About 1-2 months, I believe. But I'm not exactly sure that's true.
moths pretty much do the same thing as butterflies. they eat necter.
Adult Emperor Gum moths don't eat. They mate, lay eggs, and then die within the week. They don't even have mouth parts.
They do not eat, they only survive long enough to mate and lay 100s of eggs.
this may not be what you're looking for, but anyway, the emperor butterfly is golden yellow in colour.