MacDougall Amy K, Montgomerie Robert
Department of Biology, Queen's University, Kingston, ON, K7L 3N6, Canada.
Naturwissenschaften. 2003 Oct;90(10):464-7. doi: 10.1007/s00114-003-0459-7. Epub 2003 Aug 27.
We investigated the mating patterns in 22 breeding pairs of wild American goldfinches (Carduelis tristis) with respect to their body size, condition, and carotenoid-based, yellow plumage colour. Using reflectance spectrometry, we objectively quantified plumage colours across the bird-visible wavelengths, revealing a unexpected UV peak in the reflectance spectrum from yellow feathers. We summarized our colour measurements using a principal components analysis to create a single variable, carotenoid PC1, that represents the intensity of this carotenoid-based yellow colour, a measure of phenotypic quality in this species. We found no evidence of assortative mating with respect to measures of body size or condition but there was positive assortative mating by carotenoid PC1, such that the yellow plumage colours of males and females were significantly correlated within pairs. We argue that the yellow carotenoid coloration of goldfinches may be important in mutual mate choice and, thus, that sexual selection in this species may act upon female ornamentation, as well as the more obvious plumage signals of males. Because assortative mating results in an increase in genetic variance, we suggest that this might be a mechanism that maintains variance in ornamental traits in spite of the variance-eroding effects of sexual selection.
我们研究了22对野生美洲金翅雀（黄雀属）繁殖对的交配模式，涉及它们的体型、身体状况以及基于类胡萝卜素的黄色羽毛颜色。我们使用反射光谱法，客观地量化了鸟类可见波长范围内的羽毛颜色，发现在黄色羽毛的反射光谱中出现了一个意外的紫外线峰值。我们通过主成分分析总结了颜色测量结果，创建了一个单一变量——类胡萝卜素主成分1（carotenoid PC1），它代表了这种基于类胡萝卜素的黄色的强度，是该物种表型质量的一个衡量指标。我们没有发现关于体型或身体状况测量指标的选型交配证据，但存在基于类胡萝卜素主成分1的正向选型交配，即配对内雄性和雌性的黄色羽毛颜色显著相关。我们认为，金翅雀的黄色类胡萝卜素着色在相互择偶中可能很重要，因此，该物种的性选择可能作用于雌性装饰，以及雄性更明显的羽毛信号。由于选型交配会导致遗传方差增加，我们认为这可能是一种机制，尽管性选择会产生方差侵蚀效应，但仍能维持观赏性状的方差。
