This column first appeared in The Environmentor Dec 2003
EARTHWORM FOLK TALE:
"What else can I eat?"
In Japan very long ago, some of the 800 Shinto gods were bored. They decided to create something interesting-- something that would have life.
All the gods worked separately, modeling their creations from living clay. While some created big creatures like horses or cows, others created tiny creatures like bugs.
The creatures were hungry. The gods told the horses and cows, "You are very big, so you will need to eat much. Eat the grass that grows everywhere." They told the rabbits and rats, "You can eat grass, too."
Next monkeys and squirrels came. "Because you are agile, you will climb trees and eat nuts." Birds and frogs don't have teeth, so the gods created soft mosquitoes and flies. But these had to eat, too.
The gods said to mosquitoes, "You, sip the blood of sleeping creatures!" The gods said to the flies, "You, eat garbage!" After that, the fishes came. "You can eat anything that you can get in your mouths." So fishes eat anything, even if it is their own eggs or young. By the time the human beings came, the gods were very tired and said, "You humans, eat anything you like!"
When the gods thought their job was finished, something else asked, "What can I eat?" It was the earthworm. One god said, "What are you? You have no eyes or nose. You have no face! I don't think I created you." Another god said, "I don't think I created that, either. But when we were creating other things, bits of the living clay must have dropped off from between our fingers. It has life, so we must let it live. But it looks very weak. So you, why don't you live under the ground?" And another god said, "You can eat the soil!"
The earthworm was smart. It didn't want to eat soil, but could not say so to the gods. Instead, it said, "After I eat soil, what can I eat?" The gods were surprised. They said, "You look ugly, but you are smart. So after you eat soil, you may come up to the surface and look around for something else to eat." And after every rain, earthworms come up from underground and look around.
The Good, the Bad, and the Grizzlies
Earthworms are a boon to the environment, right? They aerate the soil, recycle dead plant and animal matter into minerals and organic fiber, and provide food for other species from songbirds to grizzly bears. But it turns out that they can cause trouble when they invade other species' habitats.
Non-native earthworms in the northern forests of North America are devouring the "duff" layer, that bed of leaf litter that is normally decomposed by microbes and fungi. In addition to releasing minerals, the duff harbors small invertebrates and mammals and shelters spring ephemeral wild flowers like trillium and yellow violet. A fallen leaf normally takes three to five years to break down in the duff.
But night crawlers can gobble those leaves in as little as four weeks, leaving the forest floor bare. The small creatures are left homeless, while invasive plants such as wild garlic take the place of the spring wildflowers.
Until recently, no earthworms lived north of the "glacial line" which stretches from Washington State to Long Island, dipping below the Great Lakes into Ohio. The ancient ice sheets had killed native species of earthworms. Northern forests depended on duff microorganisms to recycle leaf litter.
But that changed several decades ago when fisherman began bringing sturdy earthworms such as the night crawler into northern fishing haunts. Minnesota, Wisconsin, Michigan, New York and Canada have reported forest duff loss due to earthworms. The evidence is clear: bald forest floor around lakes, boat landings, and resorts, while non-native worms are found in the duff edges.
What to do? The problem is so new that no one has ideas about how to control the invaders. Poisons and other drastic measures would threaten the native species biologists want to preserve. Grizzly bears are reported to consume large numbers of earthworms, but the people who have balked about reintroducing wolves into their forests are not likely to welcome grizzlies…
SUGGESTIONS FOR CLASSROOM DISCUSSION:
Study earthworm anatomy. They "have no faces" but are basically just a long intestinal tract with adaptive features. Their moist skin suits an underground environment but makes them vulnerable to light and dessication. Why DO they come out when it rains?
"What else can I eat?" Apartment dwellers can recycle vegetable scraps into compost by means of Vermicomposting in a plastic bin. But this process uses Florida Red Worms; vermicomposters are warned not to release them outdoors even (especially) in areas with native earthworms. Why?
Folktale -- "Mimisu Tuti Kuttara Nani Kuue" -- from The Folk Tales of Toshiko Endo pg 84 transcribed by Hiroko Fujita, adapted with permission by Fran Stallings.
Fact-tale -- Fran heard a short item about invading earthworms on NPR Morning Edition. A search for more details turned up "Foreign Worm Alert" by Adele Conover (August 2000 issue of Smithsonian magazine)
MORE WORM RESOURCES:
- http://www.WormWoman.com A wide variety of resources from Mary Appelhof, "the worm woman"
- "Worm Digest," Edible City Resource Center, P.O. Box 544, Eugene, OR 97440-9998
- "Worm Composting" ( a "how to" brochure). Susie Shields, 405/702- 5166, firstname.lastname@example.org . (Other materials for school worm composting are also available.)
- Dr. Sarah Kimball, OSU Extension, email@example.com