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Fire ants RELATED VIDEO CNN's Ann Kellan explains how scientist hope to eradicate fire ants from South America Real 28K 80K Windows Media 28K 80K Zoologist Larry Gilbert on the difference between domestic and imported fire ants Real 28K 80K Windows Media 28K 80K

February 18, 1999
Web posted at: 10:19 a.m. EST (1519 GMT)

AUSTIN, Texas (CNN) -- Researchers from the University of California are fighting fire with flies -- specifically, imported flies from South America.

Their target: invader fire ants from south of the border that are overwhelming parts of the South from Texas to Florida.

Though widely despised for their unsightly mounds and painful bites, fire ants aren't all bad, researchers say. The native species perform beneficial functions, including eating ticks and insects known to damage crops.

Also, fire ants native to the North America have natural predators that control their populations. But fire ants from South America, imported to the United States in the 1920s, face no natural predators.

Today, the alien strains continue to spread through the southern United States, eating crops and other animals' food supplies.

"If we don't take any action, we're going to continue to have the diversity of our system eroded by this imported pest," says University of Texas Zoologist Larry Gilbert.

But that may be about to change. For this first time, researchers at the University of Texas have permission to release flies imported from South America to prey on the ants.

The fly dive bombs the ant

The way the fly carries out its dirty work isn't pretty.

The tiny insect, called a Phorid, takes aim, and then dive-bombs the ant, laying eggs inside of it.

After the eggs hatch, the larvae move into the ant's head, and 12 hours later the ant's head falls off. The larvae feast on the inside of the head until they emerge as a full-grown flies.

The researchers say it could take years before the imported flies thrive and breed in the United States. In the meantime, they're urging people not to kill native fire ants, which can be distinguished from the imported kind by their fat heads. Without competition from the native species, the invaders can spread more easily, the scientists say.

After years of study, the researchers are confident that the imported flies will target only imported ants and leave other species alone. Then, if all goes according to plan, they will die off along with the non-native ant populations.

The next major hurdle, they say, is getting the flies to do what the invader ants did: thrive and reproduce in the United States.

Correspondent Ann Kellan contributed to this report.

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