THE EFFECTS OF SUBLETHAL DOSES OF HEXAFLUMURON ON THE FEEDING-BEHAVIOR OF MOSQUITOS (DIPTERA, CULICIDAE)

This paper presents the first report on the sublethal effect of an insect growth regulator (IGR), hexaflumuron, on the feeding behaviour of vector mosquitoes, Culex quinquefasciatus Say, Aedes aegypti (Linnaeus) and Anopheles stephensi Liston. Percentage engorgement and feeding behaviour of the adults of the three species emerged after sublethal exposures at the larval and pupal stages were markedly affected. Depression in blood feeding was significantly higher in Aedes aegypti with lower blood engorgement ratio. The proportion of females that failed to take a blood meal was higher in A. aegypti (30.2%) than in the other species when pupae had been exposed to 0.05 mg/l hexaflumuron. Depression in blood feeding was probably due to abnormalities in the functioning of the mouth parts and feeding behaviour. No adverse effect on the feeding activity was noticed in the F1 generation of the treated species.