BUT WHAT DOES IT DO TO PEPPERED MOTHS?

The butterfly flap: In 1999, research suggested that genetically-modified corn might be killing off the monarch butterfly. What followed was exactly the kind of argument that is good for public health (Peter Pringle, July 2003, Prospect uk)

In the spring of 1999, as the monarchs embarked on their return flight north, a young Cornell University entomologist named John Losey reported in the journal Nature that the monarch's future appeared to be endangered; not from urban sprawl or toxic waste, but from eating the pollen of genetically-modified corn. At the time, 20m acres of American farmland, representing a quarter of the US corn crop, had been planted with seeds that included a toxin-producing gene from the common soil bacterium, Bacillus thuringiensis, or Bt. The insect-poisoning power of Bt had been known for over a century and the first commercial spray was developed in Europe during the second world war. It even became a favourite of organic farmers. Half a century later, there were 182 Bt products registered by the US Environmental Protection Agency (EPA).

Two other big crops-cotton and potatoes-had also been fitted out with the Bt gene. But in corn, the Bt toxin was designed primarily to kill the European corn borer, a caterpillar that destroys more than $1bn worth of the crop each year. The toxin punctures the delicate membranes of the caterpillar digestive tract, causing it to wither and die.

Most of the monarchs born in the midwest corn belt start life on a milkweed leaf in or around the edges of a farmer's land. When the corn sheds its pollen during July and August, pollen grains containing the Bt toxin are blown by the wind onto milkweed leaves. From earlier studies, Losey knew that Bt toxin could harm butterflies and moths, and he wondered if the monarch larvae might also suffer.

In a no-frills experiment at his laboratory at Cornell in upstate New York, he fed monarch larvae with Bt pollen. If they showed signs of harm, he intended to do more research in the field. In his lab, he misted milkweed leaves with water and sprinkled on the Bt corn pollen to a density that looked like the pollen he had observed on the milkweed in a cornfield. He then placed five three-day-old monarch larvae-caterpillars no bigger than a raindrop-on each milkweed leaf and watched them feed. The experiment was repeated five times. After four days, nearly half of the larvae were dead. Those that survived were half the weight of his control group feeding on milkweed leaves with no pollen. Larvae fed on leaves sprinkled with conventional hybrid corn pollen were still munching away, apparently no worse off. [...]

To test public reaction to their experiment, Losey and his co-researchers at Cornell first shared the results with colleagues. All were in favour of publication. However, a senior entomology professor at Cornell, Anthony Shelton, warned the younger researcher that he didn't have a "story." Shelton, a believer in biotech, would become increasingly unhappy that Losey's experiment had been confined to a laboratory. The results, he would complain, were "not pertinent to the real world." [...]

In a Cornell University press release, Shelton attacked Losey's experiment: "If I went to the movies and bought a hundred pounds of salted popcorn, because I like salted popcorn and then I ate those salted popcorn all at once, I'd probably die," Shelton was quoted as saying. "Eating that much salted popcorn simply is not a real-world situation, but if I died it may be reported that salted popcorn was lethal. The same thing holds true for monarch butterflies and pollen. Scientists need to make assessments that are pertinent to the real world... Few entomologists or weed scientists familiar with the butterflies or corn production give credence to the Nature article."

well, you can probably figure out where that's hheaded, eh? But you read the long and fascinating article,about a process driven at least as much by politics as science, and you get to this conclusion:

[M]ost of those involved-academics, industry and other environmentalists-thought the monarch case was a "blueprint" for how to do research in the public interest. Margaret Mellon of the UCS agreed. "It brought scientists, environmental and government folks together with industry, found a pot of money, set a research agenda and got it done."

And because of what has come before, whether you agree with that assessment or not is likely to be determined almost entirely by your politics, not by the underlying science. Posted by Orrin Judd at July 29, 2003 9:16 PM