The color of attraction: carotenoid-based coloration in the black Cherry (Prunus serotina) fruit ripening and its interaction with the gray silky-flycatcher (Ptiliogonys cinereus)

Abstract Mutualistic interactions between fruiting plants and frugivorous birds shape ecosystem dynamics, yet the links between fruit ripening, visual signaling, and seed dispersal remain underexplored. Here, we examine changes in fruit coloration during Prunus serotina (capulín) fruit ripening and its potential association with frugivores, focusing on the gray silky-flycatcher or capulinero ( Ptiliogonys cinereus) , at two sites an urban ecological reserve and a rural pine-oak forest. We measured fruit reflectance throughout maturation (400–700 nm), basic nutrient composition, frugivore visitation, and seed germination. Nutritional composition from fruits of two trees showed tendencies consistent with ripening (declining fiber and polyphenol content and increasing carbohydrates). We only observed frugivory at two different trees, where P. cinereus preferentially consumed red and purple fruits, rarely touching unripe ones. Germination trials indicated that seeds from red fruits had the highest success and germinated faster than those from earlier stages. Given limited sample sizes for chemical and germination assays (two trees), and rare feeding events, these results are preliminary and primarily hypothesis generating rather than conclusive. Our study points to coordinated shifts in fruit traits that may influence frugivore behavior and seed recruitment and provides a basis for future work integrating broader sampling to test these patterns more rigorously.