Reduced fitness of Daphnia magna fed a Bt-transgenic maize variety

Arch Environ Contam Toxicol. 2008 Nov;55(4):584-92. doi: 10.1007/s00244-008-9150-5. Epub 2008 Mar 18.


Genetically modified (GM) maize expressing the Bt-toxin Cry1Ab (Bt-maize) was tested for effects on survival, growth, and reproduction of the water flea Daphnia magna, a crustacean arthropod commonly used as a model organism in ecotoxicological studies. In three repeated experiments, D. magna were fed 100% ground maize in suspension, using either GM or isogenic unmodified (UM) maize. D. magna fed GM-maize showed a significantly reduced fitness performance: The mortality was higher, a lower proportion of females reached sexual maturation, and the overall egg production was lower compared to D. magna fed UM isogenic maize. We conclude that the tested variety of Bt-maize and its UM counterpart do not have the same quality as food sources for this widely used model organism. The combination of a reduced fitness performance combined with earlier onset of reproduction of D. magna fed Bt-maize indicates a toxic effect rather than a lower nutritional value of the GM-maize.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Feed
  • Animals
  • Bacillus thuringiensis Toxins
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / toxicity*
  • Body Size / drug effects
  • Daphnia / drug effects*
  • Daphnia / physiology
  • Endotoxins / metabolism
  • Endotoxins / toxicity*
  • Female
  • Growth / drug effects
  • Hemolysin Proteins / metabolism
  • Hemolysin Proteins / toxicity*
  • Insecticides / metabolism
  • Insecticides / toxicity*
  • Longevity / drug effects
  • Oviposition / drug effects
  • Pest Control, Biological
  • Plants, Genetically Modified / toxicity*
  • Zea mays / genetics
  • Zea mays / metabolism*


  • Bacillus thuringiensis Toxins
  • Bacterial Proteins
  • Endotoxins
  • Hemolysin Proteins
  • Insecticides
  • insecticidal crystal protein, Bacillus Thuringiensis