Bulletin of Entomological Research (2007) 97, 643-648
J.D. Harwood, R.A. Samson and J.J. Obrycki (2007)
Temporal detection of Cry1Ab-endotoxins in coccinellid predators from fields of Bacillus thuringiensis corn
Bulletin of Entomological Research 97 (6), 643-648
Abstract: The area planted to genetically engineered crops has increased dramatically in the last ten years. This has generated many studies examining non-target effects of bioengineered plants expressing Bacillus thuringiensis endotoxins. To date, most have focused on population-level effects in the field or laboratory evaluation of specific plant-herbivore or plant-herbivore-predator trophic pathways. Using a post-mortem enzyme-linked immunosorbent assay, we examined the uptake of Cry1Ab-endotoxins by predatory coccinellids and the importance of anthesis to this trophic pathway. Adult Coleomegilla maculata, Harmonia axyridis, Cycloneda munda and Coccinella septempunctata contained low, but detectable, quantities of Bt-endotoxin when screened by ELISA. This was most evident in C. maculata, with 12.8% of 775 individuals testing positive for Cry1Ab-endotoxins. Interestingly, the presence of endotoxins in gut samples was not confined to periods around anthesis, but coccinellid adults tested positive two weeks before and up to ten weeks after pollen was shed, suggesting tri-trophic linkages in their food chain facilitates the transfer of endotoxins into higher-order predators. This contrasts with adult Coleomegilla maculata entering overwintering sites where Bt-endotoxins were not detected in gut samples, indicating low levels of persistence of Cry1Ab-endotoxins within coccinellid predators. This study enhances our understanding of complex interactions between transgenic crops and non-target food webs, but further research is required to quantify the significance of specific trophic linkages in the field.
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Link to article at publishers website
Database assignments for author(s): James D. Harwood
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Coccinella septempunctata (predator) | ||||
| Harmonia axyridis (predator) | ||||
| Coleomegilla maculata (predator) | ||||
| Cycloneda munda (predator) | ||||
| Bacillus thuringiensis genes in crops (entomopathogen) | ||||
| Bacillus thuringiensis Cry1A-toxin (entomopathogen) |
