Western Tussock Moth Caterpillar

Subject: Caterpillar
Location: San Mateo, CA
May 7, 2016 6:49 pm
Found this in San Mateo, Ca. Is this caterpillar poisonous? What does it eat?
Signature: Vera

Western Tussock Moth Caterpillar
Western Tussock Moth Caterpillar

Dear Vera,
This appears to be the caterpillar of a Western Tussock Moth,
Orgyia vetusta, which is pictured on BugGuide.  BugGuide makes no mention of irritation caused by the hairs, but other members of the genus including the White Marked Tussock Moth are known for having urticating hairs.  Of that species, BugGuide notes:  “CAUTION: Contact with hairs may cause an allergic reaction.”  According to the Moth Photographers Group:  “Dozens if not hundreds of these caterpillars have been busy eating leaves on a Coast Live Oak.”

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