What's That Bug? does not endorse extermination

Subject: catepillar
Location: mn
December 8, 2012 4:40 pm
found this in the snow in minnesota today can i keep it alive all winter?
Signature: sb

Banded Woolly Bear

Dear sb,
Even though your photo is out of focus, the markings and coloration on this Banded Woolly Bear, the caterpillar of the Isabella Tiger Moth,
 Pyrrharctia isabella, are unmistakeable.  According to BugGuide:  “The second brood overwinters as a caterpillar and pupates in Spring.”  In order for this individual to survive the winter and mate in the spring, you need to keep it cool.  We would recommend a sheltered location that is protected from the elements, but not heated, like a garage or unheated porch.  Keep it in a small aquarium or large jar with air circulation provided by a screen or other air permeable cover.  A small cardboard box would also suffice.  According to folklore, the relative size of the red band is indicative of the severity of the winter.  According to CirrusImage:  “Common folklore has it the severity of the coming winter can be predicted by the amount of black on the banded woolly bear, the Isabella tiger moth’s caterpillar. However, the relative width of the black band varies with age, and has nothing whatsoever to do with weather (Wagner 2005). Isabella tiger moth caterpillars overwinter, surviving freezing weather by producing their own antifreeze, with which their cells are infused.”   The Farmer’s Almanac website has a very thorough explanation of this lore, and it posits:  “According to legend, the wider that middle brown section is (i.e., the more brown segments there are), the milder the coming winter will be. Conversely, a narrow brown band is said to predict a harsh winter. But is it true?”  If the legend is true, your caterpillar would indicate a mild winter.

What's That Bug? does not endorse extermination
Location: Minnesota

One Response to Banded Woolly Bear: A mild winter in Minnesota???

  1. Eli Larson says:

    I find these all the time when I’m outside looking for frogs and snakes with my cat. They eat a lot.

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