Other insects survive by creating galls, Mitchell said. A gall is an abnormal swelling of plant tissue like a cancer growth. Insects cause such a growth by sucking on a plant. The growth forms around the insect, shielding it from the elements.
"If you take a magnifying glass and go for a walk in the woodsa second-growth area where there's a mix of trees and shrubsand start looking at twigs and cattails, these eggs and galls are everywhere," Mitchell said.
Holscher said some insects will come out of their winter hiding places on days when the temperature rises above a "magic" threshold of about 45 degrees Fahrenheit (7 degrees Celsius).
"The sun allows them to heat up and get active, but the minute it cools down again, they're not going to be active at all," he said.
According to Mitchell, among the more conspicuous sun-loving winter insects is a type of springtail known as the snow flea. The fleas gather by the thousands on the sunny sides of trees.
Springtails are tinythey measure about an eighth of an inch (two millimeters) longand are found in damp areas where they feed on fungi and decaying organic matter. Their name comes from an apparatus on the undersides of their abdomens that allows them to jump uncontrollably into the air.
"If you look at them carefully, you'll see them hopping around. They look like hopping pepper grains, and they are everywhere," Mitchell said.
Another spot to find insects basking in the winter sun is a dead or dying tree. There, soldier beetles and mourning cloak butterflies will come out from their holes, which they bored into the bark to shield them from the winter's chill.
Also, winter stoneflies can be seen slowly lumbering through the winter sky. Other stoneflies are dormant and found in rivers and streams, clinging to the undersides of rocks in the coldest months of the year. But winter stoneflies emerge to mate and lay eggs from January to April.
Most insects in the winter, however, are found burrowed under leaf litter or bored into the bark of a tree or surrounded by a protective shell like a cocoon or gall.
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