Ant-Eating Flies May Rescue South

Wednesday, November 15th 2000, 12:00 am

By: News On 6

WASHINGTON (AP) â€” A tiny Brazilian fly whose larvae literally eat the heads off of fire ants will be unleashed across the South under a government program to control the vicious ants that are a spreading menace to homeowners, farmers and wildlife.

The Agriculture Department, which claims the gnat-like phorid fly is of no danger to anybody or anything other than fire ants, announced plans Wednesday to release hundreds of thousands of them in the South and possibly in California, where the ants have now spread.

``It is a self-sustaining biocontrol,'' said Richard Brenner, who leads a USDA research team in Florida. ``Twelve sites per state could blanket the state within five years.''

Fire ants can make life miserable for homeowners and gardeners and cause billions of dollars in damage every year to air conditioners, electrical equipment and farms, experts say. The ants can blind and even kill livestock and wildlife, and the sting is occasionally fatal to humans.

The ants, which are native to South America, have no natural enemies in the United States. Chemical treatments are only effective temporarily.

``Anything that will take care of these fire ants will be fine with me, as long as it doesn't hurt anything else or the environment,'' said Kym Bell, a Cottondale, Ala., woman whose 5-year-old daughter missed several days of kindergarten this fall because of repeated ant bites on her school playground. The stings left welts the size of a half dollar on her skin.

The phorid fly helps keep the ants under control in Brazil and Argentina, where infestation levels are far lower than they are in the United States.

The flies hover over ant mounds before darting down and injecting a torpedo-like egg into the ants. After one of the eggs hatches, the maggot decapitates the ant by eating the brain and other contents of the head. The maggot later turns into a fly and the cycle is repeated.

The flies don't kill enough of the ants to destroy colonies, but they do cause enough panic to keep the ants in check, Brenner said. The ants, which have an innate fear of the flies, stop foraging and flee when they spot them, giving native ants a chance to move back into the territory.

Some scientists are skeptical that there are enough native ants in the South to compete with the fire ants. The natives have either been poisoned by humans or driven away by fire ants.

``You've got to have a really good competing ant population for the phorid flies to have an effect,'' said Brad Vinson, an entomologist at Texas A&M University.

Scientists also are studying other biological enemies of the fire ant, including a microorganism and a parasitic ant.

The Agriculture Department started studying the flies in 1993 to see if they could harm anything other than fire ants. Nothing other than the fire ants would attract them, including animal dung or human waste, so the government is confident they will be completely safe for the environment, Brenner said.

The flies were released at four sites near Gainesville, Fla., three years ago and now have spread to 700 square miles. USDA scientists are now studying the area to see how the flies have affected ant populations.

As part of the federal project, Florida's agriculture department will begin mass-rearing the flies next spring and will ship them to field sites in Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee and Texas.

The project will cost USDA about $100,000.

Discussions also are under way about releasing the flies in California, where parts of the Los Angeles area are under a federal quarantine intended to keep the ants from spreading.

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On the Net: USDA's Agricultural Research Service: http://www.ars.usda.gov

Texas A&M University fire-ant site: http://fireant.tamu.edu