Ellen D. Ketterson

Employing techniques from neuroscience, endocrinology, and microevolutionary analysis of selection, studies role of hormones in phenotypic variation and role of 'hormonal pleiotropy' in maintaining tension between independence and interdependence in evolution of correlated traits. Discovered differential migration in Juncos--females migrate farther than males--related to differences in body size, social competition, and sexual selection. Took an experimental approach to the evolution of life histories, exploring 'phenotypic engineering.' Manipulating testosterone levels in free-living animals and comparing their behavior, physiology, and fitness to controls, has found that males with elevated testosterone exhibited greater mating success but also greater mortality than controls, providing a mechanistic understanding of the fitness consequences of altering how animals allocate time and energy to competing demands. Current research addresses variation in testosterone-activated gene expression in target tissues relative to phenotypic plasticity and rapid evolution, with ongoing goal of understanding how natural selection acts on mechanisms to induce adaptation.