Larvae of the parasitoid wasp Cotesia near phobetri (Braconidae) emerging from their host caterpillar (Grammia incorrupta).
Ongoing research of G. incorrupta addresses the manipulation of the caterpillar’s feeding behavior by a different parasitoid species. Recent evidence shows that a parasitoid wasp (Cotesia nr. phobetri) manipulates the nutrient intake of G. incorrupta caterpillars with benefits to the wasp’s growth and development. My current Ph.D. student, Melissa Bernardo, and I have developed this line of research into her NSF-funded thesis project. The context of this research topic is addressed in our recent perspective piece (Bernardo and Singer 2017). Melissa’s empirical work tested alternative functional mechanisms underlying the wasp’s manipulation of caterpillar feeding behavior. She is in the process of publishing this work as she nears her Ph.D. defense.
This project has also led my research into the realm of functional genomics. We are collaborating with Heiko Vogel (Max Planck Institute of Chemical Ecology, Germany) and Wesleyan Biology colleague Joe Coolon to study genome-wide patterns of gene expression of G. incorrupta caterpillars subjected to wasp parasitism in relation to bead-injected and control caterpillars. We hope to link some key categories of gene expression changes to physiological and behavioral changes in parasitized caterpillars in order to understand more mechanistically how Cotesia wasps manipulate the nutritional physiology of their caterpillar hosts.