A small gray moth whose furry orange-black-and-white striped caterpillars feed gregariously on milkweed leaves alongside monarchs — but unlike monarchs, they're less specialized.

Also called: Milkweed Tussock Moth, Milkweed Tiger Moth

Native status: Native to North America

§ Quick facts

SizeWingspan 3.5–4.5 cm (1.4–1.8 in)
Weight~0.15 g
LifespanAdults 1–2 weeks; multiple broods per year
OrderLepidoptera
FamilyErebidae

§ Encyclopedia

Euchaetes egle, the milkweed tiger moth or milkweed tussock moth, is a moth in the family Erebidae and the tribe Arctiini, the tiger moths. The species was first described by Dru Drury in 1773. It is a common mid- through late summer feeder on milkweeds and dogbane. Like most species in this family, it has chemical defenses it acquires from its host plants, in this case, cardiac glycosides. These are retained in adults and deter bats, and presumably other predators, from feeding on them. Only very high cardiac glycoside concentrations deterred bats as predators. Adults indicate their unpalatability to bats with ultrasonic clicks from their tymbal organs.

Source: Wikipedia — Euchaetes egle Licensed under CC BY-SA 4.0

§ Identification

Field marks. Adult: small grayish-brown moth with orange-yellow abdomen and dark wing markings. Caterpillar: hairy black-orange-white tussock with prominent tufts.

Similar species. Other tussock moth species (Lymantriidae and Erebidae; multiple species). Monarch caterpillar (yellow-white-black striped without tufts).

Voice. N/A

§ Diet & behavior

Diet. Caterpillars feed exclusively on milkweeds (Asclepias species) — same host plant as Monarch Butterfly.

Behavior. Caterpillars sequester toxic cardenolides from milkweed and are unpalatable to most predators. Adults are also unpalatable. Striking caterpillars: orange, black, and white tufted appearance reminiscent of a tropical fish; conspicuous warning coloration (aposematic). Adults are nocturnal and primarily mate at flowers of milkweeds. Despite competing for the same host plant as Monarchs, populations of both species coexist; tussock moth caterpillars often feed on slightly different parts of the plant.

§ Range

Eastern North America

§ Habitat

Anywhere milkweed grows

§ Threats

Pesticide drift, lawn-centric yards.

§ Conservation status

According to the IUCN Red List, the milkweed tussock moth is currently classified as Least Concern.

§ What helps

Plant native milkweed. Tolerate tussock caterpillars. Skip pesticides.

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§ Further reading

§ Sources cited

  • Butterflies and Moths of North America
  • Xerces Society
  • iNaturalist