温度对蠋蝽成虫捕食草地贪夜蛾功能反应的影响

Effects of temperature on the predatory functional response of Arma custos adults to Spodoptera frugiperda

【目的】为明确不同温度条件下蠋蝽Arma custos成虫对草地贪夜蛾Spodoptera frugiperda 4龄和5龄幼虫的生物防控潜能。【方法】在实验室条件下,设置温度为18、22、26和30℃处理,测定蠋蝽雌成虫和雄成虫对草地贪夜蛾4龄和5龄幼虫的捕食功能反应。其中草地贪夜蛾4龄幼虫的密度设为5、10、15、20、25和30头/盒;5龄幼虫密度设为5、8、10、15、20和25头/盒。【结果】不同温度条件下,蠋蝽成虫对草地贪夜蛾4龄和5龄幼虫的捕食功能反应均符合HollingⅡ型方程。随着温度的升高,蠋蝽雌成虫和雄成虫对草地贪夜蛾4龄和5龄幼虫的捕食量增加,且不同温度间捕食量差异显著(F_(3,16)=8.69,P<0.05)。同一温度下,随着猎物密度的增加捕食量明显上升(F_(5,24)=5.53,P<0.05),蠋蝽雌成虫对草地贪夜蛾4龄幼虫的瞬时攻击率在30℃下达到最大值,为0.812,雄成虫在26℃下达到最大值,为0.721;蠋蝽雌成虫对草地贪夜蛾5龄幼虫的瞬时攻击率在26℃下最大,为0.937,雄成虫在30℃下达到最大值,为1.233。在26℃下,雌成虫和雄成虫对4龄和5龄幼虫的最大捕食量均达到最大值,且该温度下雌成虫和雄成虫对4龄和5龄幼虫处理时间均最短。【结论】较高温度下蠋蝽成虫对草地贪夜蛾4龄和5龄幼虫有较强的捕食能力,而低温会抑制其捕食能力。

[Objectives]To clarify the effect of temperature on the ability of adult Arma custos to act as a biological control for 4th and 5th instar Spodoptera frugiperda larvae.[Methods]The predatory functional responses of adult male and female A.custos to 4th and 5th instar S.frugiperda larvae were determined at 4 temperatures(18,22,26 and 30℃)in a laboratory The density of 4th instar larvae was 5,10,15,20,25,30 larvae/box,and that of 5th instar larvae was 5,8,10,15,20,25 larvae/box.[Results]The predatory functional responses of adult A.custos conformed to the HollingⅡequation at each temperature.Temperature had a significant(F_(3,16)=8.69,P<0.05)effect on predation,which increased at higher temperatures.Predation was also significantly(F_(5,24)=5.53,P<0.05)higher at higher prey densities.The maximum rate of instantaneous attack of adult female A.custos on 4th instar larvae(0.812)was reached at 30℃,whereas that of adult males(0.721)was reached at 26.The maximum instantaneous attack rate of adult female A.custos on 5th instar larvae(0.937)was reached at 26℃,whereas that of adult males(1.233)was reached at 30℃.Maximum predation of female and male adults on 4th and 5th instar larvae(23.256,21.834,10.081 and 11.236,respectively)was reached at 26℃.The time required by adult males and females to process 4th and 5th instar larvae(0.043,0.046,0.099 and 0.089 d,respectively)was shortest at this temperature.[Conclusion]The predatory capacity of adult A.custos with respect to 4th and 5th instar S.frugiperda larvae was highest at 26 and 30℃.