【目的】 在中国海南省，普通大蓟马Megalurothrips usitatus（Bagrall）是豇豆Vigna unguiculata (L.) Walp.上的重要害虫，化学防治还是重要的控制手段。本研究旨在了解3种杀虫剂亚致死浓度对该虫繁殖的影响。【方法】 在（26±1）℃、相对湿度60%±5%、光周期L∶D = 14∶10条件下，采用叶盘浸药法测定溴氰虫酰胺、双甲脒和茚虫威48 h内对普通大蓟马1日龄已交配雌虫的毒杀效果。经杀虫剂LC₂₀处理的幼嫩豇豆叶叶盘供已交配雌虫和未交配雌虫取食48 h后，改用未浸药叶盘继续饲养。每天观察雌虫所产子代的卵数和成虫数，计算已交配雌虫的子代成虫性比和卵性比。【结果】 3种杀虫剂LC₂₀处理均使亲代雌虫的存活时间显著缩短。溴氰虫酰胺和双甲脒LC₂₀处理还能显著降低已交配亲代雌虫在胁迫处理后所产子代的成虫数量。亲代雌虫经溴氰虫酰胺、双甲脒和茚虫威LC₂₀处理后的子代成虫性比分别为0.60、0.47和0.41，与清水对照（0.52）之间的差异均未达显著水平；卵性比在各处理之间都没有显著差异。【结论】 溴氰虫酰胺、双甲脒和茚虫威LC₂₀处理对普通大蓟马亲代雌虫的存活时间和子代成虫数量有不同程度的负面影响，但对子代性别分配均没有显著的干扰作用。

[Objectives]  The aim of this paper is to explore the sublethal effects of three insecticides on reproduction of bean flower thrips [Megalurothrips usitatus (Bagnall)], one of the most economically important insect pests of cowpea [Vigna unguiculata (L.) Walp.] in Hainan Island, China. [Methods]  Under laboratory conditions of (26±1) ℃, 60%±5% R.H. and a photoperiod of 14L∶10D, with young leaves of cowpea (var. Chunfeng-changjiangdou) as food of the bean flower thrips, the lethal and sublethal concentrations of cyantraniliprole, amitraz, and indoxacarb for the 1-d-old mated adult females were determined using a leaf-disc dipping bioassay method. After 48 h exposure to LC₂₀ concentration of each insecticide, the surviving mated or unmated adult females were provided with non-treated leaf discs. The number of eggs and subsequent adult offspring were counted daily until the parental females died. Sex ratios of adult offspring produced by mated females were calculated as proportion of males, and then sex ratios of eggs laid by them were estimated using survival rates of the offspring produced by both mated females and unmated females. [Results]  Exposure to three insecticides at LC₂₀ concentration all significantly decreased the survival duration of either mated or unmated females. The number of adult offspring produced by mated females exposed to cyantraniliprole and amitraz were also significantly reduced. Sex ratios of adult offspring produced by mated females following sublethal exposure to cyantraniliprole, amitraz, and indoxacarb were 0.60, 0.47, and 0.41, respectively, which all were not significantly different from that of control. There was no significant difference in sex ratio of eggs laid by mated females among insecticide treatments and control. [Conclusion]  Sublethal exposure to cyantraniliprole, amitraz, and indoxacarb decreases to some extent the survival duration of the parental females of the bean flower thrips, and the number of adult offspring produced by them, but does not significantly change their sex allocation.