Campus News

Published by Communications and Public Affairs (519) 824-4120, Ext. 56982 or 53338

News Release

January 04, 2000

New study shows biotechnology not harmful to Monarch butterfly

The Monarch butterfly is alive and well, despite exaggerated and misleading reports that it is threatened by biotechnology, new research by a University of Guelph professor reveals.

Prof. Mark Sears, chair of the Department of Environmental Biology and the Canadian Corn Pest Coalition, conducted field research on pollen from Bt corn containing Bacillus thuringiensis, a naturally occurring soil-borne bacterium which selectively targets specific groups of insects.

Preliminary findings show that the pollen is found in too-low doses on most milkweed plants to hurt Monarch butterfly larvae. In fact, researchers found that pollen from milkweed leaves from Bt corn had no greater effect on Monarch larvae than non-Bt pollen.

"Bt-corn has always been shown to be harmless to both humans and animals, and we now know it isn't a major threat to the Monarch butterfly," Sears said.

An earlier U.S. study claimed pollen from Bt-corn damaged Monarch butterfly larvae. The study sparked a media frenzy and public concern about genetically modified foods. The U.S. study was completed in a lab, and the dosage of pollen used was not reported, Sears said.

"The actual threat to the Monarch butterfly can only be determined by assessing the dosage that affects the larvae and their degree of exposure to Bt-corn pollen in the field," he said. "Outside of corn fields, you probably wouldn't find concentrated dosages of pollen because wind and rain removes it from the surface of the milkweed leaves."

Sears is leading a two-year project to determine the ecological impacts of Bt-corn pollen on selected non-target butterfly species, including the Monarch. His study focuses on Bt pollen and how far it travels. He examined milkweed stands in and adjoining corn fields, at their edges, then at distances of five, 10, 25, 50 and 100 metres away.

He is being assisted by U of G research associate Diane Stanley-Horn and research technician Heather Mattila, along with seed industry representatives and corn growers. His research is sponsored by the Canadian Food Inspection Agency and Environment Canada.

Contact: Prof. Mark Sears Department of Environmental Biology (519) 824-4120, Ext. 3921

For media questions, contact Communications and Public Affairs, (519) 824-4120, Ext. 3338.

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