Laboratory toxicity studies demonstrate no adverse effects of Cry1Ab and Cry3Bb1 to larvae of Adalia bipunctata (Coleoptera: Coccinellidae): the importance of study design

• Published in: Transgenic research Vol. 20; no. 3; pp. 467 - 479
• Main Authors: Álvarez-Alfageme, Fernando, Bigler, Franz, Romeis, Jörg
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-06-2011; Springer; Springer Nature B.V
• Subjects: Adalia bipunctata; Animal Genetics and Genomics; Animals; Araneae; Bacillus thuringiensis; Bacillus thuringiensis - genetics; Bacillus thuringiensis - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - toxicity; Biological and medical sciences; Biomedical and Life Sciences; Biomedical Engineering/Biotechnology; Biotechnology; Coccinellidae; Coleoptera; Coleoptera - physiology; Endotoxins - genetics; Endotoxins - toxicity; Fundamental and applied biological sciences. Psychology; Genetic Engineering; Genetic technics; Hemolysin Proteins - genetics; Hemolysin Proteins - toxicity; Larva; Life Sciences; Methods. Procedures. Technologies; Molecular Medicine; Original Paper; Plant Genetics and Genomics; Plants, Genetically Modified - genetics; Plants, Genetically Modified - physiology; Research Design; Risk Assessment; Tetranychidae - physiology; Transgenic animals and transgenic plants; Transgenics; Zea mays; Zea mays - genetics; Zea mays - physiology; Study design; Environmental risk assessment; MON810; MON88017; Non-target effects; Laboratory study; Targeting; Coleoptera; Toxicity; Insecta; Adalia bipunctata; Risk analysis; Design; Target; Coccinellidae; Arthropoda; Transgenic plant; Invertebrata
• DOI: 10.1007/s11248-010-9430-5
• EISSN: 1573-9368
• ISSN: 0962-8819

Scientific studies are frequently used to support policy decisions related to transgenic crops. Schmidt et al., Arch Environ Contam Toxicol 56:221–228 (
2009
) recently reported that Cry1Ab and Cry3Bb were toxic to larvae of
Adalia bipunctata
in direct feeding studies. This study was quoted, among others, to justify the ban of
Bt
maize (MON 810) in Germany. The study has subsequently been criticized because of methodological shortcomings that make it questionable whether the observed effects were due to direct toxicity of the two Cry proteins. We therefore conducted tritrophic studies assessing whether an effect of the two proteins on
A. bipunctata
could be detected under more realistic routes of exposure. Spider mites that had fed on
Bt
maize (events MON810 and MON88017) were used as carriers to expose young
A. bipunctata
larvae to high doses of biologically active Cry1Ab and Cry3Bb1. Ingestion of the two Cry proteins by
A. bipunctata
did not affect larval mortality, weight, or development time. These results were confirmed in a subsequent experiment in which
A. bipunctata
were directly fed with a sucrose solution containing dissolved purified proteins at concentrations approximately 10 times higher than measured in
Bt
maize-fed spider mites. Hence, our study does not provide any evidence that larvae of
A. bipunctata
are sensitive to Cry1Ab and Cry3Bb1 or that
Bt
maize expressing these proteins would adversely affect this predator. The results suggest that the apparent harmful effects of Cry1Ab and Cry3Bb1 reported by Schmidt et al., Arch Environ Contam Toxicol 56:221–228 (
2009
) were artifacts of poor study design and procedures. It is thus important that decision-makers evaluate the quality of individual scientific studies and do not view all as equally rigorous and relevant.