight activity of R. completa in commercial walnut orchards,

1991-92.

emergence occurring earlier in the unsprayed trees. Inter-population differences

in emergence of Rhagoletis sp. have been reported before. Jones et al. (1989)

reported that R. pomonella populations emerged 5 weeks apart in different regions

in Utah. AliNiazee & Fisher (1985) reported that WHF emergence varied among

orchards within a given area and among different locations within an orchard.

Large variations in first emergence of R. pomonella among adjacent cages in the

same orchard were recorded in New York (Glass 1960, Dean & Chapman 1973).

Physical factors such as the depth at which the pupae overwinter, slope, soil type,

soil cover, planting density, and genetic factors are probably responsible for vari-

ation of adult emergence. Such variation may be an evolutionary adaptation

because food and mates may not be present throughout the adult life span.

The time of capture of WHF in ground emergence cages during 1991, 1992 and

1993 coincided with the time of their capture in aerial traps. This suggests a close

temporal relationship between first fly emergence in ground emergence cages

(Kasana & AliNiazee in press) and the first fly catch in Pherocon AM traps.

Daily rainfall and temperature fluctuation were found to be unrelated to flight

pattern of WHF. It appears that unlike R. pomonella for which rainfall has been

shown to accelerate fly emergence (Brittain & Good 1917, Phipps & Dirks 1933,

Jones et al. 1989), the WHF emergence does not increase after rainfall, although

further research along these lines is required. None of the studied orchards were

irrigated.

1995 KASANA & ALINIAZEE: WALNUT HUSK FLY FLIGHT IN OREGON _ 147

The first sexually mature females were trapped on 23 Jul 1990, 29 Jul 1991,

13 Jul 1992, and 23 Jul 1993. The peak activity of sexually mature females was

on 27 Aug 1990, 5 Sep 1991, and 10 Aug 1992. The last sexually mature females

were trapped on 10 Sep 1990, 16 Sep 1991, and 17 Aug 1992. This corresponds

well with the ovipositional activity in the field. Our data indicate that aerial traps

were effective in trapping both sexually mature and immature flies. However, as

season progressed, the capture of mature females increased.

Sexually immature flies represented 10.8% of the total capture in 1990; 8.2%

in 1991 and 20% in 1992 indicating that only a small proportion (13-14%) of

trapped females were sexually immature, and a majority were mature flies, ovi-

positing or ready to oviposit.

In commercial walnut Orchard 1, the first sexually mature female was caught

on 12 Aug 1991, and 27 Jul 1992. In Orchard 2, the first sexually mature female

fly was trapped on 19 Aug 1991, and 27 Jul 1992. The last immature female was

trapped in Orchard 1 on 26 Aug 1991, 24 Aug 1992, and in Orchard 2, on 2 Sep

1991, 17 Aug 1992. This indicates little difference between the untreated trees

and commercial orchards in the sexual maturity pattern of flies.

In Orchard 1, the percentage of sexually immature females trapped ranged from

19.3% in 1991 to 10% in 1992. In general, the number of sexually immature

females was 14%. In Orchard 2, 16.5% of the females trapped were sexually

immature in 1991 and only 9% in 1992.

The appearance of mature fruit flies in the field is an important event that has

a direct bearing on pest control decisions. Once it is known that the females have

attained sexual maturity, the oviposition event can be monitored, and accurate

curative measures can be taken. There was no indication of a second generation

of WHF in this study.

LITERATURE CITED

AliNiazee, M. T. 1976. Thermal unit requirements for determining adult emergence of the western

cherry fruit fly (Diptera: Tephritidae) in the Willamette Valley of Oregon. Environ. Entomol.,

5: 397-402.

AliNiazee, M. T. 1978. The western cherry fruit fly, Rhagoletis indifferens (Diptera: Tephritidae).

3. Developing a management program by utilizing attractant traps as monitoring devices. Can.

Entomol., 110: 1133-1139.

AliNiazee, M. T. & G. Fisher. 1985. The walnut husk fly in Oregon. Fact Sheet No. 168, OSU

Extension Service, Corvallis, Oregon.

AliNiazee, M. T. & R. L. Westcott. 1987. Flight period and seasonal development of the apple

maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), in Oregon. Ann. Entomol. Soc.

Am., 80: 823-827.

Anonymous. 1982. Integrated Pest Management for Walnuts. Univ. of Calif. Div. Agric. Sci. Publ.

3270, Berkeley, CA.

Brittain, W. H. & C. A. Good. 1917. The apple maggot in Nova Scotia. Nova Scotia Dept. Agric.

Bull. 9.

Dean, R. W. & P. J. Chapman. 1973. Bionomics of the apple maggot in eastern New York. Search

Agric. (Geneva, N.Y.) 3: 1-62.

Frick, K. E. 1952. Determining emergence of the cherry fruit fly with ammonium carbonate bait

traps. J. Econ. Entomol., 45: 262-263.

Gibson, K. E. & W. H. Kearby. 1978. Seasonal life history of the walnut husk fly, Rhagoletis completa

and husk maggot, Rhagoletis suavis in Missouri. Environ. Entomol., 7: 81-87.

Glass, E. H. 1960. Apple maggot fly emergence in western New York. N.Y. St. Agric. Expt. Stn.

Bull. 789.

Jones, V. P., D. G. Alston, J. F. Brunner, D. W. Davis & M. D. Shelton. 1991. Phenology of the

148 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

western cherry fruit fly (Diptera: Tephritidae) in Utah and Washington. Ann. Entomol. Soc.

Am., 84: 488-492.

Jones, V. P., D. W. Davis, S. L. Smith & D. B. Allred. 1989. Phenology of the apple maggot associated

with cherry and hawthorn in Utah. J. Econ. Entomol., 82: 788-792.

Kasana, A. & M. T. AliNiazee. (in press). Seasonal phenology of the walnut husk fly, Rhagoletis

completa Cresson (Diptera: Tephritidae). Can. Entomol.

Moffitt, H.R. 1958. Rapid determination of sex in Rhagoletis completa Cresson. J. Econ. Entomol.,

S15 53.1,

Oatman, E.R. 1964. Apple maggot emergence and seasonal activity in Wisconsin. J. Econ. Entomol.,

57: 676-679.

Phipps, C. R. & C. O. Dirks. 1933. Notes on the biology of the apple maggot. J. Econ. Entomol.,

26: 349-358.

Riedl, H. & S. A. Hoying. 1980. Seasonal patterns of emergence, flight activity, and oviposition of

the walnut husk fly in northern California. Environ. Entomol., 9: 567-571.

Trottier, R., J. Rivard & W. T. A. Neilson. 1975. Bait traps for monitoring apple maggot activity

and their use for timing control sprays. Can. Entomol., 68: 211-213.

PAN-PACIFIC ENTOMOLOGIST

71(3): 149-156, (1995)

MALE SIZE VARIATION AND MATING SITE FIDELITY

IN A POPULATION OF HABROPODA DEPRESSA FOWLER

(HYMENOPTERA: ANTHOPHORIDAE)

JOHN F. BARTHELL! AND HOWELL V. DALY

Department of Environmental Science, Policy and Management,

University of California, Berkeley, California 94720

Abstract.—The relationship between size and mating site fidelity was studied in males of the

anthophorid bee Habropoda depressa Fowler during a two year period. Males appear to separate

into two groups that locate mates differently. One group patrols patches of ground where bees

emerge from nests constructed during the previous year. These males appear able to detect

females that have recently emerged from nests or that are about to do so. Large numbers of

these patrolling males struggle for prolonged periods to gain access to mates, frequently forming

clusters around newly emerged females. Another group of males patrols flowering plants, ap-

parently in search of foraging females that did not mate at the nesting site. Bees marked from

both groups showed fidelity to their respective mating sites during mark-recapture studies. The

two groups of males also differed significantly in size, with those from the flower sites being

smaller on average than nesting site males. In addition, males from mating clusters were larger

than other patrolling males at nesting sites. These patterns of male mating behavior parallel

those found in other protandrous bee and wasp species.

Key Words.—Insecta, Anthophoridae, Habropoda depressa, protandry, mate-location, nesting

site, size

Protandrous mating systems are common among solitary bee and wasp species

(Stephen et al. 1969, Evans & West-Eberhard 1970). Early in the flight season,

large numbers of males relative to females can produce extraordinarily high levels

of competition for mates. In some species, males that patrol nesting sites form

characteristic mating clusters around newly emerged females (O’Neill & Evans

1983, Longair et al. 1987, O’Neill & Bjostad 1987). Among some anthophorid

bee species, males patrol nesting sites for mates as well as using alternative methods

of mate-location. Centris pallida Fox males form mating clusters as well as waiting

for females at the periphery of nesting sites (Alcock 1976). Similar examples exist

for species in the genera Amegilla, Diadasia and Habropoda (Gordon 1984, Hous-

ton 1991, Neff & Simpson 1992, Cane 1994). Here we report direct evidence of

alternative mate-location strategies by males of the ground-nesting vernal bee

Habropoda depressa Fowler.

MATERIALS AND METHODS

Site Descriptions. —The study was conducted during March and April of 1991-

92 on the University of California at Berkeley campus. Specimens of H. depressa

were originally described from this site by Fowler (1899). Males were commonly

observed flying near nesting sites when most females had not yet emerged. They

were also seen in flight near these sites at several flowering plant species. Each

nesting site (NS) represented an active emergence and nesting location for H.

depressa females. In 1991, a NS on one of the least developed regions of the

! Current Address: Department of Biology, University of Central Oklahoma, Edmond, Oklahoma

73034.

150 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

campus, a forested hillside known as Observatory Hill, was chosen for study.

Male behavior at this site was compared with that at a similarly sized flower site

(FS) of Indian hawthorn (Raphiolepis indica Lindley) located about 50 m away.

In 1992, male behavior was compared between another pair of sites (~ 10-20 m

apart) further up the same hillside.

Mating Site Fidelity.— Male mating site fidelity was studied by capturing and

marking males at each of the two sites during both years. On 9 Apr 1990, samples

of 80 patrolling males were netted from swarms of males while walking through

each site. Each captured bee was marked with enamel paint on the center of its

thorax and color-coded according to capture site. To ensure that males were not

acclimated to their capture site, sweep samples from one site were transferred to

the other site after being marked, i.e., those sampled from the FS were transferred

to the NS for release and those captured at the NS were released at the FS. The

following day another 80 males were captured from each site. The number and

color (if any) of captured males from each site were then tallied. All bees were

captured, marked and released within the same three hour period of each day

(11:45-14:45) when male patrolling activity was conspicuous. The above proce-

dure was repeated 18-19 Mar 1992.

Size Variation. —Size variation was examined by comparing the mean size of

male bees from each site during both years. Bees that had been captured on the

second day of each mark-recapture period were used for this purpose. A total of

80 bees from each site was therefore measured during each year. Head capsule

width was used as the size estimate, a measurement commonly used in other

studies of hymenopteran size (O’Neill & Evans 1983, Daly 1983, Alcock 1989,

Dodson & Yeates 1989, Mueller et al. 1992). Measurements were made with a

dissection scope (12 x) equipped with an ocular micrometer. The resulting means

and variances for each group of each year were then compared using t-tests (Sokal

& Rohlf 1981).

Collections were also made at nesting sites where male mating clusters, groups

of males surrounding virgin females, were commonly seen near emergence holes.

Four males from one aggregation were collected on 10 Apr 1991 and another 13

males from four aggregations were collected during a 2.5 h period on 18 Mar

1992 for comparison with NS males. Observations of mating behavior were also

made at various times during the study.

RESULTS

Behavioral Observations. — Males patrolled both nesting and flower sites. Males

at the NS flew rapidly in zigzagging patterns just above the ground where females

had begun nesting or were still emerging. Small groups of males were commonly

seen hovering near the ground, often above an emergence hole. Occasionally one

would land, enter the hole and emerge several seconds later to continue hovering

in the area. A virgin female, buried under a layer of loose soil on 8 Mar 1992,

was investigated by males in the area and she was eventually uncovered by one

male that attempted to copulate with her.

During female emergence, clusters of struggling males (each surrounding a fe-

male) were commonly seen at the NS. These mating clusters continued for several

minutes until one male remained. During these struggles, one male typically held

himself over the female dorsum while other males attempted to remove him (Fig.

1995 BARTHELL & DALY: MATING IN HABROPODA DEPRESSA 151

Figure 1. Habropoda depressa male attempting to dislodge another from a recently emerged female.

Figure 2. A mating pair of Habropoda depressa.

1). Presumably, the female at the center of a cluster had recently emerged from

her nest cell because females that had initiated nesting were rarely approached by

patrolling males. Similar, though smaller, groups of males were induced on 13

Apr 1991 at both the NS and FS by a tethered female that had been removed

from a mating cluster while still attractive to males. The attractiveness of this

female to males declined rapidly after the initial exposure to patrolling males.

Brief contacts between males in the vicinity of mating clusters and nest holes were

occassionally observed at nesting sites. It was unclear, however, if these inter-

actions were aggressive, accidental or both.

Males and females were also commonly found foraging for nectar at the Indian

hawthorn flower sites. Most males at these sites flew in erratic patterns over the

surface of the hedges as well as at other flowering ornamental species including

Chinese wisteria (Wisteria sinensis (Sims) Sweet), victorian box trees (Pittosporum

undulatum Ventenat), an Acacia bush and a Japanese flowering cherry tree (Prunus

serrulata Lindley). Unlike the NS, however, a mating attempt at flowers was

observed only once when a male and female were found struggling on the ground

under a victorian box tree directly below a group of patrolling males.

Attempted matings at the NS and FS were characterized by the same series of

behavioral stages. Each began with the male securing a position over the female’s

dorsum. The male’s front legs held the female between her front and middle legs

while his hind legs were kept along the sides of her abdomen (Fig. 2). The female’s

wings were thereby pinned between his front legs and the female’s thorax, pre-

venting her from opening her wings. Once in this position, the male began a

rhythmic opening, vibrating and then closing of his wings at regular intervals

while moving his hind legs posteriorally and along the female’s abdomen. The

male’s antennae were held straight during this process, often in alignment with

the female’s. When the abdominal apices of the female and male were nearly in

contact, the male rapidly curled his antennae downward, while positioning his

abdomen for copulation. Once in copula, the male twitched his antennae at regular

intervals while the female remained mostly inactive.

152 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Table 1. Numbers of male Habropoda depressa marked (Mrk) at respective mating sites and of

those that were later recaptured (Rec). Contingency (2 x 2) test results from comparing actual and

expected recapture numbers of bees that returned (Ret) or moved (Mov) to the other site are also

presented.

Flower site nos. Nesting site nos.

Year Mrk Rec Ret Mov Mrk Rec Ret Mov

1991 80 4 3 1 80 16 15 1 x? = 27.20, P < 0.001

1992 80 6 5 1 80 5 4 1 x7 = 4.64, P < 0.050

male twitched his antennae at regular intervals while the female remained mostly

inactive.

Individual mating attempts varied slightly and did not always culminate in

copulation. Many females resisted males by wriggling and moving their legs up-

ward to disrupt the mating process or dislodge the male. One male was observed

failing to copulate with a female despite six attempts to do so. All aborted attempts

were attributed to female resistance. Intensity of resistance by females to copu-

lation varied, and it was unclear whether this represented female mate choice or

declining receptivity of females induced by previous matings.

Mating Site Fidelity.— Although few marked males were recaptured relative to

all captured males for either the FS or NS groups during either year (<= 20%),

recaptured (marked) males remained faithful to their original capture sites (Table

1). During 1991, for example, 16 marked bees were captured at the NS; 15 had

returned and one had moved there from the FS. Four marked bees were found

at the FS, three of which had returned there and one which had originated from

the NS.

Similar results were obtained during 1992 although the distance between the

NS and FS was shorter. Six and five marked males were collected at the FS and

NS, respectively, and all but one had returned to the original capture site in each

case. The recaptured males were not randomly distributed (P < .05) between the

two sites during either year (Table 1), suggesting that they segregate into two

mating groups: those that patrol female emergence sites and those that patrol

flowering plants.

Size Variation.—The modes and means of male head capsule width samples

were greater for the NS than for the FS for both years. The NS distributions (Fig.

