Three out of four animal are insects. They have been living on Earth for over 400 years and have to climate and other changes. Today, scientists are discovering new insects every day.

Insects have a shell, called , which protects them. Their body is made up of three main parts : head, abdomen and . Their eyes can have thousands of separate , which give them very good eyesight. They smell and feel with their antennae. It makes them helpless when .

Although many insects live alone there are species that live in groups or . Ants, bees and live in organized societies with a leader, a king or a queen. Each member has a certain job to do.

Some species go through very fundamental changes during their life . After from an egg they become a and take on a wormlike shape. In this stage insects eat a lot, grow quickly and . After growth insects rest and become a , out of which adults .

Many insects are very to humans. They eat other insects that fields and crops. Some insects, like bees , produce , a valuable product. Flowers and plants rely on insects to spread and reproduce. Harmful insects are of malaria and other tropical .