关键词: 有机磷, 抗性, 淡色库蚊, 酯酶基因, PCR分型

Abstract: Organophosphate insecticide (OP) resistance in mosquitoes of Culex pipiens complex has been shown to be correlated with the increase in esterase activity resulting from overproduction of the esterase due to amplification of the corresponding structural gene. Several esterase B loci have been identified with Southern hybridization and restriction fragment length polymorphism (RFLP). In this paper, esterase B loci in four OP resistant strains of Culex pipiens pallens were identified with the restriction analysis of PCR fragments. The results indicate that various esterase loci have different selective advantages under different OP pressures. B₁ gene was amplified in temephos-resistant strain, and B₂ gene was amplified in trichlorphon and chlorpyrifos-resistant strains. The hybridzygote of B₁ and B₂ genes was detected in the malathion-resistant strain. Different natural populations of C. pipiens pallens have different probability of B gene distribution. These results are discussed in relation to the selective advantage of esterase genes to OP pressure and mosquito control strategies.

Key words: organophosphate, resistance, Culex pipiens pallens, esterase gene, PCR identification