Snow Fleas: The Hardiest Hexapod of Them All!

After a few mild winters in the past several years, this winter season has delivered the frigid temperatures and frequent snowstorms that we typically associate with the dormant months of the year. Although many of us struggled with extensive shoveling and interrupted travel schedules, the return of a more typical winter season has given us a chance to reflect on the ecological importance of snow. From recharging groundwater to insulating the soil from harsh conditions, snow provides essential services to the living world around us and has had a huge role in the evolutionary history of the ecosystems in the Chesapeake Bay Watershed. For many of us, the blankets of snow on our landscapes invoke serene images of mother nature in a deep restorative slumber, but it is actually a surprising hotspot for biological activity. Many small mammals thrive in the relatively warm and hospitable subnivean zone that forms under snow, protected from the bitter ambient temperatures and predators. But some of the critters that thrive in our snowy conditions are able to survive out in the open air, even if you have to squint to see them!

Many years ago I was out on a hike in the woods in late winter on a day when the temperatures were high enough to comfortably enjoy the outdoors. As I travelled along the trail I kept noticing clusters of tiny black specks on the surface of the snow, which I initially assumed were just small seeds or detritus from surrounding plants. When I bent down to take a closer look, I was shocked to see that these tiny specks were jumping up off of the snow! A quick google search revealed that these were called Snow Fleas (Hypogastrura nivicola), a common and prolific member of forested ecosystems worldwide.

Like many common names snow flea is a misnomer in that these organisms are actually springtails, which are not fleas nor even true insects. While springtails and insects are both arthropods contained within the sub-phyllum Hexapoda, the main difference between the two is that springtails have internal mouthparts while the insects have external mouthparts. Springtails get their namesake from an appendage on their abdomen called a furcula that allows them to thrust themselves up into the air and travel across the landscape or avoid potential predators. Snow fleas are particularly adaptable to cold winter temperatures because they produce a glycine rich protein similar to anti-freeze that helps prevent their cells from freezing. Scientists are studying these proteins in hopes to gain insight on storing transplant organs for the medical industry, and even to produce higher quality ice cream!

While snow fleas are most apparent to us on the surface of snow in winter months, they are present and abundant throughout the year. Snow fleas are beneficial to ecosystems as detritivores that help break down organic matter and enrich soil by cycling nutrients.Their diet includes leaf litter, live plants, and numerous microorganisms that thrive in these habitats such as algae, fungi, protozoans, and nematodes. Unlike the true fleas they are named after, these critters are completely harmless to humans and other animals and have no parasitic tendencies. If you get the chance to walk in the woods while there is still snow on the ground, keep your eyes peeled for these tiny, fascinating creatures!

If you see something blooming, leafing out, ripening, or otherwise changing in your woods, send us photos forestsforthebay@gmail.com to include in next month’s Forests for the Bay newsletter for more phenological fun!