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General Information

Document type
  • Peer-reviewed journal article
GE organism
  • maize
  • cotton
GE trait
  • insect resistance
  • USA


Safety for environment
  • positive effect

A meta-analysis of effects of Bt cotton and maize on nontarget invertebrates Open Access

Marvier, M; McCreedy, C; Regetz, J; Kareiva, P
Science. 2007 June. 316(5830):1475-1477

Link to full text (open access, freely available)

PMID: 17556584 DOI: 10.1126/science.1139208


Although scores of experiments have examined the ecological consequences of transgenic Bacillus thuringiensis (Bt) crops, debates continue regarding the nontarget impacts of this technology. Quantitative reviews of existing studies are crucial for better gauging risks and improving future risk assessments. To encourage evidence-based risk analyses, we constructed a searchable database for nontarget effects of Bt crops. A meta-analysis of 42 field experiments indicates that nontarget invertebrates are generally more abundant in Bt cotton and Bt maize fields than in nontransgenic fields managed with insecticides. However, in comparison with insecticide-free control fields, certain nontarget taxa are less abundant in Bt fields.


Bt; non-target insects; insecticides


Funding source
  • Environmental Protection Agency
Funding country
  • United States
Funding type
  • government

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Cite this study


Marvier, M, C McCreedy, J Regetz, P Kareiva. "A meta-analysis of effects of Bt cotton and maize on nontarget invertebrates." Science 316.5830 (2007): 1475-1477 . Web. 7 Dec. 2023.


Marvier, M., McCreedy, C., Regetz, J., & Kareiva, P. (2007). A meta-analysis of effects of Bt cotton and maize on nontarget invertebrates. Science, 316(5830), 1475-1477 . doi:10.1126/science.1139208

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