Natural selection on environmentally-mediated social behaviours under ecological inheritance

Résumé

Organisms continually modify their environments in ways that influence the fitness of conspecifics. Such environmentally mediated social behaviours can have lasting effects across generations through ecological inheritance. In this talk, I’ll review theoretical insights into how natural selection can shape the evolution of these behaviours, focusing on negative frequency-dependent selection—a key mechanism that maintains variation by favouring rare types. Using invasion analyses, we’ve shown that when ecological inheritance is combined with limited dispersal, environmentally mediated social dilemmas often lead to the long-term coexistence of two behavioural types: environmental helpers, who invest in improving their surroundings at a personal cost, and environmental free-riders, who benefit without contributing. In turn, this polymorphism generates enduring spatial heterogeneity in environmental quality, particularly under isolation-by-distance, where clusters of high- and low-quality habitats emerge and persist over time. These findings highlight how ecological inheritance, coupled with movement constraints, can stabilise variation in social traits and contribute to long-term environmental patterns.