Even with no one in charge, army ants work collectively to build bridges out of their bodies. New research reveals the simple rules that lead to such complex group behaviour.
How Ants Build Bridges
Army ants form colonies of millions yet have no permanent home. They march through the jungle each night in search of new foraging ground. Along the way they perform logistical feats that would make a four-star general proud, including building bridges with their own bodies.
Much like the swarms of cheap, dumb robots that I explored in my recent article, army ants manage this coordination with no leader and with minimal cognitive resources. An individual army ant is practically blind and has a minuscule brain that couldn’t begin to fathom their elaborate collective movement. “There is no leader, no architect ant saying ‘we need to build here,’” said Simon Garnier, director of the Swarm Lab at the New Jersey Institute of Technology and co-author of a new study that predicts when an army ant colony will decide to build a bridge.
Garnier’s study helps to explain not only how unorganized ants build bridges, but also how they pull off the even more complex task of determining which bridges are worth building at all.