小黑瓢虫对高氏瘤粉虱捕食作用的研究

在高氏瘤粉虱不同虫态共存的条件下，小黑标虫对高氏瘤粉虱各虫态的选择次序为卵＞1龄若虫＞2龄若虫＞3龄若虫＞4龄若虫和拟蛹，对卵的捕食率均最高，有明显的嗜好选择；小黑瓢虫幼虫捕食粉虱卵的数量，随着龄期的增长而递增，其中4龄幼虫的捕食量最大，4龄期捕食量平均为1565．42粒，占全幼虫期总食卵量的45．42％，整个幼虫期可捕食高氏瘤粉虱的卵数平均为3446．5粒。小黑瓢虫3龄幼虫对粉虱卵的捕食作用率在所给的猎物密度（1500粒／皿）条件下，随着自身密度的增加而降低。

Predation of Delphastus catalinae (Horn) (Coleoptera: Coccinellidae) to Aleurotuberculatus takahashi (Homoptera : Aleyrodidae)

The choose sequence of the ladybird beetle Delphastus catalinae to different stages of whitefly Aleurotuberculatus takahashi is egg >1 st instar nymph >2 nd instar nymph >3 rd instar nymph >4 th instar nymph and pupa. Delphastus catalinae obviously prefers to the whitefly eggs with the highest predatory rate. The number of whitefly eggs preyed by the beetle larvae increases as the beetle larvae growing up. The predatory count of the 4 th instar beetle larvae is biggest, with 1565.42 eggs on the average during the 4 th instar beetle larva stage, which covers 45.42% of the predatory count (3446.5 eggs) in the whole beetle larva stage. The predatory rate of the 3 rd instar beetle larvae on the whitefly eggs decreases as the density of beetle larvae increasing under 1500 whitefly eggs per treatment.