侧刺蝽对草地贪夜蛾幼虫的捕食能力评价

Predation by Andrallus spinidens on 3rd instar Spodoptera frugiperda larvae

【目的】评价侧刺蝽Andrallus spinidens对草地贪夜蛾Spodoptera frugiperda 3龄幼虫的捕食功能,以明确侧刺蝽对草地贪夜蛾的控害能力。【方法】在室内条件下设置不同密度的草地贪夜蛾3龄幼虫供侧刺蝽捕食,统计侧刺蝽3-5龄若虫及成虫对草地贪夜蛾3龄幼虫的捕食量,研究侧刺蝽对草地贪夜蛾3龄幼虫的捕食功能反应、搜寻效应及自身密度干扰作用。【结果】在设定条件下,不同龄期侧刺蝽的日平均捕食量随猎物密度增加总体上呈上升趋势,5龄若虫的捕食量最大,不同龄期侧刺蝽的捕食功能反应均表现为HollingII功能反应。功能反应参数表明,5龄若虫的捕食能力最强,雄成虫的捕食能力最弱,a/T_(h)值分别为41.241和14.519,4龄若虫的处理时间为0.010 d,明显短于其他龄期。随着猎物密度增加,侧刺蝽的搜寻效应总体上呈下降趋势,干扰作用与侧刺蝽自身密度呈正相关。【结论】侧刺蝽5龄若虫和成虫(雌)食量大、捕食能力强,可作为有效防控草地贪夜蛾种群暴发的备选天敌。

[Objectives]To investigate predation by Andrallus spinidens on 3rd instar Spodoptera frugiperda larvae and thereby determine the potential of using A.spinidens as a biological control for S.frugiperda.[Methods]Third instar S.frugiperda larvae were randomly assigned to different density treatment groups in the laboratory and the number of larvae consumed by 3rd to 5th instar A.spinidens nymphs and adults was measured and compared.The functional response,search effect and the interference effect of A.spinidens density were also estimated.[Results]Under the set conditions,the daily average predation of A.spinidens at different instars showed an overall increasing trend with the increase of prey density,and the predation amount of 5th instar nymphs was the largest,and the predation functional response of A.spinidens at different instars showed a Holling II functional response.The functional response parameters showed that the predatory ability of the 5th instar nymphs was the strongest,and the predatory ability of the male adults was the weakest,withɑ/T_(h) values of 41.241 and 14.519,respectively.The handling time of the 4th instar nymphs was 0.010 d,which was obviously shorter than that of other instars.With the increase of prey density,the search efficiency of decreased in general,and intraspecific interference was positively correlated with the density of A.spinidens.[Conclusion]The 5th instar nymphs and adults(female)of A.spinidens have large food intake and strong predation ability,and can be used as alternative natural enemies to effectively control outbreaks of S.frugiperda.