Teamwork isn’t just a human trait: army ant colonies form living ‘scaffolding’ to protect members from falling.
The insects are blind and do not have a designated leader, but according to new research, they can use simple rules of behavior to develop these safety structures without requiring direct communication.
Once scaffolding was built, worker ants were nearly 100 percent protected from falling down steep slopes.
Understanding how to design such complex structures could help engineers develop self-healing materials and swarm robotics, researchers said.
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Army ants in Central American rainforests build scaffolding out of their bodies to help them traverse steep terrain. The ‘safety net’ retains its structure even over almost vertical slopes
There are over 200 different species of army ant (Eciton burchellii), mainly found in the rainforests of Central and South America.
To traverse the treacherous forest floor, worker ants form ‘highways’ and ‘bridges’ with their bodies.
Researchers have discovered a new kind of army ant architecture, a living scaffold that prevents ants carrying prey for the colony from slipping and falling if the path gets too steep.
An international team of entomologists has studied the structures created by army ant colonies in Panama.
The scientists directed the colony’s foraging path to a platform that they could tilt horizontally up to 90 degrees
The scientists redirected the foraging paths of the colonies to a platform that they could tilt horizontally up to 90 degrees, and observed the creation of this scaffold.
There seemed to be a good spot: Anything below 40 degrees probably didn’t cause a scaffold, according to their report this week in Proceedings of the National Academy of Sciences of the USA.
Much steeper slopes “led to larger and faster growing structures,” according to a release.
“Scaffolding is also more likely when many workers are transporting heavy prey,” said biologist Matthew Lutz, co-lead author of the study.
Hardly any ants once fell a scaffold into place, not even over vertical surfaces.
Anything under a 40 degree slope probably wouldn’t create a scaffold. The steeper the slope, the faster and bigger the structure
“It’s remarkable how quickly these structures form in response to disruption when crossing slopes,” Lutz said.
“They really are a form of self-healing, responsive infrastructure.”
Army ants are the largest on Earth, and each queen has the capacity to lay millions of eggs each month.
Millions of workers are constantly foraging for food, consuming up to 500,000 grubs, eggs and other tasty bits every day.
Each ant is only a quarter to a half inch in size, but a colony’s foraging path can be over 325 feet long and 60 feet wide.
Scientists still don’t quite understand how the ants form these super scaffolds: They are practically blind, and while they have a queen, there is no central authority when it comes to moving as a unit.
Scientists still don’t quite understand how they form these superstructures: although they have a queen, there is no central authority when it comes to moving as a unit.
Additionally, army ants are virtually blind and rely on pheromones to communicate.
The researchers – including experts from the Max Planck Institute of Animal Behavior in Konstanz, Germany; Macquarie University in Sydney, Australia; the New Jersey Institute of Technology; and the Santa Fe Institute in New Mexico – theorized that the ants can sense how much they slip and spontaneously form these scaffolds if they lose their grip.
Army ants are the largest species of ant on Earth, and each queen has the capacity to lay several million eggs each month
“Our model is very consistent with the experimental results, without requiring the ants to communicate with each other or assess the size of the structure,” said study co-lead author Chris Reid, a researcher at Macquarie University.
“Army ants are small, blind, and have no leaders or blueprints to guide them, but their ability to generate advanced group-level behavior based on simple local-level rules is extremely valuable to many engineering fields, including swarm robotics.”
Cracking the code on how they generate these structures with little input or information would be a boon to robotics, architecture, and engineering.
A swarm of miniature robots could potentially be sent to a disaster site and form a necessary structure to aid in recovery, whether or not it was “ programmed ” into their network in advance, the authors wrote in The Conversation.
Other ants also create structures: Colonies of fire ants will form ‘rafts’ to ride a flood to safety.