Out in the woods
- March 20th 2025
- Out in the Woods
Snow fleas on a finger.
Photo: Roy Lukes
Winter Fleas Eat Bark, Don’t Bite
By Kevin McKeon, Maine Master Naturalist
During our winter walks along a warm, thawing snowpack, we occasionally notice black specks that seem to be moving. A closer look will reveal that we’re watching a swarm of snow fleas, a species of springtail and a common warm winter day sight.
Their name is a bit misleading: They don’t bite, but like the bane of dogs, will jump admirably. We’re more apt to see the common snow flea, Hypogastrura nivicola Fitch, which is a dull black. Less common is the snowmelt springtail, Hypogastrura armata Nicolet, which is a dull red. Both springtails are about 1/16 inch long.
There are about 3,600 springtail species that evolved from their 412-million-year-old ancestors. Although taxonomically listed in the insect order Collembola, they’re not considered insects in the strictest sense. They differ in that springtail mouthparts are internal, and their molting process is different. Also, their ancient ancestors didn’t have wings, nor do current springtails develop wings. (True insects are thought to have broken away from the evolutionary tree to develop wings, and some of those evolved to lose them!) Their ability to hop about in a springing action puts them in the Collembola order of small wingless, soft-bodied creatures with a forked structure that propels by a sudden springing action.
Springtails are omnivorous cryptozoa. They eat plants and animals and live in moist, dark places. This valuable combination allows springtails to contribute to healthy soil microbial communities by eating and recycling forest detritus {loose soil, decomposing tree bark, decaying leaves, moss, and dead microscopic soil plankton, fungi, and algae}. They move about mostly by crawling, but spring when agitated or excited. In advantageous habitats, their life cycles quicken, producing thousands of snow fleas per square foot and sometimes form a raft-like sight in puddles. With a bit of luck evading their predators — spiders, flies, beetles, ants, and tiny fish, frogs, and salamanders — they’ll live for two years.
Snow fleas need not be of concern to homeowners: They can be annoying but do not damage food, clothes, furniture or property. They’re harmless to humans and pets, and they don’t bite or transmit disease. This is one of the few insects that occur in the adult stage during the wintertime. These creatures can survive in very cold areas due to the glycine-rich proteins in their bodies that act like anti-freeze, preventing ice crystal formation and cell damage. This particular snow flea protein is rather unique in that it easily breaks down as the temperature rises, so snow flea research is ongoing, focusing on a means to increase the viable storage time for transplanted organs — and, surprisingly, for improving the ice-free texture of ice cream.
Editor’s note: Did you see something unusual last time you were out in the woods? Were you puzzled or surprised by something you saw? Ask our “Out in the Woods” columnist Kevin McKeon. He’ll be happy to investigate and try to answer your questions. Email him directly at: kpm@metrocast.net
