Insects use a variety of chemical cues to locate food sources, mates, and oviposition sites, and to avoid unsuitable habitats and situations. Most current knowledge of olfaction (sense of smell) in insects is based on studies of the sex pheromone systems of moths. Very little is known about the navigational mechanisms or the specificity of the olfactory systems of other insects, in particular parasitic wasps (parasitoids). The goal of this study is to characterize mechanisms of olfaction in two parasitoids with different degrees of host specificity, using an integration of analytical, behavioral, and electrophysiological techniques. Using the specialist parasitoid, Microplitis croceipes and the generalist parasitoid, Cotesia marginiventris as experimental models, this study will: 1) compare the behavioral responses and orientation mechanisms of both sexes of specialist and generalist parasitoids to various types of host-related compounds, and 2) characterize the electrophysiological responses of both sexes of specialist and generalist parasitoids to various types of host-related volatiles using electroantennograms and coupled gas chromatography electroantennograms and single-cell recording techniques. As a third objective, Dr. Fadamiro will acquire training in neurobiological techniques for future study of the neurophysiology of olfactory receptor neurons in the antennae of the parasitoid models. This project has implications for animal navigation and will advance the understanding of olfaction and comparative biology and generate new concepts regarding evolution of host-parasitoid interactions. In addition, the study has potential benefit to agriculture, public health and the environment by suggesting ecologically based alternative strategies for pest control. The broader impacts of the project also include integration of research and education activities to train and mentor students, in particular underrepresented minority students. This work will directly support the training of one minority graduate student, two undergraduate students, and one postdoctoral associate at Auburn University.
