What is an insect?
This is an important question, because not every small animal is an insect. There are more than one million insect species known worldwide. More than half of all known species in the world are insects. Insects have all sorts of colors, shapes and sizes.
What are typical features of insects?
Insects have three body parts. The three body parts are head (front part), thorax (middle part), and abdomen (back part).
Insects have six legs. The legs of insects consist of several jointed parts. These legs connect to the thorax (=the middle part) and not to the abdomen as in many cartoons!
Insects have wings. Usually, insects have two pair of wings, but there are insect groups with one pair (e.g. flies) or even without wings (e.g. some ants). In contrast to other animal groups, insects have their wings in addition to their legs.
Insects have compound eyes. These eyes consist of many small components, so called ommatidia. These eyes have a large view angle and are very good in detecting movements. Some insects can see colors that are invisible for us, such as ultraviolet.
Insects have a pair of antennae (=feelers) connected to the head. With the antennae, insects can smell, taste, sense touch and detect much more.
Insects have a hard exoskeleton (=outside skeleton). This exoskeleton gives structure and protects the insects. Insects do not have bones inside the body. Since the exoskeleton is hard and inflexible, the insects shed their old exoskeleton when they grow.
Most insects undergo a process called metamorphosis. This means that the young insects (larvae) transform into adults, which often look very different. The advantage of a metamorphosis is that larvae and adults feed on different things and can live in different environments (e.g. fly larvae live in water; adult flies live on land).