Characteristics of larval anopheline (Diptera : Culicidae) habitats in western Kenya

A longitudinal survey of mosquito larval habitats was carried out in Asembo Bay, western Kenya, during the rainy season of 1998. All pools of standing water along a 700-m transect were sampled twice per week. For each habitat , eight environmental variables were recorded and a sample of anopheline la rvae was collected for identification. In total, 1,751 Alopheles gambiae s. l. and 2,784 Anopheles funestus Giles were identified. Identification of A, 2, gambiae s.l, by polymerase chain reaction (PCR) indicated that 240 (14.7 %) were An, gambiae Giles and 858 (52.4%) were An. arabiensis Patron; PCR f ailed to identify 539 (32.9%) specimens. Repeated measures logistic regress ion analysis indicated that An. gambiae and An. a,arabiensis larvae were as sociated with small, temporary habitats with algae and little or no aquatic vegetation. Anopheles funestus larvae were associated with larger, semiper manent bodies of water containing aquatic vegetation and algae. Direct comp arison of habitat characteristics associated with either An. gambiae or An. arabiensis revealed that algae were associated more commonly with habitats containing An, gambiae; no other differences were detected. Chi-square ana lysis indicated that these species were collected from the same habitat mor e frequently than would be expected by chance alone. Together, these result s indicate that An. gambiae and An. arabiensis have similar requirements fo r the larval environment and that, at least in western Kenya, they do not s egregate into separate habitats.