Shutler Dave, Weatherhead Patrick J
Department of Biology, Carleton University, Ottawa, Ontario, K1S 5B6, CANADA.
Evolution. 1990 Dec;44(8):1967-1977. doi: 10.1111/j.1558-5646.1990.tb04303.x.
Extant hypotheses predict that, in the face of sexual selection, avian song and plumage may evolve in a concerted fashion, in an antagonistic fashion, or in ways unrelated to each other. To test these ideas regarding which traits sexual selection targets, and the consequences for other traits, we analyzed patterns of song complexity and plumage dimorphism in 56 species of wood warblers (Parulinae). Overall, males of more dimorphic species sang shorter songs more often, but did not have more complex songs. However, when monomorphic species were excluded from the analysis, we found that the total time spent singing and repertoire size increased with plumage dimorphism. Monomorphic species are predominantly ground-nesters and the greater risk of nest predation for these species may constrain males from becoming more visually conspicuous. Thus, sexual selection may have been restricted to targeting song in these species. Even though song may have been the only target of sexual selection in ground-nesting species, overall, song in those species is not more complex than in species that nest above the ground. We propose that traits targeted by sexual selection evolve in concert, except when constrained by some ecological factor.
现存的假说预测，在性选择的情况下，鸟类的歌声和羽毛可能会以协同的方式、对抗的方式或彼此无关的方式进化。为了检验关于性选择针对哪些特征以及对其他特征有何影响的这些观点，我们分析了56种林莺（森莺科）的歌声复杂性和羽毛二态性模式。总体而言，羽毛二态性更强的物种的雄性更频繁地唱出较短的歌曲，但歌曲并不更复杂。然而，当分析中排除单态性物种时，我们发现唱歌的总时长和曲目数量随着羽毛二态性增加。单态性物种主要是地面筑巢者，这些物种面临的巢捕食风险更大，可能会限制雄性变得在视觉上更显眼。因此，性选择可能在这些物种中仅限于针对歌声。尽管歌声可能是地面筑巢物种中性选择的唯一目标，但总体而言，这些物种的歌声并不比在地面以上筑巢的物种更复杂。我们提出，性选择所针对的特征会协同进化，除非受到某些生态因素的限制。
