Madrid, 30 years (Europe Press)
“Until now, researchers assumed that ants moved randomly when searching for targets they didn’t know the location of,” explains Stefan Pope of the University of Arizona in Tucson.
“We found that the rock ants of Temnothorax rugatulus exhibit a strikingly regular pattern when exploring the area around their nests. This means that the ants alternate smoothly left and right over a relatively uniform length scale of about three body lengths.” .
He explains that he and his colleagues call this behavior “zigzag” because it reminds them of the pattern that a meandering river forms. Moreover, their study revealed that ant equations can make their search more efficient than a purely random search. This is because ants tend to cross their own paths more often while zigzagging than when walking randomly, so they search the same area fewer times.
Popp’s team published their study in iScience to investigate how ants interact with nestmates and surface structure on a colony scale. Since ants are difficult to track in their natural environment, they moved their entire colony to the lab, where they could track them all automatically and under constant conditions.
Soon, they noticed the zigzag pattern of the ants as they walked. This raised an immediate question: Could the patterns they saw have arisen from random scribbles, without any systematic rule? Or did they move more systematically rather than haphazardly? To find out, they compared the ants’ trajectories to computer-simulated random movement patterns.
“We wanted to make sure we weren’t seeing patterns that weren’t there,” explains Bob. Then we used a simple statistical method to detect the regularity of motion trajectories to get a simple answer.
They report that their studies found that 78% of the ants showed a significant negative autocorrelation of about 10 mm, or about 3 body lengths. This means that turns in one direction are often followed by turns in the opposite direction after a nearly constant distance. According to the researchers, this makes foraging for ants more efficient, as the insects can stay close to the nest without having to search repeatedly in the same areas. What intrigued him most, Pope says, were the extremes that ant patterns could take based on these simple principles.
“Parts of some of the footprints are like jagged threads that one might tear from a piece of clothing, and in others the track zigzags on its own,” he explains, creating what appears to be a fractal structure. And it reminds me of some of the curves that fill in the space we know from mathematics.”
The new study is the first to find evidence of efficient foraging through regular rafting in a free foraging animal, they report. It also adds another complex behavior of ants, suggesting that there is still a lot to learn.
What fascinates him most, Pope says, are the questions about the rules of ant minds that allow such complex patterns of research to emerge. He also notes that ants have solved a collective search problem throughout evolution in a way that could find application in designing autonomous swarms of search robots or drones for use in disaster areas or uncharted landscapes.
