巴氏新小绥螨毒死蜱抗性选育及生物学特性

【目的】明确巴氏新小绥螨Neoseiulus barkeri毒死蜱抗性对其生物学特性的影响，为抗药性捕食螨田间应用提供理论基础。【方法】在室内采用药膜法测定毒死蜱对巴氏新小绥螨的毒力，以半致死浓度(lethal medium concentration, LC₅₀)为选择压力，对巴氏新小绥螨敏感种群进行逐代汰选。应用生命表法分析毒死蜱抗性获得对巴氏新小绥螨相对适合度(relative fitness, Rf)的影响。采用HollingII模型拟合分析不同温度下巴氏新小绥螨毒死蜱敏感和抗性品系对柑橘全爪螨Panonychus citri卵和雌成螨捕食功能反应差异。【结果】经过21代抗性筛选，获得了抗性倍数为34.77倍的巴氏新小绥螨毒死蜱抗性品系。抗性获得对巴氏新小绥螨各发育历期、子代雌性比例和捕食功能反应等特征均无明显影响，但产卵期和雌成螨寿命有所缩短。在15℃时，巴氏新小绥螨敏感品系和抗性品系均无法完成整个世代周期。在25℃条件下，巴氏新小绥螨敏感品系和抗性品系的单雌产卵量均最高，分别为41.64±1.04和38.80±0.93粒/雌，两者差异显著；该温度条件下，巴氏新小绥螨敏感品系和抗性品系的产卵期均最长，分别为24.82±1.50和21.34±1.26 d，两者也存在显著性差异。在30℃条件下，巴氏新小绥螨敏感品系和抗性品系世代周期均最短，分别为6.62±0.23和6.53±0.13 d。同时，该温度条件下，巴氏新小绥螨敏感品系和抗性品系对柑橘全爪螨的捕食能力均最强，其中对卵的最大日捕食量分别为156.25和140.85粒，对雌成螨的最大日捕食量分别为23.10和22.32头。就相对适合度而言，巴氏新小绥螨抗性品系的相对适合度在25和30℃时略低于敏感品系，但在20和35℃时略高于敏感品系。【结论】总体而言，巴氏新小绥螨毒死蜱抗性获得对其在不同温度条件下生物学特性的影响较小。研究结果为巴氏新小绥螨抗性品系筛选及田间应用提供了理论依据。

Resistance selection and biological characteristics of Neoseiulus barkeri (Acari: Phytoseiidae) to chlorpyrifos

【Aim】 To clarify the effects of acquired chlorpyrifos resistance in the predatory mite Neoseiulus barkeri on its biological characteristics, so as to provide a theoretical basis for its field application. 【Methods】 The residual film method was adopted to test the toxicity of chlorpyrifos to N. barkeri in the laboratory, and the lethal medium concentration (LC₅₀) was chosen as the selection pressure. Life table was used to assess the effects of acquired chlorpyrifos resistance on the relative fitness (Rf)of N. barkeri. In addition, Holling type II model was used to analyze the differences in the predation functional response of the chlorpyrifos-susceptible and resistant strains of N. barkeri to eggs and female adults of Panonychus citri at different temperatures.【Results】 A chlorpyrifos-resistant strain of N. barkeri with the resistance ratio of 34.77-fold was obtained after selection of 21 generations. The acquired resistance had no significant effects on the developmental duration, proportion of female offspring and predation functional response of N. barkeri, but shortened the female adult longevity and oviposition period. The susceptible and resistant strains of N. barkeri could not complete the whole generation at 15℃. The fecundity (number of eggs laid per female) of the susceptible and resistant strains of N. barkeri was the highest at 25℃, and the fecundity was significantly higher for the susceptible strain (41.64±1.04 eggs/female) than for the resistant strain (38.80±0.93 eggs/female). Likewise the oviposition periods of the susceptible and resistant strains of N. barkeri were the longest at 25℃, and the oviposition period was significantly longer for the susceptible strain (24.82±1.50 d) than for the resistant strain (21.34±1.26 d). Further, the shortest developmental duration of the susceptible and resistant strains of N. barkeri was recorded at 30℃, being 6.62±0.23 d for the susceptible strain and 6.53±0.13 d for the resistant strain. Meanwhile, the strongest predation ability of the susceptible and resistant strains of N. barkeri to eggs or female adults of P. citri was recorded at 30℃, with the daily maximum predation amounts of the susceptible and resistant strains of N. barkeri to P. citri eggs being 156.25 and 140.85, respectively, and to female adults of P. citri being 23.10 and 22.32, respectively. The relative fitness (Rf) of the resistant strain of N. barkeri was lower than that of the susceptible strain at 25 and 30℃, but slightly higher than that of the susceptible strain at 20 and 35℃. 【Conclusion】 Generally, chlorpyrifos resistance in N. barkeri has little effect on its biological characteristics under different temperatures. The study results provide a theoretical basis for screening resistant strains of N. barkeri and their field application.