Increased mutation rate in sexual populations Mutation rate increases in sexual populations during range expansion

The evolution of higher dispersal during range expansion increases invasion speed, provided that a species can adapt sufficiently fast to novel local conditions. Iterated founder effects during range expansion, however, cause low levels of local genetic diversity at these range margins. Mutation rates can evolve, too, and using an individual-based model we show that natural selection may lead to co-evolution of dispersal rates and mutation rates, which causes a faster range expansion and a larger species’ range. Surprisingly, this also occurrs in sexual populations, due to the particular properties of spatial sorting. This co-evolution results in a long-lasting maintenance of high mutation rates in both sexual and asexual species. By this we extend the existing theory on the evolution of mutation rates, which was thought to be limited to asexual populations, with possibly far-reaching ecological consequences concerning invasiveness and the rate at which species can adapt to novel environmental conditions.