Sometime during the early 1990s, a queen Solenopsis invicta with a strong case of wanderlust hopped onto a sod truck heading through the Great American Desert toward Los Angeles. The trip was long, hot and monotonous. When she finally arrived, the ant, thinking she had wound up somewhere close to heaven, stretched her incandescent wings and tore them off under the glorious sun. Then she dug about a foot deep into the soil and started having babies.
Or so goes one of the more romantic theories. No one knows for sure how Solenopsis invicta, more commonly known as the ”red imported fire ant,“ slipped into California, the most pest-managed state in the nation. But it is here now, in droves. Golf courses and back yards from Palm Springs to Orange County are infested. Gradually, the City of Angels itself has been surrounded. And so, Angeleno, if you‘re not yet familiar with the fire ant, or the aura of anxiety that surrounds it, you will be soon.
Laying claim to American soil is what the fire ant does best. Seventy-five years ago, a queen arrived at the port of Mobile, Alabama, somewhere in the cargo or ballast of a freighter from South America. Since then, her descendants have invaded 10 states in the Southeast, a majority of Texas and, now, the Golden State — hitching rides in landscape plants, in nursery shipments, in farm and construction equipment, or in the bed of a pickup truck. And all the while, we passionately plot ways to destroy them.
Over the years, we have studied the fire ant in the field and in laboratories, even crushed it into millions of pieces to examine its DNA. We have sprayed it with mysterious poisons from the tails of World War II fighter planes, attempted to contain it by building a nationwide infrastructure of monitoring agencies, and dumped millions of gallons of carcinogens into cracks in the earth. Texas alone spends more than $1 billion each year in its fight against the invader. The state Agricultural Extension Service sponsors block parties where neighborhoods are encouraged to lay out insecticidal bait, and in 1998, Governor George W. Bush declared September 14 to 20 ”Fire Ant Awareness Week.“
Awareness notwithstanding, the fire ant, scurrying through dark crevices beneath our feet, has proven a crafty and elusive adversary. Indeed, Harvard entomologist Edward Wilson once called the war against fire ants ”the Vietnam of the insect world.“ And like that earlier ill-fated campaign, the most comprehensive, aggressive and costly conflict ever between man and bug has spawned thousands of jobs and generated billions of dollars in revenue. If the fire ant truly were to disappear, so would the political maneuvering and economic opportunities — to say nothing of the entertaining folklore — that have emerged in response to it over the past five decades.
With the discovery of Solenopsis invicta, the ”invincible ant,“ in California almost two years ago, the saga enters a new chapter. Experts predict that if the insect establishes a beachhead in the southern part of the state, it will eventually infest the entire West Coast. The California Department of Food and Agriculture, however, says it will successfully eradicate the fire ant from our soil — a claim that hasn’t been made by any state in more than 20 years. Is this attempt to eradicate a whole species of insect feasible? Is it justified? And what is it, exactly, that the fire ant has done to deserve so much enmity?
Well, to begin with, it stings.
Those who have experienced the fiery sting of Solenopsis invicta — female ants come equipped with a venomous tail barb, although only the wingless female workers actually sting — surely have reason to gripe. In 1990, for example, a woman in Florida fell into a coma and eventually died after being stung on the middle toe of her left foot while pulling weeds. Four years later, a 77-year-old Houston woman recuperating from abdominal surgery was attacked by fire ants in a hospital bed. Last year, in a Mississippi nursing home, Nell Rein died after being stung hundreds of times. In 1992, 22-year-old Troy Dean Carswell of Augusta, Georgia, was charged with murder after a man he was fighting fell into a fire-ant nest and died from the ensuing stings. A year later, three people in Texas were sentenced to several years in prison after forcing a 5-year-old boy to stand on a fire-ant mound as punishment.
But these are extreme, isolated scenarios. Less than 1 percent of the human population is allergic to the fire ant‘s venom — an unlucky group of people who could die from anaphylaxis if they happen to be attacked. Most everyone else suffers a small, red, itchy welt. Over the past 60 years, 32 human deaths have been blamed on the fire ant. Not a small number, but more people have died over the same period from bumblebee stings or spider bites. The fire ant is actually a fairly clumsy predator, taking almost three seconds to position itself for a sting.
