Flagellate infections in cave-dwelling sandflies (Diptera, Psychodidae) in Belize, Central America

Abstract

Nearly 2000 Phlebotomine sandflies collected in caves in Belize were examined for flagellate infections in the gut. Infections were found in 4% of Lutzomyia trinidadensis (Newst.) and in 42% of L. beltrani (Belize form). The two species of sandflies were infected with different species of parasites. The sources of infections in L. trinidadensis were not established, but females probably became infected when taking blood-meals on a vertebrate. One specimen of L. trinidadensis infected with flagellates was also infected with filaria worms. Circumstantial evidence suggests that L. beltrani is the insect host of Trypanosoma leonidasdeanei, a parasite in the blood of insectivorous bats. An account is given of the physiological condition of infected and uninfected L. beltrani, of the distribution of flagellates in the gut and of differences in the incidence of infections. The presence of the parasites in the gut disturbs some physiological processes in the fly and it is suggested that the presumed Chiroptera/T. leonidasdeanei/L. beltrani association is a recent evolutionary development. A model of population structure for a community of New World Phlebotominae, derived from observations on L. beltrani, is presented.