The adults feed almost exclusively on rotting fruit.
The genus Caligo is Latin for fog, mist or darkness. Atreus in Greek mythology was the king of Mycene.
The Owl Butterfly is primarily found in dense rainforest but occasionally they visit plantations to lay their eggs.
The Owl Butterflies do the majority of their flying during dawn and dusk. In the evening the males patrol for receptive females. Mated females lay their eggs individually or in groups. The caterpillars are very gregarious and usually feed in groups on the host plants.
Because of the long lifespan of the adult and the multiple generations each year it is possible to find adults throughout most of the year.
As caterpillars the Owl Butterflies can eat a large amount of host plant leaves. Since one of their host plants is the banana plant the Owl Butterfly is considered a pest in areas where bananas are grown. They are such a big pest that work is being done with parasitic wasps to find a biological control agent.