中文摘要：

寄生蜂的寄主识别期是构建最优接受寄主模型的重要参数之一。本研究观察了斑痣悬茧蜂（Meteorus pulchricornis）对甜菜夜蛾（Spodoptera exigua）不同龄期幼虫的识别期,并首次用生存分析方法估计寄主被寄生的风险以及寄生经历对寄主识别期的影响。结果表明：在2.5h观察期内,除1龄寄主幼虫外,其他各龄（2-5龄）幼虫均被寄生;对首次寄主识别期的Cox回归模型拟合分析表明,与2龄寄主幼虫（参照虫龄）相比,3-5龄寄主幼虫被寄生的累计风险比率显著高于2龄寄主幼虫（2.6-4.0倍）,而对再次寄主识别期的分析未发现3-5龄寄主幼虫与2龄幼虫之间存在显著差异。根据对首次与再次寄主识别期进行的生存曲线比较表明,对2-4龄幼虫的再次寄主识别期显著短于首次寄主识别期;说明寄生经历显著提高了寄生蜂的寄主识别期。由此推测,较高龄期甜菜夜蛾幼虫被无寄生经验斑痣悬茧蜂寄生的风险高于低龄幼虫。

英文摘要：

Host recognition time is one of the important parameters in optimal host acceptance models. Aimed to assess the parasitization hazard of different Spodoptera exigua instar larvae by Meteorus pulchricornis, the host recognition time for first and successive attacks were recorded under non-choice condition, and fitted by the Cox proportional hazard model of survival analysis. In the meantime, the survivor functions of different instar larvae as affected by parasitization experience were estimated by Kaplan-Meier method. The Cox proportional hazard model fitting with the host recognition time for first attack showed that host L1 was not susceptible to parasitism, but L3, L4, and L5 were more prone to be attacked than L2 by 2. 6-4. 0-fold. However, the modelfitting with the host recognition time for successive attacks did not detect significant differences among host instars. The survival curves measuring the fraction of unparasitized host larvae were compared for the first and successive attacks, which ＂indicated that the host recognition time for the first attack of L2, L3, and L4 was much less than that for the successive attack. It was suggested that higher instar larvae were more likely to be attacked by naive parasitoids.