[3 combinations of esterases and their relation with the resistance to organophosphate, carbamate, and pyrethroid insecticides in Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) in Cuba].

The possible relationship between different patterns of esterases and the resistance to various types of insecticides was analyzed by bioassays, biochemical tests, and electrophoresis carried out in a population of Culex quinquefasciatus from Camagüey and in three colonies obtained from it by family selection. The original population was heterogeneous and presented 8 combinations of esterases in polyacrylamide gel. A3A6B6, B1B6 and B1A6B6 were the most frequent of them and characterized each selected colony. Every studied colony, including the parental one, showed different levels of resistance to diverse insecticides. Only the resistance to propoxur showed less variation. In every colony it seems to exist a combination of resistance mechanisms; however, the differences found in tests with DEF synergized insecticides show that the different bands of zymograms may represent esterases contributing in a different way to resistance.