Cuticular hydrocarbon discrimination variation among strains of the mosquito, Anopheles (Cellia) stephensi Liston

Cuticular lipids were removed from adult female Anopheles stephensi Liston and the cuticular hydrocarbons present were separated and quantified by gas chromatography. Comparison was made between the hydrocarbons of four An. stephensi strains: Russ, sensitive to DDT and malathion and originally isolated in the former U.S.S.R.; Beech, a DDT-resistant Indian strain with high sensitivity to Plasmodium species; St Mal, a strain from Pakistan shown to be resistant to malathion; and Iraq, a DDT-susceptible strain from Iraq. Discriminant analysis indicated that the four groups were distinct and that, on average, 78% of the population could be separated on the basis of the quantities of some of the cuticular hydrocarbons. The profiles of Beech and Russ or Russ and St Mal could be separated in 98%,of the cases. There was reduced segregation between the profiles of St Mal and Iraq, suggesting greater similarity in the hydrocarbons of these two strains. The usefulness of cuticular hydrocarbon in determining species relationships is discussed.