Most of us know that earthworms live in the soil, so how do worms reproduce if they mostly live underground?
- Are worms viviparous or oviparous?
- Do they reproduce sexually or asexually?
- How many eggs/cocoons do they produce and how many baby worms inside?
These questions may not be difficult for the average worm farming enthusiast or people who are accustomed to rural life.
But for those who have lived in the city or are just getting involved in vermicomposting, they may not be 100% sure.
In this post, we’ll talk you through the reproduction method of earthworms and every other little detail (well, not every little detail – let’s give them SOME privacy!)
How do earthworms mate and lay eggs?
Although earthworms are hermaphrodites, the male reproductive parts mature faster than the female reproductive organs, thus making self-fertilization not possible.
Earthworms need a partner to reproduce.
When two mature earthworms mate, they secrete mucus to keep their abdomens close, while each face the opposite direction.
Like in this diagram below:
The reproductive fluid is discharged from the male genital pores and enters the female sperm sac of the other worm and they separate after a few hours.
Later, the fertilized earthworm will secrete a sticky substance in the ring zone (clitellum), which will become a cocoon afterwards.
Here’s a video of them in action:
At this time, the mature cocoon with the eggs will move from the female genital pores to the spermatheca hole (with sperm) so that the egg is fertilized in the cocoon.
Later, the fertilized cocoon leaves the body.
Below is an image of worm eggs or cocoons containing baby worms.
How many baby earthworms hatch out of each egg?
Each egg can produce 1-3 small earthworms.
How long does it take for earthworm eggs to hatch?
It takes around 1 month for each egg to hatch.
After hatching, the small earthworms also need to grow for about 1 month until they are sexually mature (can lay eggs).
You can see a more detailed data graph in the next section which covers many different worm species.
How often do worms reproduce and how many eggs do they lay?
After mating with another earthworm, both earthworms can lay eggs.
Artificially cultivated earthworms have a strong reproductive ability.
For example, the red wiggler worm, under good conditions, can lay two to four cocoons in a week.
(see our table further below for an average for most earthworm species)
Click image to enlarge
With such rapid reproduction and a large yield of earthworm babies, many people who are into worm farming often have the trouble of clearing enough space for the new explosion of earthworms.
Make sure you have another container, worm bin or worm farm ready to go!
Can earthworms reproduce by autotomy (self-amputation)?
We’ve spoken on Wormmy before about how earthworms can escape by autotomy or self-amputation. You can find out whether worms can regenerate < – in our previous post.
But is this a viable method of reproduction?
Not really. Earthworms are usually bitten by prey or sever themselves to escape and usually require a lot of energy and time to repair.
This self-healing process takes at least two weeks to one month.
And if the cut part is located in the 2/3 section of the head (near the clitellum), the probability that the earthworm can survive or regenerate into a complete earthworm again is drastically less likely.
This is because the important organs are located in the front half of the worm as you can see below:
In other words, if you divide the earthworm into two, although the blood pressure of the earthworm is low and they stop bleeding quickly, the tail-end that is cut off is difficult to regenerate.
As long as the front important organs are still intact, usually the head end can regenerate eventually.
They certainly do not turn into 2 separate worms and this isn’t a viable method of reproduction for earthworms.
Are Earthworms Oviparous or Viviparous?
First of all, it’s important to know that earthworms are oviparous.
Let’s talk about the meaning of oviparous and viviparous.
It’s quite simple.
Oviparous means that a species grows young outside of their body e.g. lays an egg or eggs and the embryo grows inside this egg.
Viviparous, on the other hand, means that the young grows inside the mother and is born live.
Compared with the viviparous animals at the top of the food chain, in order for the bottom of the food chain animals to thrive in a large environment, most small insects, reptiles and worms are oviparous animals, which helps them to reproduce in large quantities and ensures a greater chance of their species’ survival.
Are Earthworms Hermaphrodites?
Yes, the earthworm itself is a hermaphrodite, mean it has both male and female reproductive organs.