3) are shifted to the right relative to the FS distributions. The two largest male

size categories were found only in the NS and the smallest categories occurred

only in the FS (Fig. 3a). Similar results were obtained in 1992 (Fig. 3b). Mean

male head capsule widths were significantly larger in the NS for both years (Ta-

ble 2).

Table 2. Mean head capsule widths for male Habropoda depressa collected at nesting and flower

sites.

Flower site Nesting site

Year x (SD) n x (SD) n

1991 4.71 (0.12) 80 4.75 (0.10) 80 t = 2.24, P < 0.05

1992 4.75 (0.10) 80 4.79 (0.10) 80 t = 2.54, P < 0.05

1995 BARTHELL & DALY: MATING IN HABROPODA DEPRESSA 153

3a. 1991 Distribution

Mi Flower Site (n = 80)

O Nesting Site (n = 80)

Number of Bees

53 55 57 #59 °&461 63 65 £67

3b. 1992 Distribution

M@ Flower Site (n = 80)

O Nesting Site (n = 80)

Number of Bees

5.3 5S 5.7 59 6.1 6.3 6.5 6.7

Head Width Values (1 Unit = .78 mm)

Figure 3. Distributions of head capsule widths for male Habropoda depressa collected from flower

and nesting sites during 1991 (a) and 1992 (b).

The largest mean head capsule widths were recorded from males collected from

mating clusters. The mean of four males taken from a single cluster in 1991 was

significantly greater than NS males of the same year (X = 4.86 mm; ¢t = 2.03; P

< .05). Similarly, the mean of 13 males taken from four mating clusters during

1992 was significantly greater than NS males of the same year (X = 4.88 mm; f

= 2.97; P < .01). The largest male collected during 1992 came from a mating

aggregation and had a head capsule width of 5.14 mm.

DISCUSSION

Males of H. depressa employ at least two types of mate-locating behavior by

patrolling either emergence sites or flowers to find receptive females. Males pa-

trolling flowers are smaller than those at nesting sites. Although the exact mech-

154 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

anism for this size segregation is not known, evidence from this study suggests

that intrasexual competition is important. Males attempt to pry one another away

from females in mating aggregations. Less competitive (smaller) males are prob-

ably forced to peripheral sites such as trees and other flowering plants, thus

increasing the average size of males in the NS.

The males found at flowers have a different mating strategy because direct

competitive displacement probably does not occur at these sites. Rather, males

rapidly responding to receptive females visiting flowers may have the most ef-

fective mating strategy. Smaller size may confer better flight maneuverability, an

advantage to males trying to intercept females at flowers.

Mating success of FS males appeared low with one mating attempt observed

during the study. This low mating frequency is not surprising as the many flowering

plants on the campus and adjoining urban area produced numerous patrolling

spots for males. The likelihood of a male encountering a foraging female was

therefore low relative to the NS where females are concentrated at a few patches

of ground. In addition, foraging females are presumably unreceptive to males

because they were likely to have mated at the NS and had already begun con-

structing and provisioning their nests. The possibility remains that some females

are not mated at the NS, however, and waiting for these females at foraging sites

may therefore be a viable mating strategy for smaller males.

Alternative mating strategies may be widespread in the genus Habropoda (=

Emphoropsis) (Brooks 1988). Gordon (1984) describes patrolling males and mat-

ing clusters in the beach-dwelling H. miserabilis (Cresson). Similar mating systems

have been described for two other sand-nesting species. H. /aboriosa (Fabr.) and

H. pallida (Timberlake), including the occurrence of mating clusters (Bohart et

al. 1972, Cane 1994). Timberlake (1962) also described evidence of male mating

clusters in Habropoda excellens (Timberlake). In the case of H. pallida, some

females were “unreceptive”’ to males, an apparent similarity to female resistance

to mating described here for H. depressa.

The mating system of H. depressa resembles that described for species in other

anthophorid genera, including Amegilla, Centris and Diadasia. Houston (1991)

describes males of Amegilla dawsoni (Rayment) patrolling both nesting sites and

flowering plants in Australia. Male size in this species conforms to a bimodal

distribution and larger males appear to succeed most often at NS mating clusters

while smaller males were most common at flower sites.

The mating behavior of Diadasia rinconis Cockerell closely parallels that of H.

depressa (Neff & Simpson 1992). Males patrol both flower and nesting sites and

male mating clusters were commonly observed at nesting sites, while less frequent

matings were noted at flowers. Nesting females were not pursued by patrolling

males, perhaps because previous matings had somehow rendered them unattrac-

tive. Guarding of sites containing potential mates was conspicuous among D.

rinconis males though less pronounced among H. depressa males.

Male mating strategies in H. depressa also resemble those of Centris pallida

Fox. Males of this species segregate into at least two groups, those that patrol

nesting sites and those that patrol areas peripheral to nesting sites (Alcock 1976).

Mating behavior is similar although olfaction appears to be more acute and mate-

locating behavior less pronounced in H. depressa. Habropoda depressa males

accurately located a buried virgin female and could apparently determine where

1995 BARTHELL & DALY: MATING IN HABROPODA DEPRESSA 155

females would emerge, but were not observed excavating surface pits to meet

emerging females as in C. pallida (Alcock et al. 1976). Rather, mate-location in

H. depressa more closely resembled D. rinconis as both species investigate nest

burrows but apparently without extensive excavation of unemerged females (Neff

& Simpson 1992).

At least two hypotheses might explain the basis of mate-location described for

the anthophorine genera Amegilla, Centris, Diadasia and Habropoda. First, as

described for C. pallida (Alcock et al. 1977), the presence of numerous highly

competitive males at discrete emergence sites (where females mate only once upon

emergence) selects for male dimorphism. Such conditions exist for at least some

species within each genus, although the intensity of male competition varies

between and within species. Nesting sites on Santa Cruz Island (off the coast of

southern California) generally appear less densely patrolled by Habropoda males

than on the U.C. Berkeley campus (JBF, personal observation). Alternatively,

then, it could be hypothesized that the less pronounced male dimorphism found

in H. depressa may reflect a short-term effect of local competition, perhaps an

ecological precursor to the extreme male dimorphism that may have evolved in

C. pallida populations.

Identification of the proximate origin of size variation in Habropoda, Amegilla

and Diadasia species would assist in discriminating between these hypotheses.

Alcock et al. (1977) predicted, for example, that C. pallida females determine

male progeny size by varying brood cell provisions. Unfortunately, C. pallida

typically produces only one cell per nest, making this hypothesis difficult to test

(Alcock 1979). Nonetheless, size variation of C. pallida males is over twice that

described herein for H. depressa and is maintained over time within populations

(Alcock 1989), suggesting variation is directly produced from female provisioning

behavior and is therefore genetically based. Lower variation and less pronounced

bimodality in size of males suggest that environmental factors may be sufficient

to explain male dimorphism in H. depressa, including the availability of resources

such as pollen, nectar and nesting sites.

Evidence from this study and others indicates that multiple mating systems

induced by protandry may be more widespread than previously recognized in the

Anthophoridae. Aspects of non-anthophorid bee mating strategies, including Col-

letes cunicularius (Colletidae), Nomia nevadensis (Halictidae) and Perdita texana

(Andrenidae) resemble those of H. depressa as well (Cane & Teng6é 1981, O'Neill

& Bjostad 1987, Danforth & Neff 1992). One or more characteristics of the mating

strategies of H. depressa are also known for sphecid wasp species (O’Neill & Evans

1983, Longair et al. 1987, Martin & Martin 1990). How widespread multiple

mating systems are in the Hymenoptera, however, and whether ecological and/

or genetic factors mediate their occurrence are questions that await further study.

ACKNOWLEDGMENT

Deep appreciation is extended to those who provided observations and assis-

tance in the field: K. M. Delate, D. A. Fruitt, M. A. Prentice and R. Stone. D.

M. Bromberger pointed out male behavior at flowers and provided access to plant

identifications. A. J. Slater and M. J. Hurlbert in Pest Management, Physical Plant

Services, identified plants and conveyed observations they had made on the bees.

A host of U.C. Berkeley staff and students who were onlookers during the project

156 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

were often helpful as well. The manuscript was read and improved by M. Dor-

mond, G. W. Frankie, D. M. Gordon and R. W. Thorp.

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PAN-PACIFIC ENTOMOLOGIST

71(3): 157-160, (1995)

SYSTEMATIC CHANGES IN CERTAIN EPHEMEROPTERA

STUDIED BY R. K. ALLEN

GEORGE F. EDMUNDS, JR.! AND CHAD M. MurRvosH?

‘Department of Biology, University of Utah, Salt Lake City, Utah 84112

?Department of Biological Sciences, University of Nevada,

Las Vegas, Nevada 89154

Abstract.—Heptagenia bella (Allen & Cohen) is placed herein as Nixe bella, NEW COMBI-

NATION. Serratella thailandensis Allen NEW SYNONYM is a junior objective synonym of

Cincticostella gosei (Allen). The species Ephemerella (Dentatella) bartoni (Allen) is properly

referred to as Eurylophella (Dentatella) bartoni Allen. Caurinella idahoensis Allen is confirmed

to be a valid genus and species of uncertain affinities. The genus Vietnamella Tshernova is

transferred from Ephemerellinae to Teloganodinae.

Key Words.—Insecta, Ephemeroptera, mayfly, taxonomy

Edmunds & Murvosh (1995) presented an obituary for the late Richard K.

Allen. This paper discusses and corrects some systematic situations resulting from

the taxonomic work of Allen, and detailed in an unpublished bibliography and

list of taxa (GFE & CMM, unpublished), which is available from either of us. In

most cases no comment is made on published name changes made by Allen or

others.

Labels on Type Material. —It is essential for those subsequently studying types

or paratypes of species described by R. K. Allen to note that in some cases the

slides, at least, bear names that apparently were changed before publication, and

that slides of holotypes or supplementary types are not always labeled as such.

Usually there is a red margin on a slide label where the specimen is part of a

holotype and a blue edge slide label designates a part from a paratype. This too

is inconsistent in the collection. Localities and dates will allow these specimens

to be associated with their correct names; in a few cases obvious types or sup-

plementary types in vials or parts on slides are not labeled as such. There are also

specimens or slides labeled as types or supplementary types that are manuscript

names.

Systematics. —We have examined the types of Heptagenia bella Allen & Cohen

(1977) of Mexico at the California Academy of Sciences and note that the char-

acters place this species as Nixe bella, a genus described after the name bella was

proposed. Allen (personal communication) was aware of the need for the generic

reassignment. Other specimens of Nixe from farther south appear to belong to

one or more undescribed but similar species.

Allen (1975:20) named Ephemerella (Cincticostella) gosei Allen based on Gose’s

figure 38 labeled Ephemerella TEB (Gose, 1969) based on specimens from Chanta

Buri, Thailand, 20 Jun 1961. Allen (1980: 76) named Serratella thailandensis

Allen, based on the same Ephemerella TEB (Gose, 1969) and raised Cincticostella

to generic rank. Serratella thailandensis NEW SYNONYM is a junior objective

synonym of Cincticostella gosei.

Allen & Murvosh (1983) and Allen (1990) place Epeorus (Iron) margarita

Edmunds and Allen (1964) from the U. S. and Mexico in Jron, thus restoring

158 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Tronas a full genus. Recognition of Jron as a genus is now common but the generic

placement of some Asian species of the complex are still to be resolved and will

certainly influence the final resolution of the taxonomy of the species of Jron and

related taxa.

The unnamed species Thraulodes sp. F of Allen & Brusca (1978) (Central

America) is a member of the genus Farrodes. The correct generic assignment was

recognized by R. K. Allen and H. M. Savage (personal communications). Farrodes

occurs from Argentina to Texas (see Davis 1991). Thraulodes sp. G from Mexico

was recognizable by several mayfly specialists as belonging to the genus Terpides,

but this has been indicated earlier by Savage (1987) on a distribution map of

Terpides. Savage (personal communication) confirmed that this map was based

in part on Allen’s Thraulodes sp. G.

Allen (1977) described Ephemerella bartoni Allen and placed it in the subgenus

Dannella. Ephemerella bartoni did not fit into the definitions and keys of any of

the existing subgenera of the Ephemerellidae. McCafferty (1978) transferred bar-

toni from the subgenus Dannella to Eurylophella. Allen (1980) raised the sub-

genera of Ephemerella to generic rank, retained bartoni in Dannella and placed

it in a new subgenus Dentatella. Gill 4 of bartoni does not cover the remaining

gills as fully as in other species of Eurylophella and the elongation of abdominal

segments 8 and 9 is relatively less than in other Eurylophella. Although Allen felt

strongly that he was correct about the generic placement of bartoni, we feel certain,

as did McCafferty, that bartoni is the most plesiomorphic species of Eurylophella.

We concede that the examination of either males or mature eggs from females or

mature larvae would be needed to provide overwhelming proof of the generic

assignment of bartoni, but the evidence is adequate that bartoni is cladistically a

member of Eurylophella and is informative because it is the least specialized larva

of the genus (the adult is unknown). McCafferty and Wang (1994) placed Dentatella

as a subgenus of Eurylophella.

When Allen (1984) described Caurinella idahoensis Allen as a new genus and

species of Ephemerellidae, from a single specimen, he provided no figures. In-

terestingly, the type specimen was first sent to R. W. Baumann at Brigham Young

University who noted the unique nature of the specimen and forwarded it to

Allen. When Allen described the species, he had forgotten who had sent the

specimen (Allen, personal communication). Some entomologists privately have

expressed doubt concerning the validity of the genus. The caudal filaments are

similar to those of Serratella, but this character is shared also by the Asian

Uracanthella and Cincticostella and some populations of the European Ephem-

erella ignita (Poda). We have examined the type of Caurinella idahoensis and

believe it to be a distinct valid genus. The characters of the larva suggest that

Caurinella is not a specialized derivative of Serratella. When the adults are dis-

covered, its systematic position should be clarified. We include here a lateral view

of the diagnostic apical abdominal segments of the larvae (Fig. 1). Vincent F. Lee

loaned us an additional specimen of C. idahoensis (IDAHO. VALLEY Co.: Eggers

Cr., Trib. Silver Creek, 24 May 1978, R. C. Biggam) from the California Academy

of Sciences, San Francisco. The type specimen and the Eggers Creek specimen

are female larvae, roughly the same size and both have well developed wing pads

that are not yet as dark as they would be if the specimens were ready to emerge.

In the bibliography of Allen’s mayfly papers we noted that Henry (1995) was

1995 EDMUNDS & MURVOSH: MAYFLY TAXONOMY 159

Figure 1. Caurinella idahoensis. Lateral view of abdominal segment 7 to 10 of larva.

raising the subgenus Neochoroterpes (Allen, 1974) of Choroterpes to generic status;

McCafferty et al. (1993) and Henry (1993) have since elevated Neochoroterpes to

generic rank.

Allen (1980) placed the genus Vietnamella Tshernova (1972) (V. thani Tsher-

nova) as a subgenus of Cincticostella Allen (1971), which it superficially resembles.

Allen (1984) restored Vietnamella as a valid genus in a new subtribe Vietnamellae

of the tribe Ephemerellini of Ephemerellinae. This created a new problem because

the presence of gills on abdominal segments 2-7 in V. thani is a fundamental

character of the subfamily Teloganodinae. Gills on abdominal segments 3—7 are

basic traits of the Ephemerellinae, Ephemerellini, subtribe Ephemerellae, and gills

on 4—7 the hallmark of Ephemerellini, subtribe Timpanogae. Thus, Allen gave

no characters for distinguishing Vietnamella from the subfamily Teloganodinae.

You & Su (1987) have described larvae and adult males and females of a second

species of Vietnamella (V. dabishanensis) from China. The adult characters are

those of Teloganodinae. The genus Vietnamella is herein transferred to Telogan-

odinae. The cladistic relationships with typical Teloganodes and a derived group

of Teloganodes are not known but the very flat larvae with prominent spines on

the head, pronotum and forefemora differ markedly from other Teloganodinae.

The name Vietnamellini should be retained as a tribe, but in Teloganodinae. Thus

Teloganodinae has two tribes, Vietnamellini and Teloganodini.

