Date of Award
Doucet, Stephanie (Biological Sciences)
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Phenotypic variation arises through natural selection, sexual selection, and genetic drift. Large-scale variation is often demonstrated via clinal gradients, and small-scale variation is commonly exhibited by quality-indicating traits. My goal was to investigate geographic and individual phenotypic variation in golden-crowned kinglets, with particular focus on carotenoid-based ornaments. Through a museum study, I found that kinglet body size and coloration weakly followed well-established ecogeographic rules. However, sexual dichromatism was reduced in colder climates, providing support for a poorly recognized environmentally-induced cline. In a separate study, I captured migrating kinglets to determine how carotenoid content mediates inter- and intrasexual crown colour variation. I found that crown coloration was associated with migration timing, and females displayed additional condition-dependence of this trait. Overall, small-scale variation in crown coloration is dependent on pigment differences and individual quality, while large-scale variation is likely governed by differences in selection pressures.
Chui, Celia, "Geographic and individual variation in carotenoid coloration in golden-crowned kinglets (Regulus satrapa)" (2009). Electronic Theses and Dissertations. 280.