Nicolaï M P J, Rogalla S, Yousefi M, Bowie R C K, D'Alba L, Shawkey M D
UGent Gent Belgium.
Biofisika Institute Leioa Spain.
Ecol Evol. 2024 Sep 11;14(9):e11427. doi: 10.1002/ece3.11427. eCollection 2024 Sep.
How extravagant ornamental traits evolve is a key question in evolutionary biology. Bird plumages are among the most elaborate ornaments, displaying almost all colours of the rainbow. Why and how birds evolved to be so colourful remains an open question with multiple and sometimes competing hypotheses. Different colours in different patches (i.e. body parts) might have different functions and thus result from different forms of selection (e.g. natural vs. sexual selection). Here we test the influence of three factors on colour diversity in sunbirds: (1) geographical distance, (2) differences in light environment and (3) phylogenetic distances. We show that both natural and sexual selection affect the evolution of sunbird colouration, but that their extent and direction differs between sexes, and varies with the extent of species overlap and across different patches on the body. Even though overlap in light environment partially explains colour differences among species, no colour metric (brightness, hue or chroma) covaries with light environment. Our results suggest that multiple forms of selection influence the colouration of different colour patches in different ways across an organism's body, highlighting the need to investigate colouration as a network of individual but inter-connected colour patches. These results are likely to be generalizable across the multitude of colourful animals.
奢侈的装饰性特征是如何进化的，这是进化生物学中的一个关键问题。鸟类羽毛是最为精致的装饰之一，呈现出几乎彩虹的所有颜色。鸟类为何以及如何进化得如此色彩斑斓，仍然是一个悬而未决的问题，存在多种有时相互竞争的假说。不同部位（即身体部分）的不同颜色可能具有不同功能，因此是由不同形式的选择（如自然选择与性选择）导致的。在这里，我们测试了三个因素对太阳鸟颜色多样性的影响：（1）地理距离，（2）光照环境差异，以及（3）系统发育距离。我们表明，自然选择和性选择都影响太阳鸟的颜色进化，但它们的程度和方向在性别之间存在差异，并且随着物种重叠程度以及身体不同部位而变化。尽管光照环境的重叠部分解释了物种间的颜色差异，但没有任何颜色指标（亮度、色调或色度）与光照环境共变。我们的结果表明，多种形式的选择以不同方式影响生物体身体不同颜色部位的着色，这凸显了将着色作为一个由个体但相互关联的颜色部位组成的网络来进行研究的必要性。这些结果可能适用于众多色彩斑斓的动物。
