Army ants tired of potholes take one for the team, throwing their bodies into rough spots to make a smoother road for their sisters, British researchers reported on Sunday.
They found that army ants of Central and South America match their own bodies to the size of the hole they want to plug. Several may plunge together to fill in bigger holes, they report in the journal Animal Behaviour.
Scott Powell and Nigel Franks of the University of Bristol studied an army ant species called Eciton burchellii, which march across the forests of Central and South America in swarms of up to 200,000.
These raiders always remain connected to the nest by a trail of other ants. But this highway of living ants can be extremely uneven as it passes over leaves and branches on the forest floor. So a few of the ants climb into the dips to make a smooth road.
"When it comes to rapid road repairs, the ants have their own do-it-yourself highways agency," Franks said in a statement.
"When the traffic has passed, the down-trodden ants climb out of the potholes and follow their nest mates home," Powell added.
"Broadly, our research demonstrates that a simple but highly specialized behavior performed by a minority of ant workers can improve the performance of the majority, resulting in a clear benefit for the society as a whole."
Powell and Franks conducted experiments in the lab to demonstrate this behavior.
"We inserted planks drilled with different sizes of hole into the army ants’ trails to see how well different sizes of ant matched different sizes of pot hole. Indeed, they fit beautifully," said Franks.
"I think every road user who has ever inwardly cursed as their vehicle bounced across a pothole — jarring every bone in their body — will identify with this story," said Franks.
Most ant species are believed to live in large colonies of sisters, all with the same mothers. Males are also sometimes produced, but only under certain circumstances.