Nature Nearby: Of worms and men

September 10, 2012

FRED SEITZ

BY FRED SEITZ — Fascinating for gardeners, fishermen, Aristotle, Darwin and Edgar Allan Poe, the earthworm, an unobtrusive invertebrate, is one of our most helpful partners in the animal kingdom. Unfortunately, the term worm has been applied to everything from medieval dragons to intestinal parasites to computer viruses. This must be truly stigmatizing for the hard-working earthworm, which literally helps us from cradle to grave. Worms help provide us with food throughout our lives and digest us at our end.

The earthworm is a segmented beastie (Annelids) and quite different from flatworms (such as tapeworms and flatworms), which have large eyes and a distinct head. It is also distinct from threadworms (Nematodes), some of whom are parasites and a bane to our gardens.

Our earthworm ally has some preternatural properties that make him/her downright remarkable.

A single worm has both male and female parts, but it still takes two different worms to tango and make the little ones. They exchange sperm between them and the eggs are fertilized in each partner. Finally, each worm deposits small cocoons containing the eggs in the soil.

Both before and after their encounter, the two worms make the earth move. First, each one, using its strong muscles to lengthen itself, extends tiny hairs that grasp the soil in the front. The worm compacts its body forward, retracts the front hairs and extends rear hairs to anchor itself. It can now extend its body forward and continue to aerate soil while devouring plant and animal debris and excreting materials that enrich the soil.

The extreme muscular ability and the ability to anchor itself in the soil have been the bane of more than a few birds trying to extract worms from the soil.

Still within the magical realm is the remarkable regenerative power of some earthworms, so cutting or pulling off part of an earthworm may prompt some of the species to regenerate that part. Such remarkable feats of strength, movement and regeneration are aided by its five hearts.

Earthworms do not have eyes, but they do sense light and will usually burrow into the earth when confronted with bright light. The familiar “nightcrawlers” burrow as deep as six feet. While they eat mulch and leaf litter, these 8-to-12-inch long worms are an invasive species that has consumed much of the leaf litter in our forests, and has invited invasive plants such as garlic mustard to take over forest edges.

Digging in slightly shallower depths (6 to 12 inches) is the habit of red worms, which grow to only about three inches long. These are power houses for soil improvement and also good fishing worms.

Living mostly in leaf and needle litter are some of the most favored composting worms, such as the red wigglers. They, too, are popular with fishermen, because they wiggle a lot and attract the fish.

Any of these general groups of worms are important food sources for birds, turtles, salamanders and other subterranean dwellers such as moles and shrews.

An interesting practice of fishermen and some gardeners is known as worm charming. It is a process of attracting worms to the surface for harvest and sale. At its simplest, it requires the charmer to put a pitchfork or wooden stake in the ground and to strike the pitchfork with another piece of metal or drag a piece of metal across the top of the stake. Oddly, worms will come to the surface after a period of this human noise-making. The record number of worms appearing in a half-hour is 511. Recent research has shown that the charmer’s sound is very similar to that of a mole moving through the soil or the noise of a bird pecking at the soil. The worms surface to avoid the perceived predator.