Ecol Appl. 2016 Jun;26(4):1047-54. doi: 10.1890/15-1314.
The adoption of transgenic Bt cotton has, in some cases, led to environmental and economic benefits through reduced insecticide use. However, the distribution of these benefits and associated risks among cotton growers and cotton-growing regions has been uneven due in part to outbreaks of non-target or secondary pests, thereby requiring the continued use of synthetic insecticides. In the southeastern USA, Bt cotton adoption has resulted in increased abundance of and damage from stink bug pests, Euschistus servus and Nezara viridula (Heteroptera: Pentatomidae). While the impact of increased stink bug abundance has been well-documented, the causes have remained unclear. We hypothesize that release from competition with Bt-susceptible target pests may drive stink bug outbreaks in Bt cotton. We first examined the evidence for competitive release of stink bugs through meta-analysis of previous studies. We then experimentally tested if herbivory by Bt-susceptible Helicoverpa zea increases stink bug leaving rates and deters oviposition on non-Bt cotton. Consistent with previous studies, we found differences in leaving rates only for E servus, but we found that both species strongly avoided ovipositing on H. zea-damaged plants. Considering all available evidence, competitive release of stink bug populations in Bt cotton likely contributes to outbreaks, though the relative importance of competitive release remains an open question. Ecological risk assessments of Bt crops and other transgenic insecticidal crops would benefit from greater understanding of the ecological mechanisms underlying non-target pest outbreaks and greater attention to indirect ecological effects more broadly.
转 Bt 棉的采用在某些情况下通过减少杀虫剂的使用带来了环境和经济效益。然而，由于非靶标或次要害虫的爆发，这些利益和相关风险在棉农和棉花种植地区的分配并不均衡，因此需要继续使用合成杀虫剂。在美国东南部，转 Bt 棉的采用导致了臭虫害虫 Euschistus servus 和 Nezara viridula（半翅目：Pentatomidae）的数量增加和危害加剧。虽然臭虫数量增加的影响已经得到了很好的记录，但原因仍不清楚。我们假设与 Bt 敏感靶标害虫竞争的释放可能导致 Bt 棉中臭虫的爆发。我们首先通过对以前研究的荟萃分析来检验臭虫竞争释放的证据。然后，我们通过实验测试了 Bt 敏感的棉铃虫 Helicoverpa zea 的取食是否会增加臭虫的离开率，并阻止在非 Bt 棉上产卵。与以前的研究一致，我们只发现了 E servus 的离开率存在差异，但我们发现这两个物种都强烈避免在 H. zea 受损的植物上产卵。考虑到所有可用的证据，Bt 棉中臭虫种群的竞争释放可能导致爆发，尽管竞争释放的相对重要性仍然是一个悬而未决的问题。Bt 作物和其他转昆虫性杀虫剂作物的生态风险评估将受益于对非靶标害虫爆发背后的生态机制的更深入理解，以及对更广泛的间接生态影响的更多关注。
