When the American Museum of Natural History’s new insectarium opens May 4, half a million leafcutter ants will share the title of star attraction.
The ants are biological marvels, living in huge colonies that function as a single superorganism. They are sophisticated farmers who collect leaves that they use to tend extensive fungus gardens, which provide food for the colony.
Creating the new leaf-cutter exhibit was a six-year journey that took the museum team — and the ants — from a farm in Trinidad, where the mandarin-sized colony was collected, to a lab in Oregon, where it grew large enough for a bathtub, then on a six-day drive across the country in a U-Haul van.
And that wasn’t even the hardest part. The ants, who moved into their museum habitat in January, were slow to get used to their new home, unable to harvest enough leaves to maintain their fungus gardens.
“We’ve had a few ups and downs,” said Hazel Davies, the museum’s director of living exhibits. “Solving some of the issues, as we expected, because it’s a pretty unique exhibit.”
In this way, the museum eventually helped the ants find their way.
To showcase the ants’ farming, the museum designed a sprawling, open exhibit made of lab-tested, “ant-approved” materials, from braided stainless steel to old-fashioned Legos. “The ants had to pick a lot of things,” said Ryan Garrett, a self-described “ant hunter” and founder of Leaf House Scientific, who collected the ant colony and served as a habitat consultant.
The design had the ants tend their fungus gardens in glass spheres, then take an ambitious route to collect their leaves, cross an upside-down transparent skybridge and clamber over aluminum poles.
The team filled the foraging area with blackberries and filled the surrounding moat with water to contain the ants.
They then loaded the ant-filled spheres, temporarily hidden with balls of Play-Doh, into the exhibit. (A hand vacuum was deployed to collect ants that had ventured out of the bulbs to forage and sucked up the bugs in “a friendly tornado,” Mr. Garrett said.)
They disconnected the orbs and waited for the ants to find their way, a process they expected to take at least several days.
It took weeks. Some of the ants quickly made their way to the sky bridge and even to the ant highway leading to the feeding area, but they seemed to stop there. “We knew it was a big question,” Ms Davies said. “It’s like going downtown to buy groceries, but not being told where to go.”
The team only needed a small group of ants to clear the way; when the first ants returned from the feeding area, they left behind a pheromone trail for their sisters to follow. The museum began to lure the ants forward by laying down a trail of apples and leaves.
But soon another problem loomed: the gallery, which was still under construction, was too dry for the tropical ants. That is why a humidifier was installed behind the exhibition, which led the moisture into the display case.
The path of the ants was simplified, a rope was stretched across the sky bridge so that the ants no longer had to cross it upside down. Another shortcut allowed the ants to get around some of the aluminum posts.
By mid-April, rows of ants began parading leaves back to their orbs. “It felt like the ants were celebrating,” Mr. Garrett said.
There is more work to be done. The ants aren’t too fond of the braided metal that seemed so promising in the lab, and they keep falling into the moat. Mr. Garrett recently made a temporary “ant filter” out of blackberry branches to help the bugs climb out.
But the team has now removed the major shortcuts and pushed the ants along more challenging paths. Just days ago, the ants finally completed the whole route and even started to make their way around an elevated maze detour.
“I know everyone wanted the ants to easily walk right up to the foraging jungle, but I think this process of slowly making their way through is really beautiful,” Mr Garrett said. “We see them learning every day.”
