When army ants use their own bodies to plug tiny potholes in rough trails, the whole colony benefits, a new study has found.
Without those instant road repairs, a colony's daily catch of food can drop by as much as 30 percent, say Scott Powell, now at the Federal University of Uberlândia in Brazil, and Nigel Franks of the University of Bristol in England. As the ants race along paths to and from food, filling holes helps prevent traffic backups, Powell explains.
Many species of army ants send out relentless columns of hunters at night or underground, but Powell and Franks focused on Eciton burchellii, which preys aboveground during the day. Colonies of these ants grow 700,000 strong.