Getting Antsy

Jim Atkinson cures what ails us.

THIS SUMMER WE HEAD into the third decade of groundbreaking research by one of the most underappreciated public health institutions in the state. Maybe it’s the clunky name—the Fire Ant Laboratory at the University of Texas at Austin’s Brackenridge Field Lab—but the nation’s premier fire ant experts just can’t get no respect. So the first thing I’d like to do is thank Larry Gilbert and his staff of fearless entomologists for taking on what is, gram for gram, Texas’s most formidable beast. But in the next breath, I’d like to inquire, as politely as possible, if twenty years of studying this remarkably destructive pest has mattered a damn—because based on the ant mounds I spotted in my backyard this morning, it wouldn’t seem to have. Are we any closer to conquering our fiery foes? Well, yes and no. Gilbert, who created the research program at UT back in 1986, says we’re making headway, but the fact is that they’re here to stay. The best we can aim for, he explains, is “eradication of the pest status of the ant.”

The real immigration crisis.

Given that 80 percent of us will be bitten by fire ants in the next few months, I’ll call any effort to tame them progress. As every good Texan knows, fire ants reside in that particular pantheon of species—along with, say, wolverines and black mambas and Komodo dragons—that may be best described as the meanest SOBs in the valley. They are prolific and hardy: When it is hot, they burrow deep underground; when it is wet, they build their mounds upward. Disturb or destroy a mound, and they simply relocate or rebuild—vinegar, gasoline, or urine doesn’t kill enough of them to make a difference—and they’re capable of swarming and consuming baby birds and rodents. You’ve even, no doubt, heard reports over the years of their attacking infants in their cribs or old folks trapped in beds at nursing homes; fire ants can indeed kill those who are particularly frail or allergic. They actively interfere with our crops and livestock, destroy the asphalt that paves our roads (their tunnel systems cause potholes), and disable our electrical circuit boxes, air conditioners, and traffic lights (seemingly attracted to oscillating magnetic fields, they’ll nest in and attack the equipment). Researchers estimate that fire ants cost the state $1.2 billion a year.

Yet control of these six-legged terrorists is difficult not just because they’re so tough but also because not all fire ants are the bad guys. The chief culprits in Texas, in fact, are not our several species of native fire ants, which can deliver a pretty good sting but are otherwise fairly solid citizens. The bad dudes are the red imported fire ants (RIFAs), which supposedly sneaked into the country from South America via some potted plants that showed up in the harbor at Mobile, Alabama, sometime in the first half of the twentieth century; from there they spread across the southeastern U.S. and as far west as California. RIFAs have overtaken the eastern two thirds of our state (displacing our native fire ants), and they especially like the heat and open grasslands of Central Texas. (In a few pockets of Austin our homegrown ants have managed to resist this invasion; the area now has the largest concentration of native fire ants in the southern U.S.)

Call in the cavalry.

So the first step toward a successful fight on fire ants? Figure out which type is infesting your property, says Gilbert, because the native critters can keep their more destructive peers at bay (either by killing them, in the case of some species, or by dominating available food supplies). Gilbert suggests that you disturb the mound, then look for the largest worker ants. “If their heads are conspicuously wider than their gaster [last segment], you are looking at the native species,” he explains. If so, leave them alone.

Of course, waging war on just RIFAs still presents a challenge, because they seem to require the equivalent of WMDs to kill them off—pesticides of a strength and quantity that may do more harm than good. Over the past decade, however, Gilbert and colleagues have been experimenting with a form of biocontrol that shows considerable promise. Specifically, they’ve found that a tiny insect known as the phorid fly, a parasite of fire ants, may eat away (quite literally) at their dominance: Females inject their eggs directly into the ants; the eggs then develop into larvae and eat the ants’ innards. Thus the hope is that, when released in fire ant–dense areas, phorids will keep RIFAs in check. Two species of the flies have been intro- duced in several places, including Travis and Bee counties; one species has an estimated range of six million to seven million acres in Texas.

Promising as this is, though, building a phorid force isn’t simple. There are not enough fly species being bred, says Gilbert, and it may be that the two thus far identified aren’t the best at controlling RIFAs. And even then, he adds, you can’t be certain that it’s the flies doing the job. “In the past three years,” he told me, “I have received congratulatory calls from folks around Austin who say their ants have declined. I just tell them that I can’t claim credit, even though the flies have spread, because we can’t exclude other factors such as recent droughts.” Bottom line? It’s going to take more years—and more research—for phorids to catch up to RIFAs.

On second thought, call in the boric acid.

Biocontrol may be the future of fire ant management, but for the time being we’re stuck using WMDs as judiciously as possible. If you believe fire ants have settled on your property, Gilbert suggests the following: First, the best time to deal with them is spring or fall, when it’s not wet or especially dry and hot. Put out some hot dog chunks to invite a swarm, then get a look at the ants. Do your best to

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