耶气步甲对斜纹夜蛾的捕食功能及其扩散能力研究

Predation function and dispersal ability of Pheropsophus jessoensis against Spodoptera litura

【目的】明确耶气步甲(Pheropsophus jessoensis)对斜纹夜蛾(Spodoptera litura)的捕食潜能,为田间利用耶气步甲防控斜纹夜蛾提供参考依据。【方法】在实验室条件下,于直径15.0 cm、高2.0 cm的玻璃培养皿中放置饥饿24 h的耶气步甲成虫及不同密度梯度的4~7龄斜纹夜蛾幼虫和蛹,统计耶气步甲的捕食量,并通过SPSS 26.0、GraphPad Prism 8.0和DPS 5.0等进行生物学统计分析,明确耶气步甲对斜纹夜蛾幼虫和蛹的捕食功能反应及搜寻效应;统计不同密度耶气步甲成虫对不同密度4~7龄斜纹夜蛾幼虫和蛹的捕食量,明确耶气步甲成虫种内干扰对其捕食率的影响;测定耶气步甲成虫在不同环境下的爬行速度,明确耶气步甲的扩散能力。【结果】耶气步甲成虫对斜纹夜蛾4~7龄幼虫和蛹的捕食模型均符合Holling II圆盘模型,对斜纹夜蛾4~7龄幼虫和蛹的日平均捕食量均随着猎物密度的增大而增加,但捕食量增速递减,其中,对4、5、6、7龄幼虫及蛹的最大日均捕食量分别为50.6、17.4、6.6、2.2和1.8头,瞬时攻击率分别为2.079、1.354、1.279、1.619和1.504,处理时间分别为0.013、0.032、0.098、0.383和0.468 d。耶气步甲成虫对斜纹夜蛾4~7龄幼虫和蛹的搜寻效应与猎物密度呈负相关,随着猎物自身密度的增加搜索效应降低,搜寻效应值最高时基本趋近于1.0。耶气步甲成虫分摊竞争强度随着其自身密度对数值的增加呈线性增加,其中对斜纹夜蛾幼虫蛹期的干扰效应最强,分摊竞争强度最高达0.5000,对斜纹夜蛾幼虫期的干扰强度随着龄期的增大而减小。耶气步甲成虫在不同环境中的爬行速度随着环境条件复杂度的增大显著降低(P<0.05,下同),在水平纸面和土面的爬行速度均显著大于水平地表和垂直土面,在水平纸面的平均最大爬行速度达10.5 cm/s。【结论】耶气步甲可捕食斜纹夜蛾的高龄幼虫和蛹,扩散能力相对较强,具有较大的规模化防控斜纹夜蛾潜力。

【Objective】The aim of this study was to evaluate the predation potential of Pheropsophus jessoensison against Spodoptera litura,and provide reference for the application of P.jessoensis in the field to prevent and control S.litura.【Method】One adult of P.jessoensis which had been starved for 24 h was individually placed with 4th-7th instar larvae and pupae of S.litura with different density gradients in a glass Petri dish(15.0 cm diameter,2.0 cm high).The predation amount of P.jessoensis was counted,and statistical analysis was conducted using softwares such as SPSS 26.0,GraphPad Prism 8.0 and DPS 5.0 to elucidate the functional response and search effect of P.jessoensis towards larvae and pupae of S.litura.Additionally,the effect of intraspecific interference on the predation rate of P.jessoensis adults was clarified by quantifying the predation amount of P.jessoensis adults with different densities on 4th-7th instar larvae and pupae of S.li‐tura of different densities.The crawling speed of P.jessoensis adults in different environments was also measured to deter‐mine their dispersal abilities.【Result】The predation models of S.litura 4th-7th instar larvae and pupae by P.jessoensis adults followed a Holling II disk equation model.The daily average predation amount of S.litura 4th-7th instar larvae and pupae by P.jessoensis increased with increase of prey density,although the growth rate of predation gradually declined.The maximum number of prey consumed per day of P.jessoensis adults on the 4th-7th instar larvae and pupae of S.litura were 50.6,17.4,6.6,2.2 and 1.8 insects respectively,and the instantaneous attack rates corresponded to 2.079,1.354,1.279,1.619 and 1.504,with respective handling time of 0.013,0.032,0.098,0.383 and 0.468 d.The search efficiency of P.jessoensis adults on the 4th-7th instar larvae and pupae of S.litura was negatively correlated with prey density.As the prey density increased,the search efficiency deceased,with the highest search efficiency reaching a value close to 1.0.The competition intensity of P.jessoensis adults increased linearly with the increase of its density logarithm.The interference effect on the S.litura pupal stage showcased the highest intensity,with a maximum competition intensity reaching 0.5000.Conversely,the interference intensity on the S.litura larval stage decreased with the increase of instar.The crawling speed of P.jessoensis adults in different environments decreased significantly(P<0.05,the same below)with increasing com‐plexity of environmental conditions,and was significantly greater on both the horizontal paper surface and the soil surface than on the horizontal ground surface and the vertical soil surface,with an average maximum crawling speed of 10.5 cm/s on the horizontal paper surface.【Conclusion】P.jessoensis can prey on the higher instar larvae and pupae of S.litura,with relatively high dispersal ability,and holds potential to control S.litura on a large scale.