Transgenic Bt cotton expressing Cry1Ac/1Ab does not have detrimental effects on the predator Arma chinensis through its prey Helicoverpa armigera

The commercial utilization of genetically modified crops expressing Bacillus thuringiensis (Bt) insecticidal toxins requires careful assessment of the potential impact on non-target organisms. To assess the potential ecological impact of the Bt insect-resistant cotton variety A26-5 (expressing the Cry1Ac/1Ab protein), we tested whether there was transmission of Cry1Ac toxin through the food chain from cotton to the herbivorous prey Helicoverpa armigera (Hübner) through to the non-target predatory insect Arma chinensis (Fallou). A small amount of Cry1Ac protein was detected in H. armigera and A. chinensis, indicating that Cry1Ac could be transmitted to A. chinensis. However, no differences were found in survival rate, development, or fecundity of A. chinensis after treatment with Bt-fed or Bt-free H. armigera. Cry1Ac exposure did not affect detoxification genes expression in A. chinensis, which is likely related to our finding that Cry1Ac could not bind to receptors in the midgut. Taken together, these results show that the Bt cotton A26-5 has few, if any, toxic effects on A. chinensis.