Electronic Theses and Dissertations



Document Type


Degree Name

Doctor of Philosophy



Committee Chair

Emerson Bowers

Committee Member

David A. Freeman

Committee Member

Michael H. Ferkin

Committee Member

Jennifer R. Mandel

Committee Member

James S. Adelman


In sexually reproducing species, fitness maximization requires obtaining a mate whose optimal reproductive strategy may not be compatible with one’s own optimum. Thus, the classic tradeoff between investment in current offspring vs. surviving to produce future offspring is shaped by various decisions, including one’s choice of mate. Because males and females face fundamentally different selective pressures, the “perfect match” seldom exists, requiring that individuals shift investment strategies according to social and environmental conditions. I examined these tenets of life-history evolution in two species of wild songbird. First, I manipulated incubation effort of female Carolina wrens to assess the role of incubation in the cost of reproduction, or the extent to which investment in a current breeding attempt reduces one’s ability to reproduce in the future. Costs of incubation for females were dependent upon individual condition and the current environment, but, generally, this period provided a time for females to recuperate from the demands of egg production before incurring those associated with rearing nestlings. In another experiment on prothonotary warblers, I manipulated male wing length (and, inherently, flight costs) to examine its role in paternal investment and sexual selection, and I investigated whether females differentially invest in offspring on the basis of male attractiveness and perceived “quality.” Males with longer wings acquired more mates and were more likely to mate polygynously but were also more likely to be divorced between broods compared with males that had shorter wings. Experimentally reducing wing length induced greater levels of paternal investment, thereby increasing females’ reproductive success. Finally, I conducted an observation on the role of coloration in mate preference and parental investment. Older adults and those with brighter plumage were preferred more strongly as mates, although coloration did not relate directly to parental investment. Within-brood investment decisions were mediated by signals from offspring to parents through nestling mouth coloration, where different wavelengths reflected by nestling mouthparts communicated different information to parents. Overall, these studies have shed new light on the influences of social information on parental investment.


Data is provided by the student

Library Comment

Dissertation or thesis originally submitted to ProQuest.


Open Access