Geographic variation in morphology of Dark-eyed Juncos and implications for population divergence

Geographic variation in morphology that develops among closely related populations can help drive genetic divergence, and eventually speciation, when those morphological traits are the basis for social interactions that influence reproduction. The North American Dark-eyed junco (Junco hyemalis) complex is an interesting case in speciation. The numerous subspecies have distinct breeding ranges and unique plumage coloration, but based on the presence of hybrid populations and recent genetic data, can be considered to belong to a single species. Research within various populations of juncos has shown first, that wing length and the amount of white on the tail feathers (“tail white”) influence an individual’s dominance status and mating success, and second, that these traits can undergo rapid evolution when social and environmental conditions change. Here, I used museum specimens to examine tail white and body size, as measured by wing and tail length, of males and females within and among ...

亲缘关系密切的种群间形成的形态学地理变异，若这些形态特征成为影响繁殖的社会互动基础，则可推动遗传分化乃至最终的物种形成。北美暗眼灯草鹀（Junco hyemalis）复合体是物种形成研究中的一个有趣案例。其众多亚种具有独特的繁殖范围和羽色，但基于杂交种群的存在及近期遗传数据，它们仍被视为单一物种。对灯草鹀不同种群的研究表明，其一，翅长及尾羽上的白色区域占比（“尾羽白度”）会影响个体的优势地位与交配成功率；其二，当社会及环境条件发生变化时，这些性状可发生快速进化。本研究利用博物馆标本，对不同种群内及种群间的雌雄个体，就其尾羽白度及以翅长、尾长衡量的体型特征展开分析……