Worms: Did You Know?
have no eyes or ears, but they have light-sensitive cells that
help them tell the difference between light and darkness. Their
are sensitive to vibrationsñand worms may "outrun" the
shovels of anglers digging worms for fish bait!
can be good for gardens and farmland. By tunneling through soil,
they drain water, bring in oxygen, and create space for plant roots.
night worms often come to the surface and deposit mounds of castings("worm
poop")ñ small pellet-like piles of organic matter that have
passed through the wormís digestive tract.
Darwin was one of the first to tell about the value of earthworms
to soil. He estimated that the earthworm castings on an average acre
could provide 1/5 inch of new surface soil per year.
of good garden or farm soil may be home to a million earthworms.
earthworms always here? Yes and no. During the time that
glaciers covered much of North America, earthworms disappeared
from the frozen soil. It would have taken centuries or longer
for earthworms to become re-established on their own, but
human actions speeded up the process. Farmers and gardeners
brought potted plants from other places for planting, inadvertently
releasing earthworms that were in that soil. And when farmers
tilled the soil to make it easier for tiny roots to grow,
they also made it easier for the worms to tunnel through
the soil. As worms increased, so did robins. In 1932, a scientist
named Frank Farley found that robins had increased 100 percent
in Alberta. Canada in the 50 years since the 1880s.
get their nutrition from many forms of organic
matter in soil. They eat decaying roots and
leaves, and tiny organisms such as nematodes,
protozoans, rotifers, bacteria, and fungi.
Worms also feed on the decomposing remains
of other animals. An earthworm can consume
up to one-third of its own body weight in
just one day!