Evolutionary Consequences of Anthropogenic Environmental Change: the Effects of Nutrient Pollution On Sexual Selection in Amphipods

Abstract

Sexual selection is a powerful mechanism of evolutionary change in populations. Sexually selected traits tend to be expensive to produce and thus are expected to be very sensitive to poor environmental conditions. In this study, we looked at patterns of sexual selection in amphipods in genus Hyalella (small crustaceans). The populations studied are found in natural lakes in Pennsylvania. The lakes vary in levels of nutrient pollution due to differences in surrounding agricultural land use. Samples of both mating pairs and single amphipods were collected from each lake. We focused on two sexually selected traits: gnathopods (claw-like appendages) and antennae. We predicted that patterns of sexual selection would differ across lakes because of differences in the availability of nutrients used to build expensive mating traits. Our study will provide insight into how human impact can cause changes in the environment, which affect environmentally sensitive traits. This research can potentially fill gaps in current knowledge about evolutionary implications of human impact on natural populations.