Ecological requirement. The A. gambiae Xxxxx complex comprises six named species, one unnamed species and several ‘incipient’ species. It includes two of the most effective vectors and a third minor vector of malaria parasites in Africa (Gillies & Xxxxxx, 1987, Xxxx et al. 1998). The breeding habitats of these spe- cies, notably A. gambiae s.s. A. arabiensis, and X. Xxxxx, are generally similar with slight varia- tions. The larvae of A. gambiae are commonly found in clear, sunlit pools of water in small depres- sions such as foot or hoof prints, the edges of bore holes and xxxxxx pits, roadside puddles formed by tire tracks, irrigation ditches and other man-made shallow water bodies [Mutuku et al 2007]. They have also been found breeding in polluted water rich in organic matter [Xxxxxxx et al 2004,Xxxxxx et al 2010], in large bodies of water such as flood plains, and in pools of water along lake shores especially when there are fluctuations in water level as occurs in Lake Victoria in Kenya [Xxxxxxxx et al 2008]. Environmental alterations due to deforestation, swamp reclamation mainly for agriculture, excavation of sand and building stones, brick making and vegetation clear- ance may lead to an increase in larval habitats [Xxxxxxx et al 2004]. Grass growing in the larval habitats seems to be an additional requirement, since habitats with grass growing in them have been found to have more larvae than habitats with other vegetation types or open habitats [Imba- xxxx et al 2011], Xxxxxxxxx and others [2004]. These observations suggest that grass protects mos- quito larvae from being swept or flushed away by running water [Paaijmans et al 2007]. Grass could also be convenient in offering newly emerged adult and gravid mosquitoes a shaded resting site. Consequently, this may lead to an increase in mosquito-human contact, eventually leading to an increase in malaria transmission.
Ecological requirement. A. arabiensis is considered a species of dry, savannah environments and sparse woodland [Coet- zee et al 2000], yet it is known to occur in forested areas, but only where there is a history of recent land disturbance or clearance [Xxxxxxx et al 2000]. Its larval habitats are similar to those of A. gambiae: generally small, temporary, sunlit, clear and shallow fresh water pools [Gimnig et al 2001], although A. arabiensis is able to utilize a greater variety of locations than A. gambiae, in- cluding slow flowing, partially shaded streams [Shililu et al 2003] and a variety of large and small natural and man-made habitats. It has been found in turbid waters [Xxxxxx et al 2001, 2000] and, on occasion, in brackish habitats [Xxxx et al 2003]. It readily makes use of irrigated rice fields, where larval densities are related to the height of the rice, peaking when the plants are still rela- tively short and then dropping off substantially as the rice plants mature [Xxxxxx et al 2000, Mwan- xxxxx et al 2007, Xxxx et al 2000]. A. arabiensis rapidly colonize rice fields where land use land cover change occurs (Dolo et al 2000).