Initially, the fire ant was perceived less as a direct threat to people than as a threat to agriculture. Early studies in the American South found that the ants were feeding on corn, peanut and bean seeds, potatoes, sweet potatoes and cabbage. What’s more, the mounds, typically 18 inches high or more, were making it difficult to run farm equipment in the fields. Through the 1950s, farmers complained to their congressmen, and the congressmen in turn complained to the U.S. Department of Agriculture. In 1958, with a $3 million federal appropriation, the USDA began its campaign to turn back the invader. Over the next two years, millions of acres in Florida, Georgia, Alabama, Louisiana and a Texas were sprayed from the air with the chemicals dieldrin and heptachlor. Neither had been tested adequately.
Within three weeks, independent analysis of the tissues of dead animals found in the treated areas demonstrated that more than 98 percent contained detectable residues of the poisonous compounds. Further investigation in Texas and Louisiana showed that the bird population in those states had declined more than 85 percent since the spraying. A subsequent report, called ”The President‘s Study on the Ecological Effects of Pesticides on Nontarget Species,“ found hundreds of dead animals, ranging from mammals and birds to reptiles and fish, on a handful of Louisiana farms. On one four-acre stretch of land, according to the report, ”47 days after treatment, no live animals were seen or heard on the plot, and a total of 38 dead animals had been found.“ In her 1962 environmental chronicle Silent Spring, Rachel Carson described the fire-ant campaign as ”an experiment so expensive in dollars, in destruction of animal life, and in loss of public confidence in the Agriculture Department that it is incomprehensible that any funds should still be devoted to it.“ By the end of 1962, dieldrin and heptachlor had been phased out. During the five-year experiment, 20 million acres had been treated, while the fire ant had increased its area of infestation from 90 million to 126 million acres.
Meanwhile, in Gulfport, Mississippi, at the USDA Methods Development Laboratory, a team of chemists had created a new compound called Mirex, which — mixed with soybean oil and corncob grits into an appetizing swill — disrupts the ant’s nervous system very slowly and is regurgitated through the colony, eventually making its way to the queen. Orville Freeman, the secretary of agriculture from 1961 to 1969, hailed it as the ideal pesticide. ”It has no harmful effect on people, domestic animals, fish, wildlife or even bees,“ he said. ”And it leaves no residue in milk, meat or crops.“ In 1962, the USDA began applying Mirex in large quantities and soon announced that, following several applications, the miracle poison would entirely eradicate the fire ant in the U.S. Over the next 15 years, Congress alone spent close to $100 million on the Mirex program.
Once again, a toxin had not been tested sufficiently. Mirex, it turns out, with a melting point of 349 degrees Celsius (it was patented both as a pesticide and a flame retardant), metabolizes very slowly and moves up the food chain virtually unchanged. Studies conducted more than a decade later found that 21 percent of all human inhabitants of treated areas showed positive residues of Mirex in their body fat. Aside from its devastating effect on plants and animals — the chemical was later shown to be carcinogenic — Mirex had exterminated every insect in the treated area. In the long run, the USDA‘s new tactic had actually strengthened the fire ant’s domination by wiping out all of its natural competitors.
In 1969, Congress passed the National Environmental Policy Act, President Richard Nixon created the Environmental Protection Agency, and the Environmental Defense Fund, the first federal agency formed to legally pursue environmental problems, brought suit to terminate the USDA‘s fire-ant program. The case was popularly known as EPA vs. Allied Chemical (the sole producer of Mirex). Officially, it was an investigatory hearing held to determine whether or not the registration of Mirex should be cancelled or amended and was held before the National Occupational Health and Safety Review Commission in Washington, D.C. The hearing marked a profound shift in the way Americans perceived the environment; for the first time, the unbridled use of powerful pesticides had been seriously questioned. The EPA issued a cancellation order for Mirex soon after the hearing began, but Allied Chemical protested the decision, and the proceedings lasted another six years. During that time, the EPA hired a team of scientists that ended up rebuking the USDA for its obsession with chemical warfare.
