New York Natural Heritage Program
Spiny Oakworm Moth
Anisota stigma (Fabricius, 1775)

Identifying Characteristics [-]
The spiny oakworm moth is a colorful moth. Its wingspan is approximately 40-70 mm. The forewings are pale to dark reddish orange, with many small black specks and a white reniform spot. The hind wings are similarly colored and have a darker median line (Covell 1984). Females are larger than males. Larvae (caterpillars) are various colors, but they have short spines and a longer pair of "horns." Eggs are yellowish (Tuskes et al. 1996).

Behavior [-]
There is one generation each year. In New York State, adults lay eggs in clusters of 5-20 on oaks (Quercus spp.) in July. Eggs hatch in approximately 2 weeks. Larvae (caterpillars) feed on oaks during the fall. Early instar larvae feed together in groups. Later instar larvae feed alone. Pupae overwinter in a chamber underground. After emerging in the summer, adults have been observed to mate during the day, and females have been observed laying eggs at night. Females have also been observed releasing pheromones to attract males between 1 am and 3 am (Tuskes et al. 1996).

Diet [-]
In southern New England and New York State, larvae feed on oaks (Quercus spp.), especially scrub oak (Q. ilicifolia) and scrub chestnut oak (Q. prinoides) (Wagner et al. 2003).
Spiny Oakworm Moth Images
click to enlarge
The Best Time to See
The best time to see the spiny oakworm moth is during its flight season. In New York State, it has been captured flying in July.
Present Reproducing Larvae present and active Eggs present outside adult Pupae or prepupae present
The time of year you would expect to find Spiny Oakworm Moth present (red shading), reproducing (blue shading), larvae present and active (green shading), eggs present outside adult (orange shading) and pupae or prepupae present (purple shading) in New York.