ACKNOWLEDGMENT

We thank Janice G. and W. L. Peters for calling our attention to the synonymy

of Serratella thailandensis Allen and for reviewing the manuscript; Vincent F.

Lee (Calif. Acad. Sci. San Francisco) provided a specimen of Caurinella ida-

hoensis; and W. P. McCafferty also kindly reviewed an earlier version of the

manuscript.

LITERATURE CITED

Allen, R. K. 1971. New Asian Ephemerella with notes (Ephemeroptera: Ephemerellidae). Canad.

Entomol., 103: 512-528.

Allen, R. K. 1974. Neochoroterpes, a new subgenus of Choroterpes Eaton from North America.

Canad. Entomol., 106: 161-168.

Allen, R. K. 1975. Ephemerella (Cincticostella): A revision of the nymphal stages (Ephemeroptera:

Ephemerellidae). Pan-Pacif. Entomol., 51: 16-22.

160 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Allen, R. K. 1977. A review of Ephemerella (Dannella) and the description of a new species (Ephem-

eroptera: Ephemerellidae). Pan-Pacif. Entomol., 53: 215-217.

Allen, R. K. 1980. Geographic distribution and reclassification of the subfamily Ephemerellinae

(Ephemeroptera: Ephemerellidae). Jn Flannagan, J. F. & K. E. Marshall (eds.). Advances in

ephemeroptera biology. Plenum, New York.

Allen, R. K. 1984. A new classification of the family Ephemerellidae and the description of a new

genus. Pan-Pacif. Entomol. 60: 245-247.

Allen, R. K. 1990. The distribution of southwest North American mayfly genera (Ephemeroptera)

in the Mexican transition zone. Jn Campbell, I. C. (ed.). Mayflies and stoneflies: life histories

and biology. Kluwer, Dordrecht.

Allen, R. K. & R. C. Brusca. 1978. Generic revisions of mayfly nymphs II. Thraulodes in North

and Central America (Leptophlebiidae). Canad. Entomol., 110: 413-433.

Allen, R. K. & S. D. Cohen. 1977. Mayflies (Ephemeroptera) of Mexico and Central America: new

species, descriptions and records. Canad. Entomol., 109: 399-414.

Allen, R. K. & C. M. Murvosh. 1983. Taxonomy and zoogeography of the mayflies (Ephemeroptera:

Insecta) of Baja California. Ann. Entomol. Soc. Am., 76: 425-433.

Davis, J. R. 1991. A new species of Farrodes (Ephemeroptera: Leptophlebiidae: Atalophlebiinae)

from southern Texas. Proc. Entomol. Soc. Wash., 89: 407-416.

Edmunds, G. F., Jr. & R. K. Allen. 1964. Rocky Mountain species of Epeorus (Iron). Eaton.

(Ephemeroptera: Heptageniidae). J. Kansas Entomol. Soc., 37: 275-288.

Edmunds, G. F. Jr. & C. M. Murvosh. 1995. Obituary: Richard K. Allen 1925-1992. Pan-Pac.

Entomol., 71: 1-3.

Gose, K. 1969. Mayflies (Ephemeroptera) from Thailand. Nat. S W Asia 6: 125-136.

Henry, B. C. 1993. A revision of Neochoroterpes (Ephemeroptera: Leptophlebiidae) new status.

Trans. Am. Entomol. Soc., 119: 317-333.

Henry, B. C. (in press). Phylogeny of Neochoroterpes (Leptophlebiidae: Atalophlebiinae). Jn Cibo-

rowski, J. J. H. and L. Corkum (eds.). Current directions in ephemeroptera research. Canadian

Scholars’ Publishing, Inc., Toronto.

McCafferty, W. P. 1978. A natural subgeneric classification of Ephemerella bartoni and related

species (Ephemeroptera: Ephemerellidae). Great Lakes Entomol., 11: 209-216.

McCafferty, W. P., R. S. Durfee & B. C. Kondratieff. 1993. Colorado mayflies (Ephemeroptera): an

annotated inventory. Southwest. Natur., 38: 252-274.

McCafferty, W. P. & T-Q. Wang. Phylogenetics and the classification of the Timpanoga complex

(Ephemeroptera: Ephemerellidae). J. N. Am. Benthol. Soc., 13: 569-579.

Savage, H. M. 1987. Biogeographical classification of the Neotropical Leptophlebiidae (Ephemer-

optera) based upon geological centers of ancestral origin and ecology. Stud. Neotrop. Fauna

and Environ., 22: 199-222.

Tshernova, O. A. 1972. Some new species of mayflies from Asia (Ephemeroptera: Heptageniidae,

Ephemerellidae). Entomol. Rev. (Engl. Transl. Entomol. Obozr.), 51: 604-617.

You, Da-shou & Su, Cui-rong. 1987. A new Vietnamella from China. Acta Zootaxon. Sinica, 12:

176-180.

PAN-PACIFIC ENTOMOLOGIST

71(3): 161-168, (1995)

A NEW LIRIOMYZA SPECIES FROM TAIWAN

(DIPTERA: AGROMYZIDAE)

SHIUH-FENG SHIAO AND WEN-JER Wu

Department of Plant Pathology and Entomology, National Taiwan University,

Taipei, Taiwan 106, Republic of China

Abstract. —Liriomyza litorea NEW SPECIES from Taiwan is described and illustrated. Esterase

electrophoresis and scanning microscopy are used for its discrimination from a closely related

species, L. asterivora Sasakawa. Parasitoids, host plants and mining patterns are also included

for the diagnostic discussion.

Key Words.—Diptera, Agromyzidae, Liriomyza litorea NEW SPECIES, Taiwan

Liriomyza is one of the largest genera in Agromyzidae (Diptera), over 300

species were recorded throughout the world; it attacks a wide range of crops and

the majority of species are leaf miners (Spencer 1973). In Taiwan, this genus was

represented by 10 species (Shiao et al. 1991); although it is not dominant in the

Oriental and Ethiopian regions (Sasakawa 1972), the newly discovered species

did not agree with the other Liriomyza species. This article deals with this new

species with discussions on its separation from the closely related species, L.

asterivora Sasakawa, 1956. Furthermore, we follow Zehnder et al. (1983) by using

electrophoresis and scanning microscopy for the diagnostic discrimination.

MATERIALS AND METHODS

All materials were collected from the host plants, Wedelia biflora (L.) DC., near

seashores in Taiwan and Lanyu (Orchid Is.) (Fig. 1) during 1989 to 1991. Larvae

were reared on the host plants at 24 + 1° C until they emerged. Some of the

emerged adults were preserved in liquid nitrogen for electrophoretic studies, the

others were dried and mounted for morphological observation. Male and female

genitalia were dissected after they had been boiled in 15% KOH solution. Esterase

electrophoresis were analyzed on 7.5% polyacrylamide slab gels, staining method

as described by Ayala et al. (1972). For scanning electronmicrography, gold sput-

ter-coated specimens were examined at 20 KV.

LIRIOMYZA LITOREA SHIAO & Wu NEW SPECIES

(Fig. 2)

Types. — Holotype: male; data: REPUBLIC OF CHINA. TAIWAN. Taipei Hsien:

Lungtung, 17 Feb 1990, S. F. Shiao. Paratypes: 5 males, 5 females; I/an Hsien:

Peikuan, 17 Feb 1990, S. F. Shiao. 2 males, 2 females; Pintung Hsien: Chialeshui,

3 Mar 1991, S. F. Shiao. 6 males, 4 females; Taitung Hsien: Lanyu, 6 Nov 1989,

S. F. Shiao. 2 males, 3 females; Taitung Hsien: Tawu, 25 Feb 1990, Y. C. Shiau.

Holotype and paratypes are deposited in the Department of Plant Pathology and

Entomology, National Taiwan University, Taipei, Taiwan, Republic of China.

Male.—Body length: 1.8 mm (legs and aristae not included); wing length: 1.5 mm. Head: Face

yellow. Frons about 1.4x as wide as eye. Occiput and postgena black, black region contiguous to

ocellar triangle and eye. Lunule semicircular, dorsal tip at about 0.5 x height of eyes. Antennae yellow,

with bases touching each other, 3rd segment rounded in lateral view; arista black, finely pubescent.

162 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

CHINA

PACIFIC OCEAN

20°

120° 125°

Figure 1. Collecting localities of Liriomyza litorea NEW SPECIES in Taiwan. A, Lungtung, Taipei

Hsien; B, Peikuan, Ilan Hsien; C, Tawu, Taitung Hsien; D, Lanyu (Orchid Is.), Taitung Hsien; E,

Chialeshui, Pintung Hsien.

Orbital setulae long, 5-7 pairs. Orbital bristles 4 pairs, lower 2 pairs obviously inclinate. Vertical

angles brown tinged. Vertical bristles 2 pairs, inner pairs on margins of brown ground. Ocellar triangle

yellow with 4 long bristles. Thorax: Mesonotum shining black with lateral stripes yellow. Dorsocentral

bristles 1 + 3. Acrostichals in 4—5 irregular rows. Scutellum yellow but brown-tinged laterally. Legs

with coxae and femora yellow, tibiae and tarsi brown. Wing with costa extending to M,,.; proportion

of 2nd to 4th costal sections, 2.5:1.0:0.7; inner cross vein farther from outer cross vein at about one-

third of discal cell. Halter yellow. Abdomen: Tergites brown, covered with long hairs, each segment

with a narrow caudal margin yellow tinged; Ist and 2nd tergites with yellow middle furrows. Terminalia:

1995 SHIAO & WU: A NEW AGROMYZID 163

_—$$

0.1 MM 0.0SMM 0.1 MM

0.1 MM

Figure 2. Liriomyza litorea NEW SPECIES. A, Head, lateral view; B, Left half of thorax, dorsal

view; C, Wing of male; D, Left half of epandrium with one surstylus and one cercus, posterior view;

E, Left half of hypandrium, ventral view; F, Distal end of phallapodeme with phallus, lateral view;

G, Surstylus, posteroventral view; H, Sperm pump; I, Spermatheca; J. Part of female 9th tergite and

sternite with cerci.

Surstylus with 1 spine and 2-3 sensory hairs on tip. Epandrium arched, with 1 pair of short but strong

spines on each posteroventral angle. Cercus pubescent. Hypandrium V-shaped as figured. Phallapo-

deme length 0.65 mm, with distal end hooked. Sperm pump with blade broadened and neck narrowed.

Phallus length 0.25 mm; mesophallus with 1 short setal fascicle and 1 pair of processes; endophallus

roundly broadened.

164

THE PAN-PACIFIC ENTOMOLOGIST

Vol. 71(3)

0.1MM

Figure 3. Ventral view of phallus. A, Liriomyza asterivora Sasakawa; B, L. litorea NEW SPECIES.

Female.—Body length: 2.0 mm; wing length: 1.8 mm. Head, thorax and abdomen: see Male.

Terminalia: 9th sternite with 3 pairs of marginal setae. Cercus with 5 setae and 6 short tactile sensilla

on tip. Spermatheca orbiculated, neck short.

Diagnosis. —Liriomyza litorea closely resembles L. asterivora but can be dis-

tinguished by its brown-tinged vertical angles on head, longer orbital setulae and

Figure 4. Leaf mines. A, Mines on Crassocephalum rabens by Liriomyza asterivora; B, Mines on

Wedelia biflora by L. litorea NEW SPECIES.

1995 SHIAO & WU: A NEW AGROMYZID 165

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"1 56un

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Figure 5. Setae and microsetae on thoracic and abdominal tergites. A, C and E, Liriomyza aster-

ivora; B, Dand F, L. litorea NEW SPECIES; A and B, thorax, dorsal view; C and D, thoracic microsetae,

dorsal view; E and F, abdominal microsetae, dorsal view.

strong setae on tergites. Besides, the endophallus and the processes on mesophallus

of L. litorea are mostly characteristic for separating from other species (Fig. 3).

Distribution. —Only known from Taiwan.

Host Plant. — Wedelia biflora (L.) D C. (Compositae).

166 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

L. asterivora L. litorea

(N = 30) (N = 25 )

Type A

Freq. 0.87

Figure 6. Esterase electrophoretic patterns in Liriomyza asterivora and L. litorea NEW SPECIES.

N, sample size; Type, genotype; Freq., genotypic frequency; numbers above the bands, relative mo-

bility.

Parasitoids. — Opius (Gastrosema) sp. and Bitomus sp. (Hymenoptera: Bracon-

idae: Opiinae).

Discussion. — After detailed examination, Liriomyza litorea is very similar to

L. asterivora which was also recorded from Taiwan (Shiao & Wu 1989). But we

propose the following points of view to support that these newly discovered

materials should be treated as a new species.

1. The host plant of L. litorea, Wedelia biflora, is typically a seashore species

that is known to occur in Japan, southeast Asia, tropical Africa and Australia.

There were 3 agromyzid species found on Wedelia (Melanagromyza minima, M.

1995 SHIAO & WU: A NEW AGROMYZID 167

wedeliae and M. wedeliaphoeta) (Spencer 1990), and L. litoreais the first Liriomyza

species recorded from this plant. As we described previously in 1989, the preferred

host plants of L. asterivora in Taiwan is Crassocephalum rabens (Juss. ex Jacq.)

S. Moore (Compositae), which is widely distributed up to the mountains of 1500

m high; but the distribution of W. biflora is definitely restricted to seashores.

According to this point, it is confirmed that there should be no gene flow between

these two populations.

2. Incomparison with L. asterivora, the mining patterns presented on W. biflora

by L. litorea are uniquely regular. They are shaped like ““comma” marks on all

the collected leaves, broadened at the beginning and ending in a slim serpentine

(Fig. 4B). Those of L. asterivora are much less regular in shape (Fig. 4A).

3. The parasitoids of L. litorea were sent to R. A. Wharton, Texas A & M

University, for identification; they belong to the genera Opius and Bitomus (Hy-

menoptera: Braconidae: Opiinae). The species of Bitomus was thought to be a

new and important discovery, and probably undescribed (R. A. Wharton, personal

communication).

4. The setae and microsetae on thoracic and abdominal tergites can be easily

distinguished between L. /itorea and L. asterivora (Fig. 5). The electronmicrog-

raphy presented the stronger dorsocentral bristles, dense acrostichals and special

abdominal microsetae on L. litorea. The stronger bristles inspire the adaptation

under the special circumstances of seashores.

5. The analysis of esterase electrophoresis showed two types in L. asterivora

(one is single-banded, the other is three-banded), however only one type in L.

litorea (single-banded) (Fig. 6). Although the relative mobility of the fast-migrated

band in “‘type B” of L. asterivora is the same as the mono-band of L. litorea, and

if we treat these three electrophoretic types as a dimer of two alleles, the population

of L. litorea is probably just one of the homozygotes in L. asterivora. But the high

disequilibrium of allelic frequencies indicates that some disruptive selections force

the two populations apart from each other.

Etymology. —From Latin “‘litoreus,” meaning “‘of the seashore,” for this fly is

collected from seashores.

Material Examined. —See Types.

ACKNOWLEDGMENT

We wish to thank Fei-Jann Lin and Shun-Chern Tsaur, Academia Sinica, Re-

public of China, for reviewing the manuscript; Robert A. Wharton, Texas A&M

University, for identifying the parasitoids and Yih-Cheng Shiau, University of

Illinois at Chicago, for supplying materials. This work was funded by the National

Science Council, Republic of China (NSC-80-0409-B-002-41 & NSC-84-2321-

B-002-119).

LITERATURE CITED

Ayala, F. J., J. R. Powell, M. L. Tracey, C. A. Mourao & S. Perez-Salas. 1972. Enzyme variability

in the Drosophila willistoni group. IV. Genic variation in natural populations of Drosophila

willistoni. Genetics, 70: 113-139.

Sasakawa, M. 1956. New Agromyzidae from Japan XII. Scient. Rep. Saikyo Univ., Agr., 8: 124—

134.

168 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Sasakawa, M. 1972. Formosan Agromyzidae (Diptera). Sci. Rep. Kyoto Pref. Univ., Agr., 24:

43-82.

