Intellectual Merit: It is now clear that females of many animal species often reproduce with multiple males, including females of socially monogamous species who typically form a pair bond with only a single male. Despite the widespread occurrence of multiple mating by females, there is little scientific consensus for why it occurs. Most work has focused on the hypothesis that females obtain additive genetic benefits by mating with high-quality males, but these studies have obtained mixed results. More recently, it has been proposed that females benefit by copulating with compatible males whose genes are complementary to their own; for example, females may mate with genetically dissimilar males to produce offspring with high genetic diversity. This study will be among the first to simultaneously test the predictions of four separate hypotheses, including hypotheses of genetic compatibility, to explain multiple mating by females in a socially monogamous species of bird. The study will utilize multiple years of data for genetic analyses of parentage and genetic compatibility, field assays of offspring survival in relation to parentage, and an experiment designed to determine whether genetic similarity of a female to her social mate affects her mating behavior. Together, this work will provide a comprehensive test of the hypothesized benefits of multiple mating to females in this system.
Broader Impacts: This project will contribute directly to the dissertation research and training of a graduate student. This study will also provide training and experience to 5-7 volunteer field and laboratory assistants early in their scientific careers, hopefully permitting them to pursue their own research and further contribute to the body of scientific knowledge. Past volunteer assistants have included 6 undergraduates, 14 women, and 4 minorities. Additionally, this study will develop a statistical tool for estimating individual genetic diversity from a commonly used type of genetic marker. This tool will be available for use to others studying the effects of genetic diversity on survival and behavioral patterns and may have other useful applications in conservation.
