Volume 39, Number 1,
October 1992:
Springtails

Text-only version

ABOUT THIS ISSUE
- about KSN
- about the author

IN THIS ISSUE
- part 1
- part 2
- part 3
- part 4
- part 5
- part 6
- part 7
- part 8
- part 9
- part 10

SLIDESHOW
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Springtails
by Kenneth Christiansen

Springtails
by Kenneth Christiansen

You probably have had the experience of seeing a small black speck go scurrying across a sheet of paper and suddenly disappear. IF you have ever had house plants you have probably at sometime seen large numbers of tiny white creatures crawling around under or on flower pots. You may have walked through the woods on a sunny day when the snow was still on the ground and seen some dark blue patches on the snow. If you looked at these patches more closely, you discovered they consisted of thousands of tiny insect-like creatures called "snowfleas." If you have spent time at the seashore at low tide, you may have noticed small tide pools or wet rocks with tiny blue-black animals covering the surface. Few people realize that in all these cases these motile motes were springtails or Collembola. Although Collembola are among the most numerous arthropods on earth's surface, and over four thousand different species are recognized, they are little known,a and those who are aware of their existence generally think of them either as "snow fleas" or as soil insects. This is understandable, since Collembola are almost all tiny (mostly less than 3 millimeters long) and are most conspicuous when they emerge in vast numbers on snow on a warm winter day, and since they are one of the most important elements in any soil ecosystem. However, Collembola are not limited to these situations, but occur almost everywhere from the tops of the tallest trees to the deepest soil strata where life occurs. They are in fact found everywhere life of any sort is found except the open ocean or below surface in bodies of freshwater.

For example, the black speck on the paper is one of number of household springtails which have become part of man's arthropod entourage. In North America the most common representative of this group is Willowsia nigromaculata (Figure 1) and the animated comma racing over your page was very probably a member of this species.

A good many species of Collembola thrive in the soil litter or fallen logs and sticks where they feed primarily on fungi and bacteria. Under ideal conditions, often in eh winter when predators are scarce, they may build up huge numbers under the snow. A warm sunny day may increase the level of activity so much that they appear to boil out onto the snow surface. Although a number of species can do this, occurrences in the United States usually involve the common snow flea, Hypogastrura nivicola (Figure 2). Some people become worried by the vast numbers of snow fleas and their sudden appearance on the ground. But there is no cause for alarm; they are totally harmless to us and our plants, houses, or animals. The best control measure is to wait a day and they will be gone. A few will make it back into the soil but most will die, shrivel up and blow away.

Most Collembola prefer cool, damp environments. Very few can tolerate house climate for long or even those conditions under which most crops are grown. Thus, they are unlikely to compete with the cockroach or the medfly for public attention. Another man-made habitats which better suit their requirements, they may be exceedingly common. Certain species swarm in beds of cultivated mushrooms or earthworm cultures; these and others may be conspicuous inhabitants of greenhouses, or thrive amid ornamental plants in flowerpots. Many such springtails are white or very pale; the species you found on or under your flowerpots was probably Folsomia candida (Figure 3) which lacks eyes as well as pigment.