Increasing evolvability of local adaptation during range expansion.
Marleen M. P. Cobben, Alexander Kubisch
Increasing dispersal under range expansion increases invasion speed, which implies that a species needs to adapt more rapidly to newly experienced local conditions. However, due to iterated founder effects, local genetic diversity under range expansion is low. Evolvability (the evolution of mutation rates) has been reported to possibly be an adaptive trait itself. Thus, we expect that increased dispersal during range expansion may raise the evolvability of local adaptation, and thus increase the survival of expanding populations. We have studied this phenomenon with a spatially explicit individual-based metapopulation model of a sexually reproducing species with discrete generations, expanding into an elevational gradient. Our results show that evolvability is likely to evolve as a result of spatial variation experienced under range expansion. In addition, we show that different spatial phenomena associated with range expansion, in this case spatial sorting / kin selection and priority effects, can enforce each other.