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Antagonistic interactions between sexual and natural selection influence the evolution of ornamental signals. I investigated possible functions of colourful traits in bluegills (Lepomis macrochirus). First, I conducted a descriptive study among eight lakes in Ontario to determine how colour traits varied with age, sex, season, and condition. My findings identified breast, cheek and opercular flap coloration as possible sexual ornaments. Subsequently, I investigated the role of sexual selection on coloration through observations of spawning bluegills. Results suggest that breast and cheek coloration influence female spawning behaviour and male reproductive success. Finally, I investigated effects of ecological factors on coloration. Vegetation type and density influenced coloration for all bluegills, and predator species richness influenced coloration of immature fish. These studies provide the first investigations of the function of coloration in bluegills and contribute to our understanding of the interacting influences of sexual and natural selection on the evolution of ornamental traits.
Cogliati, Karen Michelle, "Multiple social and ecological factors influence coloration in bluegills (Lepomis macrochirus)" (2009). Electronic Theses and Dissertations. 8250.