Monday, December 11, 2006 - 10:35 AM
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Development of Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae): Effects of Freezing of Host Larvae on Parasitoid’s Fitness

Ebenezer O. Onagbola, onagbeo@auburn.edu and Henry Y. Fadamiro, FADAMHY@auburn.edu. Auburn University, Department of Entomology & Plant Pathology, 301, Funchess Hall, Auburn University, Auburn, AL

Knowledge of the relationship between host quality and fitness of progeny is essential in the evolutionary ecology of parasitoids. Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae) develop on live larvae and pre-pupae of several pests of stored products. We investigated the influence of host quality (live vs. freeze-killed) on the development and fitness of P. cerealellae. Live and dead fourth instar larvae of Callosobruchus maculatus (Fabricius) (Coleoptera: Chrysomelidae) were separately exposed to parasitization by mated parasitoids for 48 h in two experimental phases: (i) live vs. dead hosts (0-day only) and (ii) live vs. dead hosts (0 - 5 days old). Parasitized hosts were incubated until parasitoids progeny emerged then, the number and the sex ratios of the progeny were determined. Pteromalus cerealellae successfully developed on live and freeze-killed hosts of all ages tested. Development time, levels of parasitism and sex ratios of the emerged progeny were similar for live and dead hosts. Levels of parasitism however, declined gradually in hosts held longer than 3 - days. We suggest that the reduced suitability of the older freeze-killed hosts may be due to putrefaction rather than desiccation. This novel study will enhance the mass release use of P. cerealellae in the control of pests of stored products and alleviate the problems associated with the use of parasitoids in biological control programs – the accidental re-introduction of pests.


Species 1: Hymenoptera Pteromalidae Pteromalus cerealellae (parasitic wasp)

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