Polygamy Slows Down Population Divergence in Shorebirds
Sexual selection may promote speciation since competition for mates can favor specific individuals more desirable for reproduction, leading to reproductive isolation. Alternatively, sexual selection may also hinder speciation since polygamous individuals access additional mates, increasing breeding dispersal and promoting genetic diversity within a species. High breeding dispersal should increase gene flow, reducing species differentiation, which can be a proxy for population divergence. Examining genetic data from different populations of 136 shorebird species, researchers found that polygamous species display significantly less genetic structure, and showed fewer subspecies, than monogamous species. By contrast, migratory behavior neither predicted genetic differentiation nor subspecies richness. Results suggest that dispersal associated with polygamy may facilitate gene flow and limit population divergence. Therefore, intense sexual selection, as occurs in polygamous species, may inhibit rather than promote speciation in shorebirds.
D’Urban Jackson, J., dos Remedios, N., Maher, K., Zefania, S., Haig, S.M., Oyler-McCance, S.J., Blomqvist, D., Burke, T., Bruford, M.W., Székely, T., Küpper, C., 2017, Polygamy slows down population divergence in shorebirds: Evolution, p. online, http://dx.doi.org/10.1111/evo.13212. [Details]