Unexpected anthropophagic behaviour in Anopheles quadriannulatus

The strongly anthropophilic behaviour of Anopheles gambiae Giles sensu stri cto (Diptera: Culicidae), the most important malaria vector in Africa, has been demonstrated by field and laboratory studies. Other members of the An. gambiae complex express varied degrees of anthropophily. Anopheles quadria nnulatus (Theobald) species A and B are more zoophilic members of the compl ex and hence are considered to be of no medical importance, Olfactometer ex periments with An. quadriannulatus species A have demonstrated attraction t o both human and cow odour. To extend these olfactometer observations a cho ice experiment was conducted in an outdoor cage with a human and a calf as baits, using laboratory-reared mosquitoes. Anopheles gambiae s.s. (from Lib eria) and two strains of An. quadriannulatus species A (SKUQUA from South A frica, SANGQUA from Zimbabwe), marked with different coloured fluorescent p owders for identification purposes, were released simultaneously and given an equal opportunity to feed on either host. The experiment was repeated si x times. Bloodmeals were identified using the precipitin technique. Anophel es gambiae s.s. showed highly anthropophagic behaviour, taking 88% of blood meals from the human host. In contrast, both strains of An. quadriannulatus fed with equal frequency on the human or the calf; the response to either host was not significantly different. These results confirm the olfactomete r findings and demonstrate anthropophagic behaviour not previously recorded in this species. This finding has implications for prospective manipulatio n of host preference for genetic control purposes.