Price J Jordan, Friedman Nicholas R, Omland Kevin E
Department of Biology, St. Mary's College of Maryland, St. Mary's City, Maryland 20686, USA.
Evolution. 2007 Apr;61(4):850-63. doi: 10.1111/j.1558-5646.2007.00082.x.
Both song and color patterns in birds are thought to evolve rapidly and exhibit high levels of homoplasy, yet few previous studies have compared the evolution of these traits systematically using the same taxa. Here we reconstruct the evolution of song in the New World orioles (Icterus) and compare patterns of vocal evolution to previously reconstructed patterns of change in plumage evolution in this clade. Individual vocal characters exhibit high levels of homoplasy, reflected in a low overall consistency index (CI = 0.27) and retention index (RI = 0.35). Levels of lability in song are comparable to those found for oriole plumage patterns using the same taxa (CI = 0.31, RI = 0.63), but are strikingly dissimilar to the conservative patterns of change seen in the songs of oropendolas (Psarocolius, Ocyalus; CI = 0.82, RI = 0.87), a group closely related to the orioles. Oriole song is also similar to oriole plumage in exhibiting repeated convergence in overall patterns, with some distantly related taxa sounding remarkably similar. Thus, both song and plumage in orioles show repeated convergence in individual elements and in overall patterns across the clade, suggesting that both of these character classes are highly labile between taxa yet highly conserved within the genus. Our results provide new insights into the tempo and mode of evolution in sexually selected traits within and across clades.
鸟类的歌声和羽色模式都被认为进化迅速且表现出高度的同塑性，但之前很少有研究使用相同的分类群系统地比较这些性状的进化。在这里，我们重建了新大陆拟黄鹂属（Icterus）鸟类歌声的进化，并将鸣声进化模式与该类群中先前重建的羽色进化变化模式进行比较。个体鸣声特征表现出高度的同塑性，这反映在较低的总体一致性指数（CI = 0.27）和保留指数（RI = 0.35）上。鸣声的不稳定程度与使用相同分类群的拟黄鹂羽色模式相当（CI = 0.31，RI = 0.63），但与拟黄鹂科（Psarocolius, Ocyalus）鸟类鸣声中所见的保守变化模式显著不同（CI = 0.82，RI = 0.87），拟黄鹂科是与拟黄鹂属密切相关的一个类群。拟黄鹂的歌声在总体模式上也与羽色相似，表现出反复的趋同现象，一些亲缘关系较远的分类群听起来非常相似。因此，拟黄鹂的歌声和羽色在整个类群的个体元素和总体模式上都表现出反复的趋同，这表明这两类性状在不同分类群之间高度不稳定，但在属内高度保守。我们的研究结果为类群内部和类群之间性选择性状的进化速度和模式提供了新的见解。
