Army ants efficient in 'minding the gap'

Washington D.C.: Army ants in South and Central America can teach humans a thing or two about efficient delivery as a new study suggests that they build bridges to shorten their journeys through the rainforest.

Army ants construct complex bridges from their own bodies to span gaps and create shortcuts in the floor of the tropical forests of Central America, according to the new study.

Army ants are nomadic species. They relocate their colonies throughout the rainforest on a regular basis. In order to facilitate the movement of their large population, a colony can have up to 1 million individuals in some species, on the very uneven forest floor, some of the ant workers use their own bodies to plug holes along the path traveled by the colony.

These workers can also attach to each other to span larger gaps, effectively building living bridges made of several dozens of ants in some instances. These bridges can assemble and disassemble in a matter of seconds, allowing the ant colony to travel at high speed across unknown and unpredictable terrain.

A collaborative team of researchers from New Jersey Institute of Technology, Princeton University, George Washington University, Harvard University and the Max Planck Institute for Ornithology and the University of Konstanz has recently discovered that these bridges move on their own from their original building point to create shortcuts across large gaps.

These bridges change dynamically with the traffic pattern on the trail, said Christopher Reid, one of the lead authors, adding that the work has implications for other self-assembling systems, such as reconfigurable materials and autonomous robotic swarms.

He noted that artificial systems made of independent robots operating via the same principles as the army ants could build large-scale structures as needed. Such swarms could accomplish remarkable tasks, such as creating bridges to navigate complex terrain, plugs to repair structural breaches, or supports to stabilize 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.

The study is published in the Proceedings of the National Academy of Sciences.