Biotechnology Industry Organization

BIO Responds To Nature Report On Bt Threat To Monarch Butterflies

WASHINGTON, D.C. (May 19, 1999) - BIO Vice President of Food & Agriculture L. Val Giddings, Ph.D. released the following statement in response to scientific correspondence published in the journal Nature (20 May 1999). The letter to Nature asserts that pollen from Bt corn can negatively affect growth and survival of the larvae of the Monarch butterfly. BIO offers the following statement:

"With this letter by John Losey to Nature, old issues have been resurrected to raise questions about the potential impact on Monarch butterflies by corn pollen containing crop-protection proteins derived from the soil bacterium Bt. Industry is fully committed to exploring the significance of this report.

"Declining Monarch butterfly populations have been a concern for decades. It is known that many factors play a role in these declines. Even if the reported results are validated, there are strong reasons to believe they are not relevant to Monarch caterpillars in the wild.

"Monarch migration and egg laying patterns ensure that the primary period of larval feeding and growth throughout nearly all the Monarch range takes place well before any nearby corn produces pollen. Ongoing monitoring of Bt corn fields by companies since their introduction further shows that very little pollen lands on adjacent milkweed leaves. It is thus highly likely that in the natural setting, outside the laboratory, most Monarch larvae would never encounter any significant amounts of corn pollen. This means the real potential for any negative impact is negligible.

"Ongoing monitoring by companies of Bt corn fields since their introduction also shows that insect biodiversity and population densities in Bt corn fields is significantly higher than in fields treated with chemical pesticide sprays. Bt corn thus helps enhance beneficial insect populations that would otherwise be threatened by the use of pesticidal sprays. This further leads to significant improvements to water quality and environmental conservation for insect eating birds, small mammals and other life."

"Reports of the potential for effects from these Bt corn hybrids on Monarch butterflies or other lepidoptera are not new. They have been reported in the scientific literature and regulatory review documents since at least 1986. Both the Environmental Protection Agency and the U.S. Department of Agriculture have been provided data on the potential for impacts on non target species from Bt pollen for years. Their analyses indicated that, when compared with the numerous other relevant factors, the impacts from such pollen were likely to be negligible.

"The key issue is how large an impact is likely, and how significant would such an impact be when compared with the numerous other significant factors known to have impacts on Monarch ranges and numbers.

"BIO members have long been working with groups concerned with Monarch butterfly conservation to address the threats they face. It is widely recognized that the principal threat facing the Monarch butterfly relates to loss of vital winter habitat in southern California and the highlands of central Mexico."