Mate-choice copying accelerates species range expansion.

Mate-choice copying is a type of social learning in which females can change their mate preference after observing the choice of others. This behaviour can potentially affect population evolution and ecology, namely through increased dispersal and reduced local adaptation. Here, we simulated the effects of mate-choice copying in populations expanding across an environmental gradient to understand whether it can accelerate or retard the expansion process. Two mate-choice copying strategies were used: (i) when females target a single individual and (ii) when females target similar individuals. We also simulated cases where the male trait singled out by females with mate choice maps perfectly onto his genotype or is influenced by genotype-by-environment interactions. These rules have different effects on the results. When a trait is determined by genotype alone, populations where copier females target all similar males expand faster and the number of potential copiers increased. However, when preference is determined by genotype-by-environment interactions, populations where copier females target a single male had higher dispersal and also expand faster, but the potential number of copiers decreases. The results show that mate-choice copying can accelerate the expansion process, although its adaptiveness depends on the information animals use in different contexts.