Plant Biotechnology Journal (2009) 7, 645-656

Michael Meissle and Jörg Romeis (2009)
The web-building spider Theridion impressum (Araneae: Theridiidae) is not adversely affected by Bt maize resistant to corn rootworms
Plant Biotechnology Journal 7 (7), 645-656
Abstract: The growth of genetically engineered maize that produces the insecticidal protein Cry3Bb1 from Bacillus thuringiensis (Bt) is an effective method to control corn rootworms (Diabrotica spp.), which are threatening maize production in North America and Europe. In this study, the risk of Cry3Bb1-expressing maize for the predatory spider Theridion impressum, a common species in European maize fields, was assessed. Quantification of Cry3Bb1 in potential prey species collected in Bt maize plots and prey spectrum analysis revealed that T. impressum ingests Cry3Bb1 in the field. Exposure to the Bt protein, however, was highly variable because some potential prey species, such as phloem-feeding herbivores and predators, contained little or no Cry3Bb1, whereas leaf-feeding herbivores contained high concentrations. Adult and juvenile T. impressum spiders were fed with Cry3Bb1-containing food (prey or maize pollen) for 8 weeks in the laboratory to examine the toxicity of the Bt protein. No differences in mortality, weight development or offspring production were observed between spiders provided with food containing or not containing Cry3Bb1. Retrospective power analysis indicated that the bioassays were sufficiently sensitive to detect meaningful differences if present. Although Cry3Bb1 is ingested by the spider in the field, our data provide no evidence for toxicity. Consequently, the growth of corn rootworm-resistant Bt maize appears to pose no risk for T. impressum.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Michael Meissle, Jörg Romeis

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Diabrotica virgifera	Maize/corn (Zea mays)
Phylloneta impressa (predator)
Bacillus thuringiensis genes in crops (entomopathogen)	Diabrotica virgifera	Maize/corn (Zea mays)
Bacillus thuringiensis Cry3B-toxin (entomopathogen)	Diabrotica virgifera	Maize/corn (Zea mays)