关键词: 中华按蚊, 拟除虫菊酯, 氟氯氰菊酯, 亚致死效应, 年龄-龄期两性生命表

Abstract: 【Aim】 Cyfluthrin, a novel pyrethroid insecticide, is extensively used in the control of agricultural and sanitary pests. This study aims to explore the sublethal effects of cyfluthrin on Anopheles sinensis and provide a theoretical foundation for the rational use of cyfluthrin in the control of An. sinensis.【Methods】 The 4th instar larvae of An. sinensis were treated with cyfluthrin for 24 h using the larval immersion method recommended by the World Health Organization (WHO). The LC₁₀ and LC₃₀ values of cyfluthrin against the 4th instar larvae of An. sinensis were determined. The 4th instar larvae of An. sinensis were exposed to LC₁₀ and LC₃₀ of cyfluthrin for 24 h by the larval immersion method. The female and male adult longevity and number of eggs laid per female of the F₀ generation were recorded. The eggs laid by the female adults of the F₀ generation were collected and used as the F₁ generation insects. The hatching rate, duration of each developmental stage, emergence rate, adult pre-oviposition period, total pre-oviposition period, and number of eggs laid per female of the F₁ generation were counted. Life table was constructed to predict the population dynamics of An. sinensis in each treatment. 【Results】The LC₁₀ and LC₃₀ values of cyfluthrin against the 4th instar larvae of An. sinensis after 24-h exposure were 1.223×10^-3 and 4.454×10^-3 mg/L, respectively. In comparison to the control (exposure to dechlorinated tap water), exposure of the 4th instar larvae of An. sinensis to LC₁₀ and LC₃₀ of cyfluthrin significantly reduced the male adult longevity and the number of eggs laid per female of the F₀ generation, and exposure of the 4th instar larvae of An. sinensis to LC₃₀ of cyfluthrin also significantly shortened the female adult longevity of the F₀ generation. f_x7 curves showed that exposure of the 4th instar larvae of An. sinensis to LC₁₀ and LC₃₀ of cyfluthrin reduced the numbers of oviposition days and eggs laid by female adults of the F₁ generation, and decreased the peak values of l_xm_x, m_x and v_xj in the F₁ generation, compared with the control group. Exposure of the 4th instar larvae of An. sinensis to LC₁₀ of cyfluthrin delayed the peak of m_x in the F₁ generation, while exposure of the 4th instar larvae of An. sinensis to LC₃₀ of cyfluthrin advanced the peak of m_x in the F₁ generation. The s_xj, l_x and e_xj curves showed that exposure of the 4th instar larvae of An. sinensis to LC₁₀ and LC₃₀ of cyfluthrin had a beneficial effect on the survival rate and life expectancy of the F₁ generation. In the treatment group with LC₁₀ of cyfluthrin, the pupal duration and pre-adult duration of the F₁ females and the egg duration of the males were significantly prolonged, while the longevity and total developmental duration of the F₁ males were significantly shortened, as compared to those in the control group. The stress of cyfluthrin at LC₁₀ and LC₃₀ to the 4th instar larvae of An. sinensis significantly increased pre-adult survival rate of the F₁ generation, yet significantly reduced the number of eggs laid per F₁ female. Furthermore, exposure of the 4th instar larvae of An. sinensis to LC₁₀ of cyfluthrin significantly prolonged the mean generation time (T) of the F₁ generation; in contrast, exposure of the 4th instar larvae of An. sinensis to LC₃₀ of cyfluthrin significantly shortened the mean generation time of the F₁ generation. 【Conclusion】The stress of cyfluthrin at the sublethal concentrations (LC₁₀ and LC₃₀) significantly inhibited the reproductive capacity of the F₁ generation of An. sinensis, but increased the survival rate and life expectancy of the F₁ generation, resulting in no significant impact on the F₁ population size. These findings provide a theoretical foundation for the rational use of cyfluthrin in the control of An. sinensis.

Key words: Anopheles sinensis, pyrethroid, cyfluthrin, sublethal effect, age-stage, two-sex life table