Nature seems to constantly throw curveballs. The other day while walking through the snow I looked down to investigate a little black object and was shocked to find an insect crawling atop the snow. This Nine Minute Naturalist will explore insects and arachnids defying freezing temperatures to be active in the winter months.

Most insects and arachnids survive winter in a state of suspended animation that breaks when stable warmer weather arrives. They survive buried in the leaf litter, in egg form or in a variety of other methods to best exploit their environment for survival. Some, such as the monarch butterfly, flee toward more suitable locations. Some annoying species, such as the Asian lady beetle, or the brown marmorated stink bug, find your house the ideal winter abode. Then there are the few creepy crawlies that are adapted to being active in freezing conditions. These insects or arachnids that actively survive in sub-freezing temperatures produce antifreeze-like compounds such as glycerol, proteins and sugars that allow their body fluids to resist temperatures well below their freezing point.

Winter stonefly

One of the most common to find at Wintergreen, especially near our waterways, is the winter stonefly. The immature stages of the winter stonefly live in water, but the adult stage emerges from the water in winter and begins to walk the frozen landscape in search of a mate. Although they have wings, winter stoneflies rarely fly due to the temperatures and can accomplish their mission on the ground. Due to their being much fewer predators in the winter, their sluggish movements have fewer dire consequences in the colder months.

Snow fleas are quite the sight when they emerge onto the snow in masse. Although not terribly common at Wintergreen, the unique finding of hordes of tiny black specks moving on top of the snow is quite memorable. These hexapods are not fleas but instead fall into the insect order Collembola commonly called springtails. They will emerge from the soil litter on warm sunny winter days and become easily found in snow cover. They are thought to be eating algae on the surface of the snow.

Snow flies are a wingless insect related to the crane fly that can be found atop the snow-covered countryside at Wintergreen. They are not believed to feed during their stay atop the winter landscape but have been seen using their proboscis to obtain water from the snow.

Dwarf spider

One predator that also uses anti-freeze techniques is the spider. While up to 85% of spiders go dormant in the winter, some species such as the dwarf spider or red sheetweaver spider will thrive in the winter on insect species mentioned above. There is very little competition for food in the winter months and thus a diet of springtails, stoneflies and snow flies is sufficient to keep these arachnids alive in sub-freezing conditions.

A walk in the woods at Wintergreen is always bound to provide something of interest. Few things are more unexpected and intriguing than insects walking atop a field of snow. Make sure the next time you are in the snow-covered woods to keep your eyes peeled for the unexpected.