Springtail refers to species of the order Collembola. A lesson on the abundance of life.
Dirt is alive. I'm not just referring to biotic material (throw ordinary soil into a beaker with some water and let it sit for a week — it'll settle like oil and vinegar, and the top layer, a good third, is dead plant matter, and that's not even really alive anyway). And I'm not feeding you some hippie earth-father crap. Dirt is alive because of springtails.
A handful of earth is probably crawling and fizzing with several dozen springtails. An acre-sized plot can contain millions. If you've ever been hit with a snowball, there were probably springtails wiggling around in the crystals of ice melting on your skin.
They are everywhere. They live all over the world. They are in your basement and in your dirt. They are the black specks on your plants. They are everywhere.
Itching after playing in the grass. Supposedly this is the work of grass mites. Supposedly.
Springtails are tiny bugs, rarely exceeding more than a few millimeters in length. They disappear when touched, like bubbles. They're fitted with an elastic fork (furcula) that folds under the body, attaching to the chest with a latching mechanism: when the springtail lets it rip, it smacks the ground and sends the body flying. A good spring will carry the little bug a foot. Most are cream-colored, but some are black, green, lavender, or iridescent blue. The body is a vaguely segmented blob — think chubby beetle-grub, except much smaller and much more nimble.
These are remarkably hardy creatures. While they prefer to inhabit moist soil, they're capable of living in snow and can reproduce at teperatures as low as 40 °F.
Order Collembola is some 6000 species strong. Genetic studies suggest that it's an offshoot of subphylum Hexapoda — six legs. Collembolites make up the second-largest group of six-leggers, second only to insects. It's a big offshoot. Even then, it's more closely related to the other hexapods no longer classified as insects, Protura and Diplura, because of the structure of its mouth. The mouth of a springtail is located inside the head rather than outside, as in a grasshopper or fly.
Collembolites enjoy a diet of rotting vegetation and fungi. A tube-shaped apparatus under the first abdominal segment, called collophere, helps with water intake. You're likely to find them in moist, dark places. Rotting logs are good places to search. Occasionally they'll take up residence in termite nests. During snowy winters, they huddle together, sometimes in large enough number to tint the snow.
Springtail growth follows the simple metamorphosis model: egg to nymph to adult. Nymphs and adults are almost identical, except for size.
Springtails can become pests when they inhabit the soil of potted plants in very large numbers. Mushroom growers don't like them because they enjoy fungus. But even in the tens of thousands, these critters aren't enough to decimate the root structure of a good aloe plant. More than anything, springtail infestation is a cosmetic problem.
Eradicating springtails is not a complex endeavor. Usually, infestation is a result of overwatering. Just stop dumping so much water on your plants. When the soil dries out a bit, your springtails will either leave or die.
If you're feeling really agressive, buy some Hypoapsis mites from a higher-end garden supplier. These guys cross the eyes at half a millimeter in length, but a single mite will generate a swath of springtail destruction, eating up to 20 of the hapless creatures a day.
Want to do some further research? Here's a list of the collembolite families, taken grudgingly from Wikipedia:
---. The 1981 Childcraft Annual: The Bug Book. Childcraft International, Inc. 1981.
---. Wikipedia. "Springtail." http://en.wikipedia.org/wiki/Springtail.
BM Drees & John Jackman. Field Guide to Texas Insects. Gulf: Houston. 1999.
MJ Munster. "Hypogastrurid Springtail."http://www.ces.ncsu.edu/depts/ent/clinic/bugofwk/970003/springta.html.
Eric Day. "Springtail." http://www.et.vt.edu/departments/entomology/factsheets/springta.html.
---. "Springtail." http://www.hapydranch.com/5.html