They are farmers, doctors and amazingly adept traffic engineers. The tropical ants that Cameron Currie studies have been practicing the good life for millions of years. What do they know that we don't?
By Adam Hinterthuer
“But look at us,” Suen says. “Think about even in Madison, when construction cuts down one lane on University Avenue. What happens? It takes 10 times longer to get anywhere. Ants have clearly figured out a way (around) this. And that is clearly an intelligence we call ‘lower’ intelligence, but really from a computer science perspective, we have not unlocked that secret.”
Swarm intelligence can be striking in its effectiveness. For example, when researchers lace maple leaves with a fungicidal agent, the ants soon discover those leaves are killing their fungus, and an announcement somehow goes out to the entire colony. After that, not a single ant brings a maple leaf back to the nest. No one knows how an individual ant identifies threats to the fungus. Or it could be the fungus alerting the ant. It’s still unclear how the rest of the colony somehow receives the news. Even though it is operating in plain sight, caught in the Tupperware bin, it is a mystery how such a complex system keeps humming along.
The answer may be found, Suen says, via genomics. The Currie lab was recently awarded a grant from Roche pharmaceuticals for 10 gigabases of genome sequencing. That’s the equivalent to the complete genetic sequences of three humans. The award is not monetary—it’s a service. Currie’s lab isolates the DNA and sends it to Roche, where scientists sequence the genome. The result will be a genetic picture of the entire ecosystem.
Once they have the genome decoded for each organism in the system, Currie’s lab will be able to use something called microarray technology to see what genes get turned off or on under certain conditions. They can then start tweaking the conditions to see how the ant, fungus, parasite and bacteria all respond to one another. For example, in the experiments where ants identify and avoid tainted leaves, scientists could look at what genes were activated or shut down in the fungus when it encounters the leaf. Then they could do the same for the ant and the parasite to look for similar responses, which will eventually lead to better understanding of what chemicals and stimuli are enabling them to all interact.
“What’s really different about this project is that so far genome sequencing has been about understanding the biology of a particular organism,” says Nicole Gerardo, an assistant professor of biology at Emory University and one of the co-investigators on the Roche grant. “And what we’re asking is can you use genome sequencing to understand the associations between an entire group of organisms.” She says taking a wider view will allow scientists to get at the inner workings of systems “we used to see as just cool natural history stories.”
The hidden mechanism that most intrigues Gerardo is the ants’ use of antibiotics to battle mold in their gardens. She already knows that microbes in the system can recognize each other, which means that there’s some kind of chemical communication going on. Unlocking that communication on a genetic level could teach scientists more about how pathogens sense and respond to antibiotics, information that could help improve antibiotic drugs for human use.
But the fascinating aspect of Currie’s lab is that no one of these potential applications holds center stage. His team is a melting pot of academic disciplines, where behavioral ecologists work alongside bacteriologists and bioinformaticists. This interdisciplinarity has led to collaborations with units such as the Great Lakes Bioenergy Research Center, which is funding part of Currie’s work in hopes of learning how the ants’ gardens break down and process the cellulose in plant leaves.
The emergence of these avenues of research are a function, Currie says, of the changes taking place in the way we study life. Science has moved from an era of field work, carried out by naturalists such as Darwin traipsing around in tangled banks, to lab work, where organisms are grown and observed in controlled conditions. Both methods have their drawbacks: Field work was hard to control, but lab work imposed a kind of false reality that didn’t capture what was really happening in the environment. Genomics is opening the door to a new kind of science, where you can just bring the whole natural system indoors, preserving the diverse interactions of nature while providing the sophisticated observational tools of the lab.
And that brings an interesting twist in the saga of the leaf-cutter ant. Consider our heroic queen. It is a half year later. Her colony is up and running, boasting a few hundred workers and a fungus garden the size of a baseball. Suddenly, the wall of the chamber gives way. A pair of gloved hands reaches in and gingerly transfers the queen and her garden into a container. Then the queen takes another flight, this time tucked into the luggage of an overhead bin.
When she lands, she finds herself in a Wisconsin lab, unknowingly helping humans uncover the secrets of how to become one of the most successful animals in the world.