Toxins in transgenic crop byproducts may affect headwater stream ecosystems

Proc Natl Acad Sci U S A. 2007 Oct 9;104(41):16204-8. doi: 10.1073/pnas.0707177104. Epub 2007 Oct 8.


Corn (Zea mays L.) that has been genetically engineered to produce the Cry1Ab protein (Bt corn) is resistant to lepidopteran pests. Bt corn is widely planted in the midwestern United States, often adjacent to headwater streams. We show that corn byproducts, such as pollen and detritus, enter headwater streams and are subject to storage, consumption, and transport to downstream water bodies. Laboratory feeding trials showed that consumption of Bt corn byproducts reduced growth and increased mortality of nontarget stream insects. Stream insects are important prey for aquatic and riparian predators, and widespread planting of Bt crops has unexpected ecosystem-scale consequences.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Bacillus thuringiensis Toxins
  • Bacterial Proteins / genetics
  • Bacterial Proteins / toxicity
  • Bacterial Toxins / genetics
  • Bacterial Toxins / toxicity
  • Ecosystem*
  • Endotoxins / genetics
  • Endotoxins / toxicity
  • Fresh Water / analysis
  • Hemolysin Proteins / genetics
  • Hemolysin Proteins / toxicity
  • Insecta
  • Lepidoptera / pathogenicity
  • Plant Diseases / parasitology
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / toxicity*
  • Pollen
  • Water Pollutants, Chemical / toxicity*
  • Zea mays / genetics
  • Zea mays / parasitology
  • Zea mays / toxicity


  • Bacillus thuringiensis Toxins
  • Bacterial Proteins
  • Bacterial Toxins
  • Endotoxins
  • Hemolysin Proteins
  • Water Pollutants, Chemical
  • insecticidal crystal protein, Bacillus Thuringiensis