Bt Corn Pollen Research Articles

Field deposition of Bt transgenic corn pollen: lethal effects on the monarch butterfly

We present the first evidence that transgenic Bacillus thuringiensis (Bt) corn pollen naturally deposited on Asclepias syriaca; common milkweed, in a corn field causes significant mortality of Danaus plexippus L. (Lepidoptera: Danaidae) larvae. Larvae feeding for 48h on A. syriaca plants naturally dusted with pollen from Bt corn plants suffered significantly higher rates of mortality at 48h (20±3%) compared to larvae feeding on leaves with no pollen (3±3%), or feeding on leaves with non-Bt pollen (0%). Mortality at 120h of D. plexippus larvae exposed to 135 pollen grains/cm(2) of transgenic pollen for 48h ranged from 37 to 70%. We found no sub-lethal effects on D. plexippus adults reared from larvae that survived a 48-h exposure to three concentrations of Bt pollen. Based on our quantification of the wind dispersal of this pollen beyond the edges of agricultural fields, we predict that the effects of transgenic pollen on D. plexippus may be observed at least 10m from transgenic field borders. However, the highest larval mortality will likely occur on A. syriaca plants in corn fields or within 3m of the edge of a transgenic corn field. We conclude that the ecological effects of transgenic insecticidal crops need to be evaluated more fully before they are planted over extensive areas.

Bt corn pollen impacts on nontarget lepidoptera: assessment of effects in nature.

The demonstrations by Losey et al. (1) and Hansen and Obrycki (www.ent.iastate.edu/entsoc/nch 99/prog/abs/D81.html) that milkweed leaves dusted with heavy concentrations of Bt corn pollen are toxic to Monarch butterfly larvae (Danaus plexippus) feeding on them were consistent with the known toxicity of Bt endotoxin to Lepidoptera in general and the expression of Bt endotoxins in the pollen of the strains of corn they studied. Much speculation and some investigations followed, concerning the extent to which the poisoning of Monarch butterflies and other nontarget Lepidoptera might be significant contributors to the mortality of these insects in nature. For example, Shelton and Roush (2) were critical of the two earlier findings, but did not provide any data from nature, despite the fact that Losey et al. (1), in the original report, stated “it would be inappropriate to draw any conclusions about the risk to Monarch populations in the field based solely on these initial results.”

EPA issues guidelines on planting Bt corn

The Environmental Protection Agency has issued new guidelines for growing Bt corn—corn that is genetically modified to contain a gene from the soil microorganism Bacillus thuringiensis, enabling the corn to produce its own insecticide. The measures are designed to protect against the emergence of insects that are resistant to the Bt toxin and to protect monarch butterfly caterpillars and other nontarget organisms. Every cell of Bt corn, including the pollen, produces a specific toxin that kills the European corn borer. Last May, John E. Losey, an entomologist at Cornell University, reported lab research that shows that Bt corn pollen can kill monarch butterfly caterpillars [ Nature , 399 , 214 (1999)]. Since May, environmentalists have been demanding that EPA take steps to protect the monarch butterfly from possible harm from Bt corn pollen. Studies to determine whether Bt corn pollen harms monarchs in the field are so far inconclusive. In its guidelines, EPA says manufacturers and sellers of ...

Bt‐corn pollen can kill monarchs

Science NewsVolume 155, Issue 21 p. 324-324 This Week Bt-corn pollen can kill monarchs First published: 01 July 2009 https://doi.org/10.2307/4011509AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume155, Issue21May 1999Pages 324-324 RelatedInformation