a. E. barrenense, b. E. zonale, breeding males. Photos: Tory Williams

Background: The elaborate breeding colors displayed by males in many animals are thought to pose a significant barrier to interbreeding among species, with females responding preferentially to the colors of conspecific males. This assumption is rarely tested explicitly.

Question: Are species boundaries maintained by female preference for conspecific male nuptial color?

Methods: 1). Females are offered a choice between painted models designed to imitate conspecific and heterospecific color. 2). Premating and postmating reproductive barriers are quantified to determine whether behavioral isolation forms the strongest barrier to interbreeding.