Bt Corn Poses Negligible Risk to Web Building Spiders

Genetically modified corn varieties that produce the insecticidal protein Cry3Bb1 provide an effective way to control corn rootworms (Diabrotica spp.). But concerns have been expressed on the possible negative effects of Cry protein-producing corn varieties on non-target arthropods. A team of researchers from Switzerland evaluated the effect of Cry3Bb1 on the predatory spider Theridion impressum, a common species in European corn fields.

Quantification of Cry3Bb1 in potential prey species collected in Bt corn plots and prey spectrum analysis revealed that T. impressum ingests Cry3Bb1 in the field. Although Cry3Bb1 is ingested by the spider, the scientists found no evidence of toxicity. In the laboratory, the team found no differences in mortality, weight development or offspring production of spiders provided with food containing or not containing Cry3Bb1.

The paper published by the Plant Biotechnology Journal is available at http://dx.doi.org/10.1111/j.1467-7652.2009.00431.x