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Field & Street



I bought my first ant farm in 1986 on Clark Street in a store that sold a typical New Town assortment of incense, Kenyan candlesticks, seashell night-lights, and refrigerator magnets. Near the cash register, in a display of toys from the 50s and 60s, was an Uncle Milton ant farm. The outside of the package had a picture of a brown ant in a top hat and bow tie holding a sign: "See the LIVE ANTS dig tunnels, build bridges, move mountains."

The store sold the ant farms as high camp, but I bought obsession. I was fascinated by ants, among the most influential animals on the planet. Ants move more soil around than any other animal, including earthworms. One-third of all plant species depend on ants to disperse their seeds. Before Europeans settled in Chicago, when the tall-grass prairie was intact, more ants lived here than any other kind of animal. In fact, if you'd been here 400 years ago and rounded up and weighed every bison and every ant, the ants would have weighed more.

When I got the ant farm back to my apartment, I discovered that the ants were not inside. The instructions suggested I capture my own by digging up a colony, letting individual ants crawl up a pencil, and gently dropping them into the ant farm. The other option was to use Uncle Milton's "stock certificate" to send away for the insects.

I was interested in learning the habits of local ants, preferably prairie ants of some type. Little is known about the habits of Chicago's native ants. The great myrmecologists of our time have devoted their energies to studying ants in the tropics, where populations of ants--and most other life forms--are densest and most diverse. In North America most insect-related research grants go to study the life cycles of pest species, so we can learn how to kill them better. Little money is available for studying benign prairie ants.

The problem with acquiring prairie ants was my timing. I'd bought the farm in December, when digging ants out of frozen earth is impossible. Feeling a little sheepish, I sent away for ants from California, figuring I could upgrade to natives in the spring.

It was a month before a padded envelope arrived from Los Angeles. Inside was a plastic tube with a dozen immobile ants crammed into one end. They looked dead, but I tipped them out into Uncle Milton's farm anyway. Their red bodies toppled down onto the green plastic barn, slipped between the windmill and the bridge, and came to rest on the fake elms.

All but three turned out to be alive. After a couple days they started to dig tunnels into the white sand. I recorded their progress in a notebook.

According to Harvard biologist Edward O. Wilson, ants are the culmination of insect evolution in the same way human beings are the summit of vertebrate evolution. Their social organization is complex. In many respects a colony of ants functions as a single organism, with tasks divided among members much as bodily functions are divided among organs in mammals.

The basic colony is composed of one fertile queen and sterile female workers. Males appear for only a short time during the summer. They hang around the colony, being fed by workers, until they fly off to mate with winged virgin queens. After that they kick the bucket.

The newly mated queen draws on her stored reserves to feed the larvae. When the workers hatch they take over the tasks of foraging for food, maintaining and increasing the size of the nest, and caring for other broods of eggs and larvae. This leaves the queen free to concentrate on egg laying.

When the nest reaches a certain size, the workers begin to specialize in their tasks. Some forage for sweet foods. Some concentrate on hunting and killing other insects for meat. Others serve as soldiers that defend the nest.

Since every organism's goal is to pass on its genetic material, it might at first seem counterproductive for a queen to give birth to ants that can't reproduce. But the workers enable the queen to produce thousands of offspring, particularly since queens can live for 20 years or more. A worker's incentive to perform its tasks is the same as the queen's: to ensure the survival of its genetic material. Since the worker can't give birth itself, its only chance of genetic survival is in preserving the life of the keeper of its genes, the queen.

The cozy plastic world of Uncle Milton's ant farm was not a comprehensive colony. I had a small group of Pogonomyrmex workers, a type of harvester ant native to the deserts of the southwest. Workers are the only kind of ants Uncle Milton Industries is legally allowed to transport.

Just as ants are alleged to be, this crew was an industrious lot. They dug almost continuously in the soft sand. But they seemed to be having a critical failure when it came to communicating a common mission. While one group of ants worked hard to build a tunnel, another cluster labored to fill it back in. I wrote in my notebook that ants, or at least this group, didn't function as the cohesive social organism biologists claimed they were.

After three months Uncle Milton's ants began to die. This was not natural death; in the wild workers can live two or three years. I attributed their demise to some failing on my part to keep the perfect balance of food, water, and fresh air in the closed system.

