SEPTEMBER
2004

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

Download the audio files or subscribe to our podcast.

 

Check out these books by Tom Turpin:

Flies in the face of fashion

What's Buggin You Now?

 

 

 

09-09-04

Download the audio of On Six Legs: MP3, WMV.

Out of Sight and Out of Mind Fine for Collembola


Insects are very common organisms. In fact, insects are so numerous that they seem to be everywhere. At least in warm weather, every nook and cranny of nature provides a home for insects. To be sure, one of the reasons for the success of insects is that their small size has allowed them to creep into spaces too small for larger animals. If insects had a motto, it surely would be that no space should go unoccupied.

Insects that occur almost everywhere are the collembola. People are generally unaware of collembola, and most have never even heard of these insects. There is a good reason why collembola have been overlooked by humans. These are tiny insects, generally no more than a few millimeters in length, which live secluded lives. They are out of sight and, therefore, out of mind!

So what do collembola look like anyway? They are wingless. Colors vary, some are gray or black, others brown or yellow, some are white, still others are mottled brown and white. What all collembola have in common is that they have the ability to jump. Actually, they don't jump in the true sense, they propel themselves with a spring. That is why a common name for collembola is spring tail.

Spring tails spring by using a device called a furcula. A furcula is a forked device that is an extension of the rear end of the insect, hence the name spring tail. In order to use the spring, it must be set, like a snap mousetrap. This is accomplished when the spring is folded back under the insect's abdomen and fastened down by a structure called the tenaculum. When released, the spring propels the collembolan forward like a stuntman out of a circus cannon.

The spring of a springtail is in modern vernacular, awesome. In fact, the silly little 5 to 6 millimeter insects can sometimes jump, or rather spring, 4 inches. They do this to escape predators.

Springtails can be found in high numbers in all kinds of habitats. They even may be the most widely distributed of all types of insects. Generally, springtails live in concealed habitats where they feed on dead and decaying material. They like a high-moisture situation and are often found in leaf liter. Turn over dead and decaying leaves almost anywhere, and you are sure to expose some springtails to the light. Under such circumstances, these little insects start a frenzied jumping -- an attempt to get into a secure hiding place. 

Not all collembola live hidden where the dead leaves meet the soil. One species that is common to woodlands is sometimes found skating around on the surface of freshwater ponds. Another species is common on the surface of tidal pools along the seashore.

While most collembola feed on dead organic matter, a few species feed on plants. Such plant-feeders can become so abundant that they damage ornamental and vegetable plants. They can also become damaging in greenhouses and mushroom cellars.

Springtails also show up in unexpected places, at least in places were insects generally fear to tread. The animal called a snow flea is actually a collembolan. These dark-colored springtails can be found springing around on the surface of the snow in the winter. This is something that cold-blooded insects just can't accomplish very often.

Springtails make up for what they lack in size by numbers. Almost every handful of leaf litter will harbor several dozen of the little jumpers. It has been estimated that as many as 10 to 15 million exist in an acre of woodland. To think most of us have never seen a springtail. But, then, most springtails have never seen a human, and that is just how the springtails like it!

 

 

Writer: Tom Turpin
Editor: Olivia Maddox