Batflies parasitic on some phyllostomid bats in southeastern Brazil: Parasitism rates and host-parasite relationships

Ectoparasitic batflies were studied on 12 species of phyllostomid bats, by making 35 nightly collections of bats using mist nets at the "Panga" Ecolog ical Reservation near Uberlandia, State of Minas Gerais, southeastern Brazi l, from August 1989 to July 1990. Eleven species of Streblidae and one of N ycteribiidae were collected on 12 species of bats. Prevalence of ectoparasi tic flies was lower than those reported by other authors for the New World and may be the result of the lack of caves in the study area, causing bats to roost in less favorable locations, forming smaller colonies. The fly, Tr ichobius joblingi Wenzel, was found on Carollia perspicillata (Linnaeus), s howing preference for adult male bats. This could be explained by the predo minance of males in the bat colonies, and by the fact that females rest in isolation during the reproductive period making them less exposed to the pa rasites. The streblid flies, Aspidoptera falcata Wenzel and Megistopoda pro xima (Seguy), were found on Sturnira lilium (Geoffroy). A. falcata occurred mainly on young and adult females, whereas M. proxima did not show any pre ferences relative to the reproductive condition of the host. Ecological fac tors are important in determining differential numbers of parasites occurri ng on the different sexes, ages and reproductive state of the hosts.