Termites are eusocial insects that are classified at the taxonomic rank of infraorder Isoptera, or as epifamily Termitoidae within the cockroach order Blattodea. Termites were once classified in a separate order from cockroaches, but recent phylogenetic studies indicate that they evolved from close ancestors of cockroaches during the Jurassic or Triassic. It is possible, however, that the first termites emerged during the Late Permian or even the Carboniferous. Approximately 3,106 species are currently described, with a few hundred more left to be described. Although these insects are often called white ants, they are not ants.
Like ants and some bees and wasps, which are in a separate order, Hymenoptera, termites divide labour among castes that consist of sterile male and female "workers" and "soldiers". All termite colonies have fertile males called "kings" and one or more fertile females called "queens". Termites mostly feed on dead plant material and cellulose, generally in the form of wood, leaf litter, soil, or animal dung. Termites are major detritivores, particularly in the subtropical and tropical regions, and their recycling of wood and plant matter is of considerable ecological importance.
Termites are among the most successful groups of insects on Earth, colonising most landmasses except for Antarctica. Their colonies range in size from a couple of hundred individuals to enormous societies with several million individuals. Termite queens have the longest lifespan of any insect in the world, with some queens living up to 50 years. Unlike ants, which undergo a complete metamorphosis, each individual termite goes through an incomplete metamorphosis that proceeds through egg, nymph and adult stages. Colonies are described as superorganisms because the termites form part of a self-regulating entity: the colony itself.