Does Bt rice pose risks to non-target arthropods? Results of a meta-analysis in China

Authors: CONG, DANG - Zheijiang University; LU, ZENGBIN - Zheijiang University; WANG, LONG - Zheijiang University; WANG, FANG - Zheijiang University; PENG, YUFA - Zheijiang University; Stanley, David; YE, GONG-YIN - Zheijiang University

Submitted to: Plant Biotechnology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2017
Publication Date: 2/20/2017
Citation: Cong, D., Lu, Z., Wang, L., Wang, F., Peng, Y., Stanley, D.W., Ye, G. 2017. Does Bt rice pose risks to non-target arthropods? Results of a meta-analysis in China. Plant Biotechnology Journal. https://doi:10.1111/pbi.12698.
DOI: https://doi.org/10.1111/pbi.12698

Interpretive Summary: Long-term agricultural sustainability is severely threatened by widespread use of classical insecticides. Threats include increasing resistance to insecticides and sharply decreasing environmental quality. One widely used alternative is growing genetically modified Bt crops, including corn and other crops. Bt rice has been developed, however, it opens the possibilities of negative interactions among Bt crops, crop pathogens and non-target insect species. In particular, information on how Bt-expressing rice plants will influence non-target species within rice cropping systems is necessary to predict the sustainability of producing genetically modified rice. Here, we report the results of a meta-analysis of existing literature on ecological risks associated with deployment of Bt rice lines. Laboratory results indicate Bt rice did not influence survival rate and developmental duration of insect species. Similarly, consuming Bt-contaminated prey did not influence survival or reproduction of predators, although their developmental rates were generally retarded. We draw two inferences. One, laboratory studies of Bt rice showing effects on rice cropping systems are either consistent with or more conservative than results of field studies; and two, the ecological services of non-target insect species would not be affected in large scale Bt rice systems. This information will be valuable to scientists working on the ecological risks associated with Bt rice and eventually benefit growers and consumers of Bt rice products.

Technical Abstract: Transgenic Bt rice expressing the protoxin proteins derived from Bacillus thuringiensis Berliner (Bt) have been developed since 1989. Their ecological risks toward non-target organisms have been investigated. However, these studies were conducted individually, yielding inconsistent conclusions and uncertainty regarding potential agroecological risks associated with large-scale deployment of Bt rice lines. Here, we developed a meta-analysis of existing literature to synthesize current knowledge of the impacts of Bt rice on functional arthropod guilds, including herbivores, predators, parasitoids and detritivores in laboratory and field studies. Laboratory results indicate Bt rice did not influence survival rate and developmental duration of herbivores, although reduced egg laying correctly predicated their reduced abundance in Bt rice agroecosystems. Similarly, consuming Bt-contaminated prey did not influence survival or fecundity of predators, although their developmental rates were generally retarded. Parasitizing Bt-contaminated hosts did not affect biological parameters and abundance of parasitoids. Compared to control agroecosystems, dritivore populations increased in Bt rice cropping systems. We draw two inferences. One, laboratory studies of Bt rice showing effects on ecological functional groups are either consistent with or more conservative than results of field studies; and two, the ecological services of functional guilds would not be affected in large scale Bt rice agroecosystems.