The Formosan Subterranean Termite- Genus Coptotermes

I. History
The termite of the most economical importance in the state of Hawaii is the Formosan subterranean termite, Coptotermes formosanus. Even though it was officially recorded in Honolulu in 1913 by Swezey, there is evidence that the termite was established at least by 1907 because there are alates in a collection at the Bishop Museum dated in 1907. The collection was made in an area of Honolulu away from the waterfront, so the alates must have come from a colony in the city. Going further back into history, in an old newspaper article published by the Pacific Commercial Advertiser of 31 July 1869 there was a description of the insect, the swarm, and a damaged fence (Tamashiro, Yates, and Ebesu). Evidently the termite first became established along the waterfront in Honolulu. There it spread throughout Honolulu following utility poles lines and streetcar routes. Some observers believe that swarming termites may have been attracted to the lights of the streetcars where they hitched a ride and were dispersed along the route (Zimmerman, 1948). It is suspected that the termite was brought to the islands from Formosa or China during the era when there was extensive trade between the Kingdom of Hawaii and China. It is likely that it arrived in a potted plant.

Since its introduction to Honolulu during the 19th century the Formosan subterranean termite has scattered throughout Oahu virtually anywhere there has been development and currently numbering at epidemic proportions having caused millions of dollars in property damage. The termite has spread to Hawaii (1925), Kauai (1929), Lanai (1932), was introduced into Maui in 1933, eradicated, then reintroduced in the late 1940s or early 1950s. The termite was found on Molokai in 1975. It is found throughout most of Kauai but is restricted to seaports or to areas surrounding seaports on the other islands. The natural spread of this termite after establishment in a new area is slow. The termite is a very poor flier and requires human assistance to move more than several hundred feet a year (Tamashiro, Yates, and Ebesu). The primary mode of transport between islands has been by ship. Potential source materials include wooden skips or palettes, poles, wood from old homes, wooden packing crates and similar items (Yates and Tamashiro).

Recently, at the University of Hawaii a technique called "allozyme electrophoresis" was used to evaluate the genetic similarity of different Formosan subterranean termite colonies on Oahu and Maui. The researchers found that the colonies were virtually identical at this genetic level, suggesting that they might all be descended from a single "founder colony" introduced to Honolulu in the 1800s. This possibility was also supported by a two-year study of chemicals found on the cuticle (skin) of termites from different colonies (Termite Times July 1993).

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II. The Caste System
The subterranean termites are very social insects with each colony observing a strict caste system. Every effort of each member is directed toward the common welfare and survival of the colony and is among the most sophisticated in the insect world. Each group has its own well-defined duties. They are either building, feeding, defending, or propagating which they carry out for the whole of their lives.

The first caste produced and by far the largest in the termite colony are the workers. These individuals have their sexual systems underdeveloped or aborted and their entire existence is guided by an unfailing instinct for continuous labor (Zimmerman 1948). They are creamy white, thin skinned, blind, small and quick-moving. Their description gives rise to the misnomer, "white ants". They perform all the tasks in maintaining the colony. They construct tunnels, excavate chambers, forage for food, feed the king, queen, soldiers, and young, take care of the eggs, maintain the nursery, open and close the flights slits for swarming, and bury or cannibalize abnormal or injured colony members. They are susceptible to drying so they work within tunnels and galleries. The workers can live for four or five years. These are the members of the colony that are responsible for all the damage (Yates and Tamashiro).

The next caste are the soldiers. They have a hard, brown, fearsome, armored head with jaws that look like pinchers. These jaws are only for fighting and are so specialized that they cannot be used to chew food, so the soldiers also must be fed by the workers (Yates and Tamashiro). Their major function is to protect the colony from all predators. If a termite tunnel or chamber is breached, an internal alarm is sounded, which calls the soldiers to the break. They will fight any invader that attempts to enter. Most of the predators are ants. Their jaws are able to break an ant in half. When they bite, the soldiers eject a sticky, white latex-like liquid through a pore in the top of their heads. This substance hinders the movement of any enemy. The soldiers will stay in the exposed area until the workers repair the break. During swarming They are found in great numbers when the flight slits are opened to protect against intruders.

The third caste to be produced are the alates. During a certain time each year a number of eggs for these reproductives are laid by the queen. These are the only sexed termites. The eggs are laid so that they will mature at just the right time for swarming during the warmer humid months. They are dark brown and have a longer flatter body than the worker termites and have four long narrow wings. (Flick) The alates have compound eyes, whereas the other castes are blind. These are the caste members with which we are all familiar as we observe them swarming around streetlights or the lights outside and inside our homes.

