page_title: Termite
section_title: Caste system
hierarchical_section_title: Termite / Description / Caste system
caption_attribution_description: English: Functional polymorphism in termites Italiano: Polimorfismo funzionale di casta nelle termiti A: en: Primary king - it: Re primario - fr: Roi principal B: en: Primary queen - it: Regina primaria - fr: Reine principale C: en: Secondary queen - it: Regina secondaria - fr: Reine secondaire D: en: Tertiary queen - it: Regina terziaria - fr: Reine tertiaire E: en: Soldiers - it: Soldati - fr: Soldats F: en: Worker - it: Operaia - fr: Ouvrier
context_page_description: Termites are eusocial insects that are classified at the taxonomic rank of infraorder Isoptera, or as epifamily Termitoidae within the order Blattodea. Termites were once classified in a separate order from cockroaches, but recent phylogenetic studies indicate that they evolved from cockroaches, as sister to Cryptocercus. Previous estimates suggested the divergence took place during the Jurassic or Triassic, however more recent estimates suggest they have an origin during the early Cretaceous with the first fossil records in the mid Cretaceous. About 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, and are not closely related to ants.
  Like ants and some bees and wasps from the separate order Hymenoptera, termites divide as "workers" and "soldiers" that are usually sterile. All 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.
context_section_description: Worker termites undertake the most labour within the colony, being responsible for foraging, food storage, and brood and nest maintenance. Workers are tasked with the digestion of cellulose in food and are thus the most likely caste to be found in infested wood. The process of worker termites feeding other nestmates is known as trophallaxis. Trophallaxis is an effective nutritional tactic to convert and recycle nitrogenous components. It frees the parents from feeding all but the first generation of offspring, allowing for the group to grow much larger and ensuring that the necessary gut symbionts are transferred from one generation to another. Some termite species may rely on nymphs to perform work without differentiating as a separate caste. Workers may be male or female and are usually sterile, especially in termites that have a nest site that is separate from their foraging site. Sterile workers are sometimes termed as true workers while those that are fertile, as in the wood-nesting Archotermopsidae, are termed as false workers.
  The soldier caste has anatomical and behavioural specialisations, and their sole purpose is to defend the colony. Many soldiers have large heads with highly modified powerful jaws so enlarged they cannot feed themselves. Instead, like juveniles, they are fed by workers. Fontanelles, simple holes in the forehead that exude defensive secretions, are a feature of the family Rhinotermitidae. Many species are readily identified using the characteristics of the soldiers' larger and darker head and large mandibles. Among certain termites, soldiers may use their globular (phragmotic) heads to block their narrow tunnels. Different sorts of soldiers include minor and major soldiers, and nasutes, which have a horn-like nozzle frontal projection (a nasus). These unique soldiers are able to spray noxious, sticky secretions containing diterpenes at their enemies. Nitrogen fixation plays an important role in nasute nutrition. Soldiers are usually sterile but some species of Archotermopsidae are known to have neotenic forms with soldier-like heads while also having sexual organs.
  The reproductive caste of a mature colony includes a fertile female and male, known as the queen and king. The queen of the colony is responsible for egg production for the colony. Unlike in ants, the king mates with her for life. In some species, the abdomen of the queen swells up dramatically to increase fecundity, a characteristic known as physogastrism. Depending on the species, the queen starts producing reproductive winged alates at a certain time of the year, and huge swarms emerge from the colony when nuptial flight begins. These swarms attract a wide variety of predators.
caption: Caste system of termites
   A – King
   B – Queen 
   C – Secondary queen
   D – Tertiary queen
   E – Soldiers 
   F – Worker
exif: {}