斑痣悬茧蜂对不同龄期斜纹夜蛾幼虫的寄生功能反应

Functional Responses of Meteorus pulchricornis(Hymenoptera: Braconidae) to Spodoptera litura Larvae at Different Instars

为评估斑痣悬茧蜂Meteorus pulchricornis(Wesmael)对其寄主斜纹夜蛾Spodoptera litura(Fabricius)幼虫的寄生作用,在室内研究了斑痣悬茧蜂对2、3和4龄斜纹夜蛾幼虫的寄生功能反应和搜寻效率。结果表明斑痣悬茧蜂对不同龄期斜纹夜蛾幼虫的寄生功能反应均符合HollingⅡ型模型的预测,对3龄寄主幼虫的攻击率大于对2龄寄主,对后者的攻击率又大于对4龄寄主幼虫的攻击;寄主处理时间随寄主龄期增大而延长。此外,斑痣悬茧蜂的搜寻效率随寄主密度增加逐渐降低,相同寄主密度下,斑痣悬茧蜂对2、3龄寄主幼虫的搜寻效率均高于对4龄寄主幼虫的搜寻。研究结果说明,斑痣悬茧蜂对斜纹夜蛾低龄幼虫的寄生作用大于对高龄幼虫的寄生。

To evaluate parasitization potential of Meteorus pulchricornis against Spodoptera litura, functional responses to and searching efficiency for 2nd, 3rd and 4th instar host larvae were assessed in the laboratory. Functional responses to host larvae were in line with predictions of Holling type-II model. The attack rate was higher for the 3rd instars than for the 2nd, and was the lowest for the 4th instars. The handling time increased with host instars. Searching efficiency of M. pulchricornis was lower for 4th instars than for 2nd and 3rd instars. Our results suggest that M. pulchricornis may have stronger parasitization potential against younger than older S. litura larvae.