Home / Saturniidae Moths (Saturniidae) / Spiny Oakworm Moth (Anisota stigma)

Spiny Oakworm Moth (Anisota stigma)

The spiny oakworm moth is a member of the family of saturniid moths found in Canada and the United States. They are named because of the presence of spines on the caterpillars.

Spiny Oakworm Moth


Scientific Classification

  • Family: Saturniidae
  • Genus: Anisota
  • Scientific Name: Anisota stigma

Description and Identification


The larva is brown, with an orange-brown head. As its name suggests, their body has an entirely spiny appearance, covered with two black spines, protruding from either side of the black stripe running down their backs. The spines close to their head seem immensely long. Besides the spiny projections, their whole body remain covered with white dots.

They are known to voraciously feed on oak leaves, often eating in groups during their initial instars. In fact, a cluster of spiny oak worm caterpillars have the ability of defoliating a young oak tree.

Spiny Oakworm Moth Caterpillar



They pupate underground in the winter.

Adult Moth

Sexual Dimorphism: Present. The males are more reddish than the females.

Color and Appearance

Forewing: When the wings are opened, two segments are observed – an upper orange-brown part and a lower purple-pink part. A purple line separates them. There are two white spots present on them while they are also covered with black freckles. When the wings are closed, the orange-brown and purplish-pink spots with the two dots remain visible.

Hindwing: When the wings are opened, they are similar in color to the forewings, with prominent black freckles on the lower edge. When the wings are closed, the color remains the same, while the black freckles are visible in the lower edge.

They even have a orangish furry head, orange-brown thorax and abdomen, and a purplish-pink shoulder,

Average wingspan: 4-7 cm

Flight pattern: Consistent

Season: Summer


Females lay the eggs in clusters of 5-20, which take 2 weeks to hatch.

Quick Facts

DistributionFlorida, Massachusetts, southern Ontario, west to Minnesota, Kansas, and Texas
HabitatDeciduous woods
Lifespan of AdultsAbout a month
Host PlantsPrimarily oak, but also basswood and hazel
Adult DietDoes not feed

Did You Know

  • Danish zoologist Johan Christian Fabricius first described this species in 1775.
Spiny Oakworm Moth Picture


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