Earthworms and Reproduction

Now that you’ve learned a little about the earthworm’s digestive system and are ready for more “juicy” details I'll tell you a little about earthworms and reproduction. I’m not going to indulge you in any graphic earthworm sex scenes, sorry, but I will give you information from a biological perspective on how they reproduce. They are truly fascinating creatures!

In order for nightcrawlers or earthworms to mate comfortably they must have a certain temperature. Anything 50 degrees are higher is too hot for the earthworm Once the surface soil heats up to 50 degrees or more the urge to find a mate ceases.

In Canada mating takes place almost all summer, but in the more southern areas of their territory most often it is early spring and late fall.

Although earthworms have both female and male sex organs, they still need to mate in order to reproduce. They cannot fertilize themselves. Not unlike the human race, worms go about finding a mate haphazardly. They sort of just stumble into their mate, relying on their extreme sensitivity, remember worms can’t see or hear, of detecting ground vibrations. They actually feel the ground vibrate or the grass move when another worm is moving through it. When the worm knows a potential mate is nearby he will start to search in the area with the tip of his body until he runs into the other worm. When they do touch the slide up next to each other and roll over on their sides—one facing left the other right.

Each worm has four pair of setae, these are like bristles on a hairbrush and can be extended out or retracted into the worm body. The third set of setae is used in the mating process. They are used to hold the earthworms together while mating. These setae actually penetrate the mate’s body during the mating act. Once they are in position, sperm from each worm passes to the other and is collected and stored in special sacks. The process lasts 2 to 3 hours! The earthworms separate and go back to their tunnels.

In the second part of the reproductive process, a special slimy substance is produced by the clitellum (some call this the sex band) the slime forms a tube around the earthworm. Then he crawls backwards into his tunnel and the slime tube slips forward off of his body. As it does, it passes over the male and female openings, the eggs (from the parent) and the sperm (from the mate) are released from the body. Fertilization takes place outside of the body, but within the protection of the slime tube. Once free in the soil, the slime tube dries, shrinks and forms a protective covering over the eggs. It is now called a cocoon.

The cocoons are deposited deep inside the worms tunnel below the frost line. The earthworms usually hatch within 30 to 60 days, but some cocoons can remain in the soil for years before the offspring appear! Eggs will remain in the cocoon almost forever. In fact, worms cannot release themselves from the cocoon. They must be set free from the outside. They will only hatch if and when the conditions are right for their survival. If there is not enough soil bacteria (the good kind) the worms will not be released. The bacteria itself decays the outer part of the cocoon allowing it to release the worms.

After they hatch it takes two to four years for the worm to reach sexual maturity. When they mature they can mate with any other earthworm they meet.

There you have it! Now ou can impress all your friends with these interesting worm facts.

If you like this article you might like my Worms and Digestion Article.

Earthworms are in the family Lumbricidae of the segmented worm phylum,Annelida. The scientific name for one common species is Lumbricus terrestris.