In all sexually reproducing species, successful reproduction depends on multiple factors, such as endocrine milieu, the physical environment, and social interactions. It is well understood that individuals of both sexes employ strategies to enhance their own reproductive success. Increasing evidence suggests that often various traits reveal information about a male?s quality as a mate, either genetically or with respect to caring for offspring. An as yet understudied question concerns what factors affect female preferences for specific male traits. That is, does a female?s condition (e.g., health, nutritional status) or experience affect her preference for one type of trait over another? Furthermore, in many systems, including monogamous species, individuals augment their reproductive success by mating with conspecifics other than their social mates. Another largely understudied question is whether females prefer different traits for social mates and for extra-pair partners. Songbirds provide an excellent system in which to investigate these questions because females often exhibit preferences for both morphological and behavioral traits and males often provide a relatively high degree of parental care. Using the songbird dark-eyed juncos (Junco hyemalis) as a model, the hypotheses that will be tested in this proposal are that male traits indicate future paternal care and that the condition and experience of a female affects her preferences for morphological versus behavioral male traits. Also, the male phenotypes that females prefer for their social mates will be compared to those of their extra-pair partners. These studies will further our understanding of the basic mechanisms underlying the behavioral regulation of sexual behavior and reproduction, including the influence of the endocrine system, social factors, and the physical environment.
