Dimensions: Collaborative Research: Diversification Dynamics of Multitrophic Interactions in Tropical Communities

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How is biodiversity generated and maintained? Much evidence suggests that parasites play an important role in both the origin and the maintenance of biological diversity. This project focuses on one of the most diverse groups of organisms on the planet: herbivorous insects, their parasites, and their microbes. The project targets three economically important groups of organisms: plants in the pumpkin/cucumber family, true fruit flies that attack these plants, and parasitic wasps that kill the flies. These wasps belong to a highly diverse and little studied group of species. Each wasp species can kill only one fly species; wasps attacking the "wrong" species of fly die. These bi-directional lethal interactions may be mediated by microbes (in wasps, flies, or both), by traits of flies' immune systems, or both. This project is designed to uncover the mechanisms (evolutionary, ecological, and immunological) affecting interactions that may help explain the diversity of life. Many species of true fruit flies are major agricultural pests; this project will greatly increase knowledge about factors contributing to their susceptibility to parasitoids. The project tests hypotheses that predict that: 1) defenses of parasites and their hosts affect diversification rates; 2) mechanisms of virulence differ among lineages, and 3) selection arising from predator-prey interactions can affect rates of species-formation. To discover and identify mechanisms of diversification, participants will generate and analyze molecular 1) high-resolution genetic data, multiple nuclear loci, and mtCOI haplotypes to delineate species, and resolve deeper phylogenetic relationships; 2) microsatellites and ddRAD-seq markers to discover and quantify fine-scale genetic diversity within and among populations; 3) phylogenies and field experiments to test hypotheses about mechanisms generating and controlling diversity on ancient, recent, and contemporary timescales. Undergraduate students from all participating colleges and universities will participate in the research.