QUANTIFYING WITHIN-POPULATION VARIATION IN MATE CHOICE; DISCRIMINATION, MATE SAMPLING RULES, MULTIVARIATE PREFERENCE & CONSEQUENCES FOR SEXUAL SELECTION

Abstract

Mate choice is foundational to the evolution of elaborate, conspicuous, and often energetically costly displays. Modelling sexual selection in any mating system is a complicated task on two fronts; we typically confront variation in both i) the strategies of signalers and ii) how choosers assess and sample among them. As selection on mate choice behaviors emerges from the relationship between these sources of variation, it is essential that they be measured in detail. Population-level measures of chooser behaviors (i.e. pooling the single responses of a sample of choosers) have long dominated the literature on mate choice, leaving open the possibility that the process of choosing a mate entails strong conflicting behaviors among- individuals that are masked (cancelled out) at a broader scale. I apply a combination of comparative population and individual-focused methods to numerous quandaries of mate choice in the gray treefrog (Hyla versicolor); a) the ability of choosers to discriminate fine-scale differences in potential mate’s displays, b) how relative signaler location determines a chooser’s capacity to navigate toward a preferred signal, and c) how signaler success is predicted by variation in individual choosers’ multidimensional mate preferences. In contrast with existing literature on this species, these approaches lead to higher-resolution and starkly differing models of trait evolution and reproductive success in this system. More broadly, this dissertation also emphasizes that there is utility in a methodology focused on the individual animals, as this is the level at which real world mating decisions occur.