FORT WORTH (May 12, 2009)--Some Texas researchers are trying a new weapon against fire ants; parasitic flies that turn the pesky insects into zombies whose heads fall off.

The tiny phorid fly is a native to a region of South America where the fire ants in Texas originated.

Researchers have learned that as many as 23 phorid species along with pathogens attack fire ants to keep their population and movements under control.

A Texas A&M study shows fire ants cost the state economy about $1 billion annually by damaging circuit breakers and other electrical equipment.

They can also threaten young calves.

So far, four phorid species have been introduced in Texas against the fire ants.

University of Texas research associate Rob Plowes says the flies "dive-bomb" the fire ants and lay eggs.

The maggot then hatches inside the ant and eats away at the brain.

"First they become zombies, their movements under the control of the parasite. Then their heads fall off and the parasite emerges," said Dr. Scott Ludwig, , AgriLife Extension integrated pest management specialist.

“We're hoping the new parasite will reduce the foraging of fire ants, and thereby allow our native ants to regain some footing," he said.