Culture as an evolutionary force: Does song learning accelerate speciation in a bat ring species?

ongoing

Culture is highly relevant for human evolution but whether animal culture can be an evolutionary force that promotes speciation is an open and highly contested issue. While culturally induced song divergence can be correlated with increased speciation rates in songbirds, it is hard to resolve whether cultural differences are promoting speciation or vice versa. Studying ring species is a perfect solution for this problem since they illustrate divergence in space instead of time, thus allowing us to determine whether cultural differences are causes or consequences of speciation. A ring species originates from a population that expands around an uninhabitable barrier and gradually diverges until the terminal forms are reproductively isolated upon secondary contact. We will study whether culturally induced song divergence accelerates speciation in the bat Saccopteryx bilineata, the first known mammalian ring species. Cultural differences between S. bilineata populations are manifested in distinct and temporally stable song dialects which juvenile males learn from adults. First, we will study song divergence around the ring and the relative contribution of song dialects to reproductive isolation of the co-occurring terminal forms of the ring. Second, we will study potential genetic predispositions for learning specific song dialects and investigate neurogenetic mechanisms involved in mammalian song learning. Third, we will reconstruct the history, evolutionary patterns and processes of speciation in a ring using a genomic approach in S. bilineata and its sympatric sister species. This comparative approach will allow us to unravel factors involved in the rapid divergence of S. bilineata on a small spatial scale. In synthesis, we will be able to determine whether sexually selected, culturally transmitted traits can accelerate speciation and elucidate the role of culture as an evolutionary force.