论文部分内容阅读
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。
The host identification period of parasitoids is one of the most important parameters to construct the optimal host model. In this study, the identification period of Meteorus pulchricornis on Spodoptera exigua larvae at different instars was observed, and the risk of host parasitism was estimated by survival analysis for the first time, and the effect of parasitism on the host identification period . The results showed that all the larvae of all ages (2-5 instars) were parasitized except for the first-instar larvae during the 2.5h observation period. The Cox regression model fitting analysis of the first host-identification period showed that the larvae of 2nd instar larvae (Reference insects ages), the cumulative risk ratio of host parasites 3 to 5 years old was significantly higher than that of second-instar larvae (2.6-4.0 times), while the re-host identification period found no 3 ~ There was a significant difference between 5th instar larvae and 2nd instar larvae. According to the comparison of survival curves between the first and the second host identification, the second host identification period of 2-4 instar larvae was significantly shorter than that of the first host identification, indicating that parasitism significantly increased the host identification period of parasitoid. It is speculated that the higher age beet armyworm larvae parasites were parasitic risk of non-parasitic spotted mole nematode was higher than younger larvae.