Sensitivity of different strains of Drosophila melanogaster to endosulfan and malathion.

Four Drosophila melanogaster populations, two of them (ER1 and ER2) previously selected for adult resistance to endosulfan, were examined for response to endosulfan and malathion treatment. Both insecticides were fed to larvae and adult males and females to test their toxic capacity. Our results show that malathion is more toxic than endosulfan, that adult males are more sensitive to both insecticides than females, and that resistance of ER1 and ER2 strains is restricted to the insecticide to which they had been exposed previously (endosulfan).