New research recently laid out the simple physics-based rules governing how ant rafts transform over time, shrinking, expanding, or growing long flanges akin to an elephant's trunk.
As indicated in a Phys.org report, findings of the team from the University of Colorado Boulder could one day help researchers engineer robots that will work together in swarms or next-generation materials in which molecules are migrating to fix damaged spots.
According to the primary investigator on the new study Franck Vernery, a professor in the Paul M. Rady Department of Mechanical Engineering, the origins of such behavior lie in "fairly simple rules." He added, single ants are not as smart as people may think, although generally, they turn very intelligent, not to mention resilient communities.
Essentially, fire ants from these huge floating blobs of wriggling insects following storms in the southeastern United States to overcome raging waters.
The Faster the Ants Move, the More Rafts Expand
In their latest research published in the PLOS Computational Biology journal, Vernerey and Robert Wagner, the study's lead author, drew on a mathematical model to figure out the mechanics underlying such lifeboats.
As a result, they found, for instance, that the faster the ants in a raft are moving, the more those rafts will expand outward, frequently forming long protrusions.
Such behavior could vitally take place spontaneously, Wagner, a graduate student in mechanical engineering, explained. He added that there does not necessarily need to be any "central decision-making by the ants," he added.
The 'Treadmilling' Process
Moreover, Wagner and Vernerey found the secrets of ant rafts nearly by accident. In separate research published in the Journal of the Royal Society Interface in 2021, the two dropped thousands of fire ants into a bucket of water with a plastic rod in the center, like a sole reed amidst the stormy waters. Then, they waited for what would happen next.
Wagner said they left the ants for up to eight hours to observe the rafts' long-term evolution. As a result, they saw that the said rafts began to form such growths.
Instead of staying the same shape over time, the researchers found that the structures would compress, drawing to form thick circles of ants.
At other points, the ants would fan out similar to pancake batter on a skillet, even developing bridge-like extensions. The researchers reported the ants appeared to modify such shape changes through a "process of treadmilling."
Simple Rules Programmed Through Algorithm
In this new study, Wagner and Vernerey wanted to discover what's making that treadmill go round. To find out, the team developed a series of models that vitally turned an ant raft into a complex game of checkers.
The study offers a program of approximately 2,000 round particles or agents to stand in for the insects. Such agents could not decide for themselves, although they did follow simple rules. For example, fake ants did not like bumping into their neighbors, attempting to avoid falling into the water. When Wagner and Vernerey let the gameplay out, they discovered that their stimulated ant rafts behaved much like actual things.
Commenting on their new study, Wagner said their work on fire ants would hopefully help them understand how simple rules can be programmed through algorithms that dictate how robots interact with others to attain a well-targeted and intelligent swarm reaction.
Related information about fire ants forming floating rafts is shown on CBC News's YouTube video below:
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