( ith phorid flies. In their native ...)Fire ant-attacking fly spreading rapidly in Texas

In their native Argentina, where Gilbert and his collaborators study the ants and flies, fire ants are assaulted by as many as 12 different kinds of phorid fly in an area smaller than a football field.

"No single phorid species will be a magic bullet," he says.

Fire ants are not typically pests or even common in South America in large part because of harassment by the phorid flies. In the presence of these flies, ants have difficulty retrieving food, having mating flights or rescuing their larvae after mounds become disturbed by animals such as armadillos during the day.

"It's not just because these tiny flies are numerous, it's also because they are diverse in kinds, coming after worker ants in many different ways at once," says Gilbert. "Different phorids specialize on small or large workers, on distinct chemicals laid down by the ants on trails, on time of day and on season and so forth. Our goal is to copy what we believe to be nature's complex control system."

Gilbert and his colleagues are looking at the fire ant-fly relationship in parts of Argentina that are similar to habitats in Texas.

"It is rewarding to see the first species expanding over more than four million acres of Texas," says Gilbert, "but we've failed miserably in parts of Texas, like South Texas, to which these first phorids apparently cannot adapt. That's why we are focusing research efforts in parts of Argentina that look exactly like the South Texas brush country."

Gilbert is also working with ranchers to help them learn how to infest their own fire ant colonies with phorid flies. He began the initiative in 2005 with ranchers from Bee County, Texas.

To introduce phorid flies themselves, people can bring ants from their property to high-density areas of phorids and return the ants to their property carrying phorid eggs inside them.

"People accidentally move fire ants around all the time," sa
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Source:University of Texas at Austin