Indoor Resting by Outdoor Biting Females of Anopheles gambiae Complex (Diptera: Culicidae) in the Sahel of Northern Senegal

Abstract

Three villages in the Senegal River basin were selected to study the biting and resting behavior of Anopheles gambiae s.l. in relation to human habits, rainfalls, and rice culture irrigation. All inhabitants sleep outside throughout the year, mainly under poor quality bednets. Mosquitoes were collected host-seeking during the night on human bait outside and resting during the day inside and outside in pit shelters. An. gambiae s.s. and An. arabiensis fed mainly outside, the only place where hosts are available; fed and gravid females resting indoors fed outside. The proportions of An. gambiae s.s. and An. arabiensis in outdoor biting catches and in indoor spray catches were not significantly different, but they differed from year to year with the latter sampling method. An. gambiae s.s. predominated in 1990, a more wet and humid year, whereas An. arabiensis was more common in 1991, which was an arid year. Both species are highly endophilic in this arid area where outdoor-resting places are limited.