ANTS IN OUR PANTS

By MICHAEL D. LEMONICK

One painfully memorable day this spring Jack Reese did a crazy dance in the middle of a persimmon grove on his farm in Oktibbeha County, Mississippi. Flailing wildly, he tried to yank off his pants and swat his ankles at the same time. He had made one of the worst mistakes a Southern farmer can make: he forgot to watch the ground for a moment and thus tromped on a foot-high mound full of fire ants. Incensed by the intrusion, the insects promptly swarmed up Reese's legs, stinging him mercilessly over and over again. It felt like dozens of hot needles being plunged into his skin.

Killer bees, it turns out, are not the most menacing marauders to hail from South America. Their less publicized cousins the fire ants are more widespread in the U.S., more destructive and, so far, deadlier. The antagonistic ants have been harassing people, mostly in the South, for decades -- ruining picnics, forcing the cancellation of high school football games, making small children afraid to venture into their backyards -- and the threat is getting worse than ever. In some areas the rapidly spreading ants are crowding out (or killing) other insects, lizards, birds and small mammals, knocking natural ecosystems completely out of whack. Their mounds -- up to hundreds of them per acre -- have made many a farm field all but unplowable. And because the ants are strangely attracted to electric current, they have been known to chew through underground cables, disrupting everything from telephone service to airport runway lights and even starting fires.

While the minuscule monsters have traditionally attacked only people who stepped on their turf, they've recently brought their mayhem indoors as well. Says Marion Bernhardt, 78, of West Palm Beach, Florida, who last year survived an ant assault in a hospital bed: "I was stung all up and down my legs, and I had welts all over them and on my side. They burned for days. I never had such an experience in all my life." She was lucky. At least 50 people have died in recent years from allergic reactions to fire-ant stings.

Worst of all, fire ants are on the move. They are already established throughout the South, from Texas east to Florida and north to Tennessee, with isolated pockets even farther north -- there's a colony, for example, in Virginia Beach, Virginia. Most of the West Coast, from Southern California up to Vancouver, British Columbia, would make fine fire-ant habitat as well. And while the moisture-loving insects can't spread westward through arid reaches of West Texas on their own, they don't have to. Fire ants have been known to hitch rides on truckloads of produce, nursery stock and even industrial chemicals. According to Richard Patterson, a U.S. Department of Agriculture entomologist based at the University of Florida, infestations of fire ants have been found in Arizona, New Mexico, California, Oregon and Washington.

So far, the bugs' aversion to frost has kept them out of the Midwest and Northeast, but even that may change. Tim Lockley, an entomologist at the Agriculture Department's fire-ant lab in Gulfport, Mississippi, says the ants have now settled in the mountains of east Tennessee, where as much as 7% of the population survived the especially frigid winter of 1993-94. Says Lockley: "It's just amazing how adaptive they are."

The threat began in the 1930s, when the aggressive red fire ants came to Mobile, Alabama, perhaps on shiploads of lumber imported from the insects' home territory in South America (the milder-mannered black fire ant had arrived, also from the Southern Hemisphere, in 1918). In the 1950s and early '60s concerned government officials tried to eradicate the insects with such powerful chemicals as heptachlor and mirex. The program was later dubbed "the Vietnam of entomology" for both its destructiveness and its futility. The poisons killed not only their targets but also most other wildlife in the treated areas. By the late '70s the pesticides were banned.

Now the ants have grown so nasty that some folks argue for a return to chemical warfare. Says Republican Congressman Tom DeLay of Texas, the House majority whip and a former exterminator: "The scientific evidence doesn't justify the mirex ban."

Still worried about the pesticides' impact on the environment, government scientists think they may have a better answer to the fire-ant menace. Patterson's lab at the Agriculture Department is studying a tiny parasitic fly that lays its eggs right on the fire ant's body. The fly maggots then eat their way into the ant's head and eventually sever the head from the body. Best of all, the fly seems to attack only fire ants. If laboratory and field tests show that the fly is indeed safe to use, says Patterson, the natural ant killer could be available within a year -- and Jack Reese will no longer have to be so careful about where he steps.

--Reported by David Bjerklie/ New York and Scott Norvell/Atlanta

With reporting by DAVID BJERKLIE/NEW YORK AND SCOTT NORVELL/ATLANTA