Don’t Worry, These Jumping “Fleas” Don’t Bite

By Ted Watt Gazette Contributing Writer

What’s that stuff on the snow? It looks like pepper, and there’s lots of it. It’s dark blue. And it’s jumping. Hey, it’s tiny bugs!

Next time you take a hike on a balmy (warmer than 25 degrees) late winter’s day, keep your eye out for snow fleas, among this area’s most fascinating native species. If you find any, don’t worry—they don’t bite. They’re only called “fleas” because they jump.

It’s never a guarantee that you’ll find snow fleas, even if you search; you’ll probably just happen upon them when you least expect it. All of a sudden you’ll notice a slate blue powder, sort of like ground pepper, on top of the snow. When you look more closely you’ll see that the particles are moving—hopping, actually. The bugs are alive and active right on top of the snow. They can jump up to one foot, pretty far for a little creature that’s only a 16th of an inch long. If we humans jumped that far relative to our body size we’d leap a whole kilometer.

Snow fleas are classified in their own order, known as Collembola. There are as many as 2,000 species in North America, and they mostly live in the soil. They’ve been on the planet a long time, with fossil remains discovered in 400-million-year-old rock deposits from Scotland. Some soil biologists speculate that these are the most common of all soil invertebrates. They have six legs but are not classified as true insects because they have fewer segments on their abdomen. At the end of their abdomen they have a pair of “tails” that are spring-loaded, held in place under their abdomen by two little “hooks.” When they decide to jump they release their two tails and are forced into the air when their tails hit the snow—hence their other name, springtails.

Snow fleas live all year in the soil and leaf litter, preferring microhabitats with adequate moisture. You can also see them floating on the surface of water in still pools and puddles. They eat detritus (the dead remains and castoffs of animals and plants), and are instrumental in helping to fragment and decompose it, recycling it back into soil. They’re eaten in turn by beetles, ants, mites, centipedes and other carnivorous invertebrates.

“Intriguing” chemistry

These animals are remarkable not only for their jumping but for some intriguing chemistry. In 2005 two biochemists, Laurie Graham and Peter Davies from Queen’s University in Ontario, Canada, isolated a new antifreeze protein (AFP) from snow fleas. (May we sacrifice the lives of little creatures with awareness and gratitude.) This amazing protein—which helps the snow fleas remain active in cold winter temperatures— works by inhibiting ice crystal formation by about six degrees and is biochemically different from other known AFPs.

AFPs were first discovered in the 1970s and primarily associated with bacteria, plants, insects and amphibians. They work by binding to the surface of nascent crystals, preventing them from growing further. The snow fleas’ AFP breaks down more quickly than other types as temperatures rise. Because of this property, it could benefit people: Some scientists believe that human organs destined for transplantation might be stored at lower temperatures without frost damage if treated with this AFP—thus extending the organs’ “shelf life.” In addition, snow fleas’ AFP may help increase frost tolerance in food crops and inhibit crystallization in frozen foods. All this from a tiny invertebrate, so easy for us to overlook.

The next time you find snow fleas, take some time with them. Get down close to them and watch them. Appreciate the wonder of their survival and adaptations. Cherish the mystery of their appearance and disappearance in the freezing snows of winter. And celebrate our place among all the intricately interconnected, finely adapted life forms with which we share the planet.

Ted Watt is an environmental educator/naturalist at the Hitchcock Center for the Environment.

Earth Matters, written by staff and associates of the Hitchcock Center for the Environment at 525 South Pleasant St., Amherst, appears every other week. For more information, call 413-256-6006, or write to us.

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