LUTZOMYIA-LONGIPALPIS IS A SPECIES COMPLEX - GENETIC-DIVERGENCE AND INTERSPECIFIC HYBRID STERILITY AMONG 3 POPULATIONS

The sand fly Lutzomyia longipalpis is the vector of Leishmania donovan i chagasi in Latin America. An analysis of genetic variability at 27 e nzyme coding loci among three laboratory populations of Lu. longipalpi s revealed substantial genetic polymorphism. Levels of genetic distanc e between all pairwise comparisons of colonies were very high, and con sistent with those previously reported among separate species in the g enus Lutzomyia. Between 7% and 22% of the loci studied were diagnostic for any two of the colony populations. Experimental hybridization bet ween colonies resulted in the production of sexually sterile male prog eny. Our results provide strong evidence that Lu. longipalpis exists i n nature as a complex of at least three distinct species. The possible effects of colonization on the genetic makeup of laboratory populatio ns is considered in extending our results to natural populations.