I regretted their fate, but I still wanted to observe a colony of prairie ants--and put my new knowledge of ant husbandry to work with something more important than sterile California insects. I scrapped Uncle Milton's farm and built a more dignified wooden and glass structure.

By now it was March. The ground thawed, and I discovered the perfect place to acquire an ant colony. It was a beat-up little prairie near Lake Forest Hospital, and it had a building crane parked next to it, an indication that its days as a prairie were numbered. I felt I could justify taking ants from a doomed spot, see it as prolonging the colony's life.

I put a couple shovelfuls of the anthill into a pillowcase. But that left the remaining ants completely exposed to predators, so I tried to replace part of the sides and piled dirt over the top of the decimated hill, hoping they'd recover.

Back home, I turned the pillowcase upside down over the tub, hoping its steep sides would keep the ants from scattering around my apartment. Ants do not have a broad emotional range. Even Wilson, their number-one fan, describes them as "feeble of intellect." There just aren't enough neurons firing in those tiny brains to support anything close to the spectrum of emotion humans experience. But one emotion they express well is panic. Every ant in the bag took off running in its own crooked path across the tub. They moved like crazed Charlie Chaplins, their little legs shaking at their sides.

I tried Uncle Milton's pencil technique for getting them into the farm--a nincompoop's approach. When I put the pencil down in front of an ant, she jumped on it, ran up my hand, and was halfway up my arm in about one second. And so were ten of her feisty sisters. Soon they were all over me, biting me as hard as they could with their tiny mandibles.

This wasn't the relationship I'd envisioned. I'd imagined coercing stunned ants into the glass box, then treating them well while I uncovered valuable scientific information. I hadn't expected all-out war.

Eventually I managed to get some ants into the farm. I closed the glass and set it up on the mantel in the living room.

Dr. Robert Hamilton of Loyola University, one of the few people to have conducted research on prairie arthropods, identified the species I'd collected as Formica montana. He told me Formica montana was one of the eight ant species identified in a 1944 report as inhabitants of true tall-grass prairie near Chicago. In a 1986 study conducted by a graduate student of Hamilton's, only four of those species were still present on the three prairie preserves where pitfall traps were set. The other four had vanished over the years, probably victims of subdivisions and corporate campuses.

In a few days the Formica montana workers began to restore order to the jumble I'd made of their colony. Soon the workers began carrying around sticky white clumps of eggs and larvae that looked like puffed wheat, keeping them almost always in motion. Obviously I'd captured a queen, but the workers had her sequestered somewhere.

It was almost three weeks before I learned that I'd captured not one but two queens. Both were sleek and beautiful, twice the size of the small brown workers. Reading Wilson, I learned that multiple queens in a colony are not uncommon in the Formica genus. The colony may be founded by two or more queens, or additional queens may be allowed to enter the colony after it's been established. Large colonies of some species may have thousands of reproducing queens.

The Formica montana family didn't spend much time building tunnels. They moved dirt around sometimes, but they weren't obsessive about it the way Uncle Milton's ants were. My new theory about his ants was that they'd been slightly nuts.

The Formica montana workers could concentrate on fulfilling their destiny of caring for the queen and her offspring. Uncle Milton's harvester workers didn't have their reason to exist. They didn't need to create nooks for eggs or chambers to keep larvae warm. Driven by an 80-million-year-old instinct, they burrowed and filled because that was all there was to do.

Though better adjusted, the Formica montana didn't have much to do either compared with their life in the wild. Since the original colony was large, the members I'd captured had likely fulfilled specialized roles before they were confined. But in my glass box the hunter ants were prevented from hunting, the foragers from finding food. They all turned their attention to moving the eggs and larvae around and feeding the queens.

By June I felt I'd learned what I could from firsthand observation. Aside from the discovery that Formica montana colonies support multiple queens, I'd acquired most of my knowledge from reading. And I wasn't convinced that the actions of Formica montana in captivity were representative of their actions in the tall-grass prairies. I decided to let them go.

I drove them to a prairie in a Cook County forest preserve. The land is protected: no house would be built on top of them. But I couldn't predict whether they'd escape their natural predators.

I cleared away some debris at the base of a clump of big bluestem. Removing the glass, I shook the hard earth out of the frame and the ants with it. They performed their Charlie Chaplin panic dance again. I watched for a moment, then piled a layer of loose dirt and leaves over the top of the mound.

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