An Integrative Study of the Evolution of Complex Sexual Signals Alexis S. Chaine
A central goal in current studies of evolutionary biology is to understand the evolution and function of animal signals. Indeed, biologists have for a long time turned their attention to understanding the bright coloration of birds of paradise or the melodious calls of songbirds. Costs associated with the production of these signals and the efficiency of information transfer to an intended receiver should cause signals to be simple; therefore, it is surprising that many species have multiple, or complex, signals. The evolution of multiple signals is still not fully understood because most previous studies on this topic have focused on only a subset of hypotheses for their evolution. Using a specific statistical framework (path analytic model) based on both observational and experimental data, this project will distinguish between all the alternative hypotheses for the evolution of multiple sexual signals in free ranging lark buntings, Calamospiza melanocorys. Lark buntings are especially suited for this question because they have complex social behaviors, a number of distinct visual signals, and are easily observed, all of which are key to a successful study of multiple signals. Furthermore, males behaviorally modify signals by rearranging their feathers to achieve chameleon-like color change, which suggests the intriguing possibility that males might flexibly and instantaneously uncouple otherwise linked sexual signals. The proposed research also includes opportunities for undergraduate research assistants to participate in all aspects of the project from experimental design and data collection through data analysis. Past assistants have mostly been from underrepresented groups (female, culturally diverse) and, as a result of direct mentoring, many are now pursuing higher degrees.
