ABSTRACT 96-15523 Werner Mechanisms and consequences of trait-mediated indirect interactions in a larval anuran community This project examines indirect interactions between species in a food web, and their effects on the structure of ecological communities. The effects transmitted from a species A to species C through an intermediate species B are termed density-mediated indirect interactions when they are transmitted through changes in the abundance of species B. There are compelling reasons to believe that trait-mediated indirect interactions also can be important in shaping communities. These are indirect effects transmitted by changes in the traits (behavior, morphology, and life history) of species B. Presently only a few studies have illustrated these effects. In this proposal, we use a model system of frog larvae and their dragonfly predators to examine when we can expect the density-mediated or the trait-mediated indirect interactions to dominate, and how they will interact when both are important. We develop a model that indicates that the trait-mediated indirect interactions have been strongly underestimated, and devise experiments to test these predictions.
