• The Earthworm​—A Most Beneficial Servant


    THE earthworm would surely have a hard time in winning a popularity contest. For thousands of years the designation “worm” has been a term of contempt. An ancient songwriter once said: “I am a worm, and not a man, a reproach to men and despicable to the people.” (Ps. 22:6) However, despite the low esteem in which it may be held, the earthworm fills a highly beneficial role in the maintenance of life on this planet.

    There are more than 1,800 different earthworm varieties. Some are at home in the Andes at a height of some 15,000 feet (4,572 meters) or more. Others go about their daily routine in the mud lying as much as 180 feet (55 meters) below the surface of a lake. These creatures may also be found in compost heaps.

    Earthworms vary considerably in size. One kind, when contracted, measures about one inch (2.5 centimeters) in length. But then there is an Australian variety that in its fully contracted state may have a length of three to four feet (.9 to 1.2 meters). And, when extended, one of these huge earthworms may measure between ten and twelve feet (3 to 3.7 meters) in length.

    What about color? You may well be familiar with the common reddish-brown earthworm. But there are also green, purple and grayish-white varieties.

    A Closer Look at a Common Variety

    The common earthworm measures about ten inches (25 centimeters) in length. It consists of about 120 (or up to 150) cylindrical segments. If a few of these segments are lost, perhaps because of being picked off by a bird, they will regenerate. However, such regeneration has limitations. Therefore, cutting an earthworm in half will not result in two separate worms. Each segment, with the exception of the first and the last, is equipped with eight bristles known as “setae.” By means of these bristles the earthworm can get a good hold on the soil through which it crawls. This creature’s longitudinal muscles enable it to contract or to stretch itself. With the circular muscles, it can make its tubelike body shrink or expand. Five pairs of hearts form part of the earthworm’s circulatory system.

    Unlike many other creatures, earthworms have no eyes, no ears, and no lungs or gills. How do they manage without such valuable equipment? The skin is supplied with light-sensitive cells. So when exposed to bright light, the earthworm will quickly withdraw into the darkness of its underground realm. Endowed with a keen sense of feeling, it can detect the slightest vibrations, including the movement of a mouse or a bird. The creature does all its breathing through the skin.

    Reproduction in earthworms differs from that of many other animals. Each earthworm is both male and female. Still, another earthworm is needed for fertilization to take place. The mating process takes between three and four hours, during which time sperm is exchanged. Describing what happens thereafter, the Encyclopædia Britannica says: “The worms separate and form cocoons; the cocoon moves forward, picking up eggs at the 14th segment; at the 9th and 10th segments it picks up the sperm deposited by the other earthworm. The cocoon slides over the head, and fertilization takes place. Within 24 hours after the worms mate, the cocoon is deposited in the soil.”

    The main food of the earthworm is dead plant matter. Much of this comes from what is found near the opening of its burrow. Other food is obtained from soil ingested during the tunneling process. The mouth serves as a suction pump, taking in everything that comes into the creature’s path. Soil and sand pass through the gullet to a crop lined with tough skin. Grit in the crop, along with the digestive juices, transforms what is ingested into a paste. Organic substances are digested and the remainder passes through the earthworm and is either dropped underground or cast on the surface.

    Of what benefit is the earthworm’s activity? Its burrows improve aeration of the soil and make it easier for water to pass through the earth. Its castings readily combine with organic debris to form humus and make the soil more fertile. Regarding the makeup of earthworm castings, Organic Gardening and Farming reports: “When earthworm castings are compared to the top six-inch layer of soil (such as your topsoil), we find that they are: Five times as rich in nitrate nitrogen, twice as rich in exchangeable calcium, two and one-half times as rich in exchangeable magnesium, seven times as rich in available phosphorus, and 11 times as rich in exchangeable potassium.”

    Experiments with earthworms have shown that their presence definitely increases crop production. Daily an earthworm passes the equivalent of its own weight through its digestive tube. When we consider that many thousands of earthworms are doing this in just one acre of cultivated soil, a tremendous job of soil building is being accomplished. Says The Encyclopedia Americana: “It has been estimated that as much as 10 or 15, and often more, tons of soil per acre per year are brought to the surface in rich meadowlands through worm castings.”

    Demonstration projects have revealed that earthworms can work marvels with areas or materials that would otherwise remain useless. Earthworms have converted city refuse into valuable fertilizer and have made depleted cornfields productive. The New York Times of July 30, 1976, quotes one worm entrepreneur as saying: “We can take a few tons of shredded garbage, plow it into wornout ground, turn worms loose on it, at five or 10 worms per square foot, and in three or four months have several inches of the richest, blackest topsoil you’ve ever seen.”

    Truly the earthworm is a most beneficial servant. How grateful we should be to its Maker, God, for providing such an efficient soil-builder!

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