Selection of Diet and Elevation by Sympatric Species of Sturnira in an Andean Rainforest

Abstract

Dietary and habitat preferences of two sympatric species of Sturnira (Chiroptera: Phyllostomidae) were studied in a wet montane forest in northwestern Argentina. S. lilium was common at lower elevations and S. erythromos dominated at higher elevations. Rates of capture correlated with phenology of chiropterocorous fruiting plants at two of three study sites. Diet of both species at all sites consisted of fruits of four to five species of Solanum and Piper. Frequencies of these two main foods paralleled increase in number of species of Solanum and decrease in densities of Piper along the elevational gradient. Together with Central American and Peruvian data, these results strongly support Solanum and Piper as core taxa in the diet of Sturnira and fail to support the suggestion that body size influences selection of habitat or diet. Elevational differences in rate of capture between species are related directly to continental distribution of the species (lowland versus montane forests).