Shiao, S. F., F. J. Lin & W. J. Wu. 1991. Redescription of four Liriomyza species (Diptera: Agro-

myzidae) from Taiwan. Chinese J. Entomol., 11: 65-74.

Shiao, S. F. & W. J. Wu. 1989. Four new records of Liriomyza leaf-miners (Diptera: Agromyzidae)

from Taiwan. J. Taiwan Mus., 42: 15-23.

Spencer, K. A. 1973. Agromyzidae (Diptera) of economic importance. Dr. W. Junk B. V. Publisher,

The Hague, The Netherlands.

Spencer, K. A. 1990. Host specialization in the world Agromyzidae (Diptera). Kluwer Academic

Publishers, Dordrecht.

Zehnder, G. W., J. T. Trumble & W. R. White. 1983. Discrimination of Liriomyza species (Diptera:

Agromyzidae) using electrophoresis and scanning microscopy. Proc. Entomol. Soc. Wash., 85:

564-574.

PAN-PACIFIC ENTOMOLOGIST

71(3): 169-172, (1995)

NEW DISTRIBUTIONAL RECORDS FOR THE ANT GENUS

CARDIOCONDYLA IN THE NEW WORLD

(HYMENOPTERA: FORMICIDAE)

WILLIAM P. MACKAY

Laboratory for Environmental Biology, The University of Texas,

El Paso, Texas 79968

Abstract. — Five species of the genus Cardiocondyla occur in the New World. All of the species

have been recorded from the United States, the genus was not recorded from South America

until 1937. I list a number of new localities for most of the species, including numerous localities

in Latin America. Specifically, C. emeryi Forel is recorded for the first time from Colombia,

Costa Rica and Venezuela; C. nuda from Alabama and Colombia, C. wroughtoni from Mexico,

Panama and Colombia. Several additional localities are also provided for these and other species

in this genus. A key is provided for the identification of workers in the New World.

Key Words. —Insecta, introductions, cosmotropical, Latin America, predation, nesting site, in-

vasions, introduced species

Cardiocondyla is an Old World genus containing about 30 (Snelling 1974) or

40 (Bolton 1982) species. The females and workers are morphologically uniform,

the males are so different they have been described in three separate genera (Kugler,

1983). Most species found in the New World are cosmotropical and all of the

species in the New World (with the possible exceptions of C. ectopia Snelling and

C. venustula Wheeler) have been introduced (Creighton 1950, Bolton 1982, Heinze

et al. 1993). Even though these ants have been introduced, and could be expected

to be pests, they are rarely collected. Little is known of their biology, but they are

apparently predators (Creighton & Snelling 1974, Lupo & Gerling 1984), feed on

dead insects (Wilson 1959) feed on nectar of Euphorbia (Creighton & Snelling

1974) or tend Homoptera (Smith 1944). Most species nest in sandy soil and the

nest entrances are very cryptic (Creighton & Snelling 1974); C. wroughtoni (Forel)

nests in galls, figs and other plant tissue (Lupo & Galil 1984).

I have accumulated significant new distributional records for Cardiocondyla for

about 25 years, and felt that a listing of these localities would be useful, together

with an updated key. Only New World records are listed. The previous distri-

butions are taken from Smith (1944), Creighton (1950), Creighton & Snelling

(1974), Kempf (1972), Smith (1979), Bolton (1982), Dowell & Gill (1989), and

Maes & MacKay (1993). All of the specimens are in the Laboratory of Environ-

mental Biology of the University of Texas, El Paso.

List oF NEw WORLD DISTRIBUTIONS OF THE SPECIES

Cardiocondyla ectopia Snelling

California (Orange and Los Angeles counties), Arizona. This species may be a

synonym of C. nuda var. mauritanica (Kugler 1983).

New Records. —USA. CALIFORNIA. LOS ANGELES Co.: Chino, 23 Sep 1972, W. MacKay, #72-

100; ORANGE Co.: Cypress, 22 Sep 1972, W. MacKay, #72-37.

170 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Cardiocondyla emeryi Forel

Southern Florida, Texas, St. Thomas, Virgin Islands, Anguilla, Bahamas, Ber-

muda, Cuba, Jamaica, Dominican Republic, Mona, Puerto Rico, Culebra, Gua-

deloupe, St. Vincent, Barbados, Mexico, Nicaragua, Brazil. Kugler (1983) con-

cluded that Borgmeier’s (1937) report of this species from Brazil is based on a

misidentification, that the correct identification is C. wroughtoni. Cardiocondyla

wroughtoni and C. emeryi are easily confused.

New Records. —USA. FLORIDA. HIGHLANDS Co.: 13 km §S of Archbold Biological Station, 20

Oct 1982, M. Deyrup. BRAZIL. MATO GROSSO DO SUL: 3 km N of Jaraguari, 17 Oct 1989, S.

Porter, #12899; 4 km NE of Rio Verde, 17 Oct 1989, S. Porter, #’s 12924, 12925; 10 km N of Posto

Chapadf4o, 18 Oct 1989, S. Porter, #12971. COLOMBIA. VALLE: El Cerrito, Bosque el Matiro, 27

Jan 1995, Myr 55, I. Armbrecht. COSTA RICA. GUANACASTE: Loma Barbudal, 3 Jun 1989, S. B.

Vinson, #12272; Loma Barbudal, Feb 1990, S. B. Vinson, #13197. MEXICO. SAN LUIS POTOSI:

Matehuala, 10 Jun 1988, 1490m, W. MacKay, #’s 10974-4, 1096-3 & 10970-1. NICARAGUA.

(LEON): Cosiguina, 25 Aug 1989, F. Reinboldt. VENEZUELA. DISTRITO FEDERAL: La Guaira,

3 Jan 1992, E. Palacio.

Cardiocondyla nuda (Mayr)

Florida, Georgia, Louisiana, California, Texas, Hawaii, Nicaragua.

New Records.—USA. LOUISIANA. IBERIA Co.: New Iberia, 19 Aug 1987, W. MacKay, #9770.

FLORIDA. HIGHLANDS Co.: Archbold Biological Station, Lake Placid, 1 Feb 1985, M. Deyrup.

ALABAMA. MOBILE Co.: Dauphin Island, 25 Aug 1987, E. MacKay, #9874. COLOMBIA. AMA-

ZONAS: Amacayaca, Jan 1991, L. Mendoza. CUNDINAMARCA: Fusugasuga, 8 Dec 1975, W. & E.

MacKay, #575. HUILA: 3 km N of Rivera, 29 Dec 1981, W. & E. MacKay, #5695. META: Puerto

Gaitan, 18 Dec 1975, #716-C. SANTANDER: Bucaramanga, 25 Dec 1973, #73-271-B. VALLE:

Loboguerrero, 26 Jun 1989, F. Fernandez, #11957, #11962; El Cerrito, Bosque el Matiro, 27 Jan

1995, Myr 45, I. Armbrecht. NICARAGUA. LEON: Leon, Mar 1991, B. Garcete; Solentiname, July

1989, F. Reinboldt.

Cardiocondyla venustula Wheeler

Florida, Louisiana, Antilles, Culebra, Cuba, Haiti, Mona, Puerto Rico.

New Records. —None.

Cardiocondyla wroughtoni (Forel)

Florida, Georgia. Kugler (1983) suggests this species may occur in Brazil.

New Records.—USA. FLORIDA. HIGHLANDS Co.: Archbold Biological Station, 8 Sep 1993, M.

Deyrup. COLOMBIA. VALLE: Cali, 6 Jan 1988, W. & E. MacKay, #1033. MEXICO. TAMAULIPAS:

Gomez Farias, 25 Sep 1987, W. MacKay, #10071. PANAMA. COLON: Gamboa Parque, 29 Apr

1988, D. Quintero, #4.

KEY TO CARDIOCONDYLA OF THE NEW WORLD

Kugler (1983) includes a key to the males of many species. Creighton’s key

(1950) can be modified to include workers of all of the known New World species.

la. Dorsum of the mesosoma, in profile, with mesopropodeal suture un-

impressed, or at most very feebly impressed; promesonotal suture

usually obsolete on dorsum; mesopropodeal suture poorly marked

on dorsum; length of propodeal spines usually short, about 4 dis-

Fore le eM aloes sais Oe NO a ce ah Sn nee oe meee Re Ee nuda

1995 MACKAY: CARDIOCONDYLA DISTRIBUTION 171

1b. Dorsum of mesosoma, in profile, with mesopropodeal suture dis-

tinctly impressed; mesopropodeal suture clearly marked on dorsum;

propodeal spines variable in length ............. 0.0... ccc eee eee 2

2a(1b). Propodeum armed with a pair of very small denticles that are not

spinose; antennal scape failing to reach occipital margin by an

amount less than the greatest thickness of scape .......... venustula

2b. Propodeum armed with a pair of spines or well developed angles;

antennal scape failing to reach occipital margin by an amount at

least as great as the length of first funicular joint ................ 3

3a(2b). Node of petiole globular, seen from above, usually broader than long;

propodeal spines relatively long, usually more than 4 length of

distance between tips; anterior border of postpetiole distinctly con-

cave when seen from above ................00 00 ce eee wroughtoni

3b. Node of petiole elongate, seen from above, longer than broad; pro-

podeal spines short, length less than '4 distance between tips; an-

terior border of postpetiole straight or feebly convex or even feebly

concave when seen from above ........... 0.0.0. c cece eee ees 4

4a(3b). Projections on propodeum angulate, not spinose, length about 4 dis-

tance between tips; anterior clypeal border weakly concave; node

of petiole not laterally compressed near apex. (California and Ar-

VENA a af say Rg Ce a an MO ets gh Se a, Soa Ene olen ee ae ectopia

4b. Propodeal spines relatively sharp and spinose, length up to about '2

distance between tips; anterior clypeal border straight or slightly

convex; node of petiole laterally compressed near apex. (not re-

corded from California or Arizona). ............... 00.0008. emeryi

ACKNOWLEDGMENT

I thank several friends for providing me with material, especially: Inge Arm-

brecht, Mark Deyrup, Fernando Fernandez, Emma MacKay, Jean-Michel Maes,

Ed Palacio, Sanford Porter and Brad Vinson.

LITERATURE CITED

Bolton, B. 1982. Afrotropical species of the myrmicine ant genera Cardiocondyla, Leptothorax,

Melissotarsus, Messor, and Cataulacus (Formicidae). Bull. Brit. Mus. Natur. Hist. (Entomol.

Series), 45: 307-370.

Borgmeier, T. 1937. Cardiocondyla emeryi Forel no Bresil, e a descoberta do macho ergatoide desta

especie (Hym. Formicidae). Rev. de Entomologia, 7: 129-134.

Creighton, W. S. 1950. The ants of North America Bull. Mus. Comp. Zool., 104.

Creighton, W. S. & R. R. Snelling. 1974. Notes on the behavior of three species of Cardiocondyla

in the United States. J. New York Entomol. Soc., 82: 82-92.

Dowell, R. V. & R. Gill. 1989. Exotic invertebrates and their effects on California. Pan-Pacif

Entomol., 65: 132-145.

Kempf, W. W. 1972. Catalogo abreviado das formigas da regido neotropical (Hym. Formicidae).

Studia Entomol., 15: 3-344.

Kugler, J. 1983. The males of Cardiocondyla Emery (Hymenoptera: Formicidae) with the description

of the winged male of Cardiocondyla wroughtoni (Forel). Israel J. Entomol., 17: 1-21.

Heinze, J., S. Kuhnholz, K. Shilder & B. Hélldobler. 1993. Behavior of ergatoid males in the ants,

Cardiocondyla nuda. Insectes Sociaux, 40: 273-282.

Lupo, A. & J. Galil. 1985. Nesting habitats of Cardiocondyla wroughtoni Forel (1890) (Hymenoptera:

Formicidae). Israel J. Entomol., 19: 119-125.

172 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Lupo, A. & D. Gerling. 1984. Bionomics of the tamarix spindle-gall moth Amblypalpis olivierella

Rag. (Lepidoptera Gelechiidae) and its natural enemies. Boll. Lab. Entomol. agr. Filippo Sil-

vestri, 41: 71-90.

Maes, J.-L. & W. P. MacKay. Catalogo de las hormigas (Hymenoptera: Formicidae) de Nicaragua.

Revista Nicarguense de Entomol., 23: 1-46.

Smith, D. R. 1979. Superfamily Formicoidea. pp. 1323-1467. Jn Krombein, K., P. Hurd, D. Smith

& B. Burks (eds.). Catalog of Hymenoptera in America north of Mexico, Volume 2. Smithsonian

Institution Press, Washington D.C.

Smith, M. R. 1944. Ants of the genus Cardiocondyla Emery in the United States. Proc. Entomol.

Soc. Wash., 46: 30-41.

Snelling, R. R. 1974. Studies on California ants. 8. A new species of Cardiocondyla (Hymenoptera:

Formicidae), J. New York Entomol. Soc., 82: 76-81.

Wilson, E. O. 1959. Communication by tandem running in the ant genus Cardiocondyla. Psyche,

66: 29-34.

PAN-PACIFIC ENTOMOLOGIST

71(3): 173-175, (1995)

A NEW SPECIES OF TRIOXYS

(HYMENOPTERA: BRACONIDAE) FROM CALIFORNIA

PETR STARY! AND ROBERT L. ZUPARKO2

‘Institute of Entomology, Czech Academy of Science, Branisovska 31, CZ-370

O05 Ceske Budejovice, Czech Republic

*Laboratory of Biological Control, University of California, Berkeley,

1050 San Pablo Avenue, Albany, California 94706

Abstract. —Trioxys californicus NEW SPECIES is described from a single specimen reared from

Eucallipterus tiliae (L.) in California. A diagnosis to differentiate the new species from T. curv-

icaudus Mackauer is provided. The new species is considered indigenous to California, and the

parasitization of E. tiliae to represent a new association; its original host is unknown.

Key Words.—Insecta, Hymenoptera, Braconidae, Trioxys californicus NEW SPECIES, Eucal-

lipterus tiliae, California, new association

The linden aphid, Eucallipterus tiliae (L.) (Homoptera: Drepanosiphidae) (=

Callaphididae) has a widespread Palearctic distribution (Blackman & Eastop 1984,

Ivanovskaya 1977, Zhang et al. 1990). It was first recorded from North America

in 1886 (Davis 1909), and from California in 1909 (Davidson 1909). The aphid

can be a pest on urban shade trees, and was the target of a classical biological

control program in 1970, resulting in the establishment of Trioxys curvicaudus

Mackauer (Hymenoptera: Braconidae: Aphidiinae) in California (Olkowski et al.

1982).

A subsequent study (Zuparko & Dahlsten 1995) found several primary para-

sitoids attacking the aphid in northern California, including an undescribed Triox-

ys species. A description of this species is presented below.

TRIOXYS CALIFORNICUS STARY & ZUPARKO, NEW SPECIES

Type. — Holotype, female: CALIFORNIA. SOLANO Co.: Vallejo, 28 Jul, 1993,

R. L. Zuparko, reared from Eucallipterus tiliae on Tilia cordata Miller; deposited

in Essig Museum of Entomology, University of California, Berkeley. Left meta-

tarsal segments partially missing, left flagellar segments missing; right antenna

mounted on card.

Description. — Female (holotype). Body length 1.9 mm. Antennae 13-segmented, as long as head,

thorax and first 2 abdominal tergites together, filiform, not thickened towards apex. Length of flagellar

segment I 2.5 x medial width, with adpressed hairs subequal to one-half width of segment; 4 rhinaria.

Flagellar segment II like segment I but with 5 rhinaria. Flagellar segments IIJ-IX as wide as I or II,

slightly shorter, with hairs subequal to one-half width of segment; 4 rhinaria each. Flagellar segment

X as wide as segments IJJ-IX; 3 rhinaria. FW with metacarpus equal to one-half pterostigma length.

Radial vein long, extending distally beyond apex of metacarpus. Propodeum smooth, with sparse

longitudinal rugosities, sparse hairs. Tergite I narrow, length 1.5 times width at spiracles, prominent

spiracular tubercles situated anterior to midpoint of segment, smooth with sparse hairs. Genitalia (Fig.

