Testing the grain-size model for the evolution of phenotypic plasticity.

Phenotypic plasticity is the ability of a genotype to modify its phenotypic characteristics in response to different environments. Theory predicts that adaptive plasticity should primarily evolve in organisms that experience heterogeneous environments. An organism's dispersal rate is a key component in these models, because the degree of dispersal partly determines the extent of environmental heterogeneity. Here, I provide the first large-scale test of the theoretical prediction that phenotypic plasticity evolves in association with dispersal rate using meta-analysis of data from 258 experiments from the literature on plasticity in marine invertebrates. In line with predictions, phenotypic plasticity is generally greater in species with higher dispersal rates, suggesting that dispersal and environmental heterogeneity are important selective agents for evolution of plasticity in marine habitats.