Walter Tschinkel was a young Ph.D. at that time who had primarily been involved in researching beetle communication patterns. He was also a key witness in the trial against the USDA. ”I was relatively new to fire-ant research then,“ he says. ”Most of the information I had was the USDA’s data on all these important biological questions, which was public information, I suppose. And I analyzed those [data] very carefully, in a way the USDA hadn‘t.“
Tschinkel’s arguments before the committee totally invalidated the idea of eradication. He showed that the fire ant was far too engaged with the environment, too specialized and too elusive for a large-scale general-application poison to have any lasting effect on it. He presented a chart, called a ”Dose Killing Curve,“ which showed that without unleashing an incredible amount of toxins into the environment, a substantial number of colonies would always be missed. There were simply too many of them. ”[When] the concept of eradication was embraced by the USDA and its allies,“ Tschinkel says, ”it was already far too late.“ By the end of the hearings, Allied Chemical had sold its plant to the state of Mississippi for $1. Dreams of eradication died with the Mirex program.
After the USDA ceased funding eradication efforts, farmers gradually learned to live with the pest, although the threat remained the same. Indeed, with the benefit of hindsight, the perceived direness of the threat becomes something of a mystery. Before the initial campaign to wipe out the fire ant began in 1957, only two of the infested states had listed it among their 20 most important insect pests, and these states had placed it near the bottom of the list. Nevertheless, the species ended up being marked for wide-scale eradication. When that dream died, it was replaced with the more economically promising alternative of managing the fire-ant population in perpetuity.
Meanwhile, the complaints against the fire ant had been taken up by America‘s rapidly expanding suburban communities. ”The amount of pesticide that’s sold against fire ants is just colossal,“ says Tschinkel (who eventually gave up on beetles and settled in at Florida State University, where he has researched Solenopsis invicta for the past 30 years). He‘s right. Allied Chemical, Dow Chemical, Thompson Hayward Chemical, Hi-Yield Chemical, American Cyanamid, Boyle Midway, Union Carbide and Chevron, just to name a few, have made killing the fire ant big business. ”You can see it in every hardware store,“ Tschinkel adds, ”in every garden store, stacks and stacks of the stuff. And in my opinion, 95 percent of it’s a total waste. But it does make money change hands. I suppose if you came up with a way to truly eradicate the fire ant from the United States, you‘d have a considerable constituency for not doing so.“
It’s not all that surprising that the notion of eradicating the fire ant has been resurrected in California. For the past 100 years, as agriculture has expanded, the state has been frantically hunting pests. The white garden snail, the obscure snail, the Mexican bean beetle, the Mexican fruit fly, the wheat stem sawfly, the fruit melon fly, the Kaphra beetle, the Japanese beetle, the medfly, the gypsy moth, the Oriental fruit fly, the Africanized honey bee, the apple maggot . . . Most recently, the state has been tracking a moth called the citrus leafminer, and a small locustlike nuisance known as the glassy-winged sharpshooter, which sucks water out of grapevines and has reportedly caused $33 million in damage in Napa, Sonoma and Mendocino counties.
During the past eight years, California‘s interstate border stations have intercepted more than 1,300 incoming shipments containing hitchhiking fire ants. But the ant was not considered a pest in the state until October 1998, when a small colony was noticed in a load of red fountain grass shipped from the T-Y Nursery in Orange County, just south of Los Angeles. By January 2000, representatives from the Agriculture Department had distributed more than 73,000 information leaflets in three different languages; spoken to 53 separate schools, businesses and citizen groups; organized 24 fire-ant displays around the state; and given five formal interviews to the media. During the same 14-month period, an (800) fire-ant hot line had received 3,163 calls.
The nerve center of the Agriculture Department’s campaign is a square one-story building in the parking lot of the Orange County Fairgrounds. The walls of this makeshift headquarters are covered with maps of the surrounding area divided into square-mile grids. When the battle began, department agents went door to door in each grid. They inspected the cracks and crevices of every lot. As the survey progressed, they placed red dots on the maps to represent infested areas. They also asked homeowners to toss potato chips into their back yards and collect any ants that showed up, then send them through the mail to Sacramento for analysis. Before long, more than 30 cities in Orange County bore the measleslike marks on the maps. And the bad news kept coming. By the end of 1999, fire ants had been found in Los Angeles County, Riverside County and points as far north as Fresno, and as far east as Palm Springs. (The most recent statistics show Orange County with 1,600 fire-ant mounds and $5.9 million earmarked to fight them, L.A. County with 193 mounds and a $627,000 budget, and Riverside County with 81 mounds and a $1.5 million budget.)
