Factors shaping sugar metabolism in Neotropical bats: A physiological and ecological perspective.

Understanding physiological constraints on adaptive capacity is essential for predicting species responses to environmental change. Sugar assimilation represents a critical physiological adaptation linked to dietary diversification, yet the intrinsic and ecological factors governing glucose homeostasis remain poorly understood. We used glucometry to evaluate blood glucose regulation across diverse Neotropical bat species, assessing the relative importance of diet, phylogeny, temporal dynamics, and individual traits. Fasting glucose levels were strongly associated with dietary guild and phylogenetic relatedness but independent of sex and body mass. Sugar assimilation capacity varied primarily with sugar type (monosaccharides versus disaccharides), dietary specialization, and temporal scale (diurnal and seasonal cycles), although omnivorous species exhibited high individual-level variability. Critically, syntopic congeners show hints of metabolic differentiation consistent with resource partitioning, suggesting physiological niche separation may reduce interspecific competition. Seasonal plasticity in sugar metabolism-particularly in frugivorous species tracking fruit availability-indicates flexible metabolic responses to resource fluctuations. These findings show that sugar metabolism in bats reflects evolutionary adaptation to their diets, influenced by evolutionary history and seasonal changes in resource availability. The metabolic specialization seen in dietary specialists, along with seasonal flexibility, has important implications for predicting species' vulnerability to habitat loss and climate-driven shifts in resource timing, as specialists may be less resilient to environmental changes compared to metabolically flexible generalists.