# Imperial moth (Eacles imperialis) > Large, showy North American silk moth with yellow to orange wings marked by purple-brown blotches; adults do not feed and live only a few days. Source: https://insectscanner.com/species/imperial-moth/ (updated 2026-10-10) ## Is it dangerous? **Non-toxic.** Imperial moths and their caterpillars are not venomous. Caterpillars have small spines and tubercles that may cause mild skin irritation in very sensitive people, but they do not sting. Handle gently or avoid touching if you have sensitive skin; wash the area with soap and water if irritation occurs. **Pets:** Generally harmless to pets. Large caterpillars could cause mild mouth or throat irritation if chewed by curious pets; monitor and discourage pets from eating them. ## Quick facts - Scientific name: Eacles imperialis - Also called: Imperial silk moth - Order: Lepidoptera (Moths and butterflies) - Family: Saturniidae (Giant silk moths) - Size: Wingspan 80-175 mm (3-7 inches), typically 90-150 mm in many populations - Colours: Yellow, Orange, Rusty brown, Purple-brown markings - Habitat: Deciduous and mixed woodlands, forest edges, suburban yards with host trees - Range: Eastern and central North America from Canada (southern Ontario, Quebec) south through the eastern United States to Mexico; exact range and form vary regionally - Active: Mostly spring to early autumn depending on location; adults are nocturnal and fly at night - Lifespan: Adults live about 3-10 days; total generation time (egg to adult) spans weeks-months depending on climate, with winter as pupa in many regions - Effect on plants: Herbivore (usually minor) - Pest: no ## Overview The imperial moth (Eacles imperialis) is a large silk moth in the family Saturniidae found across much of eastern North America and parts of Mexico and Central America. Adults are mainly active at night and are attracted to lights. The species has several regional color forms, ranging from pale yellow to deep orange or brown, usually with contrasting purplish-brown blotches and wavy lines on the wings. Larvae feed on the leaves of a wide variety of hardwood and conifer trees (see diet) and can be found on trees and shrubs in woodlands, suburban areas and along forest edges. Mature caterpillars burrow into the soil to pupate without spinning a cocoon. Adults have reduced mouthparts and do not feed; their sole purpose is reproduction, so adult life is short (about a week or less). ## How to identify it Adult imperial moths are large and robust. Forewings and hindwings are broadly rounded. Ground colour is yellow, with variable amounts of purplish-brown, pinkish-brown or orange-brown blotching and speckling, and a small dark-ringed discal spot on each wing; some northern and Texas forms are heavily brown. Males are usually more heavily marked and have more feathery (bipectinate) antennae than females. Caterpillars are large and either green or brown/orange, with long whitish hairs, small paired thoracic horns and white spiracles. Pupae are dark brown and lie in a chamber in the soil without a cocoon. - Large wingspan (typically 90-150 mm) with rounded fore- and hindwings. - Ground colour yellow to orange with distinct purple-brown blotches and wavy crosslines. - Small dark discal spot on each wing and males with feathery antennae. - Caterpillars large, green or brown/orange, with long whitish hairs and short horns behind the head. ## Lookalikes - **Polyphemus moth** (Antheraea polyphemus): Polyphemus is tan to reddish-brown with a large eyespot containing a clear window on each hindwing, lacking the yellow ground colour and purple-brown blotches of the imperial moth. - **Luna moth** (Actias luna): Luna moth is pale green with long hindwing tails and lacks the blotched pattern and yellow-orange tones of the imperial moth. - **Io moth** (Automeris io): Io moths are smaller, and adults show a single large eyespot on each hindwing; their caterpillars are green with stinging spines, unlike the harmless imperial caterpillar. ## Life cycle - **Egg:** Females lay small clusters of eggs on host plant foliage. Eggs hatch in about 1-2 weeks depending on temperature. - **Larva (caterpillar):** Caterpillars pass through several instars, growing rapidly while feeding on leaves of trees and shrubs. Late instars are large and conspicuous. - **Pupa:** Mature caterpillars burrow into the soil and pupate in a chamber without a cocoon. In cold regions pupae overwinter. - **Adult (moth):** Adults emerge, mate, and females lay eggs. Adults have reduced mouthparts and do not feed; they live only long enough to reproduce. ## Diet and predators - Young eat: Leaves of various trees and shrubs: oak, maple, pine, sweetgum, poplar, walnut and others (polyphagous). - Adults eat: Do not feed; adults have reduced mouthparts. - Predators of the young: Birds, small mammals, predatory insects, parasitic wasps and flies. - Predators of adults: Bats, nocturnal birds, and other predators of large night-flying moths; adults are short-lived which reduces predation window. ## Effect on plants and gardens Caterpillars feed on a wide range of deciduous trees and some conifers, including oak, maple, pine, sweetgum, and walnut. Heavy local outbreaks are uncommon; feeding is usually not a serious threat to mature trees. ## Where and when to find it Look for caterpillars feeding on leaves of oaks, maples, pines and other trees; search tree foliage in summer. Adults are attracted to porch and security lights at night. - Best time: Best months vary by region but generally late spring to early autumn for adults; caterpillars are most visible in mid to late summer. Nighttime is best for photographing adults at lights. - Tips: Turn off unnecessary lights to reduce attractants, use a porch light briefly and watch at night, and photograph spread wings by gently coaxing an adult onto a light surface if needed. When handling caterpillars, wear gloves if you have sensitive skin. ## Fun facts - Adult imperial moths do not eat — their mouthparts are reduced and they survive only on energy stored as caterpillars. - Color and pattern vary widely across the species' range; some regional forms can look almost entirely orange, pale yellow, or brown. - Males use feathered antennae to detect female pheromones from large distances at night. ## Frequently asked questions ### Are imperial moths dangerous? No. They are not venomous and pose no significant threat to people or pets. Handle caterpillars gently or not at all if you are sensitive to skin irritation. ### Do imperial moths bite or sting? No. Adults do not bite or sting. Caterpillars have small tubercles and occasional tiny spines that can cause mild irritation in rare cases but they do not sting. ### Why is an imperial moth in my house? Adults are nocturnal and are strongly attracted to lights, which can bring them to houses. Caterpillars may be on nearby trees or shrubs and sometimes wander to foundations or porches when searching for pupation sites. ### How can I get rid of imperial moth caterpillars in my yard? Because populations rarely cause serious damage, handpicking large caterpillars from small trees or shrubs is effective and humane. Encourage natural predators and parasitic wasps. Chemical controls are rarely necessary; if used, follow label instructions and consider targeted options. ### Where do imperial moths live and when can I see them? They live in deciduous and mixed forests, woodlands and suburban areas with host trees across much of eastern North America. Depending on location, you can see caterpillars in summer and adults from spring through early autumn, with most activity at night. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/81590), [Wikipedia](https://en.wikipedia.org/wiki/Eacles_imperialis). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.