I don't believe I've ever thought of any butterfly as being "pugnacious." Yet that's exactly how the Ohio Division of Wildlife's handy little field guide, Butterflies and Skippers of Ohio, characterizes the Hackberry Emperor—"very active and pugnacious."
The very active part I wholeheartedly agree on—having chased the fellow whose portrait appears above around the yard for some half hour before he deigned to park momentarily in the grass, wings opened, long enough for me to focus and snap.
As their name implies, Hackberry Emperors (Asterocampa celtis) are seldom found far from their namesake host tree. And since hackberry trees mainly occur along streams and adjacent moist bottoms, as well as overgrown field borders and the succession edges of drier woodlands, they're one of the more common species here along the riverbank. While the caterpillars feed on the various species of hackberry trees, the adult butterflies prefer sap, rotting fruit, carrion, and dung. Mummmmm! They're also fond of lighting on your arm and lapping up sweat salts. Double-mummmmm!
I'm still not sure about that pugnacious business. But I am certain this friendly and seemingly curious butterfly is a subtle beauty, understated but classy, lively, and one of my favorites.