Worm Facts

DID YOU KNOW...?

Over half a million earthworms can live in just one hectare of soil. Together, they can eat nine tonnes of leaves, stems and dead roots a year, and turn over 36 tonnes of soil. Imagine how much dead matter would accumulate if all of the earthworms went on strike!

Worms are also beneficial to gardeners and fishers. The Dew-worm, or Nightcrawler (Lumbricus terrestris L.), is most favoured by these people. However, when introduced into new areas, this species can disrupt the native biodiversity. For example, forests in the northeastern United States of America are not regenerating because of changes caused to the soil habitat by this long-lived earthworm species (www.nrri.umn.edu/worms). When you are finished fishing, what do you think you should do with the worms that are left over?

Many famous people have recognized the ecosystem services that earthworms provide. Cleopatra declared earthworms to be sacred, and forbade Egyptian farmers from removing them from the land. Aristotle called them the “intestines of the soil.” Charles Darwin, who studied earthworms for 39 years, said, “It may be doubted whether there are many other animals in the world which have played so important a part in the history of the world than the earthworm.”

Native vs. Introduced species

Most members of the earthworm family (Lumbricidae) are thought to have disappeared from Canada during the last ice age. Native earthworms survived only in areas that were unglaciated, such as the west coast of British Columbia, parts of the Yukon, and the most southern parts of Eastern and Atlantic Canada. Many of the earthworms we find in Canada today were introduced by European settlers, who valued the ecosystem services provided by earthworms, particularly their role in producing good crops.

In Canada, there are three families of earthworms represented: Lumbricidae, Acanthodrilidae and the Sparganophilidae. There are some species of earthworms that are native to North America and Canada: Aporrectodea bowcrowensis, Bimastos lawrenceae, Arctiostrotus perrieri, Arctiostrotus vancouverensis, Toutellus oregonensis and Sparganophilus eiseni.

MYTHS ABOUT EARTHWORMS

Is it true that you can cut an earthworm in half and get two earthworms?

No, this is a myth. If you cut close to the end of the tail, the earthworm will regrow another tail. If the earthworm is severed anywhere else on its body, it will die. Please don’t test this myth …all living creatures deserve our respect!

MAKING THE SOIL HOME

Earthworms are known to scientists as “ecosystem engineers” because their presence and activities have such a dramatic effect on the soil habitat. The underground burrowing systems that they create increase the amount of water and air that reaches the plant roots and other soil organisms, helping their growth. Most earthworms also mix the plant litter and organic matter into the soil, increasing the speed at which they decay and release nutrients into the soil. In these ways, earthworms recycle nutrients from dead plants and other soil organisms so that they can be used again.