Biology Department, Evolution and Optics of Nanostructures Group, Ghent University, Ledeganckstraat 35, 9000, Ghent, Belgium.
Department of Recent Vertebrates, Royal Belgian Institute of Natural Sciences, Leuven, Belgium.
Nat Commun. 2020 May 15;11(1):2414. doi: 10.1038/s41467-020-15894-6.
Plumage is among the most well-studied components of integumentary colouration. However, plumage conceals most skin in birds, and as a result the presence, evolution and function of skin colour remains unexplored. Here we show, using a database of 2259 species encompassing >99% of bird genera, that melanin-rich, black skin is found in a small but sizeable percentage (~5%) of birds, and that it evolved over 100 times. The spatial distribution of black skin follows Gloger's rule, which states that pigmentation of endothermic animals increases towards the equator. Furthermore, most black-skinned birds inhabit high irradiation regions, and tend to be bald and/or have white feathers. Thus, taken together, our results suggest that melanin-rich, black skin helps to protect birds against ultraviolet irradiation. More generally, our results illustrate that feathered skin colour varies taxonomically, ontogenetically and temporally, providing an additional dimension for avian colour research.
羽毛是皮肤颜色中研究最充分的部分之一。然而，羽毛覆盖了鸟类的大部分皮肤，因此皮肤颜色的存在、进化和功能仍未被探索。在这里，我们使用一个包含>99%鸟类属的 2259 个物种的数据库表明，富含黑色素的黑色皮肤存在于一小部分（~5%）鸟类中，并且已经进化了超过 100 次。黑色皮肤的空间分布遵循格洛格规则，该规则指出，温血动物的色素沉着会向赤道方向增加。此外，大多数黑色皮肤的鸟类栖息在高辐射区域，往往是秃头和/或有白色羽毛。因此，总的来说，我们的结果表明，富含黑色素的黑色皮肤有助于鸟类抵御紫外线辐射。更一般地说，我们的结果表明，羽毛状皮肤颜色在分类学、个体发生和时间上都有所不同，为鸟类颜色研究提供了一个额外的维度。
