The September issue of the journal _Nature Biotechnology_ has a refutation of the claims we've been hearing about genetically modified corn being dangerous to Monarch butterflies. The intended modification to the corn is that it contains a gene referred to as "Bt", for Bacillus thuringiensis. This particular gene produces an insecticide meant to kill the corn borer insect. The claim, from the May 20, 1999, issue of _Nature_, was that Monarch butterflies are killed by feeding on pollen from the modified corn plants. Both the originator of this idea, John Losey, and his critic, Anthony Shelton, are entomology professors at Cornell University in Ithaca, New York.
According to the _Nature Biotechnology_ article,
"The recent short correspondence in Nature reporting a laboratory study in which pollen from Bt-transgenic corn was fed to Monarch butterflies has attracted considerable coverage in the popular press and widespread rebuttals and criticisms in the scientific press. It is surprising, then, that a previous and more relevant and realistic field study has been largely overlooked. In that study, the authors examined Bt-corn pollen deposition on milkweed plants within, and adjacent to, field corn and then assayed the leaves with first instar larvae. Pollen levels were highest within the field (where Monarchs are scarce), but even there Monarch mortality was only 16%."
You can access the article at http:\\biotech.nature.com by signing up for a free account and searching for "Shelton" in the "authors last name" field of the search form.
David Blenkinsop <blenl@sk.sympatico.ca>