Datasets and Rcode for the manuscript: "Which fruit traits correlate reliably with sugar content, and does this vary with dispersal syndrome?"

Deciding which fruits to eat, and when, are key decisions made by frugivores, with implications for animal nutrition, seed dispersal and other ecosystem interactions. It has long been hypothesized that fruit traits, including colour, odour and hardness, are adapted to attract different guilds of frugivores (e.g., birds versus mammals) and facilitate fruit foraging through signaling of ripeness and nutritional reward via different sensory modalities. Yet how various traits change during ripening in fruits with different putative dispersal syndromes is poorly understood. We predicted visual traits to be more correlated with changes in sugar content during ripening in a bird-consumed fruit, and odour and hardness traits to be correlated with sugar content in mammal-consumed fruits. We measured colour via image analysis, odour via solid-phase microextraction GC-MS, hardness via a portable mechanical tester, and sugar content using a digital refractometer in n = 100 bananas (Musa acuminata) and n = 160 mangoes (Mangifera indica), two large, climacteric fruits as models of mammal-dispersed fruits, and in n = 80 black currants (Ribes nigrum), a small, non-climacteric berry as model for bird-dispersed fruit. Bananas, and to a lesser extent, mangoes, tend to get softer, have higher red-green and lower blue-yellow chromaticity values, and become more odiferous as they get sweeter. Currants get softer, darker, have lower red-green and higher blue-yellow chromaticity values, and become less odiferous as they become sweeter. Our results suggest that some traits, such as colour and odour, may vary among plant taxa with different dispersal syndromes, while other traits, such as fruit softening, may be more consistently associated with fruit ripening when they occur. We have developed a tractable framework for assessing multimodal plant cues and signals and hope this research inspires future studies of greater taxonomic diversity.