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Article
Monarch larvae sensitivity to Bacillus thuringiensispurified proteins and pollen
Proceedings of the National Academy of Sciences USA
  • Richard L. Hellmich, Iowa State University
  • Blair D. Siegfried, University of Nebraska-Lincoln
  • Mark K. Sears, University of Guelph
  • Diane E. Stanley-Horn, University of Guelph
  • Michael J. Daniels, Iowa State University
  • Heather R. Mattila, University of Guelph
  • Terrence Spencer, University of Nebraska-Lincoln
  • Keith G. Bidne, United States Department of Agriculture
  • Leslie C. Lewis, United States Department of Agriculture
Document Type
Article
Publication Date
10-1-2001
DOI
10.1073ypnas.211297698
Abstract

Laboratory tests were conducted to establish the relative toxicity of Bacillus thuringiensis (Bt) toxins and pollen from Bt corn to monarch larvae. Toxins tested included Cry1Ab, Cry1Ac, Cry9C, and Cry1F. Three methods were used: (i) purified toxins incorporated into artificial diet, (ii) pollen collected from Bt corn hybrids applied directly to milkweed leaf discs, and (iii) Bt pollen contaminated with corn tassel material applied directly to milkweed leaf discs. Bioassays of purified Bt toxins indicate that Cry9C and Cry1F proteins are relatively nontoxic to monarch first instars, whereas first instars are sensitive to Cry1Ab and Cry1Ac proteins. Older instars were 12 to 23 times less susceptible to Cry1Ab toxin compared with first instars. Pollen bioassays suggest that pollen contaminants, an artifact of pollen processing, can dramatically influence larval survival and weight gains and produce spurious results. The only transgenic corn pollen that consistently affected monarch larvae was from Cry1Ab event 176 hybrids, currently<2%corn planted and for which re-registration has not been applied. Results from the other types of Bt corn suggest that pollen from the Cry1Ab (events Bt11 and Mon810) and Cry1F, and experimental Cry9C hybrids, will have no acute effects on monarch butterfly larvae in field settings.

Comments

This article is from Proceedings of the National Academy of Sciences USA; 98 (2001); 11925-11930; doi: 10.1073ypnas.211297698

Rights
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.
Copyright Owner
National Academy of Sciences
Language
en
Date Available
2014-08-20
File Format
application/pdf
Citation Information
Richard L. Hellmich, Blair D. Siegfried, Mark K. Sears, Diane E. Stanley-Horn, et al.. "Monarch larvae sensitivity to Bacillus thuringiensispurified proteins and pollen" Proceedings of the National Academy of Sciences USA Vol. 98 Iss. 21 (2001) p. 11925 - 11930
Available at: http://works.bepress.com/richard_hellmich/27/