1): Ovipositor sheaths slightly arcuate, 2 long hairs on ventral margin. Prongs medium-sized, slightly

arcuate; 3 long semi-erect hairs on dorsal margin, their length about 3.5 x diameter of prongs at their

base; 2 semi-erect hairs on ventral margin, their length distinctly shorter than hairs on dorsal margin;

174 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Figure 1. Trioxys californicus female genitalia. Lateral aspect (left). Detail of prong apex (right).

apex of prongs with 1 semi-perpendicular claw-shaped bristle on dorsal side and 1 simple bristle on

ventral side. Head black, mouthparts brown. Antenna scape and pedicel yellow-brown ventrally, dark

brown dorsally; flagellar segments IIJ-IX dark brown, segments I-II somewhat lighter. Thorax black.

Wings subhyaline, venation light brown. Tegulae dark brown. Legs yellow, apices of tarsiand metatibiae

posteriorly, infuscated. Abdomen dark brown-black; tergite I yellow, basal area of tergite II lighter.

Ovipositor sheaths light brown; prongs dark brown basally, light brown apically.

Male. —unknown.

Diagnosis. — Trioxys californicus most closely resembles T. curvicaudus, but the

former can be readily distinguished by its 13-segmented antennae, shorter met-

acarpus and shorter ovipositor prongs (the latter has 11-segmented antennae, a

metacarpus that extends about as far as the radial vein, and prongs which extend

well past the ovipositor sheaths). The new species also tends to have slightly

darker coloration—the ovipositor prongs of 7. curvicaudus are yellow, the scape,

pedicel and first two flagellar segments are bright yellow, and the legs are uniformly

yellow-brown with no defined dark patches.

Distribution. —Known only from California.

Discussion. — Although it was reared from an introduced species, we consider

T. californicus is indigenous to California. There is no evidence of a similar species

in the western Palearctic fauna (Stary 1978, 1988), which is apparently fairly well

known [T. mosei Mescheloff & Rosen (1993) is the only new species of Trioxys

sensu latu (Trioxys + Binodoxys) described from there since 1978]. In contrast,

a genus (Cristicaudus) and 9 species from this group have been described from

Mexico and the United States since 1977 (Stary & Remaudiere 1977, 1982, Stary

& Marsh 1982, Stary 1983), indicating a New World fauna that is comparatively

less well-known.

There is also no evidence that closely links 7. californicus to E. tiliae. From

1991-93, over 1100 Trioxys were reared from E. tiliae, but only one T. californicus

was reared (Zuparko & Dahlsten 1995). Therefore, we consider that the incidence

of T. californicus on E. tiliae represents a new association, and the parasitoid’s

natural host remains unknown.

Material Examined. —See types.

1995 STARY & ZUPARKO: A NEW TRIOXYS 175

LITERATURE CITED

Blackman, R. L. & V. F. Eastop. 1984. Aphids on the world’s crops. Wiley-Interscience, Chichester.

Davidson, W. M. 1909. Notes on Aphididae collected in the vicinity of Stanford University. J. Econ.

Entomol., 2: 299-305.

Davis, J. J. 1909. Studies on Aphididae II. Ann. Entomol. Soc. Am., 2: 30-45.

Ivanovskaya, O. I. 1977. Aphids of Western Siberia. Part 1 (Families Adelgidae-Chaitophoridae).

SSSR Academy of Sciences, Siberian Division, Institute of Biology, Novosibirsk.

Mescheloff, E. & D. Rosen. 1993. Biosystematic studies on the Aphidiidae of Israel (Hymenoptera:

Ichneumonoidea). 5. The genera Trioxys and Binodoxys. Israel J. Entomol., 27: 31-47.

Olkowski, W., H. Olkowski & R. van den Bosch. 1982. Linden aphid parasite establishment. Environ.

Entomol., 11: 1023-1025.

Stary, P. 1978. Parasitoid spectrum of the arboricolous callaphid aphids in Europe (Hymenoptera,

Aphidiidae; Homoptera, Callaphididae). Acta entomol. Bohemoslov., 75: 164-177.

Stary, P. 1983. New species and records of aphid parasitoids from Mexico (Hymenoptera, Aphi-

diidae). Acta Entomol. Bohemoslov., 80: 35-48.

Stary, P. 1988. Biotypes and interspecific relations of Trioxys parasitoids on arboricolous pest aphids

(Hymenoptera, Aphidiidae; Homoptera, Callaphididae). Acta Entomol. Bohemoslov., 85: 182-

190.

Stary, P. & P. M. Marsh. 1982. A new species of Trioxys (Hymenoptera: Aphidiidae) parasitic on

a pecan aphid. Proc. Entomol. Soc. Wash., 84: 726-728.

Stary, P. & G. Remaudiere. 1977. Some aphid parasitoids (Hym. Aphidiidae) from Nearctic America.

Ann. Soc. Entomol. France (N.S.), 13: 669-674.

Stary, P. & G. Remaudiere. 1982. New genera, species, and host records of aphid parasitoids

(Hymenoptera, Aphidiidae) from Mexico. Ann. Soc. Entomol. France (N.S.), 18: 107-127.

Zhang, G., S. Tian & T. Zhong. 1990. Thirty-eight new records of Aphidoidea from China. Sino-

zoologia, 7: 325-331.

Zuparko, R. L. & D. L. Dahlsten. 1995. Parasitoid complex of Eucallipterus tiliae (Homoptera:

Drepanisiphidae) in northern California. Environ. Entomol., 24: 730-737.

PAN-PACIFIC ENTOMOLOGIST

71(3): 176-189, (1995)

STICKY TRAP CATCH OF WINTERFORM AND

SUMMERFORM PEAR PSYLLA

(HOMOPTERA: PSYLLIDAE)

OVER NON-ORCHARD HABITATS

DAviIpD R. HorTON, EVERETT C. BurTS,! TAMERA M. LEWIS AND

LEONARD B. Coop?

USDA-ARS,? Yakima, Washington 98902

Abstract.—We monitored movement by winterform and summerform pear psylla, Cacopsylla

pyricola Foerster, into non-orchard habitats using large sticky traps placed at various distances

from a source pear orchard. Psylla counts were large on traps near the orchard, rapidly decreased

between 5 and 20 meters from the orchard, and then flattened out at larger distances (20-120

m). Summerform counts were female-biased; fall winterform counts showed no bias in sex ratio.

Models of the form: trap catch = exp(B, + B, [meters]*), and trap catch = B, + B,(1/meters)

were fitted to the data, where meters is distance the trap was from the source orchard, and c is

a constant. The reciprocal model fit the data better than did the exponential models. Counts of

winterforms during spring reentry were described by the reciprocal model or by a linear model.

Catch on the back-side of traps was the same as that on the orchard-side of traps. Trap catch

did not vary with compass direction except during spring, when counts were largest on traps to

the south of the source orchard; a second orchard, directly south of the source orchard, may

have contributed to this effect.

Key Words.—Insecta, Cacopsylla pyricola, dispersal, sampling, modeling

Pear psylla, Cacopsylla pyricola Foerster, is a monophagous pest of pears in

many temperate fruit growing regions. The species occurs as two seasonal morphs

that differ in life histories (Oldfield 1970). The overwintering morph (winterform)

undergoes a reproductive diapause in fall, at which time large numbers disperse

from the orchard and overwinter on other tree fruit species (Purcell & Suslow

1984, Horton et al. 1994) or in non-orchard habitats (Hodgson & Mustafa 1984).

Reentry into pear orchards occurs the following spring as temperatures warm (Fye

1983, Horton et al. 1992). The summerform morph is lighter in color and smaller

than the winterform morph. Dispersal characteristics of summerforms are not

well understood. Some studies have shown that this morph is sedentary, in that

insects are not common outside the pear orchard (Purcell & Suslow 1984); other

studies have shown that large numbers disperse from the orchard, particularly

when psylla densities are high (Fye 1983).

Dispersal by pear psylla has consequences for management, affecting the spread

of pesticide resistance (Follet et al. 1985), timing of control efforts (Westigard &

Zwick 1972), and possibly the success, if implemented, of fall control programs

(Krysan 1990, Horton et al. 1992). Virtually all of our information about psylla

movement concerns dispersal into other orchard habitats (Hodgson & Mustafa

1984, Purcell & Suslow 1984, Horton et al. 1994). In this study, we monitored

' Washington State University, Tree Fruit Research and Extension Center, 1100 North Western,

Wenatchee, Washington 98801.

2 Department of Entomology, Oregon State University, Corvallis, Oregon 97331.

3 3706 W. Nob Hill Blvd.

1995 HORTON ET AL.: PEAR PSYLLA MOVEMENT LF7

psylla movement into non-orchard habitats using large sticky traps. We sampled

at several times of the year, allowing us to compare behavior of the fall emigrating

population, the spring colonizing population, and emigrating summerforms. We

monitored sex ratio of emigrants to determine whether one sex might be more

dispersive than the other. Finally, we modeled the relationship between trap catch

and distance from the source orchard. The distance/catch data were compared to

a number of different models, including a model that is consistent with a diffusion

process (Taylor 1978, Rudd & Gandour 1984). The diffusion model represents

the most simple description of dispersal (Kareiva 1982), and consistent deviation

from the model or agreement with the model should provide information about

pear psylla behavior.

MATERIAL AND METHODS

Sampling Methods.—The study area circumscribed an isolated pear orchard

located at the southern mouth of the Yakima canyon, 15 km north of Yakima,

Washington (Fig. 1). The surrounding habitat is composed of cropland or native

rangeland (Fig. 1). The traps were bordered to the east and west by steep hillsides

(entrance to the canyon), to the north by the canyon mouth, and to the south by

fallow fields or native vegetation. The nearest commercial pear 1s approximately

1 km south of the study area. The source pear orchard is approximately 0.5 ha

in size and composed of 10-20 year-old ‘Bartlett’ pear. An organic pest control

program was implemented for the duration of the study.

Clear barrier traps were composed of PVC pipe and clear plastic sheeting used

in construction of sails for wind surfers. Paired wooden posts were sunk into the

ground to a depth of 0.5—1 m, and the traps attached between these frames. The

clear portion of the trap was 0.92 by 1.84 m in size; the upper edge of the trap

was approximately 2.5 m above ground. The trap surface was made sticky by

coating it with a thin layer of STP Oil Treatment (Krysan & Horton 1991). Traps

were set out in four directions (Fig. 1), with the face of each trap perpendicular

to the pear orchard. Sampling was done over the following intervals: fall winter-

forms (Oct.-Dec. 1990 and 1991); spring winterforms (Feb.-May 1991, Jan.—

April 1992); summerforms (May-Sept. 1991). Traps were replaced at approxi-

mately biweekly intervals. Field-collected traps were taken to the laboratory where

psylla were counted. Because of low counts, data for all but the Oct-Dec. 1990

winterforms were analyzed for the summed catch over the trapping intervals. Data

for the Oct.-Dec. 1990 winterforms were analyzed for each sampling interval.

Both sides of the trap were coated with STP except during the 1990 intervals. Sex

ratios of trapped insects were determined for the 1990 samples and for the sum-

merform samples.

Statistical Analyses. —A number of models have been fitted to distance-density

samples. Models are often of the form:

density = exp(B, + B,[distance‘]),

where c varies between —1 and 4 (Taylor 1978). We fitted four models of this

form: c = 2, 1, 0.5, —1. We included a reciprocal model of the form:

density = B, + B,[1/distance],

as none of the exponential models described the data (see Results). The exponential

178 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

ae,

| N

## = BARRIER TRAP patie

FALLOW

APRICO

ALFALFA

Figure 1. Trap placement at isolated pear orchard, 15 km north of Yakima, Washington. Trap

locations designated by numbers (map not to scale). Trap distance from source pear—#1: 113 m; #2:

75 m; #3: 38 m; #4: 8 m; #5: 73 m; #6: 48 m; #7: 28 m; #8: 1.8 m; #9: 92 m; #10: 51 m; #11: 9 m;

#12: 116 m; #13: 81 m; #14: 41 m; #15: 6 m.

models were fitted using PROC NLIN in SAS (SAS 1987), and the reciprocal

model was fitted in PROC REG (SAS 1987). Trap catch was expressed as a fraction

of that occurring on the trap closest to the orchard (1.8 m; Fig. 1); i.e., relative

catch = (catch on trap i/catch on the 1.8 m trap). This transformation standardized

1995 HORTON ET AL.: PEAR PSYLLA MOVEMENT 179

trap catch to between O and 1, and allowed us to compare different sampling

intervals and the two morphotypes (there was large variation in numbers trapped

among sampling intervals). Slopes and intercepts were compared among intervals

and between morphotypes with analysis of covariance (ANCOVA). Analyses were

done in PROC GLM (SAS 1987).

We also compared observations and regression models with a “dilution” curve.

This model assumes that, for a constant sized trap, trap catch of an evenly dis-

persing population halves with each doubling of the distance from a point source

due to dilution or “thinning out” (Wadley & Wolfenbarger 1944; Wadley 1957);

1.e., expected catch = (1.8)(1/meters). The curve was again standardized by ex-

pressing catch relative to that at the closest trap (1.8 m). The dilution curve was

compared with results from the regression equations by placing 95% confidence

bands around the regression lines (Neter et al. 1985, 154) and noting whether the

dilution curve fell outside the bands.

To compare compass directions in trap catch, residuals from the regressions

were calculated and entered into a one-way analysis of variance (ANOVA). Vari-

ation among compass directions in size of residuals suggests that trap catch was

higher in some directions than others after adjusting catch for distance.

Finally, we estimated mean distance dispersed by trapped insects (see Fletcher

1974; Southwood 1978: 334). Trap distance was categorized into 1 of 4 ranges:

0-30 m, 30-60 m, 60-90 m, 90-120 m. We then estimated proportion (p;) of

psylla in the 7" (z = 1 to 4) annulus (Fletcher 1974):

D; = [n/m (ri? — na |S [(n;/m;)(T2;? — 11;7)],

where n; is number of psylla trapped in the ith annulus, m; is number of traps in

the 7th annulus, r,; is the inner radius of the 7th annulus, and r,,; is the outer radius

of the ith annulus. The mean distance dispersed (d) by trapped psylla is:

d= p> (9;)(0.5)(r1i + 2).

This estimate refers only to trapped insects and ignores that proportion of the

population that dispersed beyond the study area (Fletcher 1974), and we used

these estimates only to provide crude comparisons among sampling intervals and

between morphotypes in distances flown by trapped psylla.

RESULTS

The reciprocal model consistently outperformed the exponential models for

emigrating winterforms and summerforms (Table 1; Fig. 2), and much of the

remaining discussion will be restricted to the reciprocal model. The “‘dilution”’

model fell outside the 95% confidence intervals for the reciprocal model in all

sampling intervals, particularly at longer trap distances (Figs. 3-5). The best fits

for the reciprocal model occurred for intervals in which large numbers of psylla

were trapped (i.e., 1-14 Nov 1990; Fig. 3). The reciprocal model did not fit counts

obtained on the back-side of traps for the 1991 winterform data (P = 0.81; Fig.

4, open symbols). A linear model also did not fit (P = 0.30). A linear model fit

the data for the back-side of traps for the summerform data (P = 0.005; Fig. 5,

180 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Table 1. Residual mean squares and parameter estimates for five models fitted to fall winterform

and summerform trap catch (Figs. 2-5). y—daily trap catch (relative to catch on the 1.8 m trap); m—

meters.

