Automeris io neomexicana

Distinguished from other Automeris species by geographic range and subtle wing pattern differences. The nominate subspecies A. io io occurs in eastern North America; A. io neomexicana replaces it westward. Adults are separable from other large saturniids by the distinctive eyespot pattern on hindwings. Caterpillars identified by the combination of green ground color with red-and-white stripes and dense covering of branched urticating spines.

Open woodlands, forest edges, riparian corridors, and suburban areas with host plants. Found from low elevations to moderate mountain slopes. Requires areas with adequate moisture to support larval host plants.

Western Great Plains and southwestern North America. Documented from Manitoba, Canada southward through the central United States. Range extends westward into New Mexico and adjacent regions, replacing the eastern subspecies.

Adults fly primarily in late spring and summer, with timing varying by latitude and elevation. In warmer regions, may produce two generations annually; single generation in northern parts of range.

Larvae feed on a variety of broad-leaved plants including species of oak (Quercus), willow (Salix), hackberry (Celtis), and other woody and herbaceous vegetation.

• Quercus - larval food plantoak species
• Salix - larval food plantwillow species
• Celtis - larval food planthackberry species

Complete metamorphosis with four life stages. Eggs laid in clusters on host plant leaves. Larvae pass through five instars, feeding gregariously in early stages, solitary in later stages. Pupation occurs in silken cocoons, with adults emerging to mate and lay eggs. Overwintering stage varies by region.

Adults are nocturnal and do not feed. When disturbed, adults flash hindwing eyespots to startle predators. Caterpillars are solitary in final instars and remain on host plants. Both sexes attracted to light.

Larvae serve as herbivores, consuming leaves of various woody plants. Adults provide food for bats and nocturnal birds. Caterpillars are prey for parasitoid wasps and flies, though stinging spines provide defense against many vertebrate predators.

Caterpillar stings cause localized pain, burning, and swelling that typically resolves within hours. Rare severe allergic reactions have been reported. Popular subject for nature observation and photography; reared by hobbyists. Population declines in parts of range attributed to introduced biological control agents.

• Automeris io ioEastern subspecies with overlapping morphology; separated by geographic distribution
• Automeris metzliNeotropical species with similar caterpillar appearance; distinguished by range (Mexico to Ecuador) and adult wing patterns
• Antheraea polyphemusAnother large saturniid with eyespots; lacks the distinctive color pattern and has rounded rather than angular eyespots

• moth
• saturniid
• urticating spines
• eyespots
• defense
• North America

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• A rainforest beauty better for observing rather than touching: Silkmoth caterpillar, Automeris spp. — Bug of the Week