We study the forces generating and maintaining phenotypic diversity. Our focus is on life-history and social traits as these traits are closely tied to fitness, and therefore are at the intersection of ecological dynamics and evolution. Key interests for us are to understand the trade-offs underlying different phenotypes and to determine the selective context in which different variants are favored. All of the research in the lab currently focuses on insect-parasitic nematodes and their mutualist bacterial partners. We use this system to address a variety of topics: