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Bio Prof Studies Insect Arms Race

By Randall S. Barton on July 16, 2015 03:56 PM

WHEN WASPS ATTACK. This parasitic wasp is about to lay eggs in fruit-fly larva. A movie you don't want to watch.

Prof. Todd Schlenke [biology 2013-] has won a $373,000 grant from the National Institute of Allergy and Infectious Diseases, division of the National Institutes of Health, to study one of nature's most unforgiving arms races-- the struggle between fruit flies and venomous parasitic wasps.

Prof. Schlenke's project is titled “A Model System for Host-Pathogen Interactions: Drosophila and Its Parasitic Wasps” and will explore how parasites suppress host immune responses, using the fruit fly Drosophila melanogaster and its natural parasitic wasps as a model host-parasite pair. The work will identify and characterize the venom (virulence) proteins that wasps use to suppress conserved aspects of host innate immunity. By characterizing venom repertoires across a phylogeny of wasps, patterns of parasite virulence strategy evolution will be uncovered.

Drosophila melanogaster is a model system for the molecular genetics of innate immunity, but little is known about the life history and virulence strategies of its natural parasites. Parasitic wasps can infect fruit-fly larvae at frequencies greater than 50% in natural populations, and are highly amenable to laboratory and field study.

Prof. Schlenke and his students at Reed have developed a collection of 17 live wasp parasite strains, and robust protocols for extracting and manipulating the venom cocktails they use to thwart the host cellular encapsulation response mounted against their eggs.

Schlenke proposes to identify the venom gland contents of 10 related wasp species that are highly successful. He will then assay the effects of whole venom from each wasp species, and use population genetic and molecular evolution approaches to uncover how venoms maintain virulence function in their co-evolutionary arms race with host immune systems.