Yellow Woollybear Caterpillar

2015 April 18

Sandy found this caterpillar on August 12, 2014. It was crawling on the raised-bed garden frame that she’d just built in front of the house.

It looks to be fairly typical of the woolly caterpillars of the various tiger moths (Arctiini) aside from the color – most of them are dark, not golden yellow like this one.

The most likely candidate appears to be the Virginian[1] Tiger Moth, Spilosoma virginica, a widespread moth with highly variable caterpillars ranging from almost white to nearly black, but most commonly some shade of yellow like this one.

It was a fairly typical size for a woolly-bear type caterpillar, as you can see by comparing it to my thumb.

It appears to have black feet.

They eat a variety of “low growing plants”, and the range map shows them over pretty much all of North America.

They evidently are pretty good swimmers, at least for a caterpillar. According to this account on BugGuide, they can be found eating water grasses and sedges in swampy areas, and if the plant bends over and dumps them in the water, their hairs are sufficiently water-repellent that they are held up by surface tension[2]. So they can just crawl across the surface of the water until they find a new plant to eat.

[1] Note that this is “Virginian”, not “Virgin”. The “Virgin” and “Little Virgin” tiger moths are different species, with completely different coloration.

[2] Perhaps I could try to get people to start calling them “Jesus Worms”, because they can walk on water. Some people already call water striders “Jesus Bugs” for this reason.

One Response
  1. July 10, 2017

    how can they be so cool and be so cute at the same time it is so cool how they can do it.

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