Earthworm
Lumbricus
terrestris
Phylum:
Annelida
Class:
Clitellata
Order: Lumbricina
Earthworm bodies
are divided
into
lots of different segments.
Earthworms play
an important
role in helping to keep soil in
good condition.
They help to recycle plant
material, and also mix oxygen
into the soil as they tunnel.
There are about 13 different types of earthworm in Britain.
Habitat
Earthworms prefer damp soil, and can be found all over the place, including woodland, grassland and gardens.
Because they need water to live and move, they go into a sleep-like state (aestivation) in the hot, dry summer periods. They do not wake for a couple of months.
Moving around
Earthworms move by contracting the circular muscles around their bodies, then the long muscles which run down their bodies.
When the circular muscles contract, the body becomes long and thin. Then, the long muscles contract, and the body changes shape to become short and fat.
This happens in waves down the body so that different parts of the worm's body touch the burrow walls. This helps to pull and push the worm along.
Like slugs and land snails, earthworms are mostly active at night, when it is cooler - so that they do not dry out in the sun. They come to the surface at night and when it rains.
Feeding
They eat: mainly dead plant material. Earthworms sometimes drag leaves into their burrows. They eat the soil and use the dead plant material from it as food.
They are eaten by: birds, hedgehogs, badgers, shrews, frogs and even foxes.
Reproduction
Each earthworm has both male and female reproductive organs, and is therefore known as a "hermaphrodite".
Mating worms lie head to head, usually above ground, during summer night times. They swap sperm with a partner, and store it in their female tract. When mature eggs are released, the stored sperm is released and fertilises the eggs.
The egg laying often begins the next day, and can last for months. The eggs are secreted out of the worm's "saddle", into a cocoon.
Breathing
The earthworm contains "haemoglobin" which is also found in human blood. It carries oxygen, and it is bright red. When it does not contain oxygen, it is purple. This "haemoglobin" is found in many animals. Amongst invertebrates, it is found in Daphnia, Midge larvae, Ramshorn Snails and Water Boatmen.
The common earthworm
can grow up to about
8 cm.