The alates take to the air to begin new colonies in the same manner as the dry wood termites. Once they shed their wings, find a mate, the pair then finds their physical niche and starts their new colony. In less than a week after the king and queen mate, the first eggs are laid in a batch of about twenty. The eggs hatch in three to four weeks. The young nymphs are fed by the two adults because they are not able to eat undigested food.

These Formosan termites are able to eat cellulose containing products because of three symbiotic protozoa, Pseudotrichonympha grassi, Holomastigotoides hartmanni, and Sperotrichonympha leidyi, which are found in the alimentary tract of termites and turn the cellulose into simple sugars.

The young are cared for by the king and the queen as they remain in the nursery until they go through two molts. After this, the young are able to forage for themselves. They will continue to grow, molt, and develop into either workers or soldiers. The queen will then lay another batch of eggs. This group and all subsequent groups will be fed, cared for, and will acquire the necessary protozoa from the workers and not the queen.
Eventually the queen develops a very distended abdomen which precludes her from being mobile. She becomes little more than an egg laying machine. She measures about 1" in length, 1/4" in diameter. She weighs more than 100 times her original weight. She appears unusual or gross because all of the growth is in the abdomen. This produces a strange looking insect with a huge abdomen attached to a tiny head, thorax, and legs (Yates and Tamashiro). She is constantly being cared for by the other termites in the colony and at her peak she is capable of laying an egg per minute. In this way the colony will gradually develop into having several million termites within a period of more than seven years. The king which mated with her originally also grows in size but to a much lesser degree. His role is to continue fertilizing her eggs. The two of them may live for twenty years.

If for some reason, the king and queen, or primary reproductives, are removed or are lost by some accident of nature then replacement reproductives will take over the job of procreation.

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III. Habitat
In order for the Formosan termite to survive there are three basic requirements that must be met. These requirements are proper food, adequate moisture, and an environment that would be properly prepared for their shelter. The termite’s food, which is cellulose, is found in the cell walls of all plants. Any plant or plant product, such as wood, paper, canec fruits, nuts, cork or living plants, can serve (Yates and Tamashiro). In Honolulu old redwood in the ground (normally a fairly resistant wood), Metrosideros ("ohia lehua"), "Celotex," "Canec," " Masonite," coconut and a number of other woods and wood products have been reported attacked. Clothing and bolts of cloth, cotton, books, all kinds of paper, even heavily tarred paper, and such materials are damaged severely when accessible (Zimmerman, 1948). The termite's primary food, however, is wood. The symbiotic protozoa that live inside the termite's body assists in the breaking down of the cellulose so the termite is able to live.

Protein is another important ingredient in the termite diet. One readily available source is the bodies of dead termites. Another is the product of the unique fungus gardens often found in a termite nest. Inside these galleries, combs are constructed of the termite fecal matter (droppings). The relatively high humidity and temperature in these enclosed areas are ideal conditions for fungal spores to develop, providing the essential food supplement (Flick).

Moisture is the next essential for survival. The termite does not require a free source of water. High humidity will suffice. Moisture can come from normal soil moisture, poor drainage, leaking roofs or plumbing, condensation from air conditioners or pipes, water on poorly designed decks and roofs or similar sources (Yates and Tamashiro). The species normally has a subterranean nest, but if a constant source of moisture is available in buildings, even several stories above the ground, no contact with the soil is needed for a nest to be constructed. Nests are not infrequently found on the roofs of concrete buildings. These termites carry damp soil into their extended runways in order to maintain proper humidity. Nests are found at the bases of utility poles, tree stumps, or near some other underground food source. Strong colonies may be established in boats, ships, barges, dredges, water tanks, piers or any similar place where moisture and cellulose are available. The structure of the is made of "carton." This term has been applied to the friable substance constructed of soil and masticated woody substances cemented together by saliva and excrement of the termites. (Zimmerman, 1948). Unlike the drywood termite the Formosan termite does not pitch its fecal pellets but rather utilizes it in the construction of its residence. Therefore, its presence is not detectable by property owners. Extensive damage may have already taken place prior to discovery of a colony.

