Geographic variation in body size and plumage colour according to diet composition in a nocturnal raptor

Predator–prey interactions are amongst the strongest selective forces that promote the evolution of local phenotypes in both predators and prey. However, intraspecific spatial
covariation in phenotypic traits between predators and prey has been rarely investigated, especially at a large geographic scale. Here, we studied the covariation between prey composition and some phenotypic traits, such as wing length, bill length and plumage colour, of a widely-distributed nocturnal predator, the western barn owl Tyto alba. By using 3100 specimens collected across its entire range of distribution, spanning from Europe to Middle East and Africa, we showed that wing length positively covaries with prey size, but not with taxonomic composition. This finding suggests that larger prey might have selected for larger body size and/or that larger individuals might be more selective in hunting large prey. In addition, we also found that paler-plumaged populations generally hunt larger prey. Paler barn o...

捕食者-猎物互作（predator–prey interactions）是推动捕食者与猎物双方本地表型演化的最强选择压力之一。然而，捕食者与猎物间表型性状的种内空间共变关系却极少被研究，在大地理尺度下更是如此。本研究以广泛分布的夜行性捕食者西仓鸮（Tyto alba）为研究对象，探究其猎物组成与翅长、喙长、羽色等表型性状间的共变关系。本研究利用覆盖其全分布范围（从欧洲至中东与非洲）的3100份标本开展分析，结果表明翅长与猎物体型呈正相关，而非与猎物分类学组成相关。该结果提示，更大的猎物可能推动了捕食者体型的演化，或是体型更大的个体在捕猎时更倾向于选择体型较大的猎物。此外，本研究还发现羽色更浅的种群通常捕猎更大的猎物。羽色更浅的仓鸮……