Fruit colour and range size interact to influence diversification

Aim: Different fruit colours are associated with dispersal by different frugivores, largely based on colour vision type. Frugivore mobility affects overall range size for the plant being dispersed. Here we determine the interaction between different fruit colours, range sizes, and diversification rates by testing two hypotheses: That (1) fruit colours attractive to birds have larger range sizes due to their higher dispersal ability, and that (2) different frugivore disperser groups, bird or mammal, leads to different diversification rate at different range size, where intermediate range size leads to the highest diversification rate. Location: Global. Time period: Contemporary (or present). Major taxa studied: Palms (Arecaceae). Methods: Using model selection, we identified three groups of colours with similar diversification rate and likely disperser. Range sizes were estimated and categorized species as small, intermediate, or large-ranged. For model selection and to determine the relationship beween fruit color, range size and diversification rate we used Multi-State Speciation and Extinction (MuSSE) models. Results: Species with intermediate range size had the highest net diversification for all three fruit colour groups. Bird-dispersed palms more likely diversified at small than at large range size while mammal-dispersed palms more likely diversified at larger range size than small. Fruit colours associated with mammal dispersal had more large-ranged species than colours associated with bird dispersal. Main conclusions: The associated between intermediate range size and higher diversification rate indicates that spatial factors that affect diversification at small and large range sizes result in higher diversification at intermediate ranges. We find striking differences in diversification rate within each range size category between fruit color groups. This suggests that the relationship between diversification rate and range size depends on the specific frugivorous dispersers and their dispersal patterns. This study reveals how fruit traits alter dispersal patterns and how that, in turn, influences diversification.