Morphological and ecological correlates of coexistence in Malaysian fruit bats (Chiroptera: Pteropodidae)

Niche theory predicts that coexisting species should differ ecologically, morphologically, or behaviorally in ways that minimize competition. We used an ecomorphological approach to determine how coexisting species in the Old World fruit bat genus, Cynopterus, assort in morphological and ecological space. The study was conducted in peninsular Malaysia where 4 species of Cynopterus are broadly sympatric. Interspecific separation in resource use was estimated along 3 main axes: habitat, based on abundance across a habitat gradient at 2 sites; trophic niche, inferred from a suite of cranial and postcranial characters; and locomotory behavior and efficiency, inferred from wing morphology. Habitat associations, overall size, and the size and shape of the trophic apparatus were all important in separating 2 or more species, whereas interspecific differences in wing morphology were minor. In combination, the results of this study suggest that relatively minor separation among Cynopterus species pairs along single axes of resource use is sufficient to counteract overlap on other axes, and pen-nit the coexistence of potential competitors.