L'Herpiniere Kiara L, Tims Amy R, Englert Duursma Daisy, Griffith Simon C
Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.
Evolution. 2021 Dec;75(12):3132-3141. doi: 10.1111/evo.14375. Epub 2021 Oct 27.
To understand why avian eggs are so variable in colour and patterning, we investigated the characteristics of extant bird species that provide insight into the evolutionary transitions that occurred during the early radiation of the songbirds. We quantified egg colour and patterning from museum collections of 269 species of Australian passerine and collated it to nest type data (cup- or dome-nesting species). Using phylogenetically reconstructed trait data, we showed that the ancestral passerine egg was likely to be white, and to have been laid inside a domed nest. Egg colouration and nest type were both phylogenetically clustered, and there was evidence of correlated evolution between the two traits. As nests transitioned from domes to cups, there was an increase in the range of egg colours observed, presumably as a response to additional stressors. Finally, we found that egg colour changes occurred more than twice as frequently in cup-nesting species than in dome-nesting species. This suggests that colour may be an adaptive trait that compensates for the loss of the protective nest roof in cup-nesting species.
为了理解鸟类蛋的颜色和斑纹为何如此多样，我们研究了现存鸟类物种的特征，这些特征能让我们深入了解鸣禽早期辐射进化过程中发生的进化转变。我们从269种澳大利亚雀形目鸟类的博物馆藏品中量化了蛋的颜色和斑纹，并将其与巢的类型数据（杯状巢或圆顶巢物种）进行整理。利用系统发育重建的性状数据，我们发现雀形目鸟类的原始蛋可能是白色的，并且产在圆顶巢内。蛋的颜色和巢的类型在系统发育上都是聚类的，并且有证据表明这两个性状之间存在协同进化。随着巢从圆顶巢转变为杯状巢，观察到的蛋的颜色范围有所增加，这可能是对额外压力源的一种反应。最后，我们发现杯状巢物种中蛋颜色变化的频率是圆顶巢物种的两倍多。这表明颜色可能是一种适应性特征，可弥补杯状巢物种中保护性巢顶的缺失。
