[Effects of Bacillus thuringiensis transgenic rice and chemical insecticides on arthropod communities in paddy-fields].

This paper assessed the effects of cry1Abl/cry1Ac-carrying transgenic Bacillus thuringiensis rice (Bt rice) and chemical insecticides on the arthropod communities under paddy-field conditions in terms of arthropod guild dominance, family composition and dominance distribution of each guild, individuals of each guild, some common indices of arthropod communities, and community dissimilarity. In most cases, no significant differences were found between the Bt and control rice plots without any chemical insecticide spray in such arthropod community specific parameters as guild dominance, family composition and dominance distribution, temporal dynamics of the individuals of each guild or all arthropod, as well as some common community indices (including species richness, Shannon-Wiener diversity index, evenness index and dominant index) and their temporal dynamics. The similarity of arthropod community between the Bt and control rice plots were apparently higher. It was clear that Bt rice generally showed no marked negative effect on the arthropod community in paddy field. In contrast, some arthropod community specific parameters such as guild dominances in the control plot with chemical insecticide spray were in some cases markedly and even significantly different from those in the control plot without any chemical insecticide spray. The similarity of arthropod community between the control plots with and without chemical insecticide spray was relatively lower. It could be concluded that the effect of Bt rice on the arthropod community was apparently lower than that of chemical insecticides.