Frequency-dependence favors social plasticity and facilitates socio-eco-evolutionary feedback in fluctuating environments

1. Increasing attention is being devoted to the study of phenotypic plasticity in social environments. However, much remains unknown about the selection pressures driving the evolution of social plasticity, as well as the pathways by which social plasticity may facilitate or constrain feedback between ecological and evolutionary dynamics. Here we explore these questions using quantitative genetic models, providing general results regarding the causes of selection on social reaction norms, as well as their consequences for adaptive microevolution in fluctuating environments. 2. We model the fitness effects of character states expressed across spatially heterogeneous microhabitats, with variation in the degree to which trait expression and selection are affected by the local social environment. We find that when selection on character states is frequency-dependent within microhabitats, stochastic fluctuations in the social environment cause selection for reversible social plasticity across microhabitats, as quantified by the interaction coefficient