Model Residual MS By B,

Winterforms, 19-31 October 1990

y = exp (B, + B,m?) 0.966 0.069 —0.0164

y = exp (B, + B,m°5) 0.748 0.685 —0.535

y = exp (B, + B,m) 1.038 0.287 —0.153

y = exp (B, + B,m“") 1.508 —1.926 3.577

y= 8, + Bm"! 0.644 0.083 1.794

Winterforms, 1-14 November 1990

y = exp (B, + B,m?’) 1.139 0.012 —0.0151

y = exp (B, + B,m°*) 0.488 0.767 —0.588

y = exp (B, + B,m) 0.806 0.259 —0.151

y = exp (B, + B,m~') 1.442 — 1.695 3.139

y=B, + Bm"! 0.433 0.107 1.709

Winterforms, 15 November—17 December 1990

y = exp (B, + B,m?) 7.582 0.015 —0.0083

y = exp (B, + B,m°®*) 2.122 0.084 —0.180

y = exp (B, + B,m) 3.065 —0.292 —0.016

y = exp (B, + B,m—') ool os — 1.238 2.305

y= B, + Bm"! 1.789 0.261 1.428

Winterforms, 11 September—6 November 1991

y = exp (B, + B,m?’) 4.796 0.075 —0.0177

y = exp (B, + B,m°*) 4.835 0.782 —0.601

y = exp (B, + B,m) 4.922 0.331 —0.171

y = exp (B, + B,m~') 3.502 —1.736 3.213

y= B+ Bm"! 3.261 0.134 1.608

Summerforms, 9 May—11 September 1991

y = exp (B, + B,m?) 1.168 0.031 —0.0207

y = exp (B, + B,m°*) 0.806 1.014 —0.770

y = exp (B, + B,m) 0.957 0.349 —0.200

y = exp (B, + B,m—') 0.649 —2.198 4.044

y=B+ Bm"! 0.322 0.057 1.731

open symbols), whereas the reciprocal model fit poorly (P = 0.06; r? = 0.25).

There was no significant difference between numbers caught on the back-side and

orchard-side of traps for either morphotype (Figs. 4-5; paired sample t-tests: P

> 0.10).

Slope coefficients did not differ among the four sampling intervals for fall

winterforms (Figs. 3-4; ANCOVA — F = 0.37; df = 3,40; P = 0.77; common

slope coefficient = 1.63 [SE = 0.127]). Intercept terms, which estimate trap catch

at long distances, did differ among the four intervals (F = 3.1; df = 3,43; P =

0.039), indicating that heights of the four curves were not identical (see Figs. 3-

4). The largest difference appeared to be between the late November—December,

1990 interval (Fig. 3, bottom panel) and the other sampling intervals. Slope

coefficients were similar between summerform and winterform morphs (F = 0.38;

df = 4,53; P = 0.82; common slope = 1.65 [SE = 0.101]). The intercept term was

1995 HORTON ET AL.: PEAR PSYLLA MOVEMENT 181

1.074 ® OBSERVED

| ~~~ RECIPROCAL MODEL

O.8 --. DILUTION MODEL

06 === EXPONENTIAL MODES

0.4

QO.2

PSYLLA PER TRAP

QO.0

O oe SiG, ve 100

METERS

Figure 2. Example of relationship between trap catch (expressed as fraction of catch on the 1.8 m

trap) and trap distance; Oct. 19-31, 1990 winterforms. For the exponential models: c = 2 (curve

intersects X-axis at < 25 m); c = 1 (curve intersects X-axis between 25 and 50 m); c = 0.5 (curve

intersects X-axis at 100 m); c = —1 (curve fails to intersect X-axis). See Table 1 for regression statistics.

smaller for the summerform curve than the average winterform curve (single df

contrast: F = 5.8; df = 1,57; P = 0.019), indicating that trap catch at longer

distances was larger for winterforms than summerforms. However, this difference

was apparently due to the 15 Nov—17 Dec 1990 winterform sample (Fig. 3, bottom

panel); deletion of this sample resulted in a non-significant contrast (F = 1.99, P

= 0.16). The mean distance dispersed by trapped summerforms fell within the

range of means exhibited by dispersing winterforms (Table 2).

Sex ratio of trapped psylla was more female-biased for summerforms than

winterforms (Fig. 6; mean [SEM] percent female, summerforms—61.2% [2.5];

Table 2. Estimated relative frequency of psylla in each of four distance classes and mean distance

dispersed by trapped psylla.

Distance class (meters)

Sampling interval 0-30 30-60 60-90 90-120 Mean distance (SD)?

Winterforms

19-31 Oct. 1990 0.27 0.18 0.26 0.29 62.1 (34.9)

1-14 Nov. 1990 0.29 0.21 0.23 0.26 58.4 (34.7)

15 Nov.-17 Dec. 1990 0.16 0.20 0.32 0.33 70.1 (31.8)

11 Sept.—6 Nov. 1991 0.12 0.05 0.48 0.35 76.8 (31.7)

Summerforms

9 May-11 Sept. 1991 0,23 0.17 0.32 0.27 63.5 (33.4)

a See Materials and Methods (from Fletcher 1974) for calculations.

182 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

OCT. (ais ID

NOV SA, eeO

PSYLLA PER TRAP

O Zo) oie far “N00

METERS

Figure 3. Observed (filled circles) and regression models (solid lines) describing relationship be-

tween twenty-four hour trap catch of fall winterforms and trap distance (1990 data); catch expressed

as fraction of maximum catch (maximum catch always occurred on the 1.8 m trap). Dashed lines—

95% confidence bands. Dotted lines—dilution curve. Regression summaries (see also Table 1)—Oct.

19-31, 1990: trap catch = 0.083 + 1.79(1/meters); r? = 0.92. Nov. 1-14, 1990: trap catch = 0.107

+ 1.71(1/meters); r? = 0.96. Nov. 15-Dec. 17, 1990: trap catch = 0.261 + 1.43(1/meters); r? = 0.76.

To express catch as psylla per day, multiply observed values or both regression coefficients (for

prediction) by numbers captured per day on the 1.8 m trap: Oct. 19-31, 37.3 psylla/day; Nov. 1-14,

104.8 psylla/day; Nov. 15-Dec. 17, 7.6 psylla/day. Some points missing due to traps being blown

down by strong winds.

winterforms— 52.3% [1.4]; paired sample f¢-test: P = 0.012 [data paired by trap

location]). Sex ratio of summerforms departed significantly from 50% (t = 4.6, P

< 0.001).

For spring colonists, the reciprocal model fit the catch data for the orchard-

1995 HORTON ET AL.: PEAR PSYLLA MOVEMENT 183

PSYLLA PER TRAP

ao me — a

MERERS

Figure 4. Observed (filled and open circles) and regression model (solid line) describing relationship

between twenty-four hour trap catch of fall winterforms and trap distance (Sept. 11—Nov. 6, 1991);

catch expressed as fraction of maximum catch (maximum catch always occurred on the 1.8 m trap).

Solid circles, orchard-side of trap; open circles, backside of traps (regression line fitted to filled circles).

Dashed lines—95% confidence bands. Dotted line—dilution curve. Regression summary (see also

Table 1): trap catch = 0.134 + 1.61(1/meters); r? = 0.62. To express catch as psylla per day, multiply

observed values or both regression coefficients (for prediction) by numbers captured per day on the

1.8 m trap (= 0.59 psylla/day).

PSYLLA PER TRAP

0 25 50 75. 100

METERS

Figure 5. Observed (filled and open circles) and regression model (solid line) describing relationship

between twenty-four hour trap catch of summerforms and trap distance (May 9-Sept. 11, 1991); catch

expressed as fraction of maximum catch (maximum catch always occurred on the 1.8 m trap). Solid

circles, orchard-side of trap; open circles, backside of traps (regression line fitted to filled circles).

Dashed lines—95% confidence bands. Dotted line—dilution curve. Regression summaries (see also

Table 1)—orchard-side of traps: trap catch = 0.057 + 1.73(1/meters); r? = 0.95; backside of traps

(regression line not shown): trap catch = 0.34—0.0032 (meters); r? = 0.46. Reciprocal curve—to express

catch as psylla per day, multiply observed values or both regression coefficients (for prediction) by

numbers captured per day on the 1.8 m trap (= 1.13 psylla/day).

184 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

@ SUMMERFORMS

PERCENT FEMALE

O ZS 50 rae 100

TRAP DISTANCE (METERS)

Figure 6. Sex ratio (percent female) of trapped summerforms and fall winterforms (catch summed

over intervals).

side of the trap (P < 0.005 for both years), whereas linear models provided better

fits for the back-side catch (Fig. 7; 1991: P = 0.06 [reciprocal model: P = 0.38];

1992: P = 0.03 [reciprocal model: P = 0.06]). Capture rates were the same on the

orchard-side and back-side of traps both years (paired sample t-tests; P > 0.50).

There were no significant direction effects within any of the five samples for

emigrating psylla (Fig. 8; each by one-way ANOVA [although P = 0.07 for the

1990b sample]). There were significant direction effects for both the 1991 (P =

0.03; orchard-side) and 1992 (P = 0.02; orchard-side) spring reentry data (Fig.

9). Traps running to the south caught more psylla than those in other directions.

The pear orchard nearest the study area was directly in line with the traps running

to the south (approximately 1 km south of the study area), and this may partially

explain these patterns.

DISCUSSION

Trap catch-distance curves for emigrating winterform and summerform pear

psylla were very similar to curves reported for other insect species (e.g., Wadley

1957). Counts were high near the source orchard, rapidly decayed between 5 and

20 meters, and then flattened out over the longer distances. The flattest curve was

for late-fall winterforms in 1990 (Fig. 3, bottom panel; see Table 2 for mean

distances dispersed by trapped psylla, calculated from observed values). Purcell

& Suslow (1984) noted that catch-distance curves obtained from beat tray samples

in peach orchards markedly flattened out late in fall, and interpreted this as

evidence that psylla dispersed from the orchard in a wave-like pattern over a

protracted period of time. Thus, in our study, psylla that were captured at the

longer distance traps in December probably included insects that had temporarily

occupied the non-pear habitat surrounding the traps, whereas trap catch earlier

in the dispersal period (1.e., October) likely was composed primarily of insects

that had originated in the orchard.

1995 HORTON ET AL.: PEAR PSYLLA MOVEMENT 185

1995)

— @® ORCHARD-—SIDE OF TRAP

— -O BACK—SIDE OF TRAP

PSYLLA PER TRAP

— @® ORCHARD-—SIDE OF TRAP

— -O BACK-—SIDE OF TRAP

PSYLLA PER TRAP

O Zo o10 79d 100

METERS

Figure 7. Observed (filled and open circles) and regression models (dashed and solid lines) de-

scribing relationship between twenty four hour trap catch of spring winterforms and trap distance

(Feb. 22—May 9, 1991; Jan. 28—-April 10, 1992). 1991, orchard-side of trap: twenty-four hour trap

catch = 0.81 + 3.47(1/meters); r? = 0.47, P = 0.005. 1991, back-side of trap: twenty-four hour trap

catch = 1.28-0.0079 (meters); r? = 0.24, P = 0.06. 1992, orchard-side of trap: twenty-four hour trap

catch = 0.32 + 0.96(1/meters); r? = 0.54, P = 0.002. 1992, back-side of trap: twenty-four hour trap

catch = 0.56 — 0.0034 (meters); r? = 0.30, P = 0.03.

Based on residual mean squares, the reciprocal model consistently described

trap data better than did any of the four exponential models. The models provide

strictly empirical descriptions of the relationship between distance and trap catch,

and biological interpretations are speculative. The exponential model with c = 2

is consistent with a diffusive or random dispersal process (Taylor 1978, Rudd &

Gandour 1984). This model did not fit observations (Fig. 2, Table 1). A “dilution”

model, which assumes that size of trap catch is due entirely to the change in

sampling area associated with an increase in distance from a point source (e.g.,

Wadley 1957, Rudd & Gandour 1984) also fit poorly (Figs. 3-5). One explanation

for the poor fits of both models, particularly at the longer distances, is that traps

186 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

MB NORTH SOUTH

0.2; WEST BH EAST

Wo oe5eeod

X09 09004

RAAAAAA

MEAN RESIDUAL

1990 1990 1990 1991 SUMMER

WINTERFORMS FORMS

Figure 8. Mean (SEM) residual for each compass direction, fall winterforms and summerforms;

regression equations (reciprocal model) summarized in Table 1 and Figs. 3-5. 1990a, 1990b, 1990c

refer to Oct. 19-31, Nov. 1-14, and Nov. 15-Dec. 17, respectively (Figure 3). Orchard-side of traps

only. Asterisks indicate that the mean differed significantly from zero (t-test). Positive values indicate

that catch for a given direction was larger than predicted by the regression model.

were visible to dispersing psylla. Because the traps were placed in rangeland,

alfalfa, and fallow farmland, posts supporting the traps were easily the most

prominent landmark in the trapping area and may have been visible to psylla.

Counts of fall winterforms and summerforms were as large on the back-side of

traps as on the orchard-side of traps (Figs. 4-5), suggesting both that dispersal

was not highly directional (i.e., net movement had both forward and backward

components) and also that psylla were attracted to traps.

Summerforms were readily caught on traps at all distances, and the relationship

between trap catch and trap distance was similar in shape to that for winterforms

(Fig. 5). It still is not clear from this study or from the literature just how dispersive

the summerform morph is. Some studies suggest that very few summerforms

leave pear (Fye 1983, Purcell & Suslow 1984), whereas other studies have shown

that summerforms are readily caught outside the pear orchard (Fye 1983, Hodgson

& Mustafa 1984). The most important factor affecting numbers of summerforms

leaving the pear orchard appears to be psylla density. High densities prompt

movement out of the orchard (Fye 1983). In this study, summerform densities

in the source orchard were fairly high, although not atypically so (maximum

beating tray counts for summerforms were 35 psylla per tray, June 1991; DRH,

unpublished data); maximum counts for fall winterforms were about three times

as high as counts of summerforms (90 winterforms per tray were noted in October

1990 at the source orchard; DRH, unpublished data).

We cannot determine from this study whether the longer winged winterform

morph dispersed longer distances than did the summerform morph. Mean dis-

1993 HORTON ET AL.: PEAR PSYLLA MOVEMENT 187

eels Bt

ORCHARD—SIDE

Mm BACK-—SIDE

MEAN RESIDUAL

1ea2

ORCHARD SIDE

Mmm BACK-—SIDE

EAN RESIDUAL

= —0.2

NORTH WEST SOUTH EAST

TRAP DIRECTION

Figure 9. Mean (SEM) residual for each compass direction, spring (reentry) winterforms; regression

equations summarized in Fig. 7 (reciprocal model for orchard-side of traps, linear model for back-

side of traps). Asterisks indicate that the mean differed significantly from zero (t-test). Positive values

indicate that catch for a given direction was larger than predicted by the regression model.

tances travelled by captured psylla were similar between morphs (Table 2), al-

though results in Table 2 refer only to psylla within the study area. One difference

between morphs that we did note is that trapped summerforms were more likely

to be female than male (Fig. 6; also noted by Westigard & Madsen 1963), whereas

winterform sex ratios were not different from 1:1 (Fig. 6). Whether this bias for

188 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

summerforms was due to a sex ratio bias in the source orchard (Westigard &

Madsen 1963) or a tendency for female summerforms to be more dispersive than

males is not known.

In summary, results of this study suggest that there was some movement out

of the pear orchard by psylla all year. We were unable to demonstrate any strong

directional component for emigrating psylla (wind direction in the study area was

highly variable day-to-day). Also, if psylla were attracted to traps, the catch-

distance curves reported here will overestimate dispersal rates predicted by dif-

fusion models (Fig. 2). Until a completely passive trap for pear psylla is developed,

attempts to model psylla dispersal using techniques and models reported here

should anticipate this problem.

ACKNOWLEDGMENT

We thank Brad Higbee (USDA-ARS, Yakima, Washington) for field assistance.

The comments of Rick Redak (Department of Entomology, University of Cali-

fornia, Riverside, California) and Tom Unruh (USDA-ARS, Yakima, Washing-

ton) on an earlier draft are appreciated. The Washington Tree Fruit Research

Commission (Yakima, Washington), Winter Pear Bureau (Portland, Oregon), and

the Western Regional IPM Grants Program (WRCC 69) provided financial sup-

port.

LITERATURE CITED

Fletcher, B.S. 1974. The ecology of a natural population of the Queensland fruit fly, Dacus tryoni.

V. The dispersal of adults. Aust. J. Zool., 22: 189-202.

Follett, P. A., B. A. Croft & P. H. Westigard. 1985. Regional resistance to insecticides in Psylla

pyricola from pear orchards in Oregon. Can. Entomol., 117: 565-573.

Fye, R. E. 1983. Dispersal and winter survival of the pear psylla. J. Econ. Entomol., 76: 311-315.

