七星瓢虫对萝卜蚜和桃蚜捕食功能的初步研究

STUDY ON PREDATORY FUNCTION OF COCCINELL SEPTEMPUNCTATA TO THE CRUCIFEROUS VEGETABLE APHIDS (LIPAPHIS ENYSIMI AND MYZVS PERSICAE)

七星瓢虫（Ｃｏｃｃｉｎｅｌｌｓｅｐｔｅｍｐｕｎｃｔａｔａ）是山东十字花科菜田捕食菜蚜（萝卜蚜Ｌｉｐａｐｈｉｓｅｒｙｓｉｍｉ和桃蚜Ｍｙｚｕｓｐｅｒｓｉｃａｅ）的天敌优势种，其捕食能力强、发生盛期较莱蚜早，对莱蚜发生具较强的自然控制能力．室内研究了七星瓢虫各龄幼虫及成虫对萝卜蚜和桃蚜的捕食功能反应，结果表明，其功能反应均属ＨｏｌｌｉｎｇⅡ型；七星瓢虫对萝卜蚜和桃蚜均具较大的捕食潜力；１、２龄幼虫捕食量较小，且差异不大，而３龄后捕食量迅速上升，至产卵前成虫达高峰，同样条件下七星瓢虫对桃好的捕食量大于对萝卜好的捕食量；模拟后的各方程理论值与实测值相差不大，相关系数（ｒ）均大于０．９９．

Coccinella septempunctata is one of the dominant species of natural enemiesof predating Aphids in the Cruciferous vegetables(Lipaphis erysimi and Myzus persicaeand has good control effect on the aphids in nature because its occurance peak is earlierthan that of the aphids and the predatory capability is stronger.The functional responseof C.septmpunctata to Lipaphis erysimi and Myzus persicae was studied in laboratory.The results showed that their functional response all belonged to Holling Ⅱ type. C.septempunctata had bigger predatory potential to 2 species of Aphids. The predatorynumber of 1-2 instar larvae of the predators were lower and similar.They increasedrapidly from 3 instar larvae and reached the limit in the stage of adults. In the same condition,the catching number Myzus persicae by C. septempunctata were more than that toLipaphis rvsimi. The theoretical expection fits the'observed values and r>0. 99.