What are the Different Types of Insect Species?

Insects are a class of organisms that contains more than a million known species, making it one of the most diverse known classes of organisms. There are several traits that all insect species have in common: a three-part body, chitinous shell, six legs, two antennae, and compound eyes. There are also many differences; some, for example, move by walking while others primarily move by flying. Even with the million known insect species, scientists theorize that there could be millions more. In addition to being very diverse, insects are also extremely numerous: more than half of the organisms on Earth are believed to be insects.

Insect species are subdivided into many different groups based on many different traits, such as body size or the absence or presence of wings. One group of insect species, characterized by lack of wings and thin, almost translucent skin is referred to as apterygota. The pterygota subclass, on the other hand, contains winged insects and insects whose ancestors possessed wings. Most insect species, including lice, moths, and earwigs, belong to the pterygota subclass.

The oldest known class of insect species is referred to as archaeognatha, and like apterygota, it contains small, wingless insects. While the mandibles of most insects have joints with two parts, archaeognatha insects have mandibles with joints containing only one part. Evolutionarily, they have progressed very little — modern archaeognatha are not much different from the first archaeognatha. Archaeognatha species can survive in a wide range of climates — some even live in the harsh, cold conditions of the Arctic. One specific example of an archaeognatha species is the petrobius maritimus, or shore bristletail; these small insects live on rocky shorelines around the Mediterranean and North seas.

Neoptera, another subgroup of insects, contains some of the most recognizable and well-known insect species in the world. Species included in neoptera have wings that they can flex back over their abdomens, such as wasps, flies, and beetles. This is in contrast to the palaeoptera subclass of insect species, which includes primitive winged insects that are unable to flex their wings over their abdomens, such as mayflies and damselflies.

The study of insects is referred to as entomology, and the study of insect classification is known as systematic entomology. Entomologists are still discovering new species of insects at a very high rate. Many believe that there are still millions of species left to discover.