Caterpillars of Pacific Northwest
Forests and Woodlands
Tyria jacobaeae [Arctiidae]
The sparse hairs of the cinnabar moth are atypical for arctiids, as is the day-flying habit of the adult. The black and orange rings make this caterpillar apparent on its host plant tansy ragwort. The cinnabar moth was intentionally introduced into the western United States for biological control of this noxious weed. This caterpillar is very common, with rare exception it only feeds on Senecio, in particular S. jacobaea, during July and August. The gregarious caterpillars are poisonous to vertebrate predators due to the caterpillars ability to sequester pyrolizidine alkaloids from the host plant.
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