Army ants caught on camera making body bridges

ARMY ants have been caught on camera building living bridges by linking their bodies together — and this is good news for humans.

A TEAM of researchers have filmed army ants building living bridges by linking their bodies to span gaps and create shortcuts.

The ants, which live in rainforests in Central and South America, form the bridges to facilitate travel and maximise speed, but dissemble the bridges in seconds when they become too long and traffic walking over them slows down.

Clever little things ... Army ants filmed building moving bridges from their live bodies. Picture: Chris Reid/University of Sydney

It was previously thought that once the bridges had been built they didn’t really move or change but after watching the ants, researchers realised the bridges can assemble and disassemble in seconds and the ants can also change their position depending on the environment.

The dynamic nature of the bridges has been found to facilitate travel by the colony at maximum speed, across unknown and potentially dangerous terrains.

But the researchers also discovered that although ants benefitted from shorter travelling distances because of their bridges, they also incurred a cost by employing workers that could be used for other important tasks. When building their bridges the army ants had to balance this cost-benefit trade-off.

And the new evidence from observing the ants could have a pay-off for humans.

Co-lead author Dr Christopher Reid, a postdoctoral researcher at the University of Sydney’sInsect Behaviour and Ecology Lab and formerly with the New Jersey Institute of Technology, said the new findings could be applied to develop swarm robotics for exploration and rescue operations. By analysing how ants optimise utility, researchers may be able to create simple control systems to allow swarms of robots to behave in similar ways to an ant colony.

Adaptable ... The ants can change the position of their bridge depending on the environment. Picture: Chris Reid/University of Sydney

“Such swarms could accomplish remarkable tasks, such as creating bridges to navigate complex terrain, plugs to repair structural breaches, or supports to stabilise a failing structure,” Reid said.

“These systems could also enable robots to operate in complex unpredictable settings, such as in natural disaster areas, where human presence is dangerous or problematic.”

The team included researchers from the University of Sydney’s Insect Behaviour and Ecology Lab, the Max Planck Institute for Ornithology, the University of Konstanz, the United States’s New Jersey Institute of Technology, Princeton University and George Washington University.

The paper, ‘Army ants dynamically adjust living bridges in response to a cost — benefit trade-off’, is published in the journal Proceedings of the National Academy of Sciences (PNAS).