Identifying natural genetic variation for Drosophila melanogaster resistance to parasitoid wasp infection. Kate J Hutchence, Todd A Schlenke. Biology Department, Emory University, Atlanta, GA.

   Drosophila melanogaster is a model system for the study of innate immunity and parasitoid wasp species are some of the most common pathogens of fruit flies in nature. Although the melanotic encapsulation response flies amount against wasp eggs is well-characterized at the cellular level, the genetic basis for the response remains poorly understood. The Drosophila Genetic Reference Panel (DGRP) is an excellent resource for making associations between phenotypic variation and genotypic variation, and especially for identifying mutations that affect fly immune success against wasps in nature. I have performed an association study using 98 DGRP lines to investigate the genetic basis of variation in D. melanogaster resistance to infection by the parasitoid wasp Leptopilina clavipes. DGRP strains were exposed to wasp attack and four phenotypic measures were taken: the proportion of fly larvae that (i) avoided infection, (ii) that successfully survived wasp attack, (iii) that died as a result of an overactive immune response, or (iv) that were successfully parasitized by the wasp. Significant variation was observed for all traits and a number of candidate anti-wasp immune genes were identified. I am now genetically testing and functionally characterizing several of the candidate genes.