Feedbacks between evolutionary and ecological processes that occur because they operate on similar timescales is called eco-evo dynamics. For eco-evo dynamics to persist, the variation underlying both processes must be maintained, yet this fundamental component of eco-evo dynamics has received little attention. Pea aphids can evolve resistance to parasitoid wasps rapidly enough to affect the host–parasitoid dynamics. Through long-term lab experiments and simulations, we showed that moderate aphid dispersal among fields combined with non-random parasitoid dispersal cause both species coexistence and balancing selection. These two forms of dispersal together resulted in stable, persistent eco-evo dynamics (Nell et al., Science).