All or part of each infested county is currently under USDA quarantine, which means that any shipment of dirt that enters or leaves the area has to be inspected by a representative of the county‘s agriculture commissioner. Each nursery in the quarantined area, whether infested or not, is required to treat all of its soil with the fire-ant insecticides Dursban and Talstar. There are no official figures quantifying the toll of these quarantines on Southern California’s billion-dollar nursery industry, but Bob Falconer, a lobbyist for the California Association of Nurserymen, insists that millions of dollars are spent each year by nurseries to protect themselves from fire-ant infestation. ”Clearly the nursery industry is the hardest hit by this infestation,“ Falconer says. ”We certainly have a lot more to gain or lose than anyone else.“
Though the federal government no longer pursues eradication as a national policy, the quarantines remain in place until the fire ant is completely extirpated from a given area. Aware of the scale of that task (to say nothing of the political opportunities it may have offered), state Senator John Lewis from Orange County sponsored a bill in 1999 that allocated $9.5 million for the Agriculture a Department to create a fire-ant ”action plan.“ It made ”proclamations of eradication“ for 569 square miles of Orange County, 45 square miles of Los Angeles County and 175 square miles of Riverside County. The Legislature, according to the bill, ”hereby finds and declares that the red imported fire ant is known for its aggressive behavior and venomous bite, and can interfere with outdoor activities, and threaten people as well as animals and agriculture.“ Falconer and more than a dozen nurseries lobbied for the legislation. No opposition was registered, and not a single vote was cast against it. Governor Gray Davis amended the bill before signing it, but the program still received close to $10 million from the state.
This year, Assemblyman Bill Campbell, also from Orange County, upped the ante by authoring a bill that would have annually appropriated $10 million for a fire-ant-eradication program over the next five years. Again the legislation had no registered opposition; however, the Assembly Appropriations Committee recently decided that the state could not afford to allocate more than $5 million for the program in the next fiscal year. This revised amount is expected to pass the Senate Appropriations Committee on August 7, then head to the governor for final approval. If Campbell had his way, California would spend almost $60 million in the first five years of its battle against the fire ant. That would put the program at nearly a perfect pace to match the $200 million spent by the state since 1980 controlling the medfly population in the L.A. basin. In no other state does the battle with insects consume as large a portion of the budget.
Bob Falconer says it‘s money well spent. ”With most pests, people want to gauge their destructive effect on agriculture,“ he says. ”But the fire ant, this thing really goes across the board. People can’t go into parks, and can‘t go without shoes. This really goes beyond the quarantine. It’s a lifestyle issue.“
While California is alone in making confident claims about eradication, it is also the only infested state in the nation that is not devoting considerable funds to research. None of the nearly $60 million proposed by the state has been earmarked for basic fire-ant assessment. Instead, the state Agriculture Department says it is relying on previous studies done in East Texas and the South, even though both areas — being hot and moist in the same season — are not really representative of Southern California‘s situation. The state’s money is currently being spent on a furious frontline assault involving quarantine-enforcement officers and pest-management agents, who bait and poison the infested areas.
Shortly after first infestation was discovered, one small research grant from the Agriculture Department‘s general fund was given to entomologist Dr. Les Greenberg, but he was told to use the majority of the money on public education. Consequently, he spends much of his time traveling around the state with a slide-photo show: a cow trapped in a field with ant mounds to the horizon; an arm covered with glowing-red, pus-filled welts; and plenty of close-ups of ants.
Meanwhile, Greenberg’s specialization in research science has gone largely unutilized. He‘s anxious to experiment with a soil fungus, called Beauveria, that attacks fire ants. The Agriculture Department finally agreed to give him some money for the project about a month ago, although he hasn’t yet received the funding he was promised.
