稻田主要捕食性天敌的栖境生态位与捕食作用分析

本文进行了稻田捕食性天敌与稻飞虱的栖境生态位调查，并应用正交试验设计、添加试验法和排除试验法研究了?物种的栖境生态位与各天敌捕食作用的关系，结果表明：在5种灭敌与2种害虫共存系统中，天敌对褐飞虱Nilaparvata lugens Stal捕食量的正主效应大小依次为： 粽管巢蛛 Clubiona aponicola、青翅蚁形隐翅虫Paederus fuscipes、前齿肖蛸Tetragnatha praedonia、食虫沟瘤蛛 Ummeliata insecticeps，拟水狼蛛Pirata subpiraticus的负主效应值最大(随狼蛛密度增大捕食量下降)；对稻纵卷叶螟Cnaphlocrcis medinalis Guenee捕食量正主效应大小依次为： 粽管巢蛛、肖蛸、青翅蚁形隐翊虫。多物种共存系统中，狼蛛、微蛛、跳蛛主要捕食飞虱；肖蛸主要捕食稻纵卷叶螟；管巢蛛对两种害虫均具有较好的控制作用。这与各物种的生态位宽度值相一致。当飞虱密度在每穴10一30头时，多物种共存系统优良的生物序是拟水狼蛛、食虫瘤胸蛛、青翅蚁形隐翅虫各为l头，棕管巢蛛2头，此时天敌的控制作用最大。添加法和排除法试验结果表明在具-定数量的多物种共存系统中，再增加天敌密度不一定能增加猎物的被捕食数，其直接的生物学原因是种间种内干扰(包括种间种内残杀)

HABITAT NICHE AND PREDATION EFFECT OF NATURAL ENEMIES OF INSECT PESTS IN PADDY FIELD

This paper deals with the habitat niche of planthoppers and their predators on rice plant and studied the relationship between the habitat niche and the predation effect in the coexisten-ce system containing two insect pests and five species of predators. The results showed that in the system investigated the magnitude of positive main effect of predation on brown planthop-pers (Nilaparvata lugens) varied with species in a diminishing order as follows. Clubiona japoni-cola, Paederus fuscipes, Tetragnatha praedonia, and Ummeliata insecticeps; while Pirata subpira-ticus exhibited the highest negative effect. The sequence of intensity of positive main effect on rice leaf rollers (Cnaphalocrocis medinalis) was C. japonicola, T. praedonia and P. fuscipes. It had been found that P. subpiraticus, U. insecticeps and Bianor hotingchiehi mainly preyed on planthoppers, T. praedonia on rice leaf rollers and C. japonicola was important for the control of the both pests. These were consistent with their habitat nicie (niche width). Under a certain prey density, the predation effect of the predators reached a maximum when there was a good biological order (i.e. optimal proportion of various specie.;). The results from experiments using addition and exclusion methods indicated that increase in predator density could not increase the number of prey taken in a coexistence system with a defined density in each species. It is believed to be due to the interactions between inter-species and intra-species.