Reproductive Biology and Behavior of a Thelytokous Species of Eretmocerus (Hymenoptera: Aphelinidae) Parasitizing Bemisia argentifolii (Homoptera: Aleyrodidae)

Abstract

Eretmocerus sp., a thelytokous aphelinid parasitoid of Bemisia argentifolii Bellows & Perring, was imported into the United States from Hong Kong in June 1992. We investigated the foraging behavior and reproductive biology of this species as part of an evaluation of its potential for biological control of B. argentifolii . Parasitoids performed stereotyped behaviors upon encountering whitefly hosts, including antennation, circle-antennation, probing, postprobing host tapping, and host feeding. During 1-h videorecording periods, parasitoids were observed to accept all whitefly instars for host feeding and oviposition. After confining parasitoids for 24 h with whitefly nymphs, significantly more eggs were found under 2nd and 3rd instars than under 1st and 4th instars. Parasitoids fed honey, with no access to whitefly nymphs, lived significantly longer (12.5 d) than those given access to nymphs, but no honey (8.4 d). Lifetime fecundity averaged 92.8 female progeny per female, ranging from 3 to 147. Daily fecundity, measured as the number of whitefly nymphs parasitized per female each day for 9 d, averaged 20 for the first 6 d of life, and then declined to <10. On average, 4.5 nymphs were fed on by parasitoids each day during the first 3 d of life. Developmental period from oviposition to parasitoid emergence was significantly shorter in 3rd instars of the host (16.4 d), than in 2nd (16.8 d) or 1st instars (17.6 d).