Reproductive patterns and feeding habits of three nectarivorous bats (Phyllostomidae: Glossophaginae) from the Brazilian Cerrado

摘要

The reproductive patterns and feeding habits of three sympatric nectarivorous bats, Glossophaga soricina, Anoura caudifera, and A. geoffroyi were studied in the Pousada das Araras Natural Reserve, located in Central Brazil. The bats were captured with mist nets from August 2000 to July 2001. Reproductive condition was determined by external analyses of the specimens and feeding habits from fecal samples. Glossophaga soricina was the most abundant species (65%), followed by A. geoffroyi (30%) and A. caudifera (5%). Significant differences were observed in the sex-ratio of the two more abundant species. Anoura geoffroyi showed a monoestrous pattern; its reproductive peaks occurred between the end of the dry season and the beginning of the rain season. A seasonal bimodal pattern was recorded for G. soricina, with pregnant specimens showing one peak observed in the dry season and another in the middle of the rainy season. The reproductive pattern of A. caudifera could not be satisfactorily defined because of the small sample size. However, this species apparently has a reproductive cycle similar to that of G. soricina. The patterns observed in this study seem to be related with the climate in the Brazilian savanna (Cerrado), with two well-defined seasons (dry and wet). By adjusting the parturition close to or in the rain season the three species could be favoring a greates survival rate for the offspring, since the critical lactation period would then occur in a time of maximum food availability. The three bat species showed a generalist diet, consuming fruits, pollen-nectar, and arthropods. Significant differences were observed in the diet of G. soricina: fruits and arthropods predominated in the dry season and pulp (fruits) in the rainy season. Males and females of this species ate the same items in similar proportions. Although A. geoffroyi has not showed a preference for a specific item, consumption of fruits and arthropods was generally greater than that of pollen.