Understanding how new species arise ("speciation") remains one of the most important and unresolved issues in biology. Central to understanding this process is determining how barriers that prevent species from mating evolve. Recent studies are beginning to show that changes in the design of mating signal can lead to the rapid evolution of reproductive barriers; however, little is known about the factors that drive these changes in the first place. My research program attempts to fill this gap by 1) determining which environmental factors can drive changes in signal design, and 2) understanding how these changes act as reproductive barriers. Closely related subspecies of the bearded manakin (Manacus manacus ssp.) show dramatic differences in the color of male plumage -- a signal used during intense courtship displays to females. Using a combination of behavioral observations and experimental manipulations in the field, my work aims to determine if differences in male coloration are linked to aspects of the visual environment, and if these differences, in turn, act as reproductive barriers among the different manakin color forms.
