Getting stuck in traffic is one of the most common and disturbing situations in daily life. But traffic jams are not just a human experience; Even ants are prone to congestion. New research shows that ants are quite adept at extricating themselves from this chaos.
Science has long been interested in ants, masters of collective behavior, division of labor, and problem solving. But one of the understudied mysteries about ant activities is how they stop traffic jams while the colony is on the move.
In new research, published as a preprint and not yet peer-reviewed, scientists observed the migration movements of 12 colonies of Diacamma indicum, also known as the Indian queenless ant, to answer questions about ant traffic congestion.
Substitution
The researchers created a Plexiglas “arena” with the original ant nest box placed at one end and a new one at the other end, a distance similar to the displacement of the natural habitat. The bridge connecting the two was wide enough for five ants to walk abreast, but it narrowed briefly in the middle, allowing only one ant at a time, and widened again.
In addition to surrounding the bridge with water, the researchers chose this design to mimic natural habitat. During monsoons, heavy rain forces ant colonies to move, sometimes through narrow areas filled with water.
Each of the 12 colonies relocated twice, and the researchers recorded the first ant to find the new colony. At random intervals, they also recorded the direction in which all the ants were heading and whether there were any ants monitoring the entrance and exit of the narrow section of the road.
It was already known before the study that D. indicum uses a system called “sequential running” (or tandem running). This process involves a “leader” ant who knows the location of the new colony returning to the original site and directing an uninformed ant to the new colony. The team also recorded the identities of leaders and followers in this way.
unblock blockage
Observations have found that the displacement of tandem running colonies leads to significant movement in both directions, increasing the risk of head-on collisions and blockages. Researchers witnessed 56 of these traffic jams and found that the likelihood of a traffic jam increased 18 times when ants could only navigate a single-lane road.
They also identified categories of ants that cause traffic jams. Of these ants, 59 percent were returning leaders, 27 percent were brood carriers (i.e., those carrying other ants), and 14 percent were slightly lost followers.
However, the vast majority of these jams (52 out of 56) have been cleared. The ants’ success is thanks to an impressive level of behavioral flexibility.
Instead of simply going back and forth after encountering a jam, leader ants returning from the new colony changed their behavior in one of two ways. Some involved a “swap” in which a returning leader took over from a displaced leader, allowing the leader to return to the old nest and the new duo to move on to the new colony area.
Other returning leaders helped gather the lost followers who were causing the congestion and invited them to form pairs and move towards the new home.
Although these findings have not yet been peer-reviewed as a preprint, the authors believe their research provides new insight into the ants’ abilities. They also suggest that this could inform traffic management in human society.
The preprint study has been posted to bioRxiv.
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