Medically termites are grouped under the order Isoptera. Termites have a highly advanced social organization and hierarchical structure. They are also public, and can be found in colonies of different sizes. Termites are social insects that live in colonies. The termite social structure is organized into a caste system based on termites’ unique roles.
Like ants, and some bees and wasps—which are all placed in the separate order Hymenoptera—termites divide labor among castes, produce overlapping generations and take care of young collectively. Termites mostly feed on dead plant material, generally in the form of wood, leaf litter, soil, or animal dung, and about 10% of the estimated 4,000 species (about 3,106 taxonomically known) are economically significant as pests that can cause serious structural damage to buildings, crops or plantation forests. Termites are major detritivores, particularly in the subtropical and tropical regions, and their recycling of wood and other plant matter is of considerable ecological importance.
As eusocial insects, termites live in colonies that, at maturity, number from several hundred to several million individuals. Termites communicate during a variety of behavioral activities with signals. Colonies use decentralised, self-organised systems of activity guided by swarm intelligence which exploit food sources and environments unavailable to any single insect acting alone. A typical colony contains nymphs (semimature young), workers, soldiers, and reproductive individuals of both sexes, sometimes containing several egg-laying queens.
Termite Social Structure
There are three levels in the termite caste system:
Reproductives: The reproductives class includes primary reproductives (the king, queen and swarmer termites) and secondary reproductives (the primary source of egg production supporting the queen, once the colony is established). The king and queen are the colony’s founders and are responsible for increasing the colony’s population. When weather conditions are optimal, the queen produces many primary reproductive (called swarmers or alates) that fly out of the colony to start new colonies.
Soldiers: Soldier termites are responsible for defending the colony from invaders, such as ants.
Workers: Worker termites are responsible for building and repairing mud tubes and tunnel walls, feeding other termites in the colony, caring for eggs, removing mold and mildew from tunnel walls, and removing dead termites from the colony.
Termites develop into their assigned caste, reproductive, soldier or worker, to further the development of the colony. These needs continue to evolve based on the colony’s growth rate, size and stability, so each termite may have been a member of at least two different castes at different points in its lifetime.
Behavior of Termites
Termite behavior is determined by the colony’s current need for survival, such as food, protection or reproduction.
Foraging for Food
Worker termites spend a great deal of time foraging for food, and their foraging expeditions can cover a very large area. Formosan termites (a species of subterranean termite) may cover up to 1.5 acres and distances of more than 300 feet while foraging, while other subterranean termite species cover up to half an acre and distances of nearly 260 feet.
Communicating Inside the Colony
Since termites are blind, they communicate through vibrations and pheromones (chemical signals). Pheromones support the termite social structure, as these insects recognize nest mates by scent. Each colony develops its own scent. Termites can secrete pheromones to mark the trail to food or alert the colony to danger.
Some termites also communicate by banging their heads against tunnel walls. The vibrations caused by head-banging notify worker termites when holes in the tunnels need to be repaired. Vibrations also summon soldier termites when ants or other termite enemies invade.
Swarming to Start New Colonies
Swarming is the most visible sign of termite behavior around homes. Termites swarm in order to mate and start new colonies. Subterranean termite colonies can produce thousands of swarmers, while others species of termites, such as drywood termites, produce fewer swarmers and may have less noticeable swarms.
How cast differentiation is regulated?
In a termite colony cast differentiation is regulated by a number of individuals of the cast and the colony size. In a colony, the presence of one or two soldiers influences the formation of other soldiers. The workers of both sexes are larger or smaller in size, of white colour, wingless appearance, broad headed and remain sterile. Coloured wingless sterile soldiers of both sexes of large, medium and small sizes are seen in the colony. The presence of a pair of primary reproductives in a colony, produces a pheromone from their anus, which is circulated in the food and enters the other larval bodies, which in turn pass it to the other individuals through their anal discharge.
What Do Termites Look Like?
Termites range in size from 1/8 inch to 1 inch long. Termites vary in color from white to brown to black, depending on the species and the life stage of the particular termite.
Across most species of termites, a worker termite looks like an insect in the larval stage. Worker termites have soft exteriors and tend to be white or pale brown. (Drywood termites do not have a specific worker caste and instead, rely on nymphs to perform the typical “worker” role.)
Soldier termites have the same soft bodies as worker termites, but with much larger heads that have a hard exterior and large, well-developed mandibles (jaws).
In the alate stage, termites look like flying ants. However, these insects can be distinguished by inspecting their wings, antennae and abdomen. Termites have straight antennae and two sets of wings that are equal length. They also have two body segments with a straight abdomen. Ants have antennae that bend in the middle, two sets of wings of different lengths and three body segments with a very narrow waist.
What Is the Termite Diet?
Termites are generally grouped according to their nesting and feeding habits. Therefore the commonly used general groupings are subterranean, soil-dwelling, drywood, dampwood, and grass-eating. Of these, subterraneans and drywoods are primarily responsible for damage to human-made structures.
All termites eat cellulose in its various forms as plant fibre. Cellulose is a rich energy source (as demonstrated by the amount of energy released when wood is burned), but remains difficult to digest. Termites rely primarily upon symbiotic protozoa (metamonads) such as Trichonympha, and other microbes in their guts to digest the cellulose for them and absorb the end products for their own use. Gut protozoa, such as Trichonympha, in turn, rely on symbiotic bacteria embedded on their surfaces to produce some of the necessary digestive enzymes. This relationship is one of the finest examples of mutualism among animals. Most so-called higher termites, especially in the family Termitidae, can produce their own cellulase enzymes. However, they still retain a rich gut fauna and primarily rely upon the bacteria. Owing to closely related bacterial species, it is strongly presumed that the termites’ gut flora is descended from the gut flora of the ancestral wood-eating cockroaches, like those of the genus Cryptocercus.
Some species of termite practice fungiculture. They maintain a “garden” of specialized fungi of genus Termitomyces, which are nourished by the excrement of the insects. When the fungi are eaten, their spores pass undamaged through the intestines of the termites to complete the cycle by germinating in the fresh faecal pellets.They are also well known for eating smaller insects in a last resort environment.
Termite workers build and maintain nests which house the colony. These are elaborate structures made using a combination of soil, mud, chewed wood/cellulose, saliva, and faeces. A nest has many functions such as providing a protected living space and water conservation (through controlled condensation). There are nursery chambers deep within the nest where eggs and first instar larvae are tended. Some species maintain fungal gardens that are fed on collected plant matter, providing a nutritious mycelium on which the colony then feeds.
Mounds (also known as “termitaria” occur when an aboveground nest grows beyond its initially concealing surface. They are commonly called “ant hills” in Africa and Australia, despite the technical incorrectness of that name.
Termites are weak and relatively fragile insects that need to stay moist to survive. They can be overpowered by ants and other predators when exposed. They avoid these perils by covering their trails with tubing made of feces, plant matter, saliva, and soil. Thus, the termites can remain hidden and wall out unfavourable environmental conditions. Sometimes these shelter tubes will extend for many metres, such as up the outside of a tree reaching from the soil to dead branches.