Cooperate-and-radiate co-evolution between ants and plants

Abstract

Mutualisms may be \"key innovations\" that spur diversification in one partner lineage, but no study has evaluated whether mutualism accelerates diversification in both interacting lineages. Recent research suggests that plants that attract ant mutualists for defense or seed dispersal have higher diversification rates than non-ant associated plant lineages. We ask whether the reciprocal is true: does the ecological interaction between ants and plants also accelerate diversification in ants? In other words, do ants and plants cooperate-and-radiate? We used a novel text-mining approach to determine which ant species associate with plants in defensive or seed dispersal mutualisms. We investigated patterns of trait evolution and lineage diversification using phylogenetic comparative methods on a large, recent species-level ant phylogeny. We found that ants that associate mutualistically with plants have elevated diversification rates compared to non-mutualistic ants, suggesting that ants and plants cooperate-and-radiate.