甜菜夜蛾抗氯氟氰菊酯品系相对适合度、抗性生化机理及抗性遗传方式

比较了甜菜夜蛾Spodoptera exigua 抗氯氟氰菊酯品系和敏感品系的繁殖和生长发育特征。结果表明：抗性品系幼虫发育历期延长、蛹重减轻、化蛹率和产卵量降低，抗性品系的适合度为0.61，抗性品系在繁殖和生长发育上存在明显的生存劣势。用两品系3龄幼虫分别测定胡椒基丁醚（PBO）、增效磷SV₁）、脱叶磷（DEF）和顺丁烯二酸二乙酯（DEM）对氯氟氰菊酯的增效作用，抗性品系增效倍数与敏感品系增效倍数之比分别为14.1、14.8、2.3和2.3倍，胡椒基丁醚和增效磷对氯氟氰菊酯增效作用最明显，表明多功能氧化酶参与了甜菜夜蛾对氯氟氰菊酯的抗性。抗性品系3龄幼虫酯酶和谷胱甘肽S-转移酶的活性分别为敏感品系的1.05倍和0.91倍， 抗性品系5龄幼虫多功能氧化酶O-脱甲基活性为敏感品系的1.05倍，两品系间3种酶的活性差异不显著，表明甜菜夜蛾对氯氟氰菊酯的抗性与酯酶、谷胱甘肽S-转移酶及多功能氧化酶O-脱甲基酶活性无关。用剂量对数死亡机率值回归线分析法研究甜菜夜蛾对氯氟氰菊酯的抗性遗传规律，表明甜菜夜蛾对氯氟氰菊酯的抗性为常染色体遗传、多基因控制；正、反交后代的显性度分别为0.61和0.43，抗性遗传为不完全显性。

Biochemical mechanism and genetics of resistance to lambda-cyhalothrin in the beet armyworm, Spodoptera exigua, and the relative fitness of the resistant strain

Comparison of the relative fitness of lambda-cyhalothrin resistant and susceptible strains of the beet armyworm, Spodoptera exigua (Hübner), indicated that the resistant strain possessed reproductive and developmental disadvantages, including lower pupation and oviposition rates, prolonged larval period and lighter weight. The biochemical mechanism of resistance to lambda-cyhalothrin was investigated using enzyme synergists (PBO, SV1, DEF and DEM) and enzymatic activity assays of esterase, glutathione S-transferase and microsomal O-demethylase. The synergistic ratios of PBO, SV₁, DEF and DEM were 14.1, 14.8, 2.3 and 2.3 folds between resistant and susceptible strains respectively. Synergism to lambda-cyhalothrin by PBO and SV1 was the most distinct. This implied that mixed-function oxidase was involved in the resistance to lambda-cyhalothrin. The ratios of the enzymatic activity of esterase, glutathione S-transferase and microsomal O-demethylase in resistant and susceptible strains were 1.05, 0.91 and 1.05 folds, respectively. These results indicate that detoxification enzymes such as esterase, glutathione S-transferase and microsomal O-demethylase contribute little to the resistance of the beet armyworm to lambda-cyhalothrin. The results of genetic analysis indicated that lambda-cyhalothrin resistance in the beet armyworm appears to be controlled by two or more autosomal genes. The dominance degrees (D) of the F1 progenies from the reciprocal crosses (F₁, R_♀×S_♂ and F’1, R_♂×S_♀) were 0.61 and 0.43, respectively, and the major gene(s) involved is incompletely dominant. The resistant strain possessed 0.61 of the fitness value relative to the isogenic susceptible strain.