Researchers import flies to battle killer fire ants

Non-native fire ants are proliferating in North America, due to a lack of natural predators

August 11, 2000
Web posted at: 3:13 PM EDT (1913 GMT)

From Mary Pflum CNN Reporter

(CNN) -- Researchers at the University of Texas are breeding flies to control the population of imported fire ants that has rapidly spread from California to Florida, leaving substantial damage along the way.

Last year, southern U.S. states spent millions of dollars on fire ant-related damage. The venomous ants have killed livestock and pets, diminished crops and caused serious electrical fires by invading circuit boxes. A more extreme case occurred last spring, when a woman in a Florida nursing home died after fire ants attacked her in bed.

VIDEO CNN's Mary Pflum looks at methods for controlling fire ants Play video (QuickTime, Real or Windows Media)     QUICKVOTE Have you ever been stung by a fire ant? Yes No View Results     ALSO More on phorid flies from the Univerity of Texas How to distinguish between imported and native fire ants

Two kinds of fire ants inhabit the United States: those that are native and kept in check by North American predators and those that were inadvertently imported from Brazil or possibly northern Argentina in the 1920s.

Now researchers are attempting to control the ants by importing one of their native predators: phorid flies.

Larry Gilbert, an ecologist at the University of Texas, says the flies are the key to controlling the population of imported ants. Thanks to funding from the state of Texas, Gilbert has established an imported phorid fly breeding farm in Austin. "We can't find many negatives about the fly except that it might not work," Gilbert said.

The flies actually invade the bodies of fire ants and lay their eggs there. As the larval stages of the fly develop inside the body, they pupate in the fire ant's head. The head of the ant then falls off.

Researchers believe it takes about 3,000 flies to make a serious assault on a fire ant colony. So far, Gilbert and his team have released 100,000 flies in Texas. Additional phorids are being released throughout Florida and other southeastern states.

While the flies have yet to make a substantial dent in the imported fire ant population, researchers are cautiously optimistic.

Naysayers worry that releasing non-native insects to control non-native ants could create further ecological problems, but Gilbert says the flies are host-specific. They only interact with and kill the imported fire ants.

What's more, Gilbert says, the flies are more environmentally sound than chemical pesticides.

"People shouldn't forget that there's never been a successful biological control of a social insect," Gilbert said. "You can't expect a solution to come overnight."

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The University of Texas

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