Eeva Tapio, Sillanpää Saila, Salminen Juha-Pekka, Nikkinen Lauri, Tuominen Anu, Toivonen Eija, Pihlaja Kalevi, Lehikoinen Esa
Section of Ecology, University of Turku, Turku 20014, Finland.
Ecohealth. 2008 Sep;5(3):328-37. doi: 10.1007/s10393-008-0184-y. Epub 2008 Aug 13.
Birds need to acquire carotenoids for their feather pigmentation from their diet, which means that their plumage color may change as a consequence of human impact on their environment. For example, the carotenoid-based plumage coloration of Great tit, Parus major, nestlings is associated with the degree of environmental pollution. Breast feathers of birds in territories exposed to heavy metals are less yellow than those in unpolluted environments. Here we tested two hypotheses that could explain the observed pattern: (I) deficiency of carotenoids in diet, and (II) pollution-related changes in transfer of carotenoids to feathers. We manipulated dietary carotenoid levels of nestlings and measured the responses in plumage color and tissue concentrations. Our carotenoid supplementation produced the same response in tissue carotenoid concentrations and plumage color in polluted and unpolluted environments. Variation in heavy metal levels did not explain the variation in tissue (yolk, plasma, and feathers) carotenoid concentrations and was not related to plumage coloration. Instead, the variation in plumage yellowness was associated with the availability of carotenoid-rich caterpillars in territories. Our results support the hypothesis that the primary reason for pollution-related variation in plumage color is carotenoid deficiency in the diet.
鸟类需要从饮食中获取类胡萝卜素用于羽毛色素沉着，这意味着它们的羽毛颜色可能会因人类对其环境的影响而改变。例如，大山雀（Parus major）雏鸟基于类胡萝卜素的羽毛颜色与环境污染程度相关。暴露于重金属环境中的鸟类领地内的雏鸟胸部羽毛比未受污染环境中的雏鸟胸部羽毛颜色更浅。在此，我们检验了两个可以解释观察到的模式的假设：（I）饮食中类胡萝卜素不足，以及（II）与污染相关的类胡萝卜素向羽毛转移的变化。我们操纵了雏鸟饮食中的类胡萝卜素水平，并测量了羽毛颜色和组织浓度的反应。我们补充类胡萝卜素后，在污染和未污染环境中，组织类胡萝卜素浓度和羽毛颜色产生了相同的反应。重金属水平的变化并不能解释组织（卵黄、血浆和羽毛）类胡萝卜素浓度的变化，且与羽毛颜色无关。相反，羽毛黄色程度的变化与领地内富含类胡萝卜素的毛虫的可获得性有关。我们的结果支持了以下假设：与污染相关的羽毛颜色变化的主要原因是饮食中类胡萝卜素不足。
