大突肩瓢虫成虫对桃蚜的捕食作用

目的]了解大突肩瓢虫对桃蚜的捕食能力及其利用价值。方法]在放有1头大突肩瓢虫成虫的培养皿中分别放20、406、0、80、1001、20、1401、601、80头无翅桃蚜,室内自然条件下饲养,研究大突肩瓢虫成虫对桃蚜的捕食作用。结果]1头大突肩瓢虫成虫对无翅桃蚜的平均日捕食量在桃蚜密度为20~120头/培养皿时随桃蚜密度的增大而增大;在桃蚜密度为120头/培养皿时最大,达83.889头;在桃蚜密度大于120头/培养皿时下降。大突肩瓢虫成虫对无翅桃蚜的捕食功能反应符合HollingⅡ型圆盘方程,日最大捕食量的理论值为227.427 8头。结论]在室内自然条件下,大突肩瓢虫成虫对无翅桃蚜的捕食量相当大,是控制桃蚜的重要天敌资源,值得保护,应充分利用。

Predation of Synonycha grandis(Thunberg) Adult on Peach Aphid

Objective] The research aimed to known the predatory capacity and using value of Synonycha grandis(Thunberg) adult on peach aphid.Method] A head of S.grandis adult was put on a culture dish,and then the wingless peach aphids with densities of 20,40,60,80,100,120,140,160 and 180 heads were put on the each culture dish resp.and fed under the lab natural condition to study the predation of S.grandis adult on peach aphid.Result] Average daily predatory number of a head of S.grandis adult on peach aphid increased with the increment of peach aphid density when peach aphids were in 20～120 heads/dish,reached maximum(83.889 heads) and decreased when peach aphids were more than 120heads/dish.The predatory function response of S.grandis adult on the wingless peach aphids accorded to Holling Ⅱtype disc equation,and the theoretical value of maximum daily predatory number being 227.4278 heads.Conclusion] Under the lab natural condition,S.grandis adult had great number predation on peach aphid,so it is the important resource of natural enemy for controlling peach aphids and is worth protecting and being made of full use.