Leafcutter ants do not eat the leaves they cut.
Why it is true
They carry pieces of leaves to the nest and use them to grow a fungus, which feeds the colony. The leaves are the fungus substrate, not the ants' direct food.
Source: National Geographic
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.