异色瓢虫和龟纹瓢虫幼虫对番茄潜叶蛾低龄幼虫的捕食功能反应

为明确异色瓢虫Harmonia axyridis和龟纹瓢虫Propylea japonica对番茄潜叶蛾Tuta absoluta的控害能力。本试验在实验室条件下选取异色瓢虫和龟纹瓢虫4龄幼虫对番茄潜叶蛾低龄幼虫(1龄、2龄)的捕食功能反应和搜寻效应进行系统研究。结果表明,异色瓢虫和龟纹瓢虫4龄幼虫对番茄潜叶蛾低龄幼虫的捕食功能反应均符合HollingⅡ模型;两种瓢虫的日捕食量与猎物密度在一定范围内呈正相关关系,当猎物密度N→+∞时,异色瓢虫和龟纹瓢虫对番茄潜叶蛾1、2龄幼虫的理论日最大捕食量Na_max分别为147.06头、140.85头和333.33头、149.25头。异色瓢虫的最高日捕食率达98%,显著高于龟纹瓢虫的最高日捕食率79%。两种瓢虫对番茄潜叶蛾搜寻效应随猎物密度的增大而降低,且异色瓢虫对番茄潜叶蛾的搜寻效应显著高于龟纹瓢虫,异色瓢虫对番茄潜叶蛾低龄幼虫的最高搜寻效应高于0.90,而龟纹瓢虫对番茄潜叶蛾低龄幼虫的最高搜寻效应低于0.80。异色瓢虫对番茄潜叶蛾低龄幼虫的捕食能力稍强于龟纹瓢虫,但两种瓢虫对番茄潜叶蛾低龄幼虫均有较好捕食作用,可在一定程度上控制低龄幼虫的数量,故可将两种瓢虫作为番茄潜叶蛾重要的生物防治材料加以研究和利用。

Predatory Function of Harmonia axyridis and Propylea japonica Larvae to Young Larvae of Tuta absoluta

The control ability of Harmonia axyridis and Propylea japonica on Tuta absoluta was evaluated by investigating the predatory function and searching responses of the 4^th instar larvae H.axyridis and P.japonica to the young larvae of T.absoluta (1^stand 2^nd instars) under laboratory conditions.The results showed that the predatory functional responses of the 4^th instar larvae H.axyridis and P.japonica to the 1^st and 2^nd instar larvae of T.absoluta conformed to HollingⅡ model;the daily predation of the two ladybirds species was positively correlated with the prey density within a certain range,when the T.absoluta density was N→+∞,the maximum daily predation Na_maxof H.axyridis and P.axyridis to the 1^st instar T.absoluta larvae were 147.06 and 333.33,respectively,and to the 2^nd instar T.absoluta larvae,140.85 and 149.25,respectively.The highest daily predation rate of H.axyridis reached 98%,significantly higher than that of P.axyridis.The searching efficiency of the two ladybirds species on T.absoluta decreased with the increase of prey density,which was higher in H.axyridis than in P.axyridis.The highest searching efficiency of H.axyridis was >0.90,while that of P.axyridis was<0.80.The predatory ability of H.axyridis to low instar larvae of T.absoluta was slightly stronger than that of P.axyridis,but both the ladybirds species afforded high predation and control of young larvae of T.absoluta.The two ladybirds species can be further studied as important biological control agents for control of T.absoluta.