Galván Ismael, Rodríguez-Martínez Sol
Physiol Biochem Zool. 2019 May/Jun;92(3):266-273. doi: 10.1086/702720.
Even though plumage diversity is one of the most diverse phenotypic traits in nature, the reasons why some species exhibit more distinctive colors than others are poorly known. In the case of melanins, the most abundant pigments in birds, different chemical forms lead to different plumage colors and different amounts of those forms lead to different color intensities. However, the synthesis of some melanin forms is more physiologically limited than others. We hypothesize that an evolutionary solution to this scenario may consist in a negative association between melanin-based color heterogeneity and intensity. Here we confirm this prediction after analyzing the diversity and expression level of melanin-based plumage colors in 96 species of birds breeding in the Iberian Peninsula. After controlling for phylogenetic effects, the intensity of the plumage colors of birds decreased with the number of different colors, suggesting that the physiological mechanism of melanin synthesis does not favor the production of both a heterogeneity of melanin forms and large amounts of these forms. These findings contribute to a better understanding of bird phenotypic diversity.
尽管羽毛多样性是自然界中最多样化的表型特征之一，但某些物种比其他物种表现出更独特颜色的原因却鲜为人知。就鸟类中最丰富的色素黑色素而言，不同的化学形式会导致不同的羽毛颜色，而这些形式的不同含量会导致不同的颜色强度。然而，某些黑色素形式的合成在生理上比其他形式受到更多限制。我们假设，针对这种情况的一种进化解决方案可能是基于黑色素的颜色异质性与强度之间呈负相关。在此，我们在分析了伊比利亚半岛繁殖的96种鸟类中基于黑色素的羽毛颜色的多样性和表达水平后，证实了这一预测。在控制了系统发育效应后，鸟类羽毛颜色的强度随着不同颜色数量的增加而降低，这表明黑色素合成的生理机制不利于同时产生黑色素形式的异质性和大量的这些形式。这些发现有助于更好地理解鸟类的表型多样性。
