Evolution in a Community Context: Trait Responses to Multiple Species Interactions*

Species that coexist in diverse natural communities interact in complex ways that alter each other's abundances and affect selection on each other's traits. Consequently, predicting trait evolution in natural communities may require understanding ecological and evolutionary dynamics involving a number of species. In August 2016, the American Society of Naturalists sponsored a symposium to explore evolution in a community context, focusing on microevolutionary processes. Here we provide an introduction to our perspectives on this topic by defining the context and describing some examples of when and how microevolutionary responses to multiple species may differ from evolution in isolation or in two-species communities. We find that indirect ecological and evolutionary effects can result in nonadditive selection and evolution that cannot be predicted from pairwise interactions. Genetic correlations of ecological traits in one species can alter trait evolution and adaptation aswell as the abundances of other species. In general, evolution in multispecies communities can change ecological interactions, which then feed back to future evolutionary changes in ways that depend on these indirect effects. We suggest avenues for future research in this field, including determining the circumstances under which pairwise evolution does not adequately describe evolutionary trajectories.