Most insects of the Temperate Zone winter as eggs or pupae, providing nutritious snacks for mice and birds. Some, including ladybird beetles and honey bees, overwinter as adults, massing in sheltered areas to conserve heat. Though aquatic larvae are common, relatively few terrestrial insects overwinter in the larval form.
One of the more common and well known wintering caterpillars is the woolly bear, the larvae of Isabella tiger moths. These fuzzy, red-brown and black caterpillars have long been rumored to have weather-forecasting skills, the thickness or color of their coat indicating the severity of the coming winter. While this is purely folklore, woolly bears are often encountered during the winter months, seemingly out of place in the snowy landscape; in fact, my wife and I saw one yesterday, crawling across a muddy trail.
Woolly bear caterpillars spend the winter in sheltered areas, beneath log piles, leaf litter or dense vegetation. Periods of warm weather or a disruption of their hideout will bring them out into the uncaterpillar-like environment, moving about to munch on plants or locate a new winter home. There are few sights in nature more bizarre than a woolly bear on a snowbank!
