There are two flights in the North and many flights in Florida from March to December. Dunal is the only host. In the Southeast, a variety of other Asimina species are utilized. A commonly-used host in central Florida is A. longifolia Kral. Adults seek nectar at a variety of flowers and also obtain moisture from mud.
Females select plants with young leaves for oviposition.
This requirement for new leaves may limit reproduction of E. marcellus in summer and fall. Omphalocera munroei Martin. Therefore, abundance of late flights of E. marcellus may be dependent on abundance of this moth. When disturbed, they extrude the osmeterium and smear the offender with the chemicals. This has been shown to be an effective defense against small ants and spiders, but not against most other predators.