Concerns about the effect of certain genetically modified (GM) crops have been discussed widely in the butterfly and moth research community, especially the impact of Bt-enhanced crop strains that kill plant herbivores. A recent paper from Chinese researchers writing in BMC Biotechnology suggests this concern extends even to the predators of insects that feed on GM Bt crops.
At issue is the role of the wolf spider Pardosa pseudoannulata, one of the dominant predators in South China, which plays a crucial role in the rice agroecosystem. Among its prey items is the brown leafhopper, Nilaparvata lugens, a serious rice pest. A transgenic variety of rice modified to express Cry1Ab protein from Bacillus thuringiensis, Shanyou 63, is widely planted in China; it acts to inhibit the formation of the planthopper cuticle, apparently by interfering with creating the exoskeleton component chitin.
What the scientists from Hunan University found was that even wolf spiders that fed on brown planthoppers that had been exposed to the transgenic rice suffered significant developmental delays most likely linked to uptake of Cry1AB inhibiting the spiders’ cuticle formation. And that of course leads to speculation about just how far Cry1AB can travel in the food web of the rice agroecosystem and beyond, and what unintended consequences it might have for non-target species.