Abstract: Characteristics and dynamics of arthropod communities were investigated in three experimental plots of cotton, the plot where the transgenic Bt cotton R93-6 was planted and integrated pest management was carried out (IPM), the plot of the Bt cotton in which pests were controlled only by their natural enemies (NEC), and the control plot of routine cotton CCRI No. 16 with no insecticide application throughout whole growing seasons (CK). The results showed that the diversity indexes and evennesses of insect community, pest and natural enemy sub-communities were lower in NEC than in CK, while their dominant concentrations were higher than that in CK. So the insect community, pest and natural enemy subcommunities had poorer stability in NEC than in CK, suggesting some species of pests might go into outbreak. The insect community and pest sub-community in IPM were more stable as compared with those inNEC and CK. The analyses on seasonal change in the insect community in NEC showed it could be divided into three stages. The first stage was from early June to late July, the second one from the end of July to the end of August, and the third one after September. The corresponding management strategies against the insect pests were put forward according to occurring characteristics of insect pests and their natural enemies during these three stages.

Key words: transgenic Bt cotton, insect community, integrated pest management