American Snout

Libytheana carinent

American_snout_2007.jpg

American snout butterfly resting with wings folded
Most of us identify butterflies by their color patterns, but you can ID the American snout by its long “nose.”
Donna Brunet
Family

Nymphalidae (brushfooted butterflies)

Description

American snouts have greatly elongated labial palps (mouthparts) that make them seem to have long “noses.” There is only one species of snout butterfly in North America. Forewings are elongated with squared-off wingtips. The dorsal wing pattern is orange with wide dark borders with white spots. Seen from below on perched specimens, the wings usually show only the mottled brown and violet-gray wing edges, though the forewings look roughly the same on both sides. When perched on a twig, with only the gray forewing edges showing, a snout butterfly is virtually invisible.

The caterpillars are green with yellow stripes along the back and sides, and numerous tiny yellow specks. Older caterpillars are dark green. The thorax portion is enlarged, with two black tubercles (raised bumps).

Size

Wingspan: 1–2 inches.

American Snout

a brown and white butterfly with a long snout-like palps sits on a bare tree branch.
American Snout in Stone County, MO
When perched on a twig, with only the gray hindwings and gray forewing edges showing, an American snout is virtually invisible.
Habitat and conservation

Woods, woodland edges, and suburban yards. Snouts sometimes form local colonies in the vicinity of hackberry trees, with the adults resting on the leaves and visiting nearby flowers.

This is a migratory species. The first individuals arrive in Missouri from the south in May, with numbers increasing as the season progresses. They are much more common near the end of summer. Population numbers vary greatly from year to year. Some years there are immense migrations, and they can be common in the Ozarks. Such fluctuations occur when an early drought lowers populations of the butterfly’s various predators, and then heavy summer rains cause the host plants to grow profusely.

Foods

Caterpillars feed on various hackberries (genus Celtis): hackberry, dwarf hackberry and sugarberry.

The adults visit a variety of flowers and drink from mud puddles and moist soils near creek beds and lake shores.

image of American Snout Distribution Map
Distribution in Missouri

Statewide. Numbers vary from year to year. Sometimes common in the Ozarks.

Status

The American snout is probably only a summer resident in Missouri. This is the only species of snout butterfly in North America. There are only about 8 to 12 species of snouts in the world, and they are sometimes placed in their own family (the Libytheidae). In addition to the unusual "snout," these butterflies have characteristics as caterpillars that are different from most other brush-footed butterflies: they lack spines and horns, and the pupae don't have bumps along the back.

Life cycle

Adults migrate from the south, arriving in our state in May. Males can be distinguished from females by the reduced size of their first pair of legs: To walk, males use only their second and third pairs of legs. Eggs are laid on various species of hackberries, the caterpillars' food plant. Snout butterflies do not fly south in fall. Our population is renewed in May from migrants that survived the winter in the south.

Human connections

In years when the population of this species "blooms" (particularly in Texas and Mexico), the spectacle is inspiring. Because hackberries are not of huge economic importance to most Missourians, the feeding of the caterpillars is relatively benign.

Ecosystem connections

The caterpillars are herbivores that graze on vegetation. The adults serve a role in pollination. All stages provide food for predators.

Survival is of prime importance for every species. The American snout uses camouflage to avoid its predators. As caterpillars, snouts generally rest along the midribs of the leaves they feed on, which helps them hide from enemies. As adults, the butterflies perch on branches with wings folded, so only the drab gray colors are visible. They complete their "dead leaf" look by posing with their pointy mouthparts and antennae drooped downward, so those parts together look like a leaf stem.