DDT-resistance and dieldrin-resistance in Anopheles albimanus

The nature and mode of inheritance of the component resistances of a multi-resistant strain of Anopheles albimanus from El Salvador are described. Dieldrin-resistance is shown to be dependent on a single, semi-dominant, genetic factor and imparts cross-resistance to other cyclodiene chlorinated hydrocarbons and to gamma-BHC. DDT-resistance imparts cross-resistance to DDT-analogues and is dependent on a single, recessive, genetic factor. The two resistances are separate entities and can, in fact, be separated. The modes of inheritance of the two types of resistance are the same in both larvae and adults.