Sampling the Larval Population

Mosquito larvae and pupae are found in a great variety of habitats, ranging from large expanses of water such as swamps, marshes and rice fields to small collections of water in tyres, domestic utensils, tree-holes, plant axils, snail shells and fallen leaves. A number of often arbitrary classifications of larval habitats have been used (Almirón and Brewer 1996; Bates 1949; Boyd 1930; Hopkins 1952; Mattingly 1969; Mogi 1981). Almirón and Brewer (1996) coded habitat characteristics using a binary presence/ absence system and related these characteristics to the species of mosquito collected in the different habitats in Córdoba, Argentina. A basic matrix of data comprising 19 rows (species) and 86 columns (habitat characteristics) was prepared and species and habitat associations were determined. Other systems have been proposed by Service (1993a), and by Laird (1988) who gives a useful review of past classifications and presents much detail on the community ecology of mosquito larval habitats. Joy and Hildreth-Whitehair (2000) developed a classification of the larval habitats of Ochlerotatus triseriatus, the vector of LaCrosse encephalitis, in West Virginia, USA that was based on Laird’s (1988) proposed standard system, but with the addition of sunlit or shaded as criteria. Joy and Clay (2002) presented a classification of mosquito larval habitats also in West Virginia, USA comprising seven major sunlit categories and eight shaded categories.