摘要
Genetically engineered(GE)cotton,MON 88702,is protected against cer-tain sucking pests,such as plant bugs and thrips,by producing mCry51Aa2,a mod-ified protein from Bacillus thuringiensis(Bt).Predatory pirate bugs(Orius spp.),natural enemies contributing to biological pest control,are also sensitive to the insecti-cidal protein when exposed continuously to high concentrations.We evaluated effects of MON 88702 on Orius majusculus when fed prey types with different mCry51Aa2 concen-trations.When neonates were provided exclusively Tetranychus urticae spider mites reared on MON 88702(high mCry51Aa2 content),adverse effects on predator survival and de-velopment were confirmed,compared with specimens fed prey from near-isogenic non-Bt cotton.When fed a mixture of T.urticae and Ephestia kuehniella eggs(mCry51Aa2-free),predator life table parameters were similar to the treatment where eggs were fed exclu-sively.When mCry51Aa2-containing spider mites were provided for a limited time at the beginning or the end of juvenile development,effects were less pronounced.While pirate bug nymphs showed similar consumption rates for prey from Bt and non-Bt cotton,choice experiments revealed a preference for E.kuehniella eggs over spider mites.Lepidopteran larvae(Spodoptera littoralis,high mCry51Aa2 content)or cotton aphids(Aphis gossypii,mCry51Aa2-free)reared on MON 88702 as alternative prey did not result in adverse ef-fects on O.majusculus.Our study suggests limited risk of mCry51Aa2-producing cotton for O.majusculus,because its sensitivity for the Bt protein is relatively low and its natural food consists of diverse prey species with varying concentrations of Bt protein.
