Fire Ant Rafts Could Help Design Self- Assembling Robot [Video]

Fire ants use their bodies to build "super-intelligent" rafts that behave as both solids and liquids. Understanding the swarm intelligence behind this engineering marvel could help researchers develop self-assembling bots or even smart materials.

Fire ants have been studied extensively for their ability to create structures using their bodies. Previous research has shown that these ants are masters of underground locomotion and can create tunnels.

The present study, conducted by researchers at Georgia Tech, found that ants use their bodies to create rafts that act as "viscoelastic" materials, meaning that they can resist flow and retain their original shape. These materials act as both solids and liquids.

Moreover, fire ants can regroup to form or modify a structure, which helps them protect the colony from raindrops or water surges. This unique ability has helped them survive in the remote, wet lands of the Amazonian rainforests. The fire-ant rafts are usually the size of a plate, but could be as big as a garbage-lid.

Fire ants use their hands and legs to make rafts that help them stay afloat, researchers said.

"The linkage structure they form, similar to a truss structure, is elastic and so is able to sustain external forces," Zhongyang Liu, an undergraduate student in the laboratory of Georgia Tech, lead author of the study, said in a new release.

Researchers used micro-scale computer tomography and high-speed video to see how fire ants responded to changes. In the lab, the team crushed and smashed the living raft, but ants were quick enough to dissipate and regroup to form the original structure.

"Imagine thousands of people linking their arms together, but everyone has six arms instead of two, and all of their limbs have tiny hooks and adhesive pads on them. That's why fire ants can do such dynamic restructuring," biologist David Hu, also at Georgia Tech, told New Scientist.

Researchers also found that unlike bacteria films or liquid crystals, fire ants balance storing and spending energy. This behavior allows them to act as elastic as well as a viscous material.

Check videos of the fire ants in action, below:

The study was presented at the American Physical Society's Division of Fluid Dynamics (DFD).