Greenberg spent 15 years researching the fire ant in Texas, and is now trying to continue his research in Orange County. He remains fairly optimistic on the subject of eradication. ”I think a lot of people have assumed that we can‘t stop them,“ he says. ”But our case is different than the rest of the country. I tell people that we have a better chance than anyone else had, because the environment’s so different here. Until we try for several years, we‘re not going to know whether we can do it or not. And not to try at this stage of the game is a mistake, I think.“
A moment later, Greenberg is reconsidering his own words. ”Still,“ he says, ”you’re always going to have a colony out there. Under someone‘s doorstep. One colony that you didn’t find.“
Greenberg‘s laboratory is a trailer parked in an agricultural-research station in south Orange County, surrounded by massive nursery fields, avocado groves and greenhouses. The inside is sterile and cold, like a doctor’s office. The room is softly illuminated with light sifting in through gaps in the blinds. Greenberg keeps it dark so the winged ants inside don‘t get any ideas about taking flight. The far wall is covered with shelves. On each one, large plastic tubs are strapped in place with orange stretch cords. Each tub is coated with Teflon film, labeled and full of ants. A hand-written sign on a refrigerator next to the shelves says, ”For Lab Use Only. No Food or Drink for Human Consumption.“
On this day, Greenberg is entertaining Mohammed Zubaidy, an ”economic entomologist“ from the state Agriculture Department and the point man for Southern California’s eradication effort. Zubaidy has come to see Greenberg‘s setup. Greenberg pulls a tub off the shelf and places it on a counter in the middle of the room. He, Zubaidy and a couple of other guests crowd around. In the tub, several queens and thousands of workers mill peacefully.
Greenberg gently brushes aside ants with a pair of long tweezers, finally locating and capturing a queen. She’s a bit smaller than the head of a match, slightly larger than a worker, and in the airy lighting she almost glows orange. Her bulbous back half, where she produces hundreds of eggs each day, is barely attached to the rest of her body. In the next instant, frantic workers free her from the delicate grip of the tweezers and carry her to a safer place. The human observers lean in for a closer look. Suddenly, the thick black mass is moving as one body, shifting and shoving, climbing and pulling.
”They‘re swarming now, as a defense mechanism,“ says Greenberg. ”They can actually sense the carbon dioxide in our breath.“
In other words, they can feel us watching.
A mature colony of fire ants will typically consist of 200,000 to 400,000 workers, with a queen who produces up to 800 workers per day. It is generally thought that a colony of ants exists entirely for its queen, but this is not necessarily the case with fire ants. The queen emits pheromones that make her attractive to her workforce, and probably induce them to feed her, but if the overall working environment is not right, the workers may turn on the queen and kill her. Early research in the South, for example, showed that if more than one colony inhabited a confined area, the workers from each colony would join forces and execute the extra queens until only one was left. In the 1970s, however, multiple-queen colonies were discovered, and they are now the predominant type found in Texas. No one is sure why this transformation occurred — perhaps it is an evolutionary adaptation spurred by human efforts to control the insects — but it is certainly one of the characteristics that contributes to the fire ant’s invincibility there. As long as one of the queens survives, so does the entire colony.
Few arguments can be made in support of encouraging the survival of the fire ant. It nests inconveniently in walls and attics, under rugs, even in clothes drawers. It restricts outdoor leisure. It destroys longleaf pine seedlings; damages farm equipment and secondary roads by excavating soil; feeds on quail, wood ducks, spoonbills, barn swallows, lizards and the eggs of just about any animal. For reasons unknown, it is attracted to electricity, often shorting out fuse boxes, switches and air conditioners.
On the other hand, fire ants do sometimes benefit agriculture. In Texas, they are known to feed on the boll weevil, a parasite found in cotton plants. They also prey on the Lone Star tick, a serious threat to cattle. And in Louisiana, one of the states hit hardest during the early years of poisonous treatment, farmers now welcome the fire ant because it feasts on sugar-cane bores.
In its native Brazilian ecosystem, the fire ant is far less aggressive and numerous, and consequently is not perceived as a threat. This is partly due to the fact that humans and fire ants have been acquainted with one another for much longer there, but also because the fire ant has at least one significant natural enemy in Brazil. A tiny insect called a phorid fly likes to hover behind the ant and, in a split second, lay an egg on the back of its neck. The larva grows and feeds on the ant‘s brain until the head pops off. Research has shown that fire ants fear phorid flies and avoid traveling from the nest when the flies are nearby. In a lab at the University of Texas, a biologist raises phorids and releases them in designated areas as a control technique. The California Agriculture Department is not considering the use of phorid flies, because as a natural management device it would undermine the agency’s insistence that total eradication is possible.
