Polyphemus moth

Hodges #

7757

Conservation Status

IUCN Red List

not listed

NatureServe

N5 - Secure

Minnesota

not listed

Description

Polyphemus moth is a common, extra large, giant silkworm moth. With a wingspan of 4″ to 6″ it is one of the two largest moths native to North America. Females are larger than males.

Wing coloration is highly variable. The upperside of the wings is various shades of reddish-brown to yellowish-brown. The median area is dusted with black. The submarginal area is pale. Each wing has a pink, white and black subterminal line and a transparent eyespot in the median area.

The leading edge of the forewing (costal margin) is whitish and dusted with black. The line separating the basal and median areas on the forewing (antemedial line) is pink, white, dark reddish-brown, and black. The eyespot is small and oval. It is ringed with a broad yellow line and a thin black line. There is a blue crescent on the inner edge.

The eyespot on the hindwing is similar but larger and more conspicuous. It is in the middle of a large, round to irregular, black patch. A thin pink line separates the black patch from the basal area.

There are no mouth parts and no hearing organs. Males have feather-like antennae with branches on both sides of the central axis. Females have smaller, less bushy antennae.

The caterpillar is bright green, plump, and up to 3″ long. There is usually a steeply oblique yellow line that passes through the breathing holes (spiracles) of abdominal segments 2 through 7 (A2–A7). On A1–A7 there six warts, on thoracic segments 2 and 3 (T2 and T3) there eight warts. There is one wart on each side of the dorsal midline (addorsal), one above the spiracle (supraspiracular), and one below the spiracle (subspiracular). T1 to T3 also have a wart just above each leg-like structure (proleg). The addorsal and supraspiracular warts on the abdomen are flashy silver and red. The subspiracular warts on the abdomen and all of the warts on the thorax are mostly orange and lack silver. Each wart has 2 to 5 minute, white, bristle-like hairs (setae). The prolegs are green. The anal plate is dark and continues as a line across A9. T1 is short and collar-like with a flat, yellow front edge. The head is orangish-brown and is partially withdrawn into T1.

Mature caterpillars can be found from late May through November.

Size

Wingspan: 4″ to 6″

Similar Species

Luna moth (Actius luna) caterpillar is similar. A1–A7 have a yellow transverse line near the trailing edge of each segment, not passing through the spiracle.

Habitat

Deciduous hardwood forests, urban areas, suburbs, agricultural fields, orchards, wetlands

Ecology

Season

One brood: Late May to July

Behavior

Adults are attracted to lights.

Life Cycle

This moth is short-lived, lasting only 4 days, since it has no mouth parts and does not feed. In Minnesota there is one generation per year. The adults emerges in the spring and finds a mate on the night of the same day it emerged from the cocoon. The male uses its specialized antennae to detect pheromones released by the female. After breeding, the female lays up to 5 eggs either singly or in groups of 2 or 3 on either side of a leaf of a host shrub or tree. The eggs are flattened and light brown.

The eggs hatch in about 10 days. The larvae are solitary feeders. They molt 5 times in 5 to 6 weeks before pupating. In late summer or early fall the caterpillar spins a cocoon in which it will spend the winter. Many caterpillars descend to the ground and spin their cocoon in leaf litter. Most others spin their cocoon in a leaf attached to the host plant, which falls to the ground at the end of the season. In the south some cocoons remain attached to the host plant.

Larva Food/Hosts

Leaves of deciduous trees and shrubs; especially members of the birch, rose, and willow families; but also apple, ash, dogwood, elm, hazel, hickory, maple and oak.

Adult Food

Adults do not feed.

Distribution

Sources

7, 21, 24, 27, 30, 75, 82, 83.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu. Accessed 5/19/2026).

Antheraea polyphemus Cramer, 1775 in GBIF Secretariat (2023). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org. Accessed 5/19/2026.

Quinn, Edward. M., and Ron Danielson. April 27, 2009. A Survey of Lepidoptera in Three Priority Areas of the Minnesota State Parks System. https://files.dnr.state.mn.us/eco/nongame/projects/consgrant_reports/2009
/2009_quinn_danielson.pdf.