Effcets Of Transgenic Insect-resistant Rice On Nontarget Arthropods And The Selection Of Bioindicator

The effects of transgenic insect-resistant rice on non-target arthropods and the selection of bioindicators were investigated in2009and2010at the "Shoushan Experimental station", Fujian Province. Transgenic insect-resistant rice (IIYKF8) was transfected with both the crylAc and SCK genes, and a non-transgenic rice isoline (IIYM86) was used as a control. The results are as follows:IIYKF8was highly resistant to the rice leaf roller Cnaphalocrocis medinalis both in monoculture and when intercropped with IIYM86in the field. The paddy field with Bacillus thuringiensis bacterial pesticide showed no significant resistance to the leaf roller Cnaphalocrocis medinalis.Transgenic insect-resistant rice had no significant effects on the community characteristics of nontarget pests, neutral arthropods or predatory insects. Monocultured transgenic insect-resistant rice exerted negative effects on parasitoids, but these effects disappeared with intercropping. The community characteristics of the spiders showed significant differences between various treatments in2009; however, the2010results yielded no significant differences. The results for both2009and2010showed no significant differences between the community characteristics of spiders in the transgenic insect-resistant rice field and control field when they were both included in the monoculture. In other words, transgenic insect-resistant rice had no significant effect on the community characteristics of nontarget arthropods.Communities of nontarget pests, predatory insects and neutral arthropods all showed high similarities between the various treatments. Parasitoid communities from different treatments showed high similarities in2009, but the2010results showed that the two treatment levels of transgenic insect-resistant rice and the three treatment levels of control rice could be considered two assemblages. The spider communities of two of the monocultured paddy fields and the remaining three paddy fields could be identified as two assemblages to some degree. In general, communities of nontarget arthropods showed high similarities among different paddy fields, and there were no significant differences in their composition between the various treatments.Both species richness and species composition were significantly correlated among most groups, with the exception of the species richness of parasitoids and predatory insects, which indicates that no taxon has the classic characteristics of a bioindicator.