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Montana Field Guides

Polyphemus Moth - Antheraea polyphemus

Global Rank: G5
State Rank: SNR

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General Description
The upperside of the Polyphemus Moth (Antheraea polyphemus) is reddish to yellowish brown. The forewing margin is usually lighter than the basal area. The forewing submarginal line is pink, or black and pink. The clear oval eyespots are ringed with yellow, blue, and black. The hindwing eyespot is separated from the basal area of the wing by a thin pink line. The underside has rust, brown, and pink markings (Opler et al. 2010). The wing span is about 100 - 150 mm (Schmidt and Robinson no date).

The adult Polyphemus Moths emerge from their cocoons in the late afternoon, and mating occurs the same day from late evening to early morning. The females lay eggs that evening, singly or in groups of 2 or 3 on leaves of the host plant. The newly-hatched larvae eat their eggshells, and larvae of all ages are solitary. The older larvae eat an entire leaf and then cut the leaf petiole at the base so it falls to the ground, perhaps a defensive measure to eliminate signs of feeding (Schmidt and Robinson no date).

The Polyphemus Moth overwinters as a pupa in a large, silken cocoon. Although the oval-shaped cocoons usually fall to the ground with the host plant leaves they are wrapped in, they can occasionally be found in the winter still attached to the host plant by a small amount of silk thread. These moths typically rest suspended from a branch or twig during the day, with their wings folded above their back. The undersides of the wings are surprisingly cryptic for such a large moth. If these moths are disturbed when at rest, they often drop to the ground, and flap their wings once giving the appearance of a sudden "jump". With the eyespots exposed, this makes an impressive display which may startle potential predators (Opler et al. 2010).

There is one flight in the north from May-July, two flights in the Ohio Valley and southward from April-May and from July-August, two flights in the California Sierra Nevada, and several flights throughout most of the year in Florida, Texas, and Louisiana (Schmidt and Robinson no date).

Range Comments
The Polyphemus Moth is the most widely distributed silkmoth in North America. It occurs coast to coast in southern Canada and the U.S., and south to Arizona. It is known as far north as Zama City in extreme northwestern Alberta (Schmidt and Robinson no date).

Summary of Observations Submitted for Montana
Number of Observations: 22

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Deciduous hardwood forests, urban areas, orchards, and wetlands (Opler et al. 2010).

Food Habits
The larvae feed on a wide variety of trees and shrubs including oak (Quercus), willow (Salix), maple (Acer), birch (Betula) and Serviceberry. The adults do not feed (Schmidt and Robinson no date).

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Citation for data on this website:
Polyphemus Moth — Antheraea polyphemus.  Montana Field Guide.  .  Retrieved on , from