Hodgson, C. J. & T. M. Mustafa. 1984. The dispersal and flight activity of Psylla pyricola Foerster

in southern England. Lutte integree contre les psylles du poirier. Bulletin Organisation Inter-

nationale de Lutte Biologique—Section Regionale Ouest Palearctique 7: 97-124.

Horton, D. R., B. S. Higbee, T. R. Unruh & P. H. Westigard. 1992. Spatial characteristics and effects

of fall density and weather on overwintering loss of pear psylla (Homoptera: Psyllidae). Environ.

Entomol., 21: 1319-1332.

Horton, D. R., E. C. Burts, T. R. Unruh, J. L. Krysan, L. B. Coop & B. A. Croft. 1994. Phenology

of fall dispersal by winterform pear psylla (Homoptera: Psyllidae) in relation to leaf fall and

weather. Can. Entomol., 126: 111-120.

Kareiva, P. 1982. Experimental and mathematical analyses of herbivore movement: quantifying the

influence of plant spacing and quality on foraging discrimination. Ecol. Monogr., 52: 261-282.

Krysan, J. L. 1990. Fenoxycarb and diapause: a possible method of control for pear psylla (Ho-

moptera: Psyllidae). J. Econ. Entomol., 83: 293-299.

Krysan, J. L. & D. R. Horton. 1991. Seasonality of catch of pear psylla Cacopsylla pyricola (Ho-

moptera: Psyllidae) on yellow traps. Environ. Entomol., 20: 626-634.

Neter, J., W. Wasserman & M.H. Kutner. 1985. Applied linear statistical models (2nd ed.). Richard

D. Irwin, Homewood, Illinois.

Oldfield, G. N. 1970. Diapause and polymorphism in California populations of Psylla pyricola

(Homoptera: Psyllidae). Ann. Entomol. Soc. Am., 63: 180-184.

Purcell, A. H. & K. G. Suslow. 1984. Surveys of leafhoppers (Homoptera: Cicadellidae) and pear

psylla (Homoptera: Psyllidae) in pear and peach orchards and the spread of peach yellow leaf

roll disease. J. Econ. Entomol., 77: 1489-1494.

Rudd, W. G. & R. W. Gandour. 1985. Diffusion model for insect dispersal. J. Econ. Entomol., 78:

295-301.

1995 HORTON ET AL.: PEAR PSYLLA MOVEMENT 189

SAS Institute. 1987. SAS/STAT guide for personal computers. Version 6 Edition. Cary, N.C.

Southwood, T. R. E. 1978. Ecological methods, 2nd ed. Chapman and Hall, New York.

Taylor, R. A. J. 1978. The relationship between density and distance of dispersing insects. Ecol.

Entomol., 3: 63-70.

Wadley, F.M. 1957. Some mathematical aspects of insect dispersion. Ann. Entomol. Soc. Am., 50:

230-231.

Wadley, F. M. & D. O. Wolfenbarger. 1944. Regression of insect density on distance from center

of dispersion as shown by a study of the smaller European elm bark beetle. J. Agric. Res., 69:

299-308.

Westigard, P. H. & H. F. Madsen. 1963. Pear psylla in abandoned orchards. Calif. Agric., 17: 6-9.

Westigard, P. H. & R. W. Zwick. 1972. The pear psylla in Oregon. Oregon State University Agri-

cultural Experiment Station, Technical Bulletin 122, Corvallis, Oregon.

PAN-PACIFIC ENTOMOLOGIST

71(3): 190-198, (1995)

COLONIZATION OF ORNAMENTAL LANDSCAPE PLANTS

BY BEMISIA ARGENTIFOLI BELLOWS & PERRING

(HOMOPTERA: ALEYRODIDAE)

CHARLES G. SUMMERS,! PAM ELAM? AND ALBERT S. NEWTON, JR.?

Department of Entomology, University of California, Davis, California 95616

Abstract.—In a survey of ornamental and landscape plants in the southern San Joaquin valley,

we found 82 species representing 42 families that are reproductive hosts of the silverleaf whitefly,

Bemisia argentifolii Bellows and Perring. Several ornamental plant species were found to be

overwintering hosts and some landscape plantings may contribute to infestations in adjacent

agricultural areas. Sixty-three ornamental plant species examined did not support silverleaf

whitefly colonization or development.

Key Words. —Insecta, host plants, Bemisia, silverleaf whitefly, ormamental plants, overwintering

hosts

For several years, two populations of the sweetpotato whitefly, Bemisia tabaci

(Gennadius), in the United States have been distinguished as “‘strain A’’ (cotton

strain) and “strain B” (poinsettia strain). Perring et al. (1993a) provided evidence

that the two strains, although morphologically similar, were distinct species and

proposed that the whitefly previously known as B. tabaci “‘strain B” (poinsettia

strain) be designated silverleaf whitefly. Bellows et al. (1994) presented additional

evidence for considering ‘“‘strain B” a separate species and proposed the scientific

name Bemisia argentifolii Bellows and Perring.

Initially confined to southern California, silverleaf whitefly had been found in

field situations in three southern San Joaquin Valley counties by December 1991

(Gill 1992). Silverleaf whitefly was reported from most of Kern County during

the summer of 1992 (Gruenhagen et al. 1993) and by the summer of 1993, was

found extensively throughout Kern, Tulare, Kings and Fresno Counties.

Because B. argentifolii is a newly designated species, host lists have not been

fully developed. The closely related B. tabaci is reported to have over 500 hosts

(Mound & Halsey 1978, Greathead 1986) and the host list for B. argentifolii may

be larger, as B. argentifolii appears to have a broader host range than B. tabaci

(Byrne & Miller 1990, Perring et al. 1992, Gill 1992). Although most B. argentifolii

host surveys have concentrated on agricultural crops and weeds, many ornamental

and landscape plants are susceptible to infestation. Heavy infestations can cause

severe injury or death. Whiteflies create a nuisance from the swarming of adults

and the production of copious amounts of honeydew. In the San Joaquin Valley,

ornamental and landscape plants may serve as overwintering refugia for silverleaf

whitefly. Our objectives were to identify ornamental landscape plants that sup-

ported colonization and development of B. argentifolii and to determine the

relative severity of such infestations.

3 Associate Entomologist and Staff Research Associate respectively. Mailing Address: University

of California, 9240 S. Riverbend Ave., Parlier, California 93648.

? Ornamental Horticulture Farm Advisor, University of California Cooperative Extension, 1720 S.

Maple, Fresno, California 93702.

1995 SUMMERS ET AL.: ORNAMENTAL HOSTS OF B. ARGENTIFOLIT 191

Table 1. Ornamental and landscape plants found to be hosts of the silverleaf whitefly in a general

survey of the southern San Joaquin Valley, California. 1993-94.

Family name? Common name? Scientific name*

Apocynaceae Periwinkle® Vinca sp.

Oleander° Nerium oleander L.

Araliaceae Ivy? Hedera sp.

Asteraceae Chrysanthemum® Chrysanthemum sp.

Transvaal Daisy Gerbera jamesonii H. Bolus ex Hook f.

Berberidaceae Nandina® Nandina domestica Thunberg

Betulaceae Alder® Alnus sp.

Cannaceae Canna Lily? Canna sp.

Caryophyllaceae Sweet William? Dianthus barbatus L.

Euphorbiaceae Poinsettia® Euphorbia pulcherrima Willdenow ex Klotzsch

Juglandaceae Black Walnut? Juglans nigra L.

Lamiaceae‘ Sweet Basil Ocimum basilicum L.

Oregano Origanum vulgare L.

Malvaceae Hollyhocke Alcea rosea L.

Hibiscus* Hibiscus rosa-sinensis L.

Rosaceae Rose* Rosa sp.

Lady Banks Rose® R. banksiae W. T. Aiton

Solanaceae Petunia Petunia hybrida Hort. Vilmorin-Andrieux

Verbenaceae Lantana? Lantana montevidensis (K. Sprengel) Briquet

Violaceae Violet Viola sp.

4 Liberty Hyde Bailey (1976).

> Host not listed in Mound & Halsey (1978) or Greathead (1986) for B. tabaci.

¢ Plants on which silverleaf whitefly successfully overwintered in 1992-93 and 1993-94.

4 Asteraceae = Compositae, Lamiaceae = Labiatae.

MATERIALS AND METHODS

Surveys. —During the summer of 1993, we conducted a general survey for

silverleaf whitefly throughout the southern San Joaquin Valley. Whitefly infested

leaves were placed in zip-lock bags and returned to the laboratory for species

identification and evaluation. We confirmed the identity of the whitefly species

by examining mature fourth-instar nymphs under a microscope. A plant was

considered a reproductive host if we found eggs, immature nymphs, fourth-instar

nymphs and exuvia from which adults had emerged. In August 1993, we learned

of a commercial nursery in Fresno with a severe whitefly infestation and our initial

examination confirmed the presence of B. argentifolii based on descriptions de-

veloped by T..M. Perring (personal communications). We then conducted a sys-

tematic survey of the facility by examining each plant species present. When

whitefly nymphs were found, infested leaves were placed in zip-lock bags and

returned to the laboratory for species identification and infestation rating. Host

status was determined as noted above. Infestation severity was rated on a scale

of 1 to 5 where 5 = extremely heavy nymphal populations (> 50 per leaf) and 1

= nymphs present (< 10 per leaf), but sparse. Ratings were based on visual

estimates of nymphal density.

During December of 1992 and 1993, we surveyed poinsettia plants in retail

outlets in the Fresno area for the presence of live B. argentifolii. Leaves were

examined with a 10x hand lens and the presence or absence of viable eggs and

nymphs noted.

192 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

Table 2. Ornamental hosts of silverleaf whitefly found in the survey of a commercial nursery

operation. Fresno, California. 1993.

Infestation

Family name* Common name? Scientific name? severity”

Acanthaceae Shrimp Plant¢ Justicia brandegeana Wasshausen 5

& L. B. Smith

Aceraceae Japanese Maple* Acer palmatum Thunberg 3

Anacardiaceae Chinese Pistache* Pistacia chinensis Bunge 1

Apocynaceae Oleander Nerium oleander L. 1

Dwarf Periwinkle® Vinca minor L. 1

Araliaceae Variegated Algerian Ivy° Hedera canariensis ‘variegata’ Will- 1

denow

Asteraceae Blanket Flower® Gaillardia grandiflora Van Houtte 1

Chrysanthemum Chrysanthemum sp. 3

Coreopsis° Coreopsis lanceolata L. 1

Berberidaceae Nandina® Nandina domestica Thunberg 2

Betulaceae White Birche Betula pendula Roth 1

Bignoniaceae Trumpet Creeper® Campsis radicans (L.) Seemann ex Z

Bureau

Desert Willow: Chilopsis linearis (Cavanilles) 1

Sweet

Pink Dawn¢ Chitalpa sp. 2

Cat’s Claw’ Macfadyena unguis-cati (L.) A. 1

Gentry

Cannaceae Canna Lily° Canna sp. 2

Caprifoliaceae Old Fashion Weigela* Weigela florida (Bunge) A. de Can- 2

dolle

Pink Abelia® Abelia grandiflora (André) Rehder 3

Laurustinus® Viburnum tinus L. 1

Cornaceae Western Dogwood* Cornus nuttallii Audubon 1

Kousa Dogwood* C. kousa Hance 2

Ericaceae Azalea‘ Rhododendron sp. 2

Euphorbiaceae Chinese Tallow Tree® Sapium sebiferum (L.) Roxburgh p

Fabaceae‘ Snail Vine° Vigna caracalla (L.) Verdcourt 3

Western Redbud* Cercis occidentalis Torrey 5

Happy Wanderer* Hardenbergia violacea (Schnee- 4

voogt) F. C. Stern

Hypericaceae Aaron’s Beard* Hypericum calycinum L. 1

Laminaceae4 Peppermint® Mentha piperita L. 2

Mealy-Cup Salvia‘ Salvia farinacea Bentham 1

Scarlet Sage S. splendens F. Sellow ex Roeme& 2

Schult

Pineapple-Scented Sage‘ S. elegans Vahl 3

Lauraceae Grecian Laurel¢ Laurus nobilis L. 3

Loganiaceae Butterfly Bushe Buddleia davidii Franchet 3

Lythraceae Crape Myrtle* Lagerstroemia indica L. 2

False Heather Cuphea hyssopifolia von Hum- 3

boldt, Bonpland & Kunth

Magnoliaceae Saucer Magnolia® Magnolia soulangiana Soulange-Bo- 2

din

Tulip Tree* Liriodendron tulipifera L. |

Malvaceae Hibiscus Hibiscus rosa-sinensis L. 5

Rose of Sharon* H. syriacus L. 5

Blue Hibiscus* Alyogyne huegelii (Endlicher) 3

Fryxell

1995

SUMMERS ET AL.: ORNAMENTAL HOSTS OF B. ARGENTIFOLIT 193

Table 2. Continued.

Infestation

Family name® Common name? Scientific name? severity”

Chinese Lantern Abutilon hybridum Hortorum 4

Globe Mallow Sphaeralcea ambigua A. Gray 3

Moraceae Fig® Ficus carica L. 2

Myrtaceae Myrtle* Myrtus communis L. 2

Eucalyptus* Eucalyptus sp. =

Silver Dollar Eucalyptus° E. cinerea F. J. Mueller ex Ben- 1

tham

Oleaceae Forsythia Forsythia intermedia Zabel a7

Plumbaginaceae Cape Leadwort* Plumbago auriculata de Lamarck 2

Dwarf Plumbago* Ceratostigma plumbaginoides 1

Bunge

Polygonaceae Silver Lace Vine‘ Polygonum aubertii L. Henry 1

Punicaceae Dwarf Pomegranate Punica granatum ‘nana’ (L.) Per- 3

soon

Ranunculaceae Columbine® Aquilegia hybrida Sims 1

Rosaceae Rose Rosa sp. 2

Lady Banks Rose‘ R. banksiae W. T. Aiton 2

Bridal-Wreath¢ Spiraea vanhouttei (C. Briot) Zabel 2

Spiraea® S. bumalda Burvenich 2

Spiraea® S. bullata Maximowicz 2

Indian Mock Strawberry Duchesnea indica (Andrews) Focke 3

Pearlbush¢ Exochorda macrantha (Hort. Li- i

moine) C. K. Schneider

Flowering Almond* Prunus triloba Lindley 1

Rubiaceae Gardenia Gardenia jasminoides Ellis 1

Salicaceae Pekin Willow: Salix matsudana G. Koidzumi 2

Sapindaceae Golden Rain Tree* Koelreuteria paniculata Laxmann ps

Saxifragaceae French Hydrangea® Hydrangea macrophylla (Thunberg) 1

Seringe

Scrophulariaceae Beard-Tongue® Penstemon sp. 2

Monkey Flower‘ Mimulus longiflorus (Nuttall) A. L. 1

Grant

Solanaceae Blue Potato Bush* Solanum rantonnetii Carriére 4

Yesterday-Today-Tomorrow® Brunfelsia pauciflora (Chamisso & 3

Schlechtendal) Bentham

Sterculiaceae Bottle Tree* Brachychiton populneus (Schott & 2

Endlicher) R. Brown

Verbenaceae Lantana Lantana montevidensis (K. Spren- 5

gel) Briquet

Chaste Tree Vitex agnus-castus L. 5

Vitaceae Grape® Vitus vinifera L. ‘Harmony’ 3

@ Liberty Hyde Bailey (1976).

> 1 = Sparse, 2 = Light, 3 = Moderate, 4 = Heavy, 5 = Extremely Heavy.

° Hosts not listed by Mound & Halsey (1978) or Greathead (1986) for B. tabaci.

4 Asteraceae = Compositae, Laminaceae = Labiatae, Fabaceae = Leguminosae.

* Listed as a host by Bellows et al. (1994).

Population Counts and Overwintering.—Selected landscape plants at a rural

residence near Five Points, Fresno County, were examined periodically during

the winter of 1993-94 to determine the status of silverleaf whitefly populations.

Leaves were collected and the number of whitefly nymphs present were counted

over a 10 min period. The counts were used as an indication of population status.

