THE COMPLEXITY OF FEMALE TREEFROG MATE CHOICE: CHOOSINESS AND PREFERENCES ARE INDEPENDENT BEHAVIORS AND EACH ARE PRONE TO SEPARATE SOURCES OF VARIATION

Abstract

Mate choice is an important cause of natural and sexual selection, driving the evolution of ornaments and promoting diversification and speciation. Mate choice decisions arise from the interaction of several components, and knowledge of whether they interact, and how, is crucial for understanding their contributions to selection. There are multiple components of mate choice theoretically proposed, and here I focus specifically on preference functions (attractiveness ranking of prospective mates) and/or choosiness (willingness to invest effort in obtaining the preferred mate). Objective 1 (addressed in Chapter I) of this dissertation focuses specifically on the relationship between preferences and choosiness, testing the hypothesis that they are independent components of mate choice decisions. Yet, mating decisions can be inconsistent, resulting in unexpected changes to mating behaviors that can have wide-ranging implications for the strength and direction of male trait evolution. For this reason, Objective 2 focuses on numerous factors having potential to derail expected mate choice behaviors, testing the hypothesis that variation in mating decisions is explained by internal and external variables. Factors explored include hormones (testosterone and corticosterone) and reproductive investment in Chapter I, predation threat in Chapter II, personality in Chapter III, and body morphology across all three chapters. I examine such topics using phonotaxis trials in female Eastern Gray Treefrogs (Hyla versicolor) and find supportive evidence within each Chapter.