Collaborative Research: How do gall-forming insects escape diverse and evolving clades of parasitic wasps - and how do parasites catch up?

Suny At Binghamton, Binghamton NY

Investigators

Abstract

Parasitic wasps are critically important predators that control the population sizes of other insects. Why parasitic wasps attack some insect hosts but not others is a key question with major applied implications for control of forest and agricultural pest insects and human disease vectors. This work will involve the study of hundreds of insect species that specialize on oaks - one of the most ecologically important and widespread tree genus in North America. The researchers will document the parasitic wasps that attack each insect and, accordingly, discover which insects those same wasps do not attack. A major goal will be to infer which insect defenses are effective against each type of parasitic wasp, as well as whether, how, and why parasites have shifted among different insect hosts over time. Discoveries resulting from the research will be added to a public facing website, integrated into an urban ecology museum collection in collaboration with a Detroit, MI-based community organization, and incorporated into undergraduate courses. A postdoctoral scholar, three graduate students, and several undergraduate students will be trained as part of this work. The researchers will study the diversity and evolutionary histories of oak gall wasps and seven different genera of their parasitic wasps, all contextualized by the multidimensional trait space of oak galls. Each oak gall wasp induces a gall of a unique and characteristic gall morphology on a specific organ of a specific oak species during a specific time of year. At least seven genera of parasitic wasp are broadly associated with oak galls, with each gall wasp species attacked by several different parasite species. However, not every parasite genus attacks every gall type and individual parasite species have often proved to only attack galls induced by just one or a small number of gall wasp species. The researchers and a team of community scientists will collect, study, and discover new oak gall wasps and parasites from across the continental United States. They will then sequence hundreds of phylogenetically informative genetic loci from thousands of individual insects and infer evolutionary relationships among those insects. They will contextualize galler-parasite interactions by their evolutionary histories, host tree associations, and various dimensions of gall ecology, including phenology, and gall morphology. Questions the study will address include: 1) How do gall wasps escape from parasites? 2) What gall trait changes drive parasitic wasp speciation? The scale of this study (hundreds of host and parasite species) will make it the largest ecologically aware cophylogenetic study of its kind. The project is co-funded by the Systematics and Biodiversity Science program. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.