Determining the underlying mechanisms that drive biological diversification is a central pursuit in Biology. Sexual selection -- the evolution of exaggerated male ornamental traits based on differential mating success of males -- is important for shaping a male's appearance within populations, but this evolutionary mechanism may also have an important role in population-level diversification. Speciation by sexual selection occurs when changes in mate preference and the expression of male ornaments within a population leads to isolation among populations because individuals from separate populations no longer recognize one another as potential mates. This project will take advantage of an extremely tractable and widespread species complex, the barn swallows (Hirundo rustica), which are represented by six sub-species world-wide, each possessing varying combinations of morphological and behavioral traits that are known to be under sexual selection. Experiments to test hypotheses about the role of sexual selection underlying morphological, genetic, and behavioral differentiation among populations will be based in the United States, the United Kingdom and Israel where these traits are most divergent. Along with these experiments, larger-scale analyses of historical colonization patterns and genetic differentiation using the latest genomics tools will be conducted. This complementary set of analyses will provide a novel, important and comprehensive contribution to our understanding of fundamental evolutionary processes.
Several collaborative projects will directly engage students in this research. For example, the PI will collaborate with the Alliance for Technology, Learning, and Society (ATLAS) at the University of Colorado (CU) whose resources will be leveraged to develop a media-based course focused on evolutionary and behavioral biology. The PI, a young investigator in her first tenure track position, will take also take advantage of unique funding opportunities for under-represented graduate students at CU, including the NSF- and NIH-sponsored Colorado Diversity Initiative.
