Buck Moth Caterpillar, but which species???

Subject: caterpillar
Location: Williams, Oregon 97544
July 24, 2013 4:06 pm
I saw this guy at a open pollinated seed farm. Do you know what it is?
Signature: applegatetech

What's That Buck Moth Caterpillar?
What’s That Buck Moth Caterpillar?

Hi applegatetech,
This is a Buck Moth Caterpillar in the genus
Hemileuca, and all members of the genus have stinging spines.  According to the World’s Largest Saturniidae website, there are four species of Buck Moths reported from Oregon, and all have similar looking caterpillars.  BugGuide provides this image of an Elegant Sheep Moth Caterpillar, Hemileuca eglanterina, and BugGuide indicates the food plant is:  “Larvae feed on trees, shrubs, esp. Rosaceae, such as rose (Rosa), Hawthorn (Crataegus), cherry (Prunus), etc. Also willow (Salix), aspen (Populus), birch (Betula).”  Apple trees are in the rose family, so there is strong evidence this might be the caterpillar of an Elegant Sheep Moth.  According to BugGuide, the Hera Buck Moth, Hemileuca hera, has “Caterpillars feed on basin big sagebrush (Artemisia tridentata) and sand sagebrush (A. filifolia),” so unless sage was present on the farm, we can eliminate the Hera Buck Moth.  According to BugGuide, the caterpillars of the Nevada Buck Moth, Hemileuca nevadensis, feed on “Alder and willow” so again, if those trees are not on the farm, the Nevada Buck Moth can be eliminated.  BugGuide has photos of Hemileuca nuttalli, but does not provide any information.  The World’s Largest Saturniidae Site provides this list of food plants:  “Birchleaf cercocarpus, Antelope bitter brush, Firethorn, Snowberry, Mountain snowberry” so we are also confident eliminating that possibility.  Indications are good that this is the caterpillar of an Elegant Sheep Moth, a lovely and highly variable species. Perhaps if you have an opportunity to photograph an adult moth, you can send the photos to our attention with the subject line “Elegant Sheep Moth” because we would love some newer photos for our archive.

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BugMan aka Daniel Marlos has been identifying bugs since 1999. WhatsThatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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