Army Ants Build ‘Living’ Bridges Using Their Bodies, Demonstrate Collective Intelligence That Can Inspire Robotics

In the future, the most useful robots will work together as a swarm. Scientists believe that engineers can draw inspiration from nature in creating the next generation of robots. They can learn from creatures such as army ants, demonstrating collective problem-solving intelligence.

Architectural Prowess of Army Ants

Army ants are members of the subfamily Dorylinae, a dominant invertebrate predator commonly found in Africa, South America, and Central America. They are known for being a massive army that can build a new path out of themselves when encountering obstacles.

Scientists from Princeton University and the New Jersey Institute of Technology (NJIT) study the "living" bridges allowing large raiding swarms to travel efficiently. They focus on the collective intelligence exhibited by the species Eciton hamatum and how this behavior can help develop intuitive robots that can cooperate as a group.

When army ants encounter obstacles such as a gap between leaves or branches, they link themselves together like a barrel of monkeys. The workers will connect themselves across that gap while others walk on top of them. Instead of taking a convoluted path around an obstacle, the army ants create these bridges to make their hunts more efficient.

However, building the living bridges comes at a cost to the ant colony because the ants that take part in supporting the bridge are not available to hunt. Using their tiny brains, the ants can collectively weigh the costs and benefits of a bridge.

In studying the decision-making ability of E. hamatum, the researchers discovered that the ants build bridges where they get the most significant benefit for the least amount of bodies. They identified a sweet spot where the gap is large enough to justify building a bridge but not so large that it will take too many ants. It was also found that a string of bridges influences the amount of power the ants are willing to invest in each bridge.

Inspiring Human Technology

Understanding how these ants can achieve such feats can change how experts think of self-configuring natural and man-made structures. The collective intelligence of army ants has implications for human technology and can inspire scientists to build more efficient devices.

In building algorithms for self-assembling robots, engineers have learned to apply swarm behaviors, which they learned from army ants. The collective intelligence of army ants demonstrates how individual-level interactions can produce coordinated group behavior.

By extracting the rules used by individual army ants in building living bridges, engineers can program swarms of simple robots to create structures that are connected. Such systems can exhibit the beneficial properties observed in ant bridges, like real-time optimization of position and shape, adaptability to local conditions, and rapid construction and deconstruction without needing external building materials.

For a long time, it has been a challenge in robotics to take robot parts and allow the robot to piece itself together and solve more significant problems. According to engineering professor David Hu from the Georgia Institute of Technology, army ants are proof that such a kind of robot can survive and have problems to solve in the real world.