194

THE PAN-PACIFIC ENTOMOLOGIST

Vol. 71(3)

Table 3. Ornamental plants on which silverleaf whitefly was not found in the survey of a com-

mercial nursery operation. Fresno, California. 1993.

Family name*

Agavaceae

Amaryllidaceae

Anacardiaceae

Apocynaceae

Aquifoliaceae

Araliaceae

Arecaceae?

Asteraceae”

Berberidaceae

Betulaceae

Bignoniaceae

Buxaceae

Caryophyllaceae

Celastraceae

Cistaceae

Cornaceae

Fabaceae

Fagaceae

Geraniaceae

Hamamelidaceae

Lamiaceae>

Lauraceae

Liliaceae

Magnoliaceae

Melastomataceae

Myrtaceae

Oleaceae

Pinaceae

Pittosporaceae

Poaceae?

Podocarpaceae

Proteaceae

Rosaceae

Common name*

Tuberose

Lily-of-the-Nile

California Pepper Tree

Star Jasmine

Hybrid Holly

English Ivy

Queen Palm

Coyote Bush

Coreopsis

Gray-Leaved Euryops

Japanese Barberry

White Alder

Princess Tree

Argentine Trumpet Vine

Boxwood

Japanese Boxwood

Japanese Spurge

Carnation

Spindle Tree

Rock Rose

Japanese Laurel

Chinese Wisteria

Northern Red Oak

Geranium

Sweet Gum

Jerusalem Sage

English Lavender

Rosemary

Camphor Tree

Daylily

Mondo Grass

‘Myers’ Asparagus Fern

Southern Magnolia

Princess Flower

Pineapple Guava

Weeping Bottlebrush

Pink Flowering Jasmine

Wax-Leaf Privet

Common Lilac

Mugo pine

Japanese Black Pine

Colorado Blue Spruce

White Fir

Mock Orange

Bamboo

African Fern Pine

Spider Flower

Photinia

Carolina Cherry

Cotoneaster

Scientific name*

Polianthes tuberosa L.

Agapanthus sp.

Schinus molle L.

Trachelospermum jasminoides (Lindberg) Le-

maire

Ilex meserveae S. Y. Hu

Hedra helix L.

Arecastrum romanzoffianum (Chamisso) Beccari

Baccharis pilularis de Candolle

Coreopsis verticillata L.

Euryops pectinatus Cassini

Berberis thunbergii de Candolle

Alnus rhombifolia Nuttall

Paulownia tomentosa (Thunberg) Steudel

Clytostoma callistegioides (Chamisso) Bureau

Buxus microphylla Siebold & Zuccarini

B. m. japonica (Miller) Rehder & E. H. Wilson

Pachysandra terminalis Siebold & Zuccarini

Dianthus caryophyllus L.

Euonymus japonica Thunberg

Cistus purpureus Lamiare

Aucuba japonica Thunberg

Wisteria sinensis (Sims) Sweet

Quercus rubra L.

Pelargonium sp.

Liquidambar styraciflua L.

Phlomis fruticosa L.

Lavandula angustifolia Miller

Rosmarinus officinalis L.

Cinnamomum camphora (L.) J. Presl

Hemerocallis sp.

Ophiopogon japonicus (Thunberg) Ker-Gawler

Asparagus densiflorus (Kunth) Jessop

Magnolia grandiflora L.

Tibouchina urvilleana (de Candolle) Cogniaux

Feijoa sellowiana O. Berg

Callistemon viminalis (Solander ex Gaertner)

Cheel

Jasminum polyanthum Franchet

Ligustrum japonicum Thunberg

Syringa vulgaris L.

Pinus mugo Turra

P. thunberginia Franco

Picea pungens Englemann

Abies concolor (Gordon) Lindley ex Hildebrand

Pittosporum tobira (Thunberg) Aiton

Bambusa sp.

Podocarpus gracilior Pilger

Grevillea sp.

Photinia fraseri Dress

Prunus caroliniana (Miller) Aiton

Cotoneaster buxifolius Wallich ex Lindley

1995 SUMMERS ET AL.: ORNAMENTAL HOSTS OF B. ARGENTIFOLIT 195

Table 3. Continued.

Family name* Common name? Scientific name*

Cotoneaster C. procumbens G. Klotz

Japanese Rose Kerria japonica (L.) deCandolle

Indian Hawthorn Raphiolepis indica (L.) Lindley

Rubiaceae Gardenia Gardenia jasminoides Ellis

Saxifragaceae Pink Escallonia Escallonia rosea Grisebach

Scrophulariaceae _Ceniza Leucophyllum frutescens (Berlandier) I. Johnston

Snapdragon Antirrhinum majus L.

Solanaceae Cupflower Nierembergia hippomanica Miers

Strelitziaceae Bird of Paradise Strelitzia reginae Aiton

Taxodiaceae Coast Redwood Sequoia sempervirens (D. Don) Endlicher

Theaceae Sasanqua Camellia Camellia sasanqua Thunberg

Thymelaeaceae Winter Daphne Daphne odora Thunberg

Ulmaceae Chinese Elm Ulmus parvifolia Jacquin

4 Liberty Hyde Bailey (1976).

b Arecaceae = Palmae, Asteraceae = Compositae, Fabaceae = Leguminosae, Poaceae = Grami-

nae, Lamiaceae = Labiatae.

RESULTS AND DISCUSSION

We found a total of 82 species from 42 families that supported silverleaf whitefly

development (Tables 1 and 2). Only Angiospermae were found to be hosts. We

occasionally observed adults resting on Gymnospermae, but found no reproduc-

tive colonies associated with this class of plants. Neither Mound & Halsey (1978)

nor Greathead (1986) reported any Gymnospermae as a host of B. tabaci. With

the exception of Canna Lily (Cannaceae, Canna sp.), subclass Monocotyledonae,

all hosts catalogued were members of the subclass Dicotyledonae. Greathead

(1986) lists five families in the Monocotyledonae, but not Cannaceae, as containing

hosts of B. tabaci. Phylogenetically, hosts were found among the most primitive

(e.g., Magnoliaeace) to the most advanced (e.g., Asteraceae) families.

The family Rosaceae, which is among the most pest prone in landscape plantings

(Raupp et al. 1985), contained the greatest number of hosts species with eight,

followed by Malvaceae with six. Among the families we examined that were

represented by two or more hosts and for which infestation severity ratings were

taken (Table 2), Verbenaceae (n = 2) appears to be the most susceptible with a

mean (+ SE) infestation severity of 5.0 + 0.0. Malvaceae (n = 5) and Fabaceae

(n = 3) were next, with a mean infestation severity of 4.0 + 0.45 and 4.0 + 0.58

respectively, followed by Solanaceae (n = 2) with a severity index of 3.5 + 0.50.

The severity of the infestation among species within individual families was

relative consistent. The mean infestation severity in Rosaceae was 1.8 + 0.25

with a range of 1 to 3. Malvaceae and Fabaceae each had a range of infestation

from 3 to 5.

Thirty-three plant species had populations in the moderate to extremely heavy

category while forty-nine supported only light infestations. In the nursery or home

landscape, moderate whitefly numbers may render the plants aesthetically un-

pleasant due to the presence of honeydew and the growth of sooty mold. At the

wholesale or retail level, the movement of infested plants serves to spread the

infestation to new areas (Byrne et al. 1990). This is particularly true for light

infestations that are difficult to detect. Flint et al. (1993) showed that customers

196 THE PAN-PACIFIC ENTOMOLOGIST Vol. 71(3)

10000

ROSE —a—

NANDINA —*#&—

1000 CHRYSANTHEMUM ——®—

100

LOG 10 NO. NYMPHS PER 10 MINUTE COUNT

SAMPLE DATE

Figure 1. Population levels of B. argentifolii on three ornamental plants at a rural Fresno County

during winter and early spring, 1994.

ignored or did not recognize some types of pest damage and that some insect

infested or damaged plants sold as readily as did clean or undamaged ones.

During the survey of the commercial Fresno facility, we found 63 plant species

not infested by silverleaf whitefly (Table 3). The presence of adults is not an

indication of host status as many of these non-hosts served as resting sites for the

adults.

In our survey of poinsettias in retail outlets in the Fresno area we found infested

plants in 14 of 15 and 13 of 15 stores in 1992 and 1993 respectively. Poinsettias

often are planted outdoors after Christmas when the threat of frost is past. In

June 1993, we found several heavily infested poinsettias that had earlier been

transplanted into the yard of a residence near Five Points in western Fresno

County.

Ornamentals may play an important role in silverleaf whitefly biology and

spread. The poinsettias transplanted into the landscape at the Five Points site

were likely the source of infestation for several of the other ornamental species

found at that location (Table 1). These plants in turn may have contributed to a

major infestation in an adjacent cotton field, approximately 100 meters down

wind from the residence. The cotton was heavily infested by July 1993 and counts

exceeded 5000 nymphs per 10 min search period in late September (Summers,

unpublished data). This was the only infested field within several kilometers of

the residence although cotton was abundant in the area. We found viable popu-

lations of nymphs on Rose, Nandina, and Chrysanthemum throughout the winter

of 1993-94 at the Five Points residence (Fig. 1). Viable nymphs also were observed

periodically during the winter on several other species (Tables 1) that likely serve

as Overwintering hosts. Urban environments and even isolated rural residences

usually are slightly warmer than adjacent agricultural areas and may provide ideal

overwintering sites. Heat islands are associated with buildings, asphalt and con-

crete and extend outward into open areas (Duckworth & Sanberg 1954). Home-

owners may provide ornamental plants added protection from frost by covering

or placing light bulbs near them for additional warmth.

1995 SUMMERS ET AL.: ORNAMENTAL HOSTS OF B. ARGENTIFOLII 197

Susceptible ornamentals are not restricted to residential landscaping. Parks,

right-of-ways and freeway landscaping frequently contain plants susceptible to

silverleaf whitefly. Species commonly used in such plantings include: Indian Mock

Strawberry, Western Redbud, Japanese Maple, Dwarf Pomegranate, Laurel, Des-

ert Mallow, Lantana, Chaste Tree, Oleander, Eucalyptus, Rose, and Laurnstinus

(Table 2). It may be important to avoid planting highly susceptible species in the

future. In both the home landscape and public parks, there exists the likelihood

of a nuisance factor from swarming adults, the deposition of honeydew resulting

in sticky lawns, automobiles, benches, sidewalks and tables and the growth of

sooty mold resulting in unsightly vegetation. In heavily infested hosts, premature

leaf dehiscence may occur. Because of B. argentifolii’s extensive host range, its

propensity to produce large quantities of honeydew (Byrne & Miller 1990) and

its high fecundity rate (Bethke et al. 1991) it likely will be a more significant pest

in the landscape than was the ash whitefly, Siphoninus phillyreae (Haliday), before

it was brought under control by introduced natural enemies (Bellows et al. 1992).

ACKNOWLEDGMENT

We thank D. Estrada, T. Swanson, A. Borton, J. Wood, and C. Lee for assistance

with the surveys, Mrs. Frank Diener for permitting us access to her gardens

throughout this study and for remaining stoic during some rather destructive

sampling and K. Daane and M. L. Flint for their review and suggestions regarding

the manuscript. Portions of this study were funded by the University of California

Center for Pest Management Research and Extension.

LITERATURE CITED

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P. Elam, D. Flaherty, P. Gouvela, C. Koehler, R. Molinar, N. O’Connell, E. Perry & G. Vogel.

1992. Biological control of ash whitefly: a success in progress. Calif. Agric. 46(1): 24, 27-28.

Bellows Jr., T. S., T. M. Perring, R. J. Gill & D. H. Headrick. 1994. Description of a species of

Bemisia (Homoptera: Aleyrodidae). Ann. Entomol. Soc. Am. 87: 195-206.

Bethke, J. A., T. D. Paine & G. S. Nuessly. 1991. Comparative biology, morphometrics, and de-

velopment of two populations of Bemisia tabaci (Homoptera: Aleyrodidae) on cotton and

poinsettia. Ann. Entomol. Soc. Am. 84: 407-411.

Byrne, D. N. & W. B. Miller. 1990. Carbohydrate and amino acid composition of phloem sap and

honeydew production by Bemisia tabaci. J. Insect Physiol. 36: 433-439.

Byrne, D. N., T. S. Bellows & M. P. Parrella. 1990. Whiteflies in agricultural systems. pp. 227-261.

In D. Gerling (ed.). Whiteflies: their bionomics, pest status and management. Intercept Pub-

lications. Wimborne, England.

Duckworth, F.S. & J.S. Sanberg. 1954. The effect of cities upon horizontal and vertical temperature

gradients. Bull. Am. Meteorol. Soc. 35: 198-207.

Flint, M. L., S. H. Dreistadt, E. M. Zagory & R. Rosetta. 1993. IPM reduces pesticide use in the

nursery. Calif. Agric. 47(4): 4-7.

Gill, R. J. 1992. A review of the sweetpotato whitefly in Southern California. The Pan-Pacific

Entomol. 68: 144-152.

Greathead, A.H. 1986. Host plants. pp. 17-25. In M. J. W. Cock (ed.). Bemisia tabaci—a literature

survey on the cotton whitefly with an annotated bibliography. CAB International Institute of

Biological Control, Silwood Park, Ascot Berks., U.K.

Gruenhagen, N. M., T. M. Perring, L. G. Bezark, D. M. Daoud & T. F. Leigh. 1993. Silverleaf

whitefly present in the San Joaquin Valley. Calif. Agric. 47(1): 4-6.

Liberty Hyde Bailey Hortorium. 1976. Hortus third: a concise dictionary of plants cultivated in the

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Mound, L. A. & S. H. Halsey. 1978. Whitefly of the world. British Museum of Natural History and

Wiley & Sons, N.Y.

Perring, T. M., A. Cooper & D. J. Kazmer. 1992. Identification of the poinsettia strain of Bemisia

tabaci (Homoptera: Aleyrodidae) on broccoli by electrophoresis. J. Econ. Entomol. 85: 1278-

1284.

Perring, T. M., A. D. Cooper, R. J. Rodriguez, C. A. Farrar & T. S. Bellows Jr. 1993a. Identification

of a whitefly species by genomic and behavioral studies. Science. 259: 74-77.

Perring, T. M., C. A. Farrar, T. M. Bellows, A. D. Cooper & R. J. Rodriguez. 1993b. Evidence for

a new species of whitefly: UCR findings and implications. Calif. Agric. 47(1): 7-8.

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integrated pest management for landscapes. J. Arboric. 11: 317-322.

PAN-PACIFIC ENTOMOLOGIST

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Anderson, T. W. 1984. An introduction to multivariate statistical analysis (2nd ed). John Wiley & Sons, New York.

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THE PAN-PACIFIC ENTOMOLOGIST

Volume 71 July 1995 Number 3

Contents

BARTHELL, J. F. & R. STONE—Recovery of the parasite Triarthria spinipennis (Meigen)

(Diptera: Tachinidae) from an inland California population of the introduced European

KASANA, A. & M. T. ALINIAZEE— Adult flight dynamics of walnut husk fly (Diptera: Te-

phritidae) in the Willamette Valley of Oregon

BARTHELL, J. F. & H. V. DALY — Male size variation and mating site fidelity in a population

of Habropoda depressa Fowler (Hymenoptera: Anthrophoridae)

EDMUNDS, G. F., Jr. & C. M. MURVOSH~— Systematic changes in certain Ephemeroptera

studied by R. K. Allen

SHIAO, S.-F. & W.-J. WU—A new Liriomyza species from Taiwan (Diptera: Agromyzidae) .

MACKAY, W. P.—New distributional records for the ant genus Cardiocondyla in the New

World (Hymenoptera: Formicidae)

STARY, P. & R. L. ZUPARKO—A new species of Trioxys (Hymenoptera: Braconidae) from

GPU 6) LP: Crd ae ae eM FP Che A Ne eee See AE OL TWN nF he peee Pee ate AO pe) 4

HORTON, D. R., E. C. BURTS, T. M. LEWIS & L. B. COOP—Sticky trap catch of winterform

and summerform pear psylla (Homoptera: Psyllidae) over non-orchard habitats

SUMMERS, C. G., P. ELAM & A. S. NEWTON, Jr.—Colonization of ornamental landscape

plants by Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae)

137

142