Males of many species often have colorations and morphologies that are different from females. Darwin proposed that these differences were due to sexual selection; that is, the characteristics were associated with increased mating success. There are two sources of sexual selection; one arises from competition between males for mates, and the other from female choice of mates, This proposal uses a series of experiments based on transplants of males among local populations to differentiate those male characteristics that are shaped by competition from those shaped by female choice. This question has never been approached in systematic fashion before, and should greatly increase our understanding of the dynamics of sexual selection. An equally important factor affecting sexual selection is the cost to a female for exercising a choice of mates. Dr. Warner will investigate these costs in terms of the resultant mortality and fertilization rates that result from different choices.
