No Leaf Unturned

IT’S AN AGE-OLD STORY. A young woman sets out on her own. She leaves behind the only place she’s ever known, a city crawling with millions of citizens engaged in the activity of making a metropolis run. Workers build new homes and roads. Farmers plant, weed and harvest their gardens. Others are busy cleaning the streets or guarding important landmarks or deploying to fight disease.

Our heroine seeks a life less crowded. A place to call her own. So she heads somewhere new. Takes a flight. Her only carry-on a little memento from home.

When she settles down, though, her story veers from the familiar script.

Reaching her final destination, she digs a tunnel into the earth, removes the piece of home from a pouch in her cheek and tears the wings from her body. The memento is actually a fungus. Those wings are its first meal. And that piece of home grows and grows under her care—the key to sustaining the new colony that will soon spring from the eggs she lays.

Every rainy season in Central and South America, this story unfolds a million times over. It is the saga of the leaf-cutter ant, and it may one day influence everything from how we produce fuel to how we fight disease to how we think about evolution.

But first, it just might make us reconsider what it means to be human.

Ants have been growing their own food for about 50 million years, which is about 50 million years longer than we have.

Thirty years ago, noted physician and essayist Lewis Thomas observed that it is a generally accepted metaphor that humans, when viewed from a great height, resemble ants at work. However, Thomas continued, it’s frowned upon to peer through the magnifying glass and make the opposite analogy. Which is odd, he wrote in his book The Lives of a Cell: Notes from a Biology Watcher, considering that “ants are so much like human beings as to be an embarrassment.”

We regard our ancestors’ transition from hunting and gathering to agriculture as the accomplishment of human industry, one that allowed us to thrive upon this earth. But ants have been growing their own food for 50 million years, which is about 50 million years longer than we have.

Think the discovery of antibiotics was only made possible because of our big brains? For millennia, ants have used some of the same bacteria we “discovered” to create disease-fighting antibiotics. What’s more, they’ve managed to avoid the problem of antibiotic resistance that plagues our medical field.

Of course, the human-ant comparison falls apart at the individual level. A lone ant has little in the way of self-awareness or cognitive thought. The ant harbors no brain, just a few thousand neurons strung together. But once that ant joins the swarm teeming about a nest, it becomes a model for societal organization and technological accomplishment. Then, Thomas writes, “you begin to see the whole beast. And you now observe it thinking, planning, calculating. It is an intelligence, a kind of live computer, with crawling bits for its wits.”

From the fourth floor of UW-Madison’s Microbial Sciences Building, associate professor of bacteriology Cameron Currie is trying to crack the code of this “live computer.” An entomologist by training, he has since ventured into realms as diverse as microbial ecology, evolutionary biology and genomics to help him sort out the myriad interactions that help fungus-growing ants thrive. His work has led to grants from places like the U.S. Department of Energy and the pharmaceutical giant Roche. He’s also garnered several awards, the most recent (and prestigious) being the Presidential Early Career Award for Scientists and Engineers, which he’ll have handed to him by President Barack Obama this November.

It’s an enviable career arc, but it didn’t begin with the desire to study ants. Currie was first a student of ecology, finding inspiration in Darwin’s description of the “tangled bank”—an attempt, Currie says, to explain how “birds and worms and insects all interact and (how) these complex communities shape each others’ evolution and are shaped by evolution.”

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