Pierce-sucking insects, such as plant bugs or stink bugs, cause damage in cotton fields worldwide. A novel genetically engineered (GE) cotton (Gossypium hirsutum) is protected against hemipteran pests and thrips by producing the modified Bacillus thuringiensis (Bt) mCry51Aa2 protein. Herbivores that consume insect-protected GE crops, and their natural enemies, can be exposed to plant-produced insecticidal proteins. We investigated tritrophic interactions to evaluate the potential impact of the novel Bt cotton on a non-target herbivore, the spider mite Tetranychus urticae, and on a generalist predator, the pirate bug Orius majusculus. Pirate bugs belong to the same insect order as the target pests and might thus be adversely affected by mCry51Aa2. Enzyme-linked immunosorbent assays showed that levels of mCry51Aa2 in T. urticae were one order of magnitude, and those in O. majusculus were three orders of magnitude lower than in Bt cotton leaves. O. majusculus nymphs fed with spider mites collected from Bt cotton had lower survival, increased developmental time, and reduced fecundity compared to nymphs fed spider mites from non-Bt near-isogenic cotton. Because Bt cotton did not affect the survival and growth of the spider mites, we conclude that indirect prey-quality mediated effects of the Bt cotton on the predatory bugs are unlikely and that O. majusculus are directly affected by the Bt protein. Follow-up studies are indicated to assess whether the effects observed under worst-case conditions are mitigated under more realistic exposure conditions where alternative prey with low Bt protein levels is available.

诸如植物虫或臭虫之类的被刺穿的昆虫对全世界的棉田造成破坏。通过生产改良的苏云金芽孢杆菌（Bt）mCry51Aa2蛋白，可以保护新型基因工程棉花（Gossypium hirsutum）免受半翅目害虫和蓟马的侵害。食用受昆虫保护的转基因作物的草食动物及其天敌可以暴露于植物产生的杀虫蛋白。我们调查了三营养相互作用，以评估新型Bt棉花对非目标食草动物，红蜘蛛Tetranychus urticae以及通才捕食者，海盗bug Orius majusculus的潜在影响。海盗虫与目标害虫属于同一种昆虫，因此可能受到mCry51Aa2的不利影响。酶联免疫吸附试验表明mCry51Aa2在该水平T.螨是一个数量级，而那些在O. majusculus是三个数量级比低的Bt棉叶。与从非Bt近等基因棉花收获的蜘蛛螨喂养的若虫相比，用Bt棉花收集的蜘蛛螨喂养的美洲若虫若虫具有较低的存活率，发育时间和繁殖力降低。因为Bt棉花并没有影响红蜘蛛的生存和生长，我们得出结论，Bt棉对捕食性昆虫的间接猎物质量介导的作用是不太可能的，而O. majusculus则直接受到Bt蛋白的影响。已表明需要进行后续研究，以评估在更现实的暴露条件下（如果存在具有低Bt蛋白水平的替代猎物的情况）在最坏情况下观察到的影响是否得到缓解。