Dietary Overlap in Frugivorous and Insectivorous Bats from Edaphic Cerrado Habitats of Brazil

Abstract

Previous studies on size patterns within frugivorous and insectivorous bat guilds from north-eastern Brazil suggest significant ecological separation of species. Nonetheless, recent simulation studies indicate that stochastic processes alone, rather than competition or coevolution, account for the morphological structure of these communities. To evaluate the dietary consequences of observed morphological structure, monthly samples of bats were collected (September 1976–May 1978) within edaphic Cerrado habitats on the Chapada do Araripe in northeastern Brazil. For each of the 11 most common species, stomach contents were identified, and the diets characterized for wet and dry seasons. Nonparametric statistical analyses of dietary constituents revealed two non-overlapping groups of frugivores based upon a posteriori contrasts: those that specialize on one food source, Vismia sp. ( Carollia perspicillata, Artibeus planirostris, A. lituratus ), and those that are more generalistic in their feeding habits ( Glossophaga soricina, Sturnira lilium, Vampyrops lineatus ). Statistical analyses of insectivorous species produced a homogeneous group ( Anoura geoffroyi, Phyllostomus discolor, P. hastatus, Molossus molossus ) based on classification of diet into hard-bodied versus soft-bodied insects. Like the ecomorphological assessments of community structure, our results failed to detect pervasive dietary differences among species that are related to size considerations.