From the Viette's Views Gardening Blog
The woolly bears seem to be on a mission! So many are crossing the road these days – and they’re not dilly-dallying either! They’re moving along at a pretty good clip – for a caterpillar that is! I find it very curious.
Driving to work in the morning, I’ll see four or five at a time crawling across the highway. Then I’ll go a little further and find several more booking it across the road. I try to avoid them but there is only so much you can do. They seem to be everywhere.
So, why DO woolly bears cross the road?
Good question! Most of what I’ve read says that they are just looking for a place to overwinter and the road just happens to cross their path. I suppose that is as good an explanation as any but if I walked through the woods or through a field, would I come across as many as I see on the road? I wonder …
I did see several in one of my gardens this weekend when I was doing some weeding and mulching. I picked one up and he immediately curled up in a tight little ball so characteristic of these caterpillars. I even found a large solid black “woolly bear”. This guy was a different species from the banded woolly bears that I was used to seeing. It turns out that he was the larval form of the giant leopard moth (Hypercompe scribionia), a really pretty white tiger moth with a beautiful pattern of black circles and rings covering its wings. You can definitely tell where its name comes from! The caterpillar is solid black with narrow bands of red between the segments.
Banded woolly bears are the larval form of the Isabella tiger moth (Pyrrharctia Isabella). The adult moth of this species isn’t nearly as colorful as the beautiful giant leopard moth but its caterpillars are pretty adorable! There are usually at least two generations of these moths during the season. The last generation normally hatches out around August and these will overwinter in the larval caterpillar stage – the familiar, loveable woolly bears. Fortunately, these guys are not considered to be major pests in the garden.
In the fall, the woolly bears become very active and quite visible as they begin to move from their summer feeding grounds in meadows and fields to woodland areas where they will hibernate during the winter months. This is when they are seen crossing roads, sidewalks, woodland trails, your driveway …
I guess we notice them in these places because that’s where WE are and they just happen to be on the move! Most of these caterpillars will spend the winter curled up under leaf litter on the forest floor, under stones or rotting logs, or nestled down in piles of wood.
During the winter, woolly bears are able to survive freezing temperatures by producing a type of “antifreeze” or cryoprotectant in their circulatory system that protects their cells and vital organs from the damage which would occur if ice crystals formed. So they survive in a frozen state all winter long – at least in the colder parts of their range. These guys are found as far north as the arctic!
That’s pretty neat!
In the spring, the frosty caterpillars thaw out and wander around eating a little before settling down to spin a cocoon. The adult moths emerge about a month later, mate, lay eggs, and a new generation begins.