异色瓢虫显明变种对白杨毛蚜和白毛蚜选择效应研究

Study on the Selective Effect of Harmonia axyridis(Pallas) var.spectabilis to Chaitophorus populeti and C.populiabae

[目的]探究异色瓢虫显明变种对杨树主要蚜虫白杨毛蚜和白毛蚜的捕食选择趋性。[方法]在实验室条件下,在特定空间内,测定异色瓢虫显明变种对2种蚜虫不同密度值下的捕食量。[结果]白杨毛蚜和白毛蚜种群数量同步增加时,EG-S值和EJ值变化为+1～0,EI值是在0～-1范围内依次减少,且数值变化幅度较少,表明异色瓢虫显明变种喜好捕食白毛蚜略高于白杨毛蚜;当白杨毛蚜数量不变、白毛蚜数量增加时,EG-S值和EJ值变化为+1～∞,EI值在0～+1范围内依次增加,表明异色瓢虫显明变种明显喜好捕食白毛蚜;当白毛蚜数量不变、白杨毛蚜数量增加时,EG-S值和EJ值变化为在+1～0范围内依次减少,EI值在0～-1范围内依次增加,表明异色瓢虫显明变种明显喜好捕食白杨毛蚜。捕食量结果同选择指数。[结论]异色瓢虫显现变种白杨毛蚜和白毛蚜的捕食选择趋性取决于2种蚜虫的种群数量。

[Objective] To explore the selective predation of Harmonia axyridis（Pallas） var.spectabilis,to Chaitophorus populeti（Panzer） and C.populiabae（Boyer de Fonseolombe）.[Method] Under the experimental conditions,the predation amount of the two aphids by Harmonia axyridis（Pallas） var.spectabilis at different densities was detected.[Result] When the number of the two pest populations increased synchronously,EG-S and EJ changed from ＋1 to 0,EI decreased gradually within the range of 0 to-1,and the decrease extent was small,indicating that the ladybird preferred preying C.populiabae to C.populeti;when the quantity of C.populeti stayed unchanged and the quantity of C.populiabae increased,EG-S and EJ changed from ＋1 to ∞,EI increased gradually within the range of 0 to ＋1,indicating that the ladybird liked to prey C.populiabae;when the quantity of C.populiabae stayed unchanged and the quantity of C.populeti increased,EG-S and EJ gradually decreased from ＋1 to 0,EI gradually increased within the range of 0 to-1,indicating that the ladybird prefer to prey C.populeti.The predation amount was the same to the selection index.[Conclusion] The selective predation of Harmonia axyridis（Pallas） var.spectabilis to those two aphids depended on their population quantity.