PROC. ENTOMOL. SOC. WASH. 98(4), 1996, pp. 667-676 LARVAL FEEDING AND DEVELOPMENT OF LEUCOPIS NINAE TANASUTSHUK AND TWO POPULATIONS OF LEUCOPIS GAIMARII TANASUTSHUK (DIPTERA: CHAMAEMYIIDAE) ON RUSSIAN WHEAT APHID, DIURAPHIS NOXIA (MORDVILKO) (HOMOPTERA: APHIDIDAE), IN WASHINGTON Stephen D. Gaimari and William J. Turner Department of Entomology, Washington State University, Pullman, WA 99164-6382, U.S.A.; SDG, current address: Department of Entomology, 320 Morrill Hall, 505 South Goodwin Avenue, University of Illinois, Urbana, IL 61801, U.S.A. Abstract. — Three populations of Leucopis (Diptera: Chamaemyiidae), including L. ni-nae Tanasijtshuk and two populations of L. gaimarii Tanasijtshuk, were studied to deter-mine their relative larval development times and feeding rates at different temperatures. Using three experimental temperatures (20.0°, 23.3°, 26.6°C), we determined that the de-velopmental times of all three populations significantly decreased with increasing tem-perature. Additionally, the number of aphids consumed per day significantly increased from the lowest to the highest experimental temperatures for each population. There were few differences among the three populations for the aspects studied, although one popu-lation of L. gaimarii had a significantly {P > 0.005) longer third stadium (and total larval duration) at the lowest experimental temperature than either L. ninae or the other popu-lation of L. gaimarii. This coincided with a higher mean number of aphids consumed for this population at this temperature. Most importantly, we found that these Leucopis species are voracious predators on aphids, with each individual killing approximately 100 aphids throughout larval life. Also, our data suggests that the species native to the Pacific North-west, L. gaimarii, is as effective a predator on the Russian wheat aphid as the introduced species, L. ninae. Key Words: Chamaemyiidae, Leucopis, larval feeding, larval development, Aphididae, Diuraphis noxia, Russian wheat aphid, biocontrol All larval Chamaemyiidae that have been et al. 1981, Stevenson 1967, Tanasijtshuk studied are predators on soft-bodied ho-1986, Tiensuu 1951, Tracewski 1983, Wil-mopterans, particularly those in the super-son 1938), there is a need for more infor-families Aphidoidea and Coccoidea. Be-mation on larval feeding and development, cause this group of flies is potentially useful Besides a general understanding of the in biological control programs targeting Chamaemyiidae as predators of soft-bodied aphids, adelgids, scales, and mealybugs homopterans, the feeding habits are poorly (Balch 1952, Balch et al. 1956, Brown and understood. Some, but not all, genera have Clark 1957, Clark and Brown 1962, Culli-been associated with particular groups of ney et al. 1988, Delucchi and Pschorn-homopterans, e.g. C/zam<3gm3'ia Meigen and Walcher 1954, Eichhom 1968, Gaimari Parochthiphila Czemy on mealybugs of 1991, Greathead 1995, Mills 1990, Nakao grasses and Neoleucopis Malloch on Adel-
Larval feeding and development of leucopis ninae tanasutshuk and two populations of leucopis gaimarii tanasutshuk (diptera: chamaemyiidae) on russian wheat aphid, diuraphis noxia (mordvilko) (homoptera: aphididae), in Washington
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