"Insect" first appears documented in English in 1601 in Holland's translation of Pliny.

Translations of Aristotle's term also form the usual word for "insect" in Welsh ( The evolutionary relationship of insects to other animal groups remains unclear.

Insects may be found in nearly all environments, although only a small number of species reside in the oceans, a habitat dominated by another arthropod group, crustaceans.

Insect growth is constrained by the inelastic exoskeleton and development involves a series of molts.

The immature stages can differ from the adults in structure, habit and habitat, and can include a passive pupal stage in those groups that undergo 4-stage metamorphosis (see holometabolism).

The oldest definitive insect fossil is the Devonian Rhyniognatha hirsti, from the 396-million-year-old Rhynie chert.

It may have superficially resembled a modern-day silverfish insect.

Lampyridae in the beetle order communicate with light.

Humans regard certain insects as pests, and attempt to control them using insecticides and a host of other techniques.Male moths can sense the pheromones of female moths over great distances.Other species communicate with sounds: crickets stridulate, or rub their wings together, to attract a mate and repel other males.Some species, such as water striders, are capable of walking on the surface of water.Insects are mostly solitary, but some, such as certain bees, ants and termites, are social and live in large, well-organized colonies.Some insects damage crops by feeding on sap, leaves or fruits. Some insects perform complex ecological roles; blow-flies, for example, help consume carrion but also spread diseases.