Dispersal and survival of Anopheles funestus and A. gambiae s.l. (Diptera: Culicidae) during the rainy season in southeast Tanzania.

In a rural area of southeastern Tanzania, studies were undertaken on the dispersal and survival of Anopheles funestus Giles and A. gambiae Giles s.l. during the rainy season. Blood fed, resting mosquitoes were collected indoors, marked with fluorescent powder and released on the same day from two different sites in the study area. For two weeks indoor resting mosquitoes were collected from 11 houses in the release area. Additional collections were made with a light trap from a sentinel house in the centre of the study area. Anopheles funestus was more abundant than A. gambiae s.l. Of 4262 A. funestus and 645 A. gambiae s.l. released, 4.3% and 7.4%, respectively, were recaptured. Dispersal of mosquitoes was not random: one of three areas was favoured significantly more than the other areas, as shown by the recapture and movement rates of marked mosquitoes. Based on the regression of the recapture rate, estimated daily survival rates of A. funestus and A. gambiae s.l. were 0.63 and 0.78, respectively. These were significantly different. The differences in dispersal and survival rates between the two species are discussed in view of local topography and species-specific characteristics.