Rethinking the role of colour in avian fruit choices and foraging mechanisms

Abstract Mutualistic interactions between fleshy‐fruited plants and frugivorous animals that disperse seeds are important for the organization and regeneration of ecosystems worldwide. According to the dispersal syndrome hypothesis (DSH), the colour of ripe fruits influences interactions with different groups of frugivores (e.g. birds, bats, other mammals). Although widely accepted, conclusive evidence for the functional role of fruit colour remains equivocal, as frugivory interactions often deviate from the DSH's expectations. To test the fruit colour syndrome hypothesis, we analysed avian fruit preferences across tropical and temperate ecosystems using observational data and field experiments with artificial fruits. The results show that the interactions or preferences of avian frugivores with fruit resources are only weakly associated with the coloration of ripe fruits across plant communities in Puerto Rico, Peru, Brazil and Argentina. Additionally, field experiments using artificial fruits in Pennsylvania, Puerto Rico and Argentina revealed that birds were initially more attracted to novel, unfamiliar colours. Collectively, our findings indicate that fruit colour syndromes have limited predictive power for frugivory and seed dispersal interactions. We argue that the function of fruit colours in structuring frugivore–plant interactions should be reinterpreted within a broader foraging framework. We propose that fruit consumption consists of two alternating phases: (1) an exploration phase initiated through the discovery of novel resources and (2) an exploitation phase where frugivores use their prior knowledge to make informed decisions about which fruits to eat, based not only on nutritional value but also on factors such as palatability, handling time and the availability of alternative resources in the community. Our study highlights the limitations of classifying fruits by colour syndromes, suggesting that the relationship between fleshy fruit traits and frugivory interactions—particularly with avian frugivores—is more nuanced than that such categories can capture. Read the free Plain Language Summary for this article on the Journal blog.