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One shy moth, a flashy gene, and a crossroads

By Staff writer of The Christian Science Monitor / April 29, 2004

You might call Pectinophora gossypiella - pink bollworm moths - publicity shy. You're unlikely ever to meet one: They fly around at night and hide underground during the day. And they live only in commercial cotton fields.

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But someday they may be a lot better known. An arm of the US Department of Agriculture (USDA) has filed an application to release a batch of them carrying a fluorescent marker gene inserted by scientists, making it the first approval sought for releasing a genetically altered insect in the wild. If approved, it would pave the way for approval of other lab-produced insects - from super productive honeybees to drugmaking silkworms - that could benefit mankind.

But the program faces several hurdles - not to mention opposition from a swarm of environmentalists worried about the release of genetically altered traits into the environment. Releasing insects into the wild raises special concerns because unlike, say, a genetically modified (GM) cow, altered insects are extremely hard to track.

The biggest worry: that new genes could be passed on to other insects, resulting in unintentional consequences, says Michael Rodemeyer, executive director of the Pew Initiative on Food and Biotechnology in Washington.

Of course, the whole point of the bollworm project is that they won't reproduce and continue causing big losses to cotton farmers. If the GM moths produce viable offspring, "then we've done something wrong," says Thomas Miller, an entomologist at the University of California at Riverside, who led a team that developed the GM pink bollworms.

Right now, though, the bollworm moth program is on hold, says Robert Rose, a USDA biotechnologist involved in the regulatory process. The reason is financial. Researchers haven't gotten the government funds needed to carry out the experiment this year. Even if they get the money in 2005, they still face regulatory hurdles, including an environmental impact study, Dr. Rose says.

In the initial proposed field test, where the bollworms are simply altered to make them glow, Dr. Miller and his colleagues would study their behavior. They would be looking to answer questions like how far the transgenic bollworms move, how they will compete with wild bollworms, and what sort of a buffer zone would be needed to make sure they don't stray too far.

But all this is mere preparation for the real payoff: releasing genetically altered male bollworm moths that would mate with wild females but produce no viable offspring. Miller has three versions of sterile male bollworms that might do the job.

From Egypt with larvae

The moths, which arrived in the United States in the early 20th century in cotton shipments from Egypt, wreak havoc on commercial cotton crops, causing an estimated $20 million to $30 million of damage per year, Miller says. They've happily settled in cotton fields in the hot, dry climate of the southwestern US and Mexico.

"It is a marvelous insect," Miller says. "It's so suited to survival, it's not even funny. The more we learn about it, the more astounded we get."

For decades, scientists have used sterilized male bollworm moths to try to keep the population down. To do this, the moths are irradiated before release, a process that also weakens them and makes them less competitive with wild bollworm moths in the hunt for females. GM moths could be a much better answer - if they don't create more problems than they solve.