Insects have one pair of antennae on top of their heads. They have six legs (three pairs) Insects have one or two pairs of wings. Most insects can walk, but some can jump and fly. Insects represent about 90 percent of all life forms on earth and are incredibly adaptable organisms. Insects are invertebrates because they don't have a vertebral column (backbone). Instead, they have a hard exterior covering, called an exoskeleton. They have six legs and two antennae, and their body is made up of three main regions: head, thorax and abdomen. Many insects can fly and most have compound eyes. They typically have four separate life stages: egg, larvae or nymph, pupa and adult.