Signs of Spring: Report Your Observations!

Earthworms

Life Cycle

Q. How do earthworms reproduce?

A. The clitellum produces a mucous sheath and nutritive material, and as the sheath slides forward, it picks up ova from the earthworm's ovaries then packets of sperm that had been transferred to the worm from another worm during mating. As the clitellum sheath slides off the worm's head, the ends are sealed to form the cocoon.

Q. What is an earthworm cocoon like?

A. At first, the cocoon is quite soft. Soon after it is deposited in the soil it becomes slightly amber, leather-like, and very resistant to drying and damage. Cocoons are very tiny, and the shape of a lemon. They can survive underground until conditions are right for hatching.

Q. What happens inside the cocoon?

A. The ova within each cocoon are fertilized, and the resulting embryos grow inside the sealed cocoon. It's similar to the way a chick develops inside an egg. When the embryos have consumed all the nutritive material, they completely fill the cocoon and are ready to hatch out one end.

Q. How long does it take worms to hatch?

A. Young worms hatch from their cocoons in three weeks to five months. The gestation period varies for different species of worms. It also depends on conditions like temperature and soil moisture. Hatching is delayed if conditions are poor, and cocoons may overwinter in soil to hatch in the spring.

Q. How many young come out of one cocoon?

A. Each cocoon holds from one to twenty fertilized ova or eggs-depending on the species and also nutrition of the adults laying them and environmental conditions like soil moisture. Usually only a few to several young worms successfully emerge from each cocoon.

Q. How many cocoons can an earthworms produce in a year?

A. Earthworms can produce between 3 and 80 cocoons per year depending on the species. The deeper-dwelling species don't have to produce as many cocoons because they are protected much better from predation. Surface-dwelling species tend to produce many more cocoons.

Q. How long does it take earthworms to mature?

A. Worms mature in 10 - 55 weeks, depending on the species.

Q. How long do earthworms live?

A. Certain species could live 4-8 years. It depends on predators and environmental conditions.