Sección Ornitología, División Zoología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n (B1900FWA), La Plata, Argentina.
IEGEBA, CONICET-UBA, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II Ciudad Universitaria (C1428EGA), Buenos Aires, Argentina.
Sci Rep. 2019 Jul 29;9(1):10958. doi: 10.1038/s41598-019-47498-6.
Avian plumage coloration deriving from carotenoid-based pigments is among the most honest signals of individual quality. It has been argued that females may differentially allocate resources based on mate attractiveness or quality, paying the costs of investing more in a current breeding attempt. We tested predictions of the differential allocation hypothesis on the natural variation of carotenoid-based plumage using the brightly red-colored head plumage of the Red-crested Cardinal (Paroaria coronata). It is to our knowledge the first time this hypothesis is tested on the natural variation of this pigment on a wild bird. We found that the brightness of the males' red plumage patch is positively associated with their reproductive success and the nest defence they provide. We also found that brighter males invest less in their offspring (by delivering less food to their nestlings and poorly cleaning the nest) than duller males and, by contrast, females mated with brighter males invest more in parental care. Our results are consistent with the differential allocation hypothesis: differential allocation allowed breeding pairs with brighter males to produce more offspring, suggesting that it can be considered adaptive and should be included in studies of eco-evolutionary dynamics.
鸟类羽毛的颜色源于类胡萝卜素色素，是个体质量最诚实的信号之一。有人认为，雌性可能会根据配偶的吸引力或质量来分配资源，为当前的繁殖尝试付出更多的投资成本。我们使用红顶唐纳雀（Paroaria coronata）鲜艳的红色头部羽毛，对基于类胡萝卜素的羽毛的自然变异，检验了差异分配假说的预测。据我们所知，这是首次在野生鸟类中对这种色素的自然变异检验该假说。我们发现，雄性红色羽毛斑块的亮度与它们的繁殖成功率和提供的巢防御呈正相关。我们还发现，比暗淡的雄性更明亮的雄性对后代的投资较少（向雏鸟提供的食物较少，巢的清洁度较差），而与之相反的是，与更明亮的雄性交配的雌性会在亲代养育上投入更多。我们的研究结果与差异分配假说一致：差异分配使具有更明亮雄性的繁殖对能够产生更多的后代，这表明这种差异分配是适应性的，应该包含在生态进化动态的研究中。
