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The Formosan subterranean termite (Coptotermes formosanus) is often nicknamed the super-termite because of its destructive habits and the enormous size of the colonies. A single colony may contain several million individuals (whereas other subterranean termite species typically number several hundred thousand individuals) in extensive underground foraging galleries and tunnels. The queen, which lives about 15 years, is responsible for producing all the eggs for the colony, up to 2000 eggs a day. Colonies pose serious threats to any nearby structures (boats, high-rise condominiums, even live trees and crops). While they rapidly eat wood and lumber which is composed mostly of cellulose, they also attack asphalt and plastic and even some soft metals to some degree. Once established, Formosan subterranean termites are extremely difficult, if not impossible, to eradicate from an area. Like other termite species, C. formosanus are social insects and their colonies consist of three castes: workers (food gatherers), reproductives, and soldiers. When a colony grows large and splits, or if the colonies queen dies, up to 70,000 winged reproductives (alates) swarm from the nest and fly to mate and form a new colony. Alates are attracted to lights, and at night these insects can be seen as an impressive cloud, with the individuals being rapidly preyed on by lizards, birds, toads, ants and other predators.
Although C. formosanus was first described in Formosa, Taiwan in the early 1900s, this species is probably endemic to southern China. The Formosan subterranean termite invaded the continental United States in the 1960s, having been transported to South Africa about a decade earlier. Coptotermes formosanus is limited to warm and humid climates, and is restricted to ten of the most southern continental states in the US and to Hawaii, where it is a economically important insect pest. Control and repair of damage done by C. formosanus in New Orleans, which has been heavily infested, is estimated at an annual total of $300 million. In Hawaii, homes built over an established colony can be destroyed in just two years unless the home is protected. Traditional control methods usually involve infusing chemical termicides into the ground to create a barrier between the colony and the endangered structure. Depending on the type, termicides either repel the termites or kill them on contact. Another approach is to use baited traps around the surface of a structure. Termites then take the bait, which is laced with a pesticide that the termite transports back to other members of the colony.
The Formosan subterranean termite is often nicknamed the super-termite because of its destructive habits. This is because of the large size of its colonies, and the termites' ability to consume wood at a rapid rate. A single colony may contain several million individuals (compared with several hundred thousand termites for other subterranean termite species) that forage up to 300 feet (100 m) in soil. A mature Formosan colony can consume as much as 13 ounces of wood a day (ca. 400 g) and severely damage a structure in as little as three months. Because of its population size and foraging range, the presence of a colony poses serious threats to nearby structures. Once established, Formosan subterranean termites have never been eradicated from an area.
Formosan subterranean termites infest a wide variety of structures (including boats and high-rise condominiums) and can damage trees. In the United States, along other species, Coptotermes gestroi, also introduced from south east Asia, they are responsible for tremendous damage to property resulting in large treatment and repair costs.
C. formosanus is a generalist, colonial, social insect building colonies either above or below ground (Howarth 1985) and produces naphthalene as a protective poison. Termites have a caste system including: a king, queen, workers, soldiers, and reproductives or alates (winged termites). The workers provide the food, soldiers defend the nest, and reproductives breed the colony. The queen of the colony has a life span of approximately 15 years and is capable of producing up to 2,000 eggs per day. The workers and soldiers may live 3–5 years with caste proportions of approximately 360 workers: 40 soldiers (Grace et al. 1996a). A colony is surrounded by an extensive foraging system consisting of tunnels underneath the ground, with a mature colony containing millions of termites (Tulane 2002, ARS 2002). Grace et al. (1995) found older and less vigorous colonies contained workers who had a larger body mass than workers in younger colonies.
The diet of the subterranean termite consists of anything that contains wood fiber (homes, building, live trees), crops, and plants. Live trees include: Oak, Ash, and water-bound Cypress (ARS 2002). Crops include sugarcane (Broughton and Grace 1994).
Cabrera et al. (2001) found that "Like many other termites, the Formosan termite feeds on wood and other materials that contain cellulose, such as paper and cardboard. Bacteria and other single-celled organisms live in the termite digestive system and digest cellulose providing nutrition and energy for these termites. Although they feed mostly on wood, they will eat other cellulose-containing materials such as cardboard and paper. However, they are known to chew through foam insulation boards, thin lead and copper sheeting, plaster, asphalt, and some plastics."
Morales-Ramos and Rojas (2003) found that "colonies of C. formosanus feeding on pecan, Carya illinoensis (Wangenh.), and red gum, Liquidambar styraciflua L., produced significantly more progeny than colonies feeding on other wood species tested. Progeny of colonies feeding on pecan and American ash, Fraxinus americana L., had significantly greater survival than progeny of colonies feeding on other wood species. Colonies feeding on nutritionally supplemented cellulose based matrix showed similar fitness characteristics as colonies feeding on the best wood treatments. These results indicate that differences observed in colony fitness can be partially explained by nutritional value of the food treatment, raising the possibility that wood from different tree species have different nutritional values to the Formosan subterranean termites. This suggests that feeding preference of C. formosanus is at least partially influenced by the nutritional value of the food source."
Su and Scheffrahn (2000) report that, "A single colony of C. formosanus may produce over 70,000 alates. After a brief flight, alates shed their wings. Females immediately search for nesting sites with males following closely behind. When the pair find a moist crevice with wooden materials, they form the royal chamber and lay approximately 15 to 30 eggs. Within two to four weeks, young termites hatched from the eggs. The reproductives nurse the first group of young termites until they reach third instar. One to two months later, the queen lay the second batch eggs which would be eventually nursed by termites from the first egg batch. It may take three to five years before a colony reach substantial number to cause severe damage and produce alates."
Cabrera et al. (2001) state that, "After swarming and landing on the ground, the alates break off their wings and search for a mate. Once a mate is found, the male and female search for a crevice in damp ground or wood, hollow out a small chamber, and crawl inside. The pair, now known as the king and queen, mate and within a few days the queen starts laying eggs. The young, known as larvae, hatch from the eggs and are fed by the king and queen. A mature colony contains distinct groups called castes. These castes look different from one another and each has a special duty within the colony. The king and queen C. formosanus are the primary reproductives and are responsible for reproduction. If the queen or king dies or the colony becomes large, secondary reproductives may form and begin reproduction. Soldiers defend the colony against predators and other natural enemies. Workers take care of and feed the larvae, reproductives and soldiers, tend the eggs, build and maintain the nest, and search for food. Alate nymphs become alates when they are fully grown."
C. formosanus is the most economically serious pest in Hawaii, costing residents $100 million a year (Tulane 2002). Historic structures in Hawaii have been threatened, such as Iolani Palace in Honolulu (Grace et al. 2002).
C. formosanus has its greatest impact in North America. Lax and Osbrink (2003) states that, "C. formosanus Shiraki is currently one of the most destructive pests in the USA. It is estimated to cost consumers over US $1 billion annually for preventative and remedial treatment and to repair damage caused by this insect." In New Orleans, 30-50% of the city's 4,000 historic live Oak trees are believed to be infected with total damage costing the city $300 million a year (Tulane 2002). Raloff (2003) states that in North America C. formosanus, "create significantly bigger colonies, and therefore more damage, than do their native U.S. cousins, which reside underground and enter buildings only to forage." Fei and Henderson (2003) state that, "The Formosan subterranean termite, C. formosanus Shiraki is the most destructive, difficult to control and economically important species of termite in the southern United States."
Impacts of increased use of pesticides to control the termite population has led to higher costs for homeowners and destructive effects on the environment, including contamination of water supplies caused by runoff (Yates et al. 2000).