One shy moth, a flashy gene, and a crossroads

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.

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.

"We're not in a hurry because we want to make sure it works right first," Miller says. Some people mistakenly interpret the project as spreading new altered genes into a wild population, he says, which makes them uncomfortable. But "that is exactly not what is supposed to happen."

Though the moths initially would carry only the marker gene, not the lethal one, the open field test would be "potentially precedent setting," says Peter Jenkins, an attorney and policy analyst for the Center for Food Safety and the Center for Technology Assessment in Washington.

But he says it's far from actually happening. "Our view of it is that the [USDA] has to do a full environmental study before it does any field releases," he says. "It certainly hasn't done that yet. We haven't seen any evidence that they've been able to come up with something that is shown to be environmentally safe yet."

Meanwhile, Miller says he welcomes public scrutiny. "The more people who know [about our work], the better," he says. "This is a new technology that people are just getting used to," and the public ought to have an opportunity "to poke holes in our strategy."

In the future, scientists hope that insects that transmit diseases such as malaria, dengue fever, yellow fever, typhus, and river blindness can be genetically altered to no longer be carriers. Malaria alone is estimated to afflict 300 million to 500 million people per year, causing 1 million to 3 million deaths.

Super silkworms?

Insects might also be altered to become better workers for humankind. Genes inserted into silkworms might cause them to produce pharmaceuticals or superstrong silk. GM honeybees could be designed to better resist diseases and pesticides, increasing their value and productivity.

But would genetically altering honeybees, for example, change their honey in any way that would be harmful to humans? This is the kind of question that will have to be answered.

"If the public is to support the introduction and release of GM insects, it will need assurances that the issues these insects raise regarding the environment, public health, agriculture, society, and food safety have been carefully considered," concludes a January report by Pew Initiative on Food and Biotechnology. The group is also planning a major conference on regulating genetically modified insects this fall.

Because of their mobility and small size, the report notes, GM insects would be "difficult to recall once they are released."

Super bugs

Scientists are tinkering with the genetic makeup of several insects to benefit people. Following are some of the bugs they're testing and their possible uses.

Honeybee: Create an insecticide-resistant honeybee to protect investment in honeymaking.

Kissing bug: Engineer a bacteria to live inside the bug and kill the parasite that causes Chagas' disease.

Mosquitoes: Create and breed a mosquito that inhibits the spread of malaria to humans.

Planthoppers: Engineer bacteria that would block the transmission of rice-stripe virus by planthoppers, protecting rice crops.

Silkworm: Develop a worm that can produce low-cost pharmaceuticals or other medical/industrial proteins.

SOURCE: "Bugs in the System" (January 2004), a report by the Pew Initiative on Food and Biotechnology

You've read  of  free articles. Subscribe to continue.
QR Code to One shy moth, a flashy gene, and a crossroads
Read this article in
QR Code to Subscription page
Start your subscription today