Ecological significance of fruit displays in Myrtaceae: relationship between fruit colour, maturation stage, attractiveness and seed germination

Fruit colour has long fascinated scientists and is widely considered an evolutionary adaptation to attract both avian and mammalian frugivores. While fleshy fruits play a key role in plant–animal interactions by promoting seed dispersal, the functional significance of colour variation, particularly multicoloured displays during ripening, remains poorly understood, largely because the selective and ecological drivers behind these colour changes are still unclear. Here, we evaluate the relationship between fruit colour, maturation stage, attractiveness and seed germination in 12 Myrtaceae species, by testing three hypotheses: 1) the visual delay hypothesis, which predicts that seeds reach physiological maturity prior to the appearance of visual ripening signals in the fruit, 2) the reward hypothesis, which predicts that mature fruits are more consumed than fruits in intermediate ripening stages, and 3) thecontrast hypothesis, which suggests that multicoloured displays enhance detectability and removal by frugivores. To test these hypotheses, we quantified colour changes during fruit maturation, conducted germination assays in the laboratory and performed removal experiments with artificial fruits in the field. Our results supported the visual delay hypothesis, as all Myrtaceae species, regardless of display type, exhibited high seed germinability even at early ripening stages. We also corroborated the reward hypothesis, as fruits in the final ripening colour were removed more often, independent of display type. Additionally, multicoloured fruits were more frequently removed by frugivores, supporting the contrast hypothesis and suggesting that multiple coloration facilitates detection and extends the dispersal window. Our findings contribute to a better understanding of the ecological role of fruit colour in seed dispersal and highlight the importance of considering species‐specific traits in ecological studies, providing novel information on germination speed index and germination percentages that can inform restoration efforts, such as the selection and propagation of native species.