The fire ant will doubtless always be classified as a pest in North America because it has very few natural enemies here. Biologists call it a ”weed species.“ During his quarter-century studying the insect, a Walter Tschinkel has noted that the fire ant thrives in precisely the areas from which we are trying to eradicate it. ”The fire ant is clearly and dramatically associated with ecologically disturbed habitats, created mostly by man,“ Tschinkel says. ”It is abundant in old fields, pastures, lawns, roadsides and any other open, sunny habitats. It shares these habitats with many other ‘weedy’ plant and animal species.“
Tschinkel was neither surprised nor sympathetic when he learned of the recent infestation of the Golden State. ”In California, development is so grotesque,“ he says. ”How should I put it? It‘s eco-crime. They scalp entire mountaintops, and they remove the soil and everything. Then, on big trucks, they roll in huge numbers of species of exotic plants. All the native biota are replaced, animals and plants both. It’s a total eradication of the native ecosystem. I think that‘s the root of it. That is why the fire ant can exist in California. There is no other reason. No other reason whatsoever. Man is the fire ant’s best friend.“
For a long time now, human colonization of uncharted territory has made pests out of ordinary species. At the turn of the century, sweet chestnut trees along the East Coast were virtually wiped out by a parasitic fungus shipped in from Asia, where it was harmless. A Czechoslovakian landowner bought five North American muskrats in 1905; 30 years later, millions of them inhabited Europe. In 1929, a handful of African mosquitoes made it to the coast of Brazil on a French destroyer; within 10 years, a wave of malaria had swept the country and killed thousands of people. ”We are living in a period of the world‘s history when the mingling of thousands of kinds of organisms from different parts of the world is setting up terrific dislocations in nature,“ wrote biologist Charles Elton in 1958.
Take Palm Springs, California. In this town made by curbing the Colorado River through hundreds of miles of desert, this resort community for some of America’s wealthiest, sand dunes and green lawns literally border each other. ”Coming Soon“ and ”Build To Suit“ signs are posted everywhere. Home Depot, Decorators Depot and Jetspa USA cluster near roads called Country Club, Frank Sinatra, Dinah Shore and Gerald Ford. Of Palm Springs‘ 87 golf courses, at least 10 are already infested with the fire ant. Each time a swimming pool is installed, and before the dirt can be removed, a state agriculture agent is alerted and baits the yard with diced Spam to see if fire ants turn up.
Economic entomologist Mohammed Zubaidy is in Palm Springs to oversee several classes in which new state agents are being trained for the fire-ant war. Zubaidy, several veteran officers and eight recruits walk through a lush green lawn infested with sandy fire-ant nests, just outside the wall of a gated community.
A ”No Trespassing“ sign is posted on a towering palm. The new agents are shown how to apply the poison — which looks like Parmesan cheese and is kept in a Parmesan-cheese dispenser — to the mounds. They kneel and poke and prod and open their mouths in amazement. They jab pencils and sticks into the hearts of the mounds and watch the ants swarm madly and attack in vain. They ask questions: How long before the poison kills a colony? How did the fire ant get here?
”The fire-ant problem is a problem made by man,“ Zubaidy tells them, echoing Walter Tschinkel’s remarks 3,000 miles away at Florida State University.
Despite our long and complicated involvement in the fate of the fire ant, at least one nexus of energy and beauty in the insect‘s life still eludes human interference. Scientists call it the ”nuptial flight.“ The moment begins when all the winged ants, both female and male (they are few in number and do no work in the colony), are marshaled to a new purpose, usually the day after a summer rain. In mounds everywhere, flightless female worker ants, stricken with an uncontrollable rage, chase the winged males and females to the surface of the mound, nipping at their ankles, urging them to take to the sky. Finally they do.
Now the fire ants are on their own. Somehow, in the vast open air, beyond the observation of man, they release and follow the mandate of a mysterious sexual pheromone. Four hundred feet above the warm darkness of the earth, blown by a soft wind, they collide, have sex and are perhaps picked off by a group of passing sparrows. A few moments later and nearly a mile away, a fertilized female drops to the soft dirt of a fenced yard or a crop field. She is now a queen. She plucks off her wings and digs.