No Effect of Bt-transgenic Rice on the Tritrophic Interaction of the Stored Rice, the Maize Weevil Sitophilus Zeamais and the Parasitoid Wasp Theocolax elegans

Abstract

During Bt transgenic rice storage, Bt Cry1Ab/Cry1Ac fused protein is exposed to the maize weevil Sitophilus zeamais and the parasitoid wasp Theocolax elegans. We have carried out a long-term risk assessment for Bt rice to these non-target organisms in the storehouse. Effects of Bt rice on S. zeamais and T. elegans have been carefully detected in a laboratory experiment of over 5 years. The survival, development, fecundity, and longevity of the maize weevil were compared between Bt rice and non-Bt rice treatments for every 5 generations from generation 1 to 25. Moreover, the development, adult body size and sex ratio of T. elegans were compared between them parasitizing S. zeamais feeding on Bt rice or non-Bt rice. We found that although Bt Cry1Ab/Cry1Ac fused protein exists in the Bt rice grains and S. zeamais digestive tracts, Bt rice is not harmful to the maize weevil S. zeamais and its parasitoid T. elegans.