Of butterflies and caddisflies -- what's a regulator to do?

Yoggi Berra called it “deja vu all over again” — the feeling that you’ve been there done that. For biotech supporters, the recent study published in Proceedings of the National Academy of Sciences is causing flashbacks to 1999. That’s the year when a paper published in The Lancet showed you could kill Monarch butterfly larvae by feeding them gobs of pollen from Bt corn — corn genetically engineered to express a naturally occurring pesticidal protein. To activists it was the “smoking gun” they desperately needed to end the advance of biotechnology in agriculture. Soon, Monarch butterflies were everywhere, marching in front of supermarkets, flying around Web pages — the Monarch butterfly quickly became the symbol of the anti-biotechnology movement.
There was only one problem. John Losey, the researcher who published the study, fed the pollen to the Monarch larvae in the laboratory. Critics of the study said the levels of pollen needed to kill the larvae were way higher than those found in corn fields. Sure enough the critics were right. After several years of actual field studies, researchers at the USDA’s Agricultural Research Service concluded “There is no significant risk to monarch butterflies from environmental exposure to Bt corn.” To this day there is a USDA Website devoted to the controversy.

The study just published in PNAS claims that Bt corn byproducts and pollen are toxic to caddisflies, small insects that live in streams. When these streams flow near corn fields planted with Bt corn, some of the stalks end up in the streams where they are eaten by the caddisflies. This led the authors to conclude that “Bt corn byproducts may have negative effects on the biota (read caddisflies) of streams in agricultural areas.”

The parallels between the 1999 study and the recent PNAS study are eerily similar. Both the Monarch larvae and the caddisflies were killed by pollen administered in the laboratory. Both authors qualified their results with words like “may have” or “potentially” when suggesting Bt corn was harming the environment. Experts in the field were strongly critical of both studies. Both times, the media ignored the qualifiers and the critics when reporting on the studies. And both times the activists seized on the studies as the long sought “smoking gun” they were looking for.
The criticism of the caddisfly study is persuasive. The concentrations of Bt needed to cause mortality were way higher than that found in the field. From the way the study was designed, you can’t know for sure what was killing the insects. And most importantly, the study didn’t look at the effect of Bt on caddisflies under actual field conditions.

Several things we know for sure. More work will be done, but this time it will be carefully done under actual field conditions, just as with the Monarch butterfly. We can be certain that activists, undaunted by their past embarrassments, will seize on the research to press their case with regulators and legislators. What we won’t see is activists parading in front of supermarkets dressed as caddisflies — they are ugly little devils.

It will take some time to resolve this issue. Good science takes time. In the meantime, Maine regulators and legislators can do little but wait and watch. Taking action on the basis on one scientific study is not only bad policy, it shows a profound lack of understanding of science itself.

(Orginally posted 11/09/07)