Admixture is a driver rather than a passenger in experimental invasions

In this issue of Journal of Animal Ecology, Wagner et al. (2017) demonstrate that genetic diversity can alter the course of spread of biological invasions. They employ Callosobruchus seed beetles in a clever array of linked habitat patches to compare experimental invasions using individuals from single population sources or from mixes of two, four or six population sources. By taking a model-selection approach, they find that any amount of mixture propels growth rates and spread of introduced populations. This suggests that heterosis alone can alter the course of an invasive range expansion.