Ecological speciation in reed buntings
Our project aims to determine whether divergent selection for bill size is occurring and causing the evolution of reproductive barriers in reed buntings Emberiza schoeniclus. We are focusing mostly, but not exclusively, on the two Iberian near-endemic subspecies, which are severely threatened, as well as on the nominate subspecies. In order to achieve our goals, ecological and morphological data will be used in combination with genetic and stable isotope analysis. We expect to clarify some fundamental aspects of the evolutionary process, understand the unusual phenotypic variation of our study species and contribute to its conservation.
The reed bunting is a common, polytypic passerine that occurs in wetlands across the Palearctic region. Its numerous subspecies differ substantially in bill size and shape, as well as plumage colour and migratory behaviour. Because the diversification of beak morphology and body size is known to cause bioacoustic evolution in several species, it might also affect mating patterns, acting as a “magic trait” of speciation.
It is known that the genetic divergence between reed bunting subspecies is slight but significant, indicating that phenotypic differences between subspecies evolved rapidly by natural selection. Hence, this system is very promising for the study of local adaptation and the evolution of reproductive barriers. It is particularly interesting to study organisms at this stage of evolution, where the actual ecological and genetic mechanisms potentially leading to speciation can be observed.