What do imperial moths eat?

Adult moths do not eat leaves. Some eat nectar and pollen from flowers, but most, like your Imperial Moth, do not eat at all in the adult stage. They live off of their reserves (that were stored when they were caterpillars) until they can find another moth, mate, lay eggs, then die. Unfortunately for your moth, it has emerged too early in the year. These moths spend the winter in their cocoons, and emerge when the weather warms. This one was fooled into emerging by artificially high temperatures in your house. You can enjoy your moth around the house for a couple weeks, but it will probably die before it gets warm enough to let it go.