Inside the Scramble to make half a million ants feel at home

When the American Museum of Natural History’s new insectarium opens May 4, half a million leafcutter ants will share the title of the main attraction.

The ants are biological marvels, living in vast colonies that function as a single superorganism. They are shrewd farmers, collecting leaves which they use to tend sprawling mushroom gardens that provide food for the colony.

Creating the new leafcutter exhibit was a six-year journey that took the museum’s team – and the ants – from a farm in Trinidad, where the tangerine-sized colony was collected, to a lab in Oregon, where it grew large enough to fill one bathtub, and then on a six-day trip across the country in a U-Haul van.

And that wasn’t even the hard part. The ants, which moved into their museum enclosure in January, were slow to adjust to their new home as they couldn’t harvest enough leaves to maintain their mushroom gardens.

“We’ve had a few ups and downs,” said Hazel Davies, the museum’s director of living exhibits. “Some troubleshooting, as we expected as it’s quite a unique exhibit.”

So the museum finally helped the ants find their way.

To showcase ant agriculture, the museum designed an expansive, open exhibit using lab-tested, ant-approved materials, from woven stainless steel to old-fashioned Legos. “The ants have a lot of stuff to pick,” said Ryan Garrett, a self-proclaimed “ant wrangler” and founder of Leaf House Scientific, who collected the ant colony and served as a habitat consultant.

The design had the ants tend their mushroom gardens in glass spheres, and then travel an ambitious route to collect their leaves, crossing a transparent skybridge upside down and climbing aluminum poles.

The team filled the foraging area with brambles and filled the surrounding ditch with water to contain the ants.

Then they loaded the ant-filled balls, which had been temporarily clogged with Play-Doh balls, into the exhibit. (A hand-held vacuum was used to collect ants that had ventured out of the spheres to forage, sucking the insects into “a friendly tornado,” Mr. Garrett said.)

They removed the balls and waited for the ants to find their way, a process they expected to take at least several days.

It took weeks. Some ants quickly made their way to the skybridge and even down the ant trail leading to the feeding area, but there they seemed to falter. “We knew it was a big challenge,” Ms Davies said. “It’s like going downtown for groceries but not being told where to go.”

The team only needed a small subgroup of ants to pave the way; When the first ants returned from the foraging area, they left a pheromone trail for their sisters to follow. The museum began luring the ants forward by laying a trail of apples and leaves.

But another problem soon arose: the tunnel still under construction was too dry for the tropical ants. For this reason, an air humidifier was installed behind the exhibit, which directs moisture into the showcase.

The path of the ants was simplified, a rope was stretched across the skybridge so that the ants no longer had to cross it upside down. Another shortcut allowed the ants to bypass some of the aluminum bars.

By mid-April, rows of ants had started putting leaves back into their balls. “It felt like the ants were partying,” said Mr. Garrett.

There’s more to do. The ants didn’t really accept the braided metal that seemed so promising in the lab and keep falling into the moat. Mr. Garrett recently made a temporary “ant filter” out of bramble branches to help the insects climb out.

But the team has now removed the major shortcuts and pushed the ants onto more challenging paths. Just a few days ago, the ants finally completed the entire route and even began snaking their way through an elevated maze detour.

“I know everyone wanted the ants to just go straight to the food jungle, but I think this process of slowly finding their way is really beautiful,” said Mr. Garrett. “Every day we watch them learn.”