"Tremors,” a 1990 horror/comedy movie, features not one but four serious subterranean wormlike creatures dubbed “Graboids” — at 30 feet long and traveling at 20 miles per hour, they devoured everything from trucks to outhouses. Worms in real life compare only in shape and assumed bodily function, and hopefully we have more than four.
In 1881, Charles Darwin wrote: “It may be doubted whether there are many other animals which have played so important a role in the history of the world, as have these lowly organized creatures.” The benefits to us: soil aeration, changing minerals and nutrients into plant-accessible forms with their castings, conversion of large amounts of organic material into rich hummus, minimizing thatch and, in general, creating healthy soils.
Worldwide there are some 6,000 species of worms. Spade into healthy Kansas soil and you should find an abundance of night crawlers (Lumbricus terrestris); in not-so-healthy soil, the common field worm (Allolobophora caliginosa). If no worms are found, you are missing an important asset.
Why no worms? Many lawn and garden chemicals repel, if not kill, worms. Artificial fertilizers provide no nourishment for them. Grub control chemicals applied to your lawn, usually not indicated as necessary, are fatal to worms and the benefits they provide.
Earthworms flee from vibrations, and, if chopped in half, attempt to regenerate. They surface during heavy rains, not because they are drowning, as they breathe through their skin and can actually survive for hours in oxygenated water, but because they have found an easy way to move from point to point in search of food. Worms keep their skin moist by excreting a bodily fluid and residing in a cool, moist medium.
The Graboids in “Tremors” moved through dry desert sand and toward the vibration — a small technical error by the filmmakers.
Earthworms form the base of many food chains. Birds (especially robins), snakes, mammals (bears, foxes, hedgehogs, pigs, moles) and invertebrates (ground beetles, snails, slugs) prey on them. Earthworms reproduce and leave behind a small white cocoon birthing the fully formed worms.
Earthworms — not grubs — are a major food source for moles. In fact, grubs make up less than 10 percent of a mole’s diet. A grub control put down for mole prevention does work, but for the wrong reason.
Vermicomposting is a classic demonstration of the activity and benefit of worms and composting. Red Wigglers (Eisenia fetida) flourish in shredded newspaper and kitchen waste to produce the castings and urine cherished by plants. In a dark corner of a NYC apartment closet, with little care, I have seen the results, and some entertainment for the grandchildren.
“Graboids’” came from a writer’s mind. Worms came here from nature — many from the Europeans in plants, soil and ships’ ballast. Nature brought us these beneficial invertebrates. Let’s work to keep them around.
— Stan Ring is the Horticulture Program Assistant for K-State Research and Extension in Douglas County. Extension Master Gardeners can help with your gardening questions at 843-7058 or firstname.lastname@example.org.