Speaker
Description
Species interactions take many forms, including antagonism and mutualism, yet the evolutionary conditions under which interactions change character remain poorly understood. Here we investigate how antagonistic interactions can evolve into mutualistic ones using a coevolutionary modeling framework inspired by experimental evolution, where a species interaction transitioned from predator–prey to cross-feeding. Using adaptive dynamics and invasion fitness analysis, we study trait evolution in both interacting species. Mutations can occur in different orders, generating alternative evolutionary paths. Within this framework, we identify the minimal conditions under which antagonism can transition to mutualism. We further ask (1) which evolutionary paths are most likely and (2) which paths most often lead to mutualism. Our analysis shows that some evolutionary paths are more common than others, but the order of mutations does not affect the probability that mutualism evolves, conditional on completing the full trajectory. This path independence indicates that interaction type depends only on the final combination of traits. These results suggest that antagonistic interactions can provide evolutionary starting points for diverse mutualisms, including symbioses and cross-feeding systems.
