9623468 Maddison The role of spider venoms in predation strategies or defense varies widely among spiders. The chemical composition of venoms also varies among spider species and there is even evidence of variation within species. In this study, we will use a comparative approach to test for the influence of ecological demands on venom diversification. We will determine phylogenetic levels at which variation in venoms exists, and then determine whether venom changes are more pronounced in systems with behavioral and ecological variability. First, we will assay nongenetic variation by determining the effect on adult venom expression that results from rearing broodmates on different diets. Second, we will determine amounts of variation below the species level in three spider systems: (1) Agelenopsis aperta, a species with known behavioral differences among populations; (2) Tegenaria agrestis, a species with evidence of interpopulational differences in venom pharmacology; and (3) populations of Hawaiian Tetragnatha that are similar ecologically but isolated on different islands. Finally, we will determine venom differences above the species level and investigate ecological and behavioral correlates of these changes in Hawaiian Tetragnatha, a clade which has undergone a radiation involving a shift in foraging behavior. The ability to predict venom characteristics, based on phylogenetic position or ecological circumstances, would help to streamline the ongoing search for novel toxins with useful physiological applications.
