Eacles imperialis

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Eacles imperialis, known as the imperial moth, is a large moth in the Saturniidae family. It lives from Argentina in South America up to southern Canada in North America, and is common in the eastern United States. It has many regional forms and colors.

Appearance and size
- Adults are mainly yellow with red, brown, and purple blotches. They show a lot of variation, and there are light and dark forms. Northern moths often have fewer dark markings.
- Wingspan is about 3 to 7 inches (80–175 mm).

Life cycle
- Eggs hatch in about 10 to 14 days.
- The caterpillar (larva) goes through five molts (instars). Early instars are orange with black bands and big spines; later instars reach 3–5.5 inches (75–100 mm) long and can be brown, burgundy, green, or other colors with various markings.
- Larvae feed on many plants (they are polyphagous). Common hosts include pines, maples, oaks, sweetgum, and sassafras. Subspecies can have preferred plants; for example, E. i. pini mainly eats pine, and the Martha’s Vineyard population often feeds on pitch pine.
- Pupation happens in the soil. Pupae are dark brown with spines and heavy body segments.

Adults
- Adults do not eat; their mouthparts are reduced.
- They emerge once a year to mate, usually at sunrise. Mating happens the following night.
- In the north, adults appear mainly in summer (June–August); in the south, timing is more spread out (April–October). Males often emerge before females.

Subspecies and range
- Eacles imperialis imperialis (the nominate form) has been recorded across a wide area from New England and southern Canada to Florida Keys and west to Nebraska; today it may be limited in some places (e.g., Martha’s Vineyard).
- Eacles imperialis pini occurs in the northern edges of the range, from New England and the Great Lakes region into Canada.
- Eacles imperialis magnifica is found in Brazil and nearby areas.
- In the southwest, a closely related form is Eacles oslari. Other subspecies are found in Mexico and South America.

Declines and habitat
- The imperial moth is declining in parts of the northeastern United States, possibly due to pesticides, artificial lights, and introduced parasitoids used to control other pests.
- They are still common in many forest, rural, and suburban areas.

Summary
The imperial moth is a large, colorful, widely distributed species with a long larval stage that feeds on many plants. Adults don’t eat, live once-a-year life cycles, and show many regional forms and subspecies.