Data from: Plastic responses to parents and predators lead to divergent social behaviour in sticklebacks

Population divergence in antipredator defense and behaviour occurs rapidly and repeatedly. Genetic differences, phenotypic plasticity, or parental effects may all contribute to divergence, but the relative importance of each of these mechanisms remains unknown. We exposed juveniles to parents and predators to measure how induced changes contribute to shoaling behaviour differences between two threespine stickleback species (benthics and limnetics: Gasterosteus spp). We found that limnetics increased shoaling in response to predator attacks while benthics did not alter their behaviour. Care by limnetic fathers led to increased shoaling in both limnetic and benthic offspring. Shoaling helps limnetics avoid trout and avian predation; our results suggest this adaptive behaviour is the result of a combination of paternal effects, predator-induced plasticity, and genetic differences between species. These results suggest that plasticity substantially contributes to the rapid divergence in shoaling behaviour across the post-Pleistocene radiation of sticklebacks.