Leaf-cutter ants start their lives with razor-like jaws, or mandibles, to cut through the leaves they harvest.
But as these "wear out", the insects tend to carry the leaves cut by their younger counterparts.
The findings suggest that individual ants can extend their useful lifespan as their skills decline.
They are reported in the journal Behaviour Ecology and Sociobiology.
The US-based scientists discovered that older ants were significantly less efficient at cutting leaves.
They estimated these older colony members' "worn-out teeth" halved the speed at which the entire colony was able to harvest leaves.