SELECTION OF BITING SITES ON A HUMAN HOST BY ANOPHELES-GAMBIAE SS, ANOPHELES-ARABIENSIS AND ANOPHELES-QUADRIANNULATUS

The selection of biting sites on a human host of three closely related mosquito species belonging to the African Anopheles gambiae complex ( Diptera: Culicidae), Anopheles gambine Giles s.s., An. arabiensis Patt on and Art. quadriannulatus Theobald, was investigated under controlle d laboratory conditions. Although these species differ in host prefere nce, they all showed a significant preference to bite the legs and fee t, suggesting that a mutual not specifically human factor was involved in the selection of biting sites. In subsequent experiments with An. gambine s.s. this factor was revealed by altering the position of the test person. In experiments with the test person silting on a stool, t he legs and feet were significantly preferred as biting sites, whereas lying on the ground, with the legs and feet sticking up, the latter b ody parts were bitten significantly less than the body parts closest t o the ground (head, trunk and arms). The results indicate that mainly convection currents along the host are used by members of the An. gamb iae complex in selecting a biting site. In contrast to An. gambine s.s . and An. arabiensis, large numbers of bites by An. quadriannulatus al so occurred on the head, possibly in response to exhaled breath. It is concluded that the selection of biting sites of members of the Anophe les gambiae complex is guided by convection currents and partially med iated by host odours.