Resumo em Inglês:

The upper valley of the Rio Ribeira, a carbonatic rock region in the south of the state of São Paulo, Brazil, has a great number of caves; the bat community of the area is the subject of the present study. Between October 1978 and October 1980 specimens of five families and 23 species were captured. The species showed an irregular distribution among 32 of 39 caves visited. The community is very diversified, consisting of a specially abundant species (Desmodus rotundus), some very common species (Carollia perspicillata, Artibeus lituratus and Anoura caudifer), and several common and rare species. It differs from other neotropical communities studied in the relatively high frequence of A. caudifer, which probably takes over the ecological role of Glossophaga soricina, and in the great diversity of medium to large sized Phyllostominae. The great diversity and the high relative abundance of some species is probably related to the availability of food afforded by farms and domestic stock Ñ important for the herbivorous and hematophagous species Ñ and to the high number of caves Ñ important mainly for the Phyllostominae and probably for D. rotundus. It is suggested that the structure of a roost's community is primarily determined by the location: the more isolated a cave, the greater and more diversified tends to be its community, regardless of the caveis morphometric characteristies («opportunistic occupation»). Only in densely grouped caves factors such as size would tend to be of some importance. Due to the great number of roosts and the lotv sociability of the bats, the Upper Ribeira populations tend to be distributed all over the available caves, that have small populations (with exception of some relatively isolated ones) varying in density through the year. The occurrence of certain species in individual caves seems to be affected by presence of others in the same roost: A. lituratus, Diphylla ecaudata and Chrotopterus auritus tend to occupy the same caves as D. rotundus, whereas Puripterus horrens and A. caudifer avoid them. Common species showed a «sunset-related» timing of flight activity. The emergence of the majority of the populations begins at dusk, but the activity peak at cave entrance varies in timing and duration. The strictly insectivorous species (Peropterix macrotis, Myotis nigricans and P. horrens and also A. caudifer leave the roost earlier, showing an emergence peak during the crepuscle; for the others, the peak occurs after darkening. A few species, such as D. rotundus and Lonchorhina aurita, emerge only after total darkness. The use of temporary, nocturnal roosts seems to be frequent in the Upper Ribeira, occurring during or after foraging activities; individuals of A. lituratus can use caves as ingesting places. C. perspicillata finishes its feeding activities earlier than the other common species, which indicates a high foraging efficiency. With few exceptions, bats of the Upper Ribeira do not carry their young during foraging. The supply of food for the hematophagous species is represented by small and medium sized domestic animals (poultry and pigs); wild animals may also be significant as prey.