The ramie moth is a large moth from Asia and Oceania whose hindwings carry bright silvery-blue markings. In the US it lives only in Hawaii, where it was first found on Maui in 2018 and is now known from five islands. Its showy yellow, black, and red caterpillars strip nettle-family plants such as native māmaki, the same plants the native Kamehameha butterfly depends on.
Appearance
- Appearance
- A large, stout moth with a wingspan of about 2.4–3.5 in (60–90 mm). The forewings are mostly brown with black markings and scalloped edges. The hindwings carry bright silvery-blue markings.
Look-alikes
Young Kamehameha caterpillars feed from the leaf edge and fold it over into a tent, while young ramie moth caterpillars chew holes in the middle of the leaf. A disturbed ramie moth caterpillar rears up and spits green fluid; Kamehameha caterpillars don't do this.
Why they get mixed upBoth feed on māmaki in Hawaii, and the two caterpillars can look similar.
Where it lives
- Typical habitats
- Native forests
- Yards and gardens
- Range
- Widespread across Asia and into Oceania, including India, Japan, Fiji, and New Guinea. In the US it is known only from Hawaii: first found on Maui in 2018, then on Hawaiʻi Island in 2020, Oʻahu in 2025, and Kauaʻi and Lānaʻi in late 2025 and early 2026.
- Preferred conditions
- Found wherever its nettle-family host plants grow, both in neighborhoods and in native Hawaiian forests.
Behavior
- Diet
- Adults sip tree sap and the juice of overripe or rotting fruit. They don't damage plants; only the caterpillars do.
- Activity
- When a caterpillar is disturbed, it rears up its head, thrashes from side to side, and spits up green liquid.
Life cycle
- Reproduction
- Eggs are tiny (about 1 mm), clear-white, and laid one at a time on the undersides of leaves.
- Larva
- Young caterpillars are green and black. Older ones grow to about 3 in (70–80 mm) and are bright yellow and black with orange-red spots and long, thin white hairs; some are mostly black but still have the red spots. They chew holes in the middle of leaves and can strip plants down to the main veins.
- Caterpillar food plants
- Plants in the nettle family, such as ramie. In Hawaii they prefer native māmaki and also eat ʻōpuhe and maʻoloa, including the endangered Neraudia angulata.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
- Status
- Hawaii treats it as an invasive pest. To slow its spread, māmaki and other host plants, including olonā, shouldn't be moved between islands without inspection, and sightings can be reported to the state pest hotline (643pest.org).
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