Ant bridges can shimmy along walls to span wider gaps

24 Nov 2015

We all knew, well some of us did, that ants build bridges using their own bodies, creating a structure to help them cross over divides. But did you know these bridges can move?

Ants are incredibly interesting things to study, even if just for a short period of time. And now researchers have checked out their bridge building to pick up any clues for future robotics creations.

Ants in South America have long been known to build bridges, which is amazing in itself, but the discovery that these constructions can shimmy along walls to help span wider gaps could be significant in the evolution of robotic disaster relief and deep-sea exploration advancements.

The bridge keeps shimmying until it stops making sense to the ants, that is, until the ants feel the shortcut is short enough. They then disband as they notice less ants walking across their backs.

A time-lapse video of the ants building moving bridges, via Chris R Reid, Matthew Lutz & New Jersey Institute of Technology

Swarm robotics

Dr Christopher Reid, co-author of the study, said the findings could be applied to develop swarm robotics for exploration and rescue operations.

The way they manipulate their bodies, and interact with each other, may provide clues as to how researchers can form algorithms to best replicate what clearly works in practice.

Reid and his colleagues found that these bridges take seconds to assemble and disassemble, shifting along to respond to the “immediate environment” – translation, they move along to span over wider ranges.

“Indeed, after starting at intersections between twigs or lianas travelled by the ants, the bridges slowly move away from their starting point, creating shortcuts and progressively lengthening by addition of new workers, before stopping, suspended in mid-air,” said Dr Reid to the University of Sydney, where he is currently a researcher.

“In many cases, the ants could have created better shortcuts, but instead they ceased moving their bridges before achieving the shortest route possible.”

Cost-benefit analysis

What is remarkable is the decision making process as, often, creating a bridge takes away valuable resources from the colony. When building their bridges, army ants had to balance this cost-benefit trade-off.

“Artificial systems made of independent robots operating via the same principles as the army ants could build large-scale structures as needed,” said Reid.

“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.

“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.”

Ant bridge image, via Shutterstock

Gordon Hunt was a journalist with Silicon Republic