Ecologia alimentar de morcegos insetívoros de área urbana do município do Rio de Janeiro, RJ (Mammalia: Chiroptera)

Abstract

This dissertation reports on the feeding ecology of insectivorous bats from urban areas of county of Rio de Janeiro, state of Rio de Janeiro, Brazil. The study was carried out between November of 1991 and July of 1993. The most frequently captured species were the following: Myotis nigricans (Schinz, 1821 ), Eptesicus brasiliensis (Desmarest, 1819) and Molossus molossus (Pallas, 1766); Tadarida brasiliensis (Geoffroy, 1824) and Lasiurus cinereus (Beauvois, 1796) were captured less frequently. It was verified that specimens of M. nigricans and M. molossus captured in urban areas weighted more than those captured in rural and/or wild preserved areas. ldentification of fragments of insects in fecal samples showed that M. nigricans feeds mainly on Lepidoptera. E. brasiliensis and M. molossus are more diversified in their diet, insetcs of three orders (Lepidoptera, Coleoptera and Hymenoptera) were identified in comparable proportions. The results also show T. brasiliensis feeds mainly on Lepidoptera and L. cinereus on Lepidoptera only. M. molossus feeds on insects that are more abundant, and thus more easily located and captured, at a given point in time (e.g., ants in reprodutive period). The results do no point to geographical variation in feeding practices. Notwithstanding, the feeding ecology of the bats investigated in this dissertation is closely associated with sazonal change in precipitation. The major conclusion is that, despite living in the same environment and presenting peaks of activity roughly at the same time, this data suggest the species of Chiroptera do not compete for food resources. A possible explanation is that they feed on insects of different sizes which may also fly at different altitudes.