Phorid Flies in West Alabama

Auburn, April 18, 2003 --- Fire ants can cause minor harm to humans in the form of painful stings and occasional welts, but that’s nothing compared to what scientists are doing to them.

For years, they have been working steadily to introduce the ant’s mortal enemy to fire-ant mounds across the Southeast.

(Above: Marengo County Extension Agent Kevan Tucker introduces phorid flies into samples of fire ant mounds that will then be returned to the mounds. This procedure has been used to introduce phorid flies into heavily fire-ant infested pasturelands throughout the state in hopes of reducing infestations to manageable levels.)

Sweet revenge for all those painful stings and welts?

Actually, no.

Since their arrival in Mobile Bay from South America more than 70 years ago, fire ants have been able to operate with virtually free rein on pasturelands and landscapes throughout the South. So reacquainting these ants with their natural South American predators, scientists hope, will eventually lead to steep reductions in fire-ant populations.

Though barely visible to the naked eye, phorid flies, as the fire ant’s mortal nemeses are commonly known, attack the ants in the goriest way imaginable – injecting their eggs in the bodies of ants with strikes lasting only a tenth of a second.

Over time, the emerging larva makes its way into the fire ant’s skull and begins eating out the inside of the head. Eventually, the head falls off and from it a new fly emerges – small wonder these tiny insects are often called “decapitating flies.”

As each new generation emerges, the ghastly cycle of egg laying and decapitation begins again.

Phorid flies were first introduced into Alabama in 1998 as part of a regional project aimed at controlling fire-ant populations throughout the South. The project is the brainchild of Dr. Sanford Porter, a Florida-based USDA researcher who spent years studying the phorid fly in South America.

Dr. L.C. “Fudd” Graham, director of the Alabama Fire Ant Management Program, is working with Extension agents and Master Gardeners to introduce the flies throughout Alabama.

The flies already have been introduced as far north as Madison County, as far east as Macon County, and as far south as Baldwin County.

Now, Graham is working with Marengo County Extension Agent Kevin Tucker to establish a toehold for the flies in West Alabama. The sooner the better, says Tucker, who has received numerous complaints, especially from pastureland owners, about problems associated with the ants.

“Pretty much everybody is spending some money now. It’s one of those deals where the homeowners are trying to keep it out of the backyard barbeques to protect children. Golf course and recreational fields are trying to protect their customers and reduce the wear and tear on equipment.”

Pasturelands are a particular concern in this West Alabama county, where cattle is king and where fire ants have found a hospital environment in prairie soils.

“You’ll have a loss of productivity in a hayfield and loss of yields with the grasses,” Tucker says.

“With hayfields, you’ve got expensive equipment that runs over these mounds repetitively.

“Cutters run through them – added wear. Rakes run through – added wear.”

“And then there are the balers – more wear.”

Grass doesn’t grow on fire-ant mounds. That means the more numerous the mounds, the less productive the pasture. Continual stinging by fire ants also impacts the cattle’s weight gain. In some rare cases, the consequences for younger animals can be even worse.

“Two newborn calves actually died after repeated stinging by the ants in Chilton County last year – the first time I’ve ever heard of that happening in Alabama,” Graham says.

Fierce as they are, though, phorid flies will never succeed in wiping out fire ants entirely.

Nevertheless, scientists hope the flies will make the ants’ lives a living hell through constant attacks. Mortally frightened by the flies, the worker ants will cower in their mounds, missing out on the day-to-day foraging necessary for survival. And once food sources are depleted, fire-ant populations will begin dropping off.

Eventually, using the flies in tandem with other control methods, Graham hopes to keep fire-ant populations at manageable levels. Currently there are between 60 and 80 fire-ant mounds per acre in Alabama.

(Source: Dr. L.C. “Fudd” Graham, Director, Alabama Fire Ant Management Project, 334-844-2563, and Kevin Tucker, Marengo County Extension Agent, 334-259-5959)

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