Iowa skipper

not listed

N3 - Vulnerable

S3 - Vulnerable

Special Concern

Species in Greatest Conservation Need

Iowa skipper is a rare, small to medium-sized, grass skipper. It has a wingspan of 1⅛″ to 17 ⁄16″. The female is larger than the male.

The wings are proportionately short and broadly triangular. The hindwing is distinctly rounded. The upperside of both wings is yellowish-orange with a broad, dark, grayish-brown border. On the male, the the border is dark and sharply differentiated. On the female, the border is more extensive, is not as dark, and is not sharply defined. It diffuses into the yellowish-orange area, and on the hindwing it sometimes completely obscures lighter color. The veins are unmarked, not darkened. There are no pale or translucent spots. The female has a prominent, black, thin, longitudinal streak in the center of the yellowish-orange area of the forewing where the stigma would be on most male grass skippers. Males of this genus do not have a stigma. Males of this species do not have this black mark.

The underside of both wings is yellowish-orange. The veins on the hindwing are whitish. The fringe on the hindwing is usually white.

The antennae are short and faintly striped. Each antenna has a long black swelling (club) at the tip, and a pale, thin, hooked extension (apiculus) at the end of the club.

The caterpillar is pale yellowish-green with orange markings.

Wingspan: 1⅛″ to 17 ⁄16″

In Minnesota, moderately dry to moderately moist native tallgrass prairie

One generation per year: Late June through July

Adults are active during the day. When at rest, the forewings are held at a 45° angle and the hindwiings are held horizontal, a configuration that resembles an F-15 Eagle fighter jet.

Males perch on low vegetation near host plants in the afternoon waiting for passing females. The female lays pale yellow eggs singly on the underside of leaves of host plants. Larvae make shelters near the tips of leaves by tying two adjacent leaves together with silk. These shelters can be up to 11¾″ off the ground. They live in their shelters, exiting only at night to feed. They overwinter in their shelters as fourth stage (instar) caterpillars. They pupate in shelters about 3 feet above the ground in the spring.

Larvae feed near the leaf tips of tall grasses, near shelters up to 11¾″ off the ground. They pupate about 3 feet above the ground. This makes them particularly vulnerable to prescribed burns on managed prairies any time of year.

Nectar from flowers, especially narrow-leaved purple coneflower

Sources

6, 21, 24, 29, 30, 72, 75.

Rare; small, widely scattered populations

Arogos Iowa skipper butterfly

Fillmore County