Aureli, F. | Search bioRxiv

bioRxiv2026

Pervasive ethanol in the fruits and floral nectars consumed by tropical frugivores

Dietary ethanol has long been proposed as a selective force shaping the diets and physiology of tropical frugivores and nectarivores, yet this idea has rested on measurements from only a few species and sites. Here, we present the first global survey of ethanol in wild fruits and flowers (591 and 37 species, respectively, across 18 countries) and test ecological and phylogenetic predictors of its variation. We detected ethanol in the ripened fruits of 72% of angiosperm species (211 species, N [≥] 3 per species; 0.021% - 3.9% alcohol by volume (ABV)). Ethanol was also detected in the flowers of 12 species (0.037% - 0.73% ABV). Maximum fruit ethanol varied with temperature, humidity, and phylogenetic relatedness, and it was higher in ripe fruits collected from the forest floor relative to their canopy counterparts. We then extrapolated potential daily ethanol consumption for 10 primate species. Estimated maximum daily ethanol ingestion for primates ranged from negligible to 0.72 g/kg/day on average (equivalent to 5.1 international standard drinks, 10 g ethanol each, for a 70 kg human). Our findings show that ethanol is widespread in plant reproductive tissues and shaped by both phylogeny and environment, supporting the hypothesis that dietary ethanol has been a pervasive selective pressure on fruit- and nectar-feeding animals.

ecology↗

bioRxiv2025

Social integration in temporal multiplex association networks predicts offspring survival in female Geoffroy's spider monkeys (Ateles geoffroyi)

While sociality is considered an important factor influencing female reproductive success, it is unclear how temporal social dynamics relate to it. We address this by evaluating the influence of social integration and its stability over time on offspring production and survival in Geoffroys spider monkeys (Ateles geoffroyi). Using 52,670 subgroup scan samples collected between 1997 and 2020, we compiled yearly association matrices among the sexually mature individuals of a wild group of spider monkeys, based on spatio-temporal co-occurrence in subgroups. We built Bayesian edge-weight models with the association matrices and generated 1000 samples of each yearly network, which we then used as layers in temporal multiplex networks. For each female with adult tenure [≥] 5 years (n= 17), we estimated strength and eigenvector versatility in the multiplex network that comprised the last 5 years of her tenure. We also estimated six (monolayer) centrality-based metrics in the yearly networks of females with adult-tenure [≥] 1 year and at least one recorded offspring born in the group (n=22). We tested the influence of these eight indicators of social integration as predictors of offspring production and survival. Results showed overall positive relationships between social integration and offspring survival, but not offspring production. The former could be due to better access to food resources or protection from within-group aggression. Our temporal multilayer approach contributed to the body of evidence regarding the fitness benefits of sociality. Significance StatementDespite the growing evidence of the influence of sociality on female fitness, there is limited information on how temporal variation in social dynamics relates to female reproductive success. We used long-term data on spatio-temporal co-occurrence in subgroups of spider monkeys to estimate network centrality metrics. We found that females with higher and more stable social integration had higher offspring survival, particularly for female offspring who reached age 5 (the onset of sexual maturity). Our study offers insights into the relationship between association and offspring survival in species with a high degree of fission-fusion dynamics and female dispersal.

animal behavior and cognition↗