What is an insect?

You can probably recognise and name a large number of insects, but what is an insect? What do all insects have in common?

You already know that insects are invertebrates. This only indicates that insects do not have an internal skeleton. You are more interested in what insects do have.

Now discover the things about an insect's appearance that make it different from anything else.

There are basically four features of insects that make them different from other animals - the body, eyes, antennae and legs. Look at each of these features, one at a time, to build a picture of an insect.

The insect body

An insect has an interesting body. It is divided into three distinctive parts - head , thorax and abdomen .

insect body

An insect's body

Incidentally, you have these parts too. The head is obvious. Your chest in your thorax - you might have heard the space for your lungs called your thoracic cavity. And your abdomen is your belly, below your tummy button.

Insect eyes

The second identification feature of insects is the eyes. Insects can see in all directions at once because they have two large eyes known as compound eyes . This is why insects such as flies are so hard to catch! Some insects even have another three eyes. These are smaller and on top of their heads.

insect with eyes

Insect antennae

The third feature of insects is the hair-like antennae. Some insects use their antennae for smelling!

insect with eyes and antennae

Insect with antennae

Insect legs

The last feature of insects is the easiest to observe - the legs.
If a creature is an insect then it must have six legs. These six legs are all attached to the thorax.

insect with eyes, antennae and legs

Insect legs

Now that you have built up a picture of an insect, list the four main features used to identify insects.

Lesson 15- Looking at insects

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