Neighbouring crop diversity mediates the effect of Bt cotton on insect community and leaf damage in fields
Effects of large-scale cultivation of transgenic crops on agricultural biodiversity remain unclear, particularly in the context of complex ecological interactions between transgenic crops and other organisms. Here we conducted a comprehensive survey to investigate the number of species, population abundance, community evenness and dominance of insects and weeds as well as leaf damage to weeds in Bt and non-Bt cotton fields at 27 sites across northern China. The role of neighbouring crop diversity around cotton fields in controlling insects and weeds in the cotton fields was also assessed. In addition, we conducted a 3-year field experiment to verify the results of the survey. Weed diversity in Bt and non-Bt cotton fields was similar, but the species number and diversity indices of insects are significantly decreased in Bt fields aligning with reduced leaf damage to broadleaf plant species including cotton as well as crops in neighbouring plots. The leaf damage to Bt and non-Bt cotton negatively associates with the diversity of neighbouring crops in cotton fields. Our study demonstrates the neighbouring crop diversity mediates the effects of Bt crops on agricultural diversity in complex interactions among transgenic crops, in-field weed and insect communities, and neighbouring crops.
KeywordsNeighbouring crop diversity Ecosystem services Non-target insects Leaf damage Transgenic cotton
We thank Mr. Huang H, Ms. Yao Y and Bao MX and local farmers for their assistance in field investigation as well as Dr. Ouyang F in insect identification and Dr. Zhang JL in weed identification. This work was financially supported by the National Environmental Protection Public Welfare Science and Technology Research Program of China (grant 201309038).
Y.L. designed the study. Y.L. and J.L. performed the field investigation. Y.L. and Z.L. performed the analyses and wrote the paper. All authors contributed to interpreting the results and discussions and gave final approval for publication.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
- Anderson MJ (2001) A new method for non-parametric multivariate analysis of variance. Aust Ecol 26:32–46Google Scholar
- Arshad M, Suhail A (2010) Studying the sucking insect pests community in transgenic Bt cotton. Int J Agric Biol 12:764–768Google Scholar
- Bohan DA et al (2005) Effects on weed and invertebrate abundance and diversity of herbicide management in genetically modified herbicide-tolerant winter-sown oilseed rape. Philos Trans R Soc B Biol Sci 272:463–474Google Scholar
- ISAAA (2016) Global Status of Commercialized Biotech/GM Crops: 2016. ISAAA Brief 52: Ithaca, NYGoogle Scholar
- R Development Core team (2008). R: a language and environment for statistical computingGoogle Scholar