AUSTIN (KXAN) — Thousands of Red Imported Fire Ants gather in a bucket in Edward LeBrun’s lab. They crawl over each other, forming balls of red stingers, in an attempt to escape the bucket. Moments later, one of these balls is picked up by LeBrun and dropped in a bowl of water.
The ants do not drown. They originated along the river banks of South America and know what to do. Quickly, they bite each other, wrapping legs within legs, and form a raft. Their wax-covered skin prevents them from drowning, and the tightness of the raft keeps them afloat.
“It’s called a self-organizing or self-assembling process. And it’s something only social insects do,” LeBrun said. A research scientist at the University of Texas’ Brackenridge Field Lab in central Austin, LeBrun has researched ants for three decades.
“There are a lot of other structures that ants make in a similar way. For example, army ants will make bridges across rivers,” LeBrun said, but still, this raft is rare. Fire ants he believes are the only ants that do this.
These little fellas have survived and flourished as a result of this technique. When floods rushed in, they would gather at the top of their mounds, form the raft, then be washed downstream.
Once they dried off, they would disassemble and then build a new mound. This new home would have the exact same layout as their previous home.
Fire ants can survive floods by transforming their colonies into floating rafts. This technique is inspiring engineers in the development of medical devices. (Credit: Todd Bailey/KXAN)
“It’s simply that they encounter a stimulus. And then they follow a series of decision rules,” LeBrun said this sort of thinking is similar to how many machines and computers work.
Now that way of thinking and how these ants, in particular, are behaving, is inspiring engineers to develop something unique.
Ants and the shape-changing rubber
“I think that for those of us who live in Texas, fire ants are a part of our life,” said Taylor Ware. An associate professor of Biomedical Engineering and Material Science and Engineering at Texas A&M University, Ware found inspiration from these ants.
“Their individual beings, they latch on to one another, they form this solid,” Ware said.
His team included Dr. Mustafa Abdelrahman, along with a former Ph.D. student and collaborators at Texas A&M, the University of Colorado Boulder and Carnegie Mellon. They all developed a new technique for a type of rubber.
This rubber, made of tiny ribbons, was taught to change shape when heated and cooled. Each tiny strip could intertwine with other strips and form objects, much like the ants do to form the raft.
“You can have something that was flat and would bend, you could have things that twist, you can have things that morph that fold into different geometries,” Ware said.
Wax on the ant’s body allows them to float for weeks in flood waters. (Credit: Todd Bailey/KXAN)
The material, which is an oily substance when cool, can be poured into a mold. When heated, it will take the shape of the mold. It can then be cooled again. As long as it doesn’t get too cool when heated it will return to the shape it was molded into.
Ware said this substance can be used in motors or medical devices. “You might imagine this might be useful if you were healing a wound, right, so you’re gonna fill some oddly shaped cavity,” Ware said.
LeBrun said this method of nature-inspiring technology isn’t uncommon. “Understanding how those assembly processes work allows, for example, scientists that work on small robots to figure out how to organize groups of small robots.”
Ware and his team received funding for their research from the National Science Foundation, the Army Research Office and the National Institutes of Health. Ware said the technology is still in the testing phase. They expect to see it on the market in the next few years.
Until then, LeBrun’s ants dry off and the raft falls apart. They go back to their bucket, feasting on sugar water and crickets, unaware of what they could inspire next.
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