Abstract: In this paper, a laboratory study was made on the predation of Orius minutus on the 3rd~4th instar nymphs of Odontothrips loti, and the intraspecific interference within O. minutus. The results showed that the functional responses of adult O. minutus to O. loti nymphs fitted Holling II type equation, i.e., N_a＝1.0113N／(1＋0.04149N) in test tubes, N_a＝0.6777 N／(1＋0.03395N) in Petri dishes, and N_a＝0.6417 N／(1＋0.03934 N) in enveloped pots. The predation of O. minutus had strong intraspecific interference, and the relationship between predation efficiency and individual interference fitted Hassell model. Under the same spatial conditions, the predation rate of O. minutus was positively related, while its searching efficiency was negatively associated with the prey density. With the increase of the space, the attack rate (a′) and maximum predation (N_a) of O. minutus decreased, its handling time (T_h) increased, while the type of its functional responses to the densities of 3 rd~4 th instar O. loti, still fitted Holling II model.

Key words: canopy, broadleaf plant, leaf dry mass., leaf length and width ratio, empirical model, leaf area