MITOCHONDRIAL-DNA CHARACTERIZATION OF POPULATIONS OF LUTZOMYIA-WHITMANI (DIPTERA, PSYCHODIDAE) INCRIMINATED IN THE PERI-DOMESTIC AND SILVATIC TRANSMISSION OF LEISHMANIA SPECIES IN BRAZIL

A comparative analysis was performed on 18 mitochondrial DNA sequences , or haplotypes, of Lutzomyia (Nyssomyia) whitmani (Antunes & Coutinho ) isolated by PCR from 28 individual flies originating from 10 Brazili an locations 150-2500 km apart. A phylogenetic analysis using maximum parsimony indicated support for three to four major lineages (Outgroup s were haplotypes of Lutzomyia (Nyssomyia) intermedia (Lutz & Neiva)). One L. whitmani lineage was found in the Atlantic Forest zone of the North East, including the species' type locality, and is distinct from a second monophyletic group of haplotypes located in the drier interi or of Brazil, stretching from the Tropic of Capricorn to Teresina just outside Amazonia. This provides no support for a previous hypothesis that L. whitmani sensu stricto is a single form widely-distributed sou th of Amazonia, and characterized by derived anthropophilic and synant hropic behavioural traits. The ranges of both lineages include populat ions incriminated in the peri-domestic transmission of Leishmania braz iliensis sensu stricto. A third, Amazonian, group of haplotypes was le ss well-defined. It appears to consist of two sub-lineages which, like the two Leishmania species associated with them, are strictly silvati c and are separated by the Amazon floodplain. The zoophily of the Amaz onian populations was not shown to be an ancestral trait. The geograph ical distributions of the Brazilian lineages are concordant with the b road patterns of bioclimate believed to have persisted since the late Tertiary period. These findings are part of ongoing research on the be havioural genetics of L. whitmani sensu late aimed at understanding th e evolution and maintenance of peri-domestic transmission of human cut aneous leishmaniasis.