There are many groups of animals. Insects are in one group, called a Class. Most Insects share some traits.
Insects have several body traits that shows that they are insects. They have three body parts – a head, thorax and abdomen, one pair of antennae, two pairs of wings and three pairs of legs.
They often have large, compound eyes.
They grow up in one of two ways. Some undergo incomplete metamorphosis. This is when young hatch and look like miniature adults, called nymphs. As they grow, they shed their hard outer layer – their exoskeleton. Each new size is called an instar. Insects like grasshoppers grow this way.
Most insects, however, go through a complete metamorphosis. This is when the new hatchlings, called larvae, look completely different from the adults. They feed until they reach a certain size and then form a protective cocoon or chrysalis and pupate. During pupation their body breaks down and changes into the adult form. Insects like moths and butterflies grow this way.
Though many insects are pests, they also play important roles we cannot live without like pollinating our plants, decomposing waste, and producing things like honey and silk.
Insects are broken down into more than 25 smaller groups (Orders).