How Do Earthworms Reproduce?

The birds, the bees and the earthworms

Earthworms need to find a mate in order to reproduce. But they don't have to look far. Every other earthworm they meet is a potential partner, since earthworms are both male and female. They mate with whatever other earthworm they come across. Unlike many other species, earthworms do not put out any kind of call or scent to find a mate. As long as the temperature is over 50 degrees, all earthworms will be looking for love. It's thought that worms can detect when another worm is coming through the vibrations they make when crawling.

Copulation

Image from Wikimedia Commons

Both worms press against each other's sides, with their heads facing each other's tails. They both have four body openings, although three serve only to hold the worm together. You can thump the ground near a pair and they will not seperate. The other opening is where the exchange of sperm takes place and then stored for further use. The openings extend bristle-like organs called setae. This process can take up to three hours.

Fertilization and egg laying

The eggs aren't fertilzed by the sperm until slime is produced by the thickest part of the worm (called a clitellum). The earthworm crawls above ground and lays slimy egg sacks, called coccoons. It's in the coccoon that the eggs and sperm finally get together. They can be up to a 1/3 of an inch long. There are up to 15 eggs in the coccoon. Inside, the baby worms grow from eggs into tiny versions of their parents. When they're ready, they emerge from the cocoon and make their way into the world.

Resources

• Earthworms and Reproduction
• Earthworm Reproduction