hackberry emperor

not listed

N5 - Secure

S5 - Secure

not listed

Hackberry emperor is a medium-sized brushfooted butterfly, with a wingspan of 2″ to 2⅞″. Females are usually much larger than males and have broader wings.

The coloration of the wings is geographically variable. Within the state both dark forms and light forms are found. The upperside of the forewing is usually grayish-brown (dark form) near the base, fading to orangish brown toward the center of the wing, and black near the tip. On the pale form the base color is brownish-yellow. The central area of the forewing (cell) has a single black bar and two separated black spots. There is a single submarginal eyespot with a black pupil surrounded by orange. The pupil may have a small blue center. In the black area near the tip there is a jagged row of seven cream-colored subapical spots and a jagged row of four white submarginal spots.

The hindwing is orangish-brown. The basal portion of the hindwing is covered with long hairs. The margin is orangish with dark veins and a straight black border. There is a submarginal row of black chevrons and a postmedial band of black spots. The postmedial spots may have small blue centers.

The underside of both wings light brown and gray. The black spots from the upperside become on the underside yellow-ringed black eyespots with white centers.

The caterpillar is pale green and up to 1½″ long. It is densely covered with short hairlike structures (setae). Each seta has an enlarged white base, giving the caterpillar a finely spotted appearance. A narrow subdorsal white stripe extends on each side from the head to the last abdominal segment. The neck is narrow. There are two antler-like horns attached to the upper (dorsal) surface of the head, and two spine-like projections extending from the last abdominal segment.

Mature caterpillars of the first brood are found in May and June, of the second brood in July and August.

1⅜″ to 2½″

Edges and openings of moist deciduous woodlands, streams, parks—virtually any site with more than one northern hackberry tree

Two broods: early June to mid-July and late July to early September

Adults perch head down of tree trunks and the sides of buildings. Their flight is fast and erratic. Males are attracted to bright colors, and can be lured with red and white paper.

Though common within its range it is sometimes overlooked due to its tendency to fly around the tops of trees.

The male will perch on a tall object waiting for a passing female. After mating the female will lay clusters of eggs on the leaves of a host tree. When the eggs hatch the larvae feed individually, not communally. The second brood overwinters as larvae.

In Minnesota, leaves of northern hackberry (Celtis occidentalis) and possibly elm.

Some sources state that the larvae feed communally. According to Caterpillars of Eastern North America (Wagner, 2005), caterpillars of tawny emperor “feed communally through the third instar”, but the hackberry emperor does not feed communally.

Tree sap; rotting fruit; animal dung, urine, sweat, and carrion; and occasionally flower nectar of staghorn sumac, red clover, common milkweed, and yellow sweet clover.

Sources

7, 20, 21, 24, 29.

Locally common in the southern half of Minnesota, occasional visitor further north

Plenty of these flying around today, even landing on me. They seemed to be probing for salts on me as well as on rocks.

Upper side

Underside

Location: in my backyard in La Crescent, MN.

Plenty of these flying around today, even landing on me. They seemed to be probing for salts on me as well as on rocks.

You are free to use the attached pic.  It shows the "hackberry emperor" butterfly.  It was taken on Tuesday along the paved bike-hike trail about 1/2 mile east of the Schaar's Bluff trailhead in a Dakota County park.  The butterfly has landed on the paved surface.

I would call this butterfly "locally common".