Because immune defenses against parasites are costly, hosts are expected to balance the use of different defense mechanisms and to forego immunity when they do not need it. However, experimental evidence for trade-offs between alternative defense mechanisms is scarce. The ideal system to test for immune response tradeoffs would be a group of closely related host species that face similar parasites in the wild, and that employ multiple kinds of defenses. The investigators will use fruit flies of the melanogaster species group of the genus Drosophila, along with their shared endoparasitoid wasps from the family Figitidae, to test the hypothesis that cellular and behavioral immune defenses trade off with each other on a macro-evolutionary scale. The investigators will take advantage of the fact that D. melanogaster is a genetic model system to test the suspected roles of sight and brain neuropeptide F signaling in fly self-medication responses against wasp parasites. The investigators will also take a combined RNA-seq and association mapping approach to uncover further brain genes required for initiating behavioral defenses. This project will result in the identification of evolutionary trade-offs between different immune mechanisms as well as the mechanistic and genetic underpinnings of behavioral immune responses.
Broader impacts of the project include the maintenance and distribution of parasitic wasp strains for the scientific community and the education and training of undergraduate and graduate students in aspects of behavior, cellular biology, and genetics. The investigators will also collaborate with public high school teachers to develop classroom projects focused on hands-on, student-centered, and inquiry-based learning approaches using the fly-wasp immunological interactions.
