蜘蛛对稻纵卷叶螟和白背飞虱的选择捕食作用

讨论蜘蛛的主要种群拟水狼蛛、食虫瘤胸蛛、粽管巢蛛对稻纵卷叶螟、白背飞虱的选择捕食特性。由结果可见：猎物被捕食量与参试种群编码值（密度）的数量关系可由二次多项式模型技术。当取每科水稻上有稻纵卷叶螟５头，白背飞虱１０头，拟水狼蛛２头，粽管巢蛛２头，食虫瘤胸蛛２头时，蜘蛛种群对白背飞虱有较大的选择捕食比率。

The Selective Predation of the Spider in Rice Ecosystem on the Rice Leaf Roller(Cnapholocrocis medinalis)and Whteback Planthopper(Sogatella furcifera)

The spider was the main compenent of the predator in rice field. The predator was animportant factor which effected on the population dynamics of the main rice insect pests,rice leafroller(Cnapholocrocis medinalis,RLF),whiteback planthopper(Sogatella furcifera,WBPH) andthe brown planthopper(Nilaparvata lugens,BPH).In this paper the selective predations of the spi-ders,wolf spider (Pirata subpiratus),hunting spider(Clubiona japonicola)and the dwarf spider(Odeothroax insecticeps) on RLF and WBPH were studied.The results showed that the relationshipsbetween the number attacked of host and the code of the experiment popsilation could been describ-ed with the quadratic model.When the defisity of the RLF was 5 per hill of rice,the WBPH was10,the density of each spider was 2,at this combination the spider perfered to prey the WBPH.