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Coptotermes formosanus (Shiraki)

Formosan Subterranean termite
Hosts Distribution Damage Biology Behavior Management Reference

Author

Julian R. Yates III

Extension Urban Entomologist

College of Tropical Agriculture and Human Resources

University of Hawaii at Manoa

HOSTS

Cellulosic materials (wood, paper, plants, trees, etc.)

DISTRIBUTION

The current world distribution of this pest now includes: China, Taiwan, Japan, Guam, Midway, Hawaii, Sri Lanka, South Africa, and the continental United States including Texas, Louisiana, South Carolina, Florida, Mississippi, Alabama and Tennessee (Su and Tamashiro, 1987). The distribution of this termite has dramatically increased in the last 20 years. Since its introduction, the termite has spread to all of the major islands: Hawaii (1925), Kauai (1929), Lanai (1932), Maui (1933) and Molokai (1975). The original infestations on Maui and Lanai were eradicated, but the termite was reintroduced to both islands in the late 1940s or early 1950s. The Formosan subterranean termite is now found throughout most of Oahu and Kauai but is still limited to seaports or areas surrounding seaports on the other islands. On Hawaii, it is now found in the Hilo and Kona; on Maui in Kahului and Wailuku with isolated infestations in Maalaea, and Kihei; on Molokai in Kaunakakai and Kalaupapa and at the Kaumalapau Harbor on Lanai.

DAMAGE

In spite of its relatively limited distribution, it is, by far, the most economically damaging pest in Hawaii. The cost to prevent and/or control infestations and to repair the damage caused by this pest has been conservatively estimated at more than $60 million a year. Moreover, this cost will probably increase as (a) the termite moves into areas in Hawaii where it does not occur (b) the colony density increases in areas where the termite does occur (c) the values of the existing buildings increase and (d) additional buildings are constructed putting more buildings at risk.

Much of the loss is due to the aggressive but secretive nature of attack by this pest. There will be little or no external evidence of attack. Often, the first indication of an infestation is a sagging floor or door, leaking roof, warping of walls, hollow sounding beams, short circuits, telecommunication blackouts, etc. Moreover, they can cause a great deal of damage in a relatively short time because of the large numbers of aggressive termites involved in the attack. Colonies of ground termite in Hawaii average over 2 million individuals with large colonies exceeding 10 million. Unprotected homes built over strong existing colonies have been almost completely destroyed in 2 years. Prevention and/or early detection of infestations, therefore, is critical with this pest. This requires detailed knowledge of the biology and habits of this termite.

BIOLOGY

Swarmers are attracted to lights. In major swarms, thousands of termites can be seen around street lights or the lights in or around houses. After a short flight, the termites land on the ground and drop their wings. The wings break off close to the termite's body when it folds them up and forward.

The wingless adults pair off and move about in tandem, with the male following the female. They are searching for a place to live (physical niche). Fortunately, very few of the pairs survive to start new colonies. Most of the swarmers are eaten by geckos, spiders, chameleons, toads, ants, or other predators. Those that escape being eaten still have the problem of finding the right conditions to survive. These must include food, moisture, and shelter.

EGGS

The first batch of 15-25 eggs is laid about five days after the male and female mate within a sealed mating chamber. The eggs hatch in 21-30 days.

WORKERS

Can live for four or more years.

ADULTS

No information available.

BEHAVIOR

This termite is known to have major swarms occurring in May and June, but small flights can occur at any time of the year. Swarming is the primary way the termite naturally spreads after it has been transported to a new area. Three elements are needed for swarming to be effective: 1) Proper food resources (cellulose and wood), 2) moisture, and 3) a physical niche.

As the colony grows, specialized castes are produced for the different tasks required. The first caste produced are the workers. These are small, white, blind, and quick-moving. They perform all of the tasks required to maintain a colony. THey forage for food, feed the king, queen, soldiers, and young, take care of the eggs, maintain the nursery, build tunnels and carton nests, open and close the flight slits for swarming, and bury or cannibalize abnormal or injured colony members. They are very susceptible to drying, so they work within tunnels and galleries. The workers can live for four or more years. They are responsible for all of the damage caused by termites. The great majority of the individuals in a colony are workers.

The second caste produced are the soliders. They have hard, brown heads with jaws that look like pincers. These jaws are strictly for fighting ad are so specialized that they cannot be used to chew food, so the soldiers also must be fed by the workers.

The soldiers' job is to defend the colony against all enemies. Whenever there is a break in a tunnel, an internal alarm is triggered, which summons the soldiers to the break. The soldiers congregate around the break and bite any invader that tries to enter. When they bite, the soldiers can also eject a white latex-like liquid through a pore at the top of their heads. This sticky material can hinder the movement of enemies. The soldiers will stay in the exposed area until the workers repair the break. They will also fan out and protect the area around the open flight slits when the swarmers leave the nest.

The third caste to appear are the reproductives. Two types, primary and supplementary, are produced in a Formosan subterranean termite colony. The two types have different functions. Primary reproductives swarm and start new colonies. They are called alates or swarmers. They are brown, and they have wings and functional eyes. The skin of the primary is thick so the termites can swarm and survive in a dry environment for many days.

Although thousands of primary reproductives are produced each year, they all leave the nest. Primaries cannot become reproductive if they remain in their colony of origin. In a Formosan colony, the only primaries that reproduce are the original king and queen that started the colony.

Supplementary reproductives, on the other hand, can become reproductive only in the colonies in which they were born. Supplementaries are wingless, blind, and lighter in color that the primaries. They never leave the colony. They take over reproduction when the primary king or queen dies or becomes separated from the main colony. It takes many supplementaries to equal the productivity of a pair of primaries.

MANAGEMENT

Although control measures, such as treating the soil with insecticides, may cut off the part of the colony attacking a house from the reproductives in the ground, it does not necessarily mean that the infestation in the house will die out.

NON-CHEMICAL CONTROL

When swarming starts, turn off your lights to reduce the attractiveness of your home. If there are many swarmers inside your house, look around for flight slits inside to be sure that the termites are not coming from an infestation in your home. Kill any tandem pairs you find. They will be seen running around after the swarming has stopped. Periodically, inspect in and around your home for evidence of infestations. Keep the area immediately adjacent to your house clear of plants, so you can see the base of the slab or pier. Plants in the area not only will screen the tunnels but also will set up ideal conditions for the termites. The plants will provide the food, and you will provide the moisture when you water them. Avoid having any wood or wooden part of the house touching the ground. The termites will come through the piece directly into the house. If you live in an unifested area, do not transport materials that may harbor the termites from infested areas without being sure that the material is termite-free. BTB

CHEMICAL CONTROL

Wood treatment, soil treatment, fumigation

REFERENCES

 

 

DEC/1992.

 

C-FORMOS

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