Worms do not lay traditional eggs like birds or reptiles. Instead, they reproduce by laying cocoons, which are protective capsules containing developing worms. These cocoons serve a similar function to eggs, safeguarding the embryonic worms until they hatch.
How Worms Reproduce
Most worms, particularly earthworms, are hermaphroditic, possessing both male and female reproductive organs. Most species cannot self-fertilize and require a partner for reproduction. During mating, two worms align themselves, typically with their heads facing opposite directions, and exchange sperm.
A swollen, glandular band called the clitellum, located near the worm’s head, secretes a mucus ring after sperm exchange. As the worm moves forward, this ring slides off its head, collecting eggs from its female reproductive pores and stored sperm from its partner.
Fertilization occurs within this mucus ring as it detaches and seals, forming a protective cocoon. This cocoon, containing fertilized eggs, is then deposited into the soil. The cocoon’s formation functions as the equivalent of “laying eggs” for worms.
What Worm Cocoons Look Like
Worm cocoons resemble small seeds, typically lemon-shaped or oval with tapered ends. They are generally small, comparable to a grape seed.
When freshly laid, cocoons usually exhibit a light yellowish or golden color. As they mature, their color deepens, transitioning to shades of amber, golden brown, or reddish-brown. The texture of these cocoons is often described as leathery or papery, providing a durable casing. Each cocoon can contain multiple worms, commonly ranging from 1 to 20 depending on the species, though common composting worms often produce 1-3 worms per cocoon.
The Worm Life Cycle
The worm’s life cycle begins inside the protective cocoon. The incubation period varies based on species and environmental conditions like temperature and moisture, typically ranging from a few weeks to several months. Some cocoons can delay hatching and survive adverse conditions for extended periods.
When conditions are favorable, young worms, known as hatchlings, emerge from the cocoon. These hatchlings are miniature versions of adult worms and do not undergo larval stages. Upon hatching, they immediately begin to feed on organic matter.
As they feed and grow, hatchlings gradually darken in color and develop their characteristic segments. The time it takes for them to reach sexual maturity and develop a visible clitellum varies by species and conditions. Once mature, worms begin to reproduce.