We evaluated the effects of
Leishmania spp infection on several population parameters of
Lutzomyia longipalpis sensu lato>
and
Lutzomyia pseudolongipalpis, vectors of visceral leishmaniasis in Venezuela, under experimental conditions during the first post-feeding period. Females of both species were allowed to feed and engorge on a suspension of fresh washed human red blood cells in foetal calf serum. These blood cells were either non-infected or infected with one of the four
Leishmania spp strains and were offered through a chicken skin membrane. The longevity, life expectancy and the fecundity of uninfected flies were similar in both species, but the fertility was significantly lower in uninfected Lu. longipalpis females. In all cases, the infection of
Lu. longipalpis and
Lu pseudolongipalpis by the
Leishmania strains resulted in significant detrimental effects, which exerted a fitness cost expressed by reduced survival and life expectancy, as well as decreased fertility and fecundity compared with the control groups. Nevertheless, differences in these parameters were observed between these vector species depending on whether they were infected with the autochthonous Venezuelan
Leishmania infantum strain (NESA) or the Brazilian reference strain (PP75). The experimental data obtained agree with field data on the natural infection of these vector species and the significance of this scenario is discussed.
