Nyssomyia intermedia
and
Nyssomyia neivai
constitute a species complex associated with
Leishmania
transmission. The aim of this study was to analyse the ecological profiles of the
Ny. intermedia and
Ny. neivai populations in a sympatric area in the Brazilian savannah along the banks of the Velhas River. Captures were performed from July 2003-June 2005 in two distinct environments: a gallery forest with various degrees of anthropogenic modification and animal shelters. A total of 20,508
Ny. neivai (86%) and
Ny. intermedia (14%) sandflies were collected. The dif- ference between the proportions of the sandflies that were collected (
Ny. neivai/
Ny. intermedia) per bank was signif- icant. The right bank presented a greater number of sandflies (65%) and more preserved vegetation. The abundance of
Ny. neivai was higher than that of
Ny. intermedia on both banks. The results demonstrate that anthropic activities can affect the sandfly populations in this area, thereby leading to a reduction in species abundance. Nevertheless, the environments with higher levels of antropogenic modification displayed sandfly population numbers that favour the
Leishmania transmission cycle.