Pollinators and herbivores interactively shape selection on strawberry defence and attraction

Abstract

Plant-herbivore-pollinator interactions are of ecological relevance for most angiosperms. However little is known on how plants evolve in response-and in particular how these tripartite interactions influence phenotypic selection on traits that link pollination and herbivory. We here conducted a common garden experiment with woodland strawberry (Fragaria vesca L.) to quantify pollinator-and herbivore-mediated selection on nine traits related to plant defence and attraction. Our results showed that pollinators imposed stronger selection than herbivores on both direct and indirect (i.e., tritrophic-related) defence traitswhereas conflicting selection was imposed on inflorescence density. However, in all cases, selection imposed by one agent was context-dependant on the other, suggesting that dynamic patterns of selection are likely a prevalent feature of these interactions. Our findings highlight the significance of plant-herbivore-pollinator interactions as potential drivers of evolutionary change, and reveal that pollinators may play a generally underappreciated role as selective agents on plant defence.