Northland Nature: Snow fleas pepper the snow

Early March is a time of huge variations. Subzero temperatures offset by fifties are both possible. Snow in the form of blizzards have hit at this time, as well as rain and ice. March has often been our snowiest month of the year or, as happened in 2010, we get virtually none.

Despite all this variety, one thing that is consistent is the lengthening of the days. We begin the month with slightly more than eleven hours of daylight and this stretches to nearly thirteen hours by early April. Regardless of the weather conditions, the longer period of light brings two important changes to us.

On Sunday, March 10, we begin daylight savings time, a return to more darkness in the early morning with longer evenings. And on March 20, we reach the vernal equinox, the first day of spring. From this date until next September’s autumnal equinox, light hours outlast those of darkness. The longer days win the battle with a lingering winter that may continue through much of the month. By the end, we will see the new season coming into its own.

The time changes are seldom dramatic and instantaneous, and the season gradually slides in through the next several weeks. Many of the earlier changes were small and hard to see but, as we now enter this dramatic month, they do exist.

Though we may look for migrants, I find this a good time for us take notice of trees. These tall woody plants stood out in the cold all winter and now feel the changes. Twigs take on color. Some kinds of dogwoods are red while a few willows are yellow. Buds of other willows and aspen are opening to reveal fuzzy growths. Indeed, winter-weary Northlanders may collect these twigs as a remedy for cabin fever.

Others go to trees for a snack, and soon tapping of maples will be taking place. At the bases of these same trees, we’ll see the circular indentations that I call tree circles. Warmth from the sun gets absorbed by the dark bark and re-radiates back into the snow, causing a melt. Many deciduous trees of woods, lawns and parks are now ringed by these tree circles.

And then there are snow fleas.

Tiny insects (less than a tenth of an inch) living in the leaf litter of the forest floor all year, including under the cover of the snow, now come to the surface. Being as little as they are, they prefer to climb from under the snow on an easy route. The open circles surrounding the trees provide for such a route. The same can be seen in our footprints in the snow. They quickly move into these spaces and work their way to the snow’s surface.

When temperatures are in the thirties or forties, they litter the snow in uncountable numbers. Indeed, the snow takes on an appearance of having been covered with a generous dose of pepper. It would fool many of us who see them as we pass by except for the fact that the “pepper” is moving, often jumping around.

The tiny snow fleas (not at all fleas, belonging to a group of insects known as collembolans) are all black. Like other insects, they have two antennae and six legs. Unlike most insects, they do not have wings. Instead of having wings to move and jump on the snow surface, they have a small tail-like appendage under the posterior part of the body that they rapidly push down to fling them into the air. This leads to their other, and more accurate name, springtails.

Why do they make this movement from the leaf litter, under the snow, to the surface? With mild temperatures, they are able to feed on tiny bits of algae, fungi or decay matter on the snow, and when gathering in such large numbers, they also will mate here.

Some birds that have subsisted on a mostly-seed diet all winter will find these insects as a snack; but being as little as they are, most are passed by. Unless we, or other large animals, come by and disturb them, these minute insects are mostly overlooked.

Yes, on these mild days of late winter, the snow comes alive, mostly in the afternoons, with an abundance of springtails. They return to the protection under the snow at night. With the melting of the white blanket that allows them to be seen, they return to their hidden leaf litter homes.

But on some of these March days, peppery springtails take over the snow surface.

Retired teacher Larry Weber is the author of several books, including “Butterflies of the North Woods,” “Spiders of the North Woods” and “Webwood.” Contact him c/o budgeteer@duluthbudgeteer.com.

Tags: budge opinion, budgeteer, environment