Insecticide resistance in Chinese populations of the Culex pipiens complex through esterase overproduction

• Published in: Entomologia experimentalis et applicata Vol. 120; no. 3; pp. 211 - 220
• Main Authors: Cui, F, Lin, L.-F, Qiao, C.-L, Xu, Y, Marquine, M, Weill, M, Raymond, M
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.09.2006; Blackwell Publishing Ltd; Blackwell; Wiley
• Subjects: alleles; Biodiversity and Ecology; Biological and medical sciences; carbamate; carbamate pesticides; Culex pipiens; Culicidae; Diptera; Environmental Sciences; esterases; Fundamental and applied biological sciences. Psychology; genetic resistance; geographical variation; insecticide resistance; insecticide resistance genes; insecticides; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; organophosphate; organophosphorus insecticides; overproduced esterases; resistance genes; resistance management; resistance mechanisms; Vectors. Intermediate hosts; China; Asia; China, People's Rep., Guangdong Prov., Guangzhou; China, People's Rep., Beijing; organophosphate; Enzyme; Insecta; overproduced esterases; Parasite; Culex pipiens; Esterases; Defense; Gene; insecticide resistance genes; Arthropoda; Culicidae; Hydrolases; Organophosphorus compounds; Ectoparasite; Pesticide resistance; Invertebrata; Vector; Diptera; Carbamate; Geographical variation
• ISSN: 0013-8703; 1570-7458
• DOI: 10.1111/j.1570-7458.2006.00453.x

In most parts of China, mosquitoes have been subjected to organophosphate (OP) insecticide treatments since the mid-1960s, and resistance gene monitoring in the Culex pipiens complex (Diptera: Culicidae) started in only a few locations from the end of the 1980s. Many resistant alleles at the Ester locus have been found in field populations, including those commonly found around the world (EsterB¹ and Ester²), and those endemic to China (EsterB⁶, EsterB⁷, Ester⁸, and Ester⁹). This situation is atypical, and may represent a complex situation for the evolution of insecticide resistance genes in China. To increase our understanding of the Chinese situation and our ability to manage resistance in the C. pipiens complex, a large study was performed. Twenty field populations were sampled from Beijing to Guangzhou. Bioassays with five insecticides (dichlorvos, parathion, chlorpyrifos, 2-sec-butylphenyl methyl carbamate, and propoxur) disclosed resistance levels variable according to the geographic origin, and up to 85-fold for dichlorvos. Six overproduced esterases were identified, including two that have not been previously described. Most of them were found in all samples, although at variable frequencies, suggesting variable selection or a transient situation, e.g., each one was recently restricted to a particular geographic area. The results are discussed in the context of recent alterations to insecticide campaigns, and of the evolution of resistance genes in Chinese C. pipiens populations.