On the architecture of mate choice decisions: preference functions and choosiness are distinct traits

Mate choice is an important cause of sexual selection; it can drive the evolution of extravagant ornaments and displays, and promote speciation through the reproductive isolation generated by rapid divergence of sexual traits. Understanding mate choice requires knowledge of the traits involved in generating mating preferences, and how those traits may interact with each other. It has been proposed that mate choice decisions are the outcome of two components that vary independently: the preference function (the ranking of the attractiveness of prospective mates) and choosiness (the effort invested in mate assessment). Here we test this hypothesis by examine individual variation in female preference functions and choosiness in Green Treefrogs (Hyla cinerea). We show that measures describing preference functions and choosiness are not correlated. We also show that both components are influenced differently by variation in female body size, and that preference function shape (closed and pre...