Snow Fleas – Yes Virginia There Are Such Things!
As you know we write articles for Gardner News about a month in advance of the printing, so as I sit in 60 degree weather here in Northern New Jersey, I prepare for an interesting article on Snow fleas. This year so far El Niño has brought us warmer than usual weather. Let’s hope La Niña brings us some cold weather and snow. We will get snow and when we do there is a chance you could experience an insect that does occur in New Jersey called “Snow Fleas”. In February insects are the last things on your mind. You look down on what seems to be dirty snow and you see lots of little black specks. Suddenly you remember something you read on Gardner News and you stoop down for a closer look. Just as the snow turns to cold water melting onto your knee, you notice some of the small black specks springing into the air! Yes, you’ve found ‘em! Snow fleas! They are not fleas at all. They will not bite you, jump on your dog or really care about you at all. They are insects in the Order Collembola, commonly called springtails. In North America there are 7 families and @677 species of springtails. They are the most abundant of soil-dwelling arthropods. Living in a variety of habitats where they feed as scavengers on decaying vegetation and soil fungi, these insects are beneficial in that they help decompose organic matter. They are small in size usually 6 mm or less in length. They are named for a forked like jumping organ called the furcular. Springtails are able to jump by positioning the furcular up underneath their body, releasing it and propel into the air. Experts believe this mechanism was developed to avoid predation and escaping from other arthropods that may feed on them. The immature Collembola are similar in appearance to adults. They are dark blue in color making a nice contrast to snow. They usually molt 4-5 times before reaching sexual maturity. Unlike other arthropods, springtails have evolved in cooler climates. Snow fleas can tolerate cold temperatures down to 31 degrees Fahrenheit. When the ground is covered with snow, they tend to emerge from leaf litter during warm sunny days. Keep in mind that decaying leaf litter can generate heat during the winter months and many times you can find insects and other arthropods warm and cozy even during the coldest of winter days.
The economic importance of springtails is that of decomposition. They break down and recycle organic waste. A few species feed on living plants and are sometimes regarded as pests. The garden springtail (Bourletiella hortensis) may damage seedlings in early spring. Other species will attack alfalfa and mushrooms.
Bug Bytes (courtesy of NC State University). Springtails may be extremely abundant in certain habitats. Population densities exceeding 750 million individuals per hectare have been found in some grassland communities. Springtails “hop” by snapping their furcula against the substrate. In this manner, they may propel themselves up to 20 cm in the air — a distance 50-100 times their own body length! Unlike most other arthropods, springtails appear to have evolved in cool climates. Their relative abundance in the soil tends to increase as the mean annual temperature decreases. Other cold-loving species are found on the surface of glacial ice in the far North. Females of some Sminthuridae cover their eggs with a glaze of freshly eaten soil and fecal material. This mixture evidently protects the eggs from dehydration and fungal attack. Like other non-insect hexapods, Collembola continue to molt after they reach sexual maturity. But unlike other taxa, reproductive activity occurs only during alternate instars: each reproductive stage is followed by a molt, a short period of feeding, and another molt. Some springtails live in caves or in the burrows of small mammals. A few species, including all members of the family Cyphoderidae, live in the nests of social insects. Springtails come in a wide variety of decorator colors, including white, pink, yellow, green, orange, red, blue, and indigo.
Editor’s Note: William A. Kolbe, BCE is a Board Certified Entomologist for Viking Pest Control based out of Warren, NJ. He has a Bachelor’s Degree in Entomology with a minor in Ecology from the University of Delaware. He is a member of The Denville NJ Community Gardens. He can be reached at 800-618-2847 or visit www.vikingpest.com