How Do They Reproduce?
Worms have a very interesting method of reproduction. There are no male and female worms – all worms are the same and each produce both sperm cells and egg cells.
When a worm is mature and ready to reproduce, it finds a partner worm. They line up head to head attaching themselves together at the clitella (the thick light colored band around each mature worm) and mucous is secreted . The sperm cells are exchanged by the worms through this mucous. After the worms separate, the clitellum on each worm secretes albumin (similar to egg-whites) which hardens to form a cocoon. The worm backs out of the cocoon-sort of like pulling a shirt off over your head. As the cocoon slides over the worm’s head, sperm and eggs that have been stored in that area of the worm’s body are squeezed out from small pores in the worm’s body into the cocoon.
The cocoon detaches from the worm. The ends close up sealing the eggs and sperm into the cocoon. Fertilization takes place in the cocoon and usually 2-4 baby worms develop in each cocoon. The cocoon may hatch in a month if conditions are good. If it is too dry, or cold, or hot, or whatever, the cocoon will become dormant like a seed and will not hatch until conditions are better.
Sometimes animals swallow worm cocoons and the cocoons pass through the animal’s digestive system. Then they are “pooped out” in the animal manure some distance away from where they were swallowed. This is one way worm populations spread to new areas.
Here are the reproductive rates of Eisenia foetida (Red Wiggler Worm) from an excellent reference book “Biology and Ecology of Earthworms” by C.A. Edwards and P.J.Bohlen.
- Each worm produces 3-4 cocoons per week
- Approx 83% hatch.
- Approx 3 worms emerge from each cocoon.
- It takes 32- 73 days for a cocoon to hatch.
- It takes 53-76 days for the baby worm to mature and be ready to reproduce.
Photo of 2 worms linked to exchange sperm.
Here is a photo of 2 worm cocoons. Cocoons are round yellowish gold colored; about 2mm in diameter. In a well established worm bin cocoons are easy to find, but you must look closely.
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