Do Woolly Worms Know Something That We Don't?

Can woolly worms forecast winter weather? Folklore has it that woolly worms are really miniature weather forecasters. Careful observation of these short, fuzzy caterpillars in the fall supposedly can tell you what kind of weather the coming winter will hold.

The woolly worms of winter weather forecasting fame are black at each end with a reddish brown band in the middle. The size of the brown band is said to be an indicator of winter's severity. The narrower the band, the harsher the winter. If woolly worms are more brown than black and the middle band tends toward orange, that indicates the winter will be mild.

Well, that's a fun bit of folk wisdom, but it's simply not true. The experts at the West Virginia University Extension Service say there is no scientific evidence suggesting that woolly worms can predict the weather.

Woolly worm is a common name for the larval stage of the Isabella tiger moth. The scientific name for this insect is Pyrrhactia isabella. Other common names for this caterpillar are woolly bears, black-ended bears and banded woolly bears (the name approved by the Entomological Society of America).

Woolly worms grow from 1-3 inches long and are found throughout the United States. The West Virginia University scientists say variations in their bands are linked to differences in species and larval stage, not the weather.

The genus Pyrrhactia includes many different species. Some are solid black, without any bands and others have bands of varying sizes. Woolly worms go through six larval stages before entering their pupal or winter cocoon stage. In other words, the caterpillar molts six times and the color and size of its bands may change from molt to molt.

So, woolly worms cannot be counted on to provide a peek at what the coming winter holds. Still, this fall's woolly worms will become next spring's moths. And that in itself is a pretty amazing feat.

Source: Grace Truman, West Virginia University Extension Service

Winter 1996
Winter Preparation for Ornamental Plants | Deicing Salt Can Injure Plants | Bug Bites: Woolly Worms | Hort Shorts | Hort Tips | Food Safety: A Procrastinator's Guide to a Safe Holiday Dinner | Food for Thought: Help! Refrigerator Overload! | Healthy Cooking: A Quick Start Breakfast | Health and Household Tips

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