Variation of dipteran ectoparasites (Streblidae) on Anoura geoffroyi Gray, 1838 (Phyllostomidae) in two caves in southeastern Brazil.

Bats are parasitized by many different arthropods, among which the dipteran families Nycteribiidae and Streblidae are exclusive to bats. Researches that relate the ecology of ectoparasites with their hosts are fundamental for understanding issues related to the interactions between these two groups, in addition to epidemiological aspects of pathogen transmission. The present study evaluated the rate of infestation by dipteran (Streblidae) ectoparasites in two colonies of Anoura geoffroyi associated with caves in the southeastern Brazil. It also evaluated whether parasitological indices differ significantly with regard to host sex and reproductive condition. A total of 1377 bats were captured, of which 84% were parasitized. From these, a total of 5047 streblid bat flies belonging to three species of three genera were collected and identified. The most abundant was Exastinion clovisi (57%), followed by Anastrebla modestini (30%) and Trichobius propinquus (13%). In general, the populations of ectoparasites fluctuated throughout the year, with peaks of abundance during the rainy season. The sex ratios for the species of ectoparasites were close to one, which differs from what is reported in the literature. In addition, there were significant differences in parasitism rates in relation to host sex and reproductive condition. In both populations, ectoparasite infestation of pregnant or lactating females was significantly higher than for non-reproductive females. New studies aimed at assessing whether these higher rates of infestation have any effect on female bat reproduction are needed.