Short Communication Do herbicide treatments reduce the sensitivity of mosquito larvae to insecticides

AbstractInvasive mosquitoes are economic and sanitary concerns especially in Europe and America. Most work has emphasized the role ofresistance [Berrada, S., Fournier, D., Cuany, A., Nguyen, T.X., 1994. Identification of resistance mechanisms in a selected laboratorystrain of Cacopsylla pyri (Homoptera: Psyllidae): altered acetylcholinesterases and detoxifying oxidases. Pesticide Biochemistry andPhysiology 48, 41–47; Hemingway, J., Hawkes, N.J., McCarroll, L., Ranson, H., 2004. The molecular basis of insecticide resistancein mosquitoes. Insect Biochemistry and Molecular Biology 34, 653–665] to insecticides. Compounds acting on larval sensitivity to insec-ticides are not well studied and their action remains poorly understood. Among several residual chemicals in ecosystems, particularly inwetlands, we identified a possible interaction of an herbicide on larval resistance to an insecticide. Our work contributes to the globalcontrol of mosquito populations by identifying possible pathways of resistance to insecticides of these vectors. Resistance or toleranceto insecticide treatments might contribute to successful invasion by mosquitoes. Here we report an ecotoxicological approach to test thehypothesis of an indirect effect of atrazine on mortality of an invasive vector. A brief contact (48 h) between Aedes aegypti mosquitolarvae and atrazine led to a modification of larval sensitivity to an insecticide: using atrazine as an inducer led to a decrease in the mor-tality of larvae treated with Bacillus thuringiensis var. israelensis (Bti). 2006 Elsevier Ltd. All rights reserved.