Earthworms spend their life underground, slithering around mud and sand, and you only ever see them if you’re gardening, at the beach, or looking really really closely at the floor. But have you ever wondered how they were born?
They’re fascinating creatures, almost alien-looking if you stop to think about it, so how does it work? Are there males and females? How do they mate? And how are they born? Do they maybe lay eggs?
We can answer all these questions and more, so you will know exactly how worms are born and how it all happens. Let’s get right into it!
Do worms lay eggs?
Let’s start with one of the biggest questions, do worms lay eggs?
The answer is yes! Worms are born by hatching out of little eggs. Although scientifically speaking, it’s more of a cocoon than an egg!
But basically, worms lay eggs, and then more worms are born out of these eggs. As for the exact process, we’ll get into that next!
How do worms mate with each other?
Okay, let’s get into the interesting stuff: how worms mate with each other so that the eggs can be a thing and more worms are born.
Basically, the anatomy of a worm includes a part called the clitellum, and this can be identified by it being an orange or light pink band near the head that stands out from the rest of the body.
This clitellum doesn’t actually form until the worms are around six weeks old, but when it does, inside the clitellum there are both male and female reproductive organs.
For the mating to occur, two worms join together, by coming into contact and joining both of their clitellum, with their heads pointing in different opposite directions. Once the worms touch and they’re connected at the clitellum, then they both exude a mucous membrane.
This mucous membrane then envelopes them completely, protecting them throughout the duration of the mating. Meanwhile, inside the membrane, the worms exchange sperm.
Each worm will then store the sperm they have received from the other worm, inside their seminal receptacle. And once this is nicely stored away, the mating ritual is complete.
The worms will then separate, leaving the membrane behind, and they will both go on with their lives as usual. Well, not quite as usual, because both of these worms will not go on to the next stage: preparing the cocoon and filling it with the eggs! So yeah, both worms will have baby worms.
How do worms give birth?
Okay so first of all let’s clarify one thing: worms technically don’t give birth, because they lay eggs, and therefore they are not birthing live-born worms. Although in a way, we suppose you could refer to laying the eggs as giving birth to them in some way.
But anyway, the process of “giving birth” to the worm eggs, begins as soon as the two mated worms separate and go their own way.
As soon as the worms separate, they begin to individually form a new mucous membrane, shaped like a tube, which is then moved so that it passes over the area of the worm’s anatomy where the eggs are contained. The eggs then stick to the inside of the tube, as it travels over them, and on towards the head of the worm.
The mucous tube then reaches the seminal receptacle, where the sperm of the other worm has been stored. So this also gets added to the mucous tube, and it comes into contact with the eggs, causing them to be fertilized so that the eggs will provide new baby worms.
The mucous tube with the now fertilized eggs makes its way off the worm, and as it does, the end gets sealed off so that the eggs are protected. Inside, on average, there will be between 1 to 20 worm embryos, so that will be the number of new baby worms.
The gestation of these fertilized worm eggs takes between 2 to 11 weeks, and the mucous cocoon membrane is what provides all of the necessary and vital nutrients to sustain these eggs. Once the gestation is complete, the worms will hatch out of the eggs, leave the membrane cocoon, and they will burrow themselves into the soil, where they will grow and develop a life of their own.
Something that is quite fascinating about the whole process, is that the cocoon membrane can sense whether the conditions are right or not for the worms to be born.
So, for example, if the soil is too dry, then the cocoon will purposefully stay dormant for months, waiting. And once the conditions are right, then it will have the worms hatch out of their eggs. So in a way, it’s like the cocoon is aware of its surroundings, and it wants to make sure the time is right for the baby worms to be born.
What are worm eggs like?
Now that you know that worms lay their eggs by leaving them in a cocoon somewhere around where they’ve been, you might be wondering what they look like, to see if you can spot one in your garden.
Depending on the species of worm, the cocoon can be slightly different in appearance, so sometimes it’s easier to spot them, sometimes harder.
Some cocoons are very small, kind of like a grain of rice in size, while some can be slightly bigger and therefore easier to see. Most earthworm egg cocoons will be yellow or white, and then they will turn a deep yellow or gold as the gestation period progresses.
Worm eggs of all sizes will tend to harden and deepen in color, so that they become brown or dark red, right before they are ready to hatch. So you can use the color to determine how soon worms are going to hatch.
However, keep in mind that less than half of the potential worm hatchlings usually survive, so even though some cocoons are bigger, it is still not a guarantee that you will see lots and lots of baby worms.
What do baby worms look like?
Once the worm eggs have hatched, if you’re lucky to be there on time, you will be able to see baby worms! But what do they look like?
Baby worms that are newly hatched are almost translucent, with a whitish sort of color. On average, they are between one-half to one inch long. They have skinny bodies, so they are pretty hard to spot. (In fact, sometimes if there’s a bunch of baby worms, the soil just looks like it has a hairy fungal growth when really it’s all the baby worms together!)
After a few hours of being born, the worms gain hemoglobin, and they turn from white to pink, sometimes even red. They start to look like adult worms, but without the clitellum band, as this will not form until around 6 weeks of age.
Are there genders in worms?
After finding out about how worms mate with one another, but both worms have babies because both worms have the eggs but also both worms are giving each other the sperm, you might be slightly confused as to how gender works with them. The thing is, there is no male and female for worms.
Instead, worms are simultaneous hermaphrodites. This means that every worm has both female and male reproductive organs, so they are both at the same time.
The worms still need one another in order to mate and reproduce, so they can’t self reproduce despite having both organs. They need another worm to provide the sperm for their eggs, while they simultaneously provide the sperm for the other worm’s eggs.
However, there are some species of worms that are parthenogenic hermaphrodites, which essentially means that they reproduce by using only their own reproductive organs. This comes in handy when mating isn’t possible, like when they can’t come in contact with another worm.
And if that wasn’t enough, most worms can also regenerate parts of their anatomy and body, if they get cut off or damaged in any way. So no matter what, worms will find a way to reproduce, and keep the species going!