BIONOMICS OF MICROPLITIS MEDIATOR (HYM: BRACONIDAE) PARASITIZING PSEUDALETIA SEPARATA (LEP: NOCTUIDAE)*

Abstract

This paper deals with the bionomics of Microplitis mediator parasitizing Pseudaletia separata. There were some stings (ca. 3. 1%) in which female wasps oviposited more than one eggs and about 4. 6% stings that there was no egg laid into a host. A negative correlation existed between the host age and percentage of parasitization. When the host suffered more stings by the parasitoid wasps, the percentage of parasitization was higher. But there was no correlation between the parasitoid sex ratio and the host age or the frequency of stings by the parasitoids. The host age is not the major factor affecting the offspring sex ratio of the parasitoid. Some putative sex determinant factors in the parasitoid are discussed and the 2nd instar of the host is recommended as a suitable host age in which parasitization could be performed for the purpose of the parasitoid mass culture.

Sting frequency and progeny production of lab-cultured Cotesia marginiventris

“…That an average of 13% of hosts stung once did not yield any progeny could be a reflection of the frequency at which stinging behavior did not result in deposition of an egg. Note that approximately 4.6% of initial stings by the solitary braconid Microplitis mediator (Haliday) resulted in no egg being laid into its noctuid host, Pseudeletia separata Walker, in the laboratory (Qin et al 1999). When stinging did in fact result in oviposition, only one C. marginiventris progeny was capable of completing its development from resources provided in one host larva in this study.…”