Are Worms Insects? (Is An Earthworm An Insect?)

are worms insects

There are a few key differences between insects and worms. However, there are also a few species that cross the lines between invertebrates and insects. 

In this article, we will see the differences between worms and insects, what makes worms invertebrates, and what these incredible invertebrate insects are, and what exactly makes them so unique. 

No, neither earthworms, nor any other kind of worm, is an insect. 

However, due to their small size, habitat, and nutrition, it is no wonder why people call worms insects in everyday language.

Is a worm a bug or an animal?

worms curled up

The term insect, or bug, is typically very loosely applied to any small or microscopic animal that we can find in the ground, on the surface of the soil, or even flying around us.

People commonly use the terms to encompass everything from

  • flatworms
  • tapeworms
  • roundworms
  • parasitic worms
  • bristle worms
  • velvet worms
  • teredo worms
  • spiders
  • centipedes
  • nematodes
  • parasites

And more!

In truth, worms are not insects at all. 

However, these little creatures and insects, too, all belong to the animal kingdom. 

There are six major animal groups: mammals, fish, birds, reptiles, amphibians, and invertebrates.

Whereas the other five categories of animals are vertebrates (meaning that they have a bone structure in their bodies), worms are intact invertebrates (meaning that they have no bone structure).

In this category, you will also find jellyfish, octopuses, coral, etc. 

Other invertebrate groups include invertebrate insects, too.

Insects are partially defined as being animals with bodies divided into three distinct areas: the head, the abdomen, and the thorax. 

Within the invertebrate insect family, you will find ants, bees, flies, the praying mantis, crickets, ladybirds and similar insects. 

There are plenty of other animals in this line, and they are perhaps seen as more diverse in look and behaviour than worms. But no – they are not worms.

What type of insect is a worm?

roundworms, flatworms and segmented worms

Although there are indeed invertebrate insects, worms definitely are not insects.

Even segmented worms (i.e. annelids) do not have the same distinct body sections that insects do. 

Worms are typically classified into three distinct groups.

The first group being flatworms

The second group being roundworms

The third group being segmented worms

Although each group consists of invertebrate animals, the worms vary in:

  • size
  • habitat (living habitats such as damp earth, the surface of the soil, or salt water, fresh water, etc.)
  • and nutrition (i.e. do they eat live organic matter or decaying substances)

Earthworms, in particular, are free-living segmented worms that live in the soil and feed on decaying organic matter.

They play a vitally important role in feeding other animal species, including some insects and directly or indirectly, all of the people living in the world! 

Although other worms can prove to be a detriment to nature, such as parasitic worms, the common earthworm is undeniably essential to life on earth. 

From the marine nemertean worm to the bootlace worm – they’re not insects at all.

Generally, if they are called worms, they are invertebrates. That goes for the African giant earthworm, spiny headed worms and more, too.

What is the difference between worm and insect?

As stated, worms are different from insects as their bodies do not have three distinct areas

Instead, they have elongated bodies that do not differ in size throughout the length.

Insects also have exoskeletons that are used to support their bodies.

Although the word “skeleton” will often make us think of bones and cartilage, exoskeletons are often made up of protein, calcium, and chitin.

This is the case with invertebrate insects such as ants, bees, ladybirds, etc. 

Another difference between worms and insects is that worms breathe through their skin.

Indeed, worms do not have lungs as we humans do.

That is why them being in a moist environment at all times is essential to their comfort and their survival. 

On the other hand, other invertebrates, such as invertebrate insects, breathe through their abdomen in tubes called the tracheae. 

Finally, insects often have six legs that are all jointed. This is also the case with invertebrate insects.

In contrast, worms do not have limbs. 


Overall, the term worm isn’t used to describe an insect. They are different.

When it comes to defining certain animals and differentiating them from one another, the task can seem a little daunting, especially comparing worms vs insects.

Many creatures have similar features, lifestyles, and diets, making us assume that they are a part of the same family, when in fact, they could not be more different. 

Earthworms happen to be in a league of their own called invertebrates. They are fascinating creatures that are quite literally responsible for life on earth.

However, their friends, the insects, play just as much of an important role, and invertebrate insects have their place in the circle of life, too. 

However, as long they live, all of these creatures have a role to play and need to be treated with as much respect as we would assume that we humans deserve.