Researchers say that they've discovered a new kind of traffic sign on ant highwaysâ”a chemical "Do not enter" that lets the insects avoid wasting time on paths that don't lead to food.
Ant science has for decades focused on chemical attractants that define trails, says Elva J.H. Robinson of the University of Sheffield in England. However, the new tests give evidence of a repellent pheromone, which hasn't yet been identified, she and her colleagues report in the Nov. 24 Nature.
"Nobody believed that such a thing existed," says Robinson.