Subject: Orange caterpillar
Location: Wyoming
May 13, 2017 9:31 am
Hi Bugman,
A few years ago, my daughter found this neat looking caterpillar. We were fascinated by its colors. We were hoping you could tell us what kind of caterpillar it is and what it turns into? We don’t see many colorful caterpillars here in Wyoming. Thank you!
Signature: Anneka & Samantha

Pre-Pupal Western Tiger Swallowtail Caterpillar

Dear Anneka & Samantha,
This is a Western Tiger Swallowtail Caterpillar,
Papilio rutulus, and for most of its life it was green to camouflage itself on the leaves upon which it had been feeding.  Its orange color is based on its pre-pupal state as it was likely searching for an ideal location to transform into a chrysalis.  According to BugGuide:  “Males patrol canyons and hilltops. Larvae feed on foliage of deciduous trees, including cottonwood, birch, elms, willow, alder, sycamore, and aspen. They rest in shelters made of silk and curled leaves. Overwinters as pupa (chrysalis).”  BugGuide also notes the habitat is:  “Woodlands and more open areas, often near streams. Also common in cities and suburbs due to the popularity of sycamores in landscaping.”  We were able to distinguish your Western Tiger Swallowtail Caterpillar from the numerous other North American Tiger Swallowtail species because of your location and this BugGuide statement:  “Larvae very similar to those of Pale Tiger Swallowtail, but black pupil of false eye-spot larger, and yellow spot inside eyespot entirely separated from it, not just notched.”  The adult Western Tiger Swallowtail is a gorgeous butterfly.

Location: Wyoming

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