Termite Castes

Subterranean termites are the most destructive insect pests of wood in the world. In the U.S. alone, they cause more than $2 billion in damage each year, more property damage than that caused by fire and windstorm combined.

Many Termite species are important in relation to our environment. They break down many dead trees, bush waste, and other wood materials that would otherwise accumulate. In doing so they replace the otherwise lost nutrients and minerals back into the soil.

Due to this natural hunger for dead or dying wood, Termites also present a serious risk to building owners when they attack the wooden elements of human structures - homes, business and warehouses. Their presence is not readily noticed because they hide their activity behind panel sheeting, tiles, or paint. Of the more than 3000-4000 species worldwide, approximately 5-10% are a significant menace to man.

Termites are social insects. They are similar to ants in their habits of living together and their small size, but similar to bees and wasps where they consist of several hierarchies which differ physically and in terms of duties to perform and have a well developed social order controlled by a Queen. The other members of a termite colony or castes are a king, workers, soldiers, reproductives and alates. All of these castes contribute in individual ways to growth and protection of a colony. Each colony can contain in excess of a million termites.

The Queen and King
The queen and king are the original winged reproductives (alates) that left the parent colony during the colonizing or dispersal flight. Their function in the colony is reproduction. After leaving the parents colony, they drop to the ground, shed their winds (de-alate), seek out a suitable nesting site, mate and commence to form a new colony. In the case of many of the subterranean species, moisture and decaying wood are critical during the very early period of development. Timber in moist ground or a rotting scar at the base of a tree is a favoured nesting area for a potential new colony. The king and queen will care for their young until sufficient workers and soldiers are able to take over the duties of the colony. In a well established colony, the queen's duty is solely egg laying, and her daily egg production has been estimated to be over 2,000.

For a species such as the destructive pest termite Coptotermes acinaciformis, to reach a potentially damaging stage from a single pair usually required 3-5 years, but this depends on the site, food and climatic conditions in the chosen environment.

The queen and king live for many years, often over 20, but as the queen ages, her reproductive capacity declines, and the colony may then select developing reproductives to assist the queen and king in their duties.
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The workers are males and females whose sexual organs and characteristics have not developed. They make up the largest number of individuals within a colony because they perform all the tasks except defence and reproduction. It is the Workers that do all of the work of the colony - feeding the other castes, grooming and queen, excavating the nest and making tunnels. In working, they chew and eat wood, causing the destruction that makes termites economically important.

They are blind, wingless and sterile, generally about 1/8 to 3/8 of an inch long, and they have a thin body covering (cuticle), which makes them susceptible to drying out (desiccation) when they leave the confines of the colony. Workers are the palest individuals in the colony, apart from the eggs and developing young.

Workers leave the security of the colony or the underground tunnels and shelter tubes only when the humidity is high, and then only to search for food sources.
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Soldiers resemble workers in colour and general appearance, except that soldiers have large, well-developed brownish heads with strong mandibles or jaws. Soldiers defend the colony against invaders, primarily ants and other termites.

Soldiers are abundant in species that have a large central colony system, but scarce in some other species. Sightless, they have no compound eyes, except in some primitive species where the eyes are poorly developed. Like workers, their cuticle is thin and they are susceptible to dessication and seldom leave the environmental security of the colony and shelter tubes.

There are two types of soldiers: Mandibulate and Nausate. Manibulate soldiers have large, obvious jaws or mandibles on the head, and Nausate soldiers have a large head that tapers to a point at the front. Their mandibles are small and hidden by the head when viewed from above. Rather than using their mandibles to attack, they are able to produce a sticky substance to entrap their enemies, leaving them vulnerable to attack.
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Reproductives are the sexual forms of a colony - the future kings and queens. The young (nymphs) of reproductives grow by successive skin shedding (molts) until they are fully winged alates in most species. Their cuticles are denser than that of the other castes, being more resistant to drying out when they leave the parent colony to establish new colonies.

Reproductive males are females can be winged (primary) or wingless (secondary or tertiary). Each can produce new offspring. The bodies of primary reproductives, also called swarmers or alates, vary by species from coal black to pale yellow-brown. Wings may be pale or smoky grey to brown and have few distinct veins. swarmers termites are about 1/4 to 3/8 of an inch long.

Secondary and tertiary reproductives in the colony are generally white to cream-coloured and may have short wing buds. Developed as needed, they replace a primary queen when she is injured or dies.

Colonizing flights often occur when the temperature and humidity outside is similar to that inside the colony. The warmer months of an areas season are usually selected for the colonizing flights, although it may differ depending on the species.
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Through the construction of tunnels both underground and over edges of concrete slabs, up subfloor walls and over or through items that appear in their way, they can travel a radius of at least 50 metres and to a depth of at least 300mm underneath the ground.

Shelter Tubes (commonly referred to as "Mudding" or "Leads") are built if they need to travel above ground over items to get to food and also to protect them from the dry air outside and other insect predators.
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