The third essential for a Formosan termite colony to thrive is proper shelter. The king and queen are unable to set up their home on bare, smooth surfaces. They will need a warm, moist area, such as a buried fence post or the base of an old tree stump. A totally controlled environment is required so they will burrow down and seal the entry point. The nest is expanded with countless tunnels and chambers. The queen's chamber is deep and central within the colony. In times of drought the nest may be developed deeper into the ground to preserve the humidity and temperature. It is thought that the growth of the spores in the fungus gardens also helps to regulate these environmental factors (Flick).

As the original food source diminishes, tunnels are built underground in search of new stumps, logs etc. This is the stage of real threat to building, fences and other property. In their quest for food, the termites will build covered "runways" from the ground over foundations and ant-capping and along pipes. Sometimes the runways are even free-standing to reach above ground wood sources. These runways are enclosed to preserve the atmosphere of the nest, shield the termites from light and protect them from natural predators. They are built of a mud-like substance which is in fact the feces of the termites tightly compacted and molded by the workers (Flick).

Termites will follow minute cracks and flaws in concrete slabs or piers and it is known that they will penetrate a surprising variety of material in order to reach wood. Once the new wood is located, the colony virtually excavates the whole of the inside leaving only a honeycomb of tunnel walls and the outer layer which preserves the controlled atmosphere. The destruction is devastating and can be remarkably quick (Flick).

These termites are a formidable pest because of their adaptability. This species, once introduced to Hawaii's tropical climate, has adapted to building nests wherever they find food, moisture and shelter. There has been a dramatic increase in the incidence of aerial colonies of this termite. This is especially true in high rise roofs. Termites get carried to the roof tops of building on the winds. There they pair off and crawl under the roofing material. There is usually wood used to bolt roof-top equipment to and this provides the food. They can live here for several years before entering the penthouse units through openings in the roof.

A nest was found on the roof of a twenty-story condominium in Makiki and another one was found on the roof of a building at the Dole Cannery. Neither of these was a supplementary nest. The alates had flown or been carried there by the wind. They had somehow managed to find each other and get down through the pitch and gravel roof. Once there, they worked their way down through the concrete building following the wiring and plumbing eating any wood they found along the way. A most unusual nest was discovered in the attic crawlspace of a garage in Maunawili. Dozens of corrugate boxes had been taken apart, flattened, and stacked one on top of the other. This contained the perfect place for the alates to crawl into and built a nest. The house and garage were built from untreated lumber so there was an adequate supply of food. The boxes were stacked in the center of the attic so there was no moisture source nearby despite Maunawili being a very wet area. There was, however, one mud tunnel which led from the nest over to the lowest edge of the roof. It ended there and was saturated from the constant runoff of rain. One could only surmise that the termites used this for their water source as the remainder of the attic was quite dry.

In a house in Kailua I discovered an extensive ground termite infestation that had entered through the slab in several areas. In the master bathroom they entered around the drain for the shower and traveled along the carpet tack strips in the bedroom until they came to the plywood frame of the waterbed. They had done minimal damage to the wood but had eaten through the plastic liner and then through the thick plastic bladder to provide themselves with a secondary source of water. They opened a hole only large enough to allow water to seep out without draining the mattress. My observation here and repeated elsewhere is that termites possess an ‘intelligence’ that we don’t completely comprehend. They knew that by penetrating the bladder of the waterbed they would find a water source that would allow them to establish a secondary nest. Also, they did minimal damage to the plywood frame so it did not collapse under the weight of the water. Again, it has been my observation that termites do not damage structural members of a house to the point of collapse. This would expose them to their predators. I have seen beams split open from termite damage usually but only after the termites have departed.

Conducive conditions
Here we have a house with a wooden exterior that extends to the ground around it allowing termites easy access to the house. To compound the situation the wooden fence post is anchored down in the soil and nailed to the house and the downspout keeps the area wet. The vegetation is too close to the house prohibiting an easy inspection.

Soil-to-wood contact
This post-and-beam house, made with pressure treated posts, beams and floor joists, had no soil-to-wood contact except for this one two-by-four. The ground termites found it, traveled through the redwood tongue-and-groove to the untreated window frame which they destroyed and up to the attic and severely damaged about a dozen rafters that were also untreated.

Form boards left in place
When a concrete foundation or slab is poured wooden form boards are used to contain it. Too often they are left in place and ground termites find them. Once they are consumed they move on to the rest of the house.

Plants too close to the house
This tree and the plants grew too close to the house and termites used it as a bridge into the structure. Note that the beam protruding from the side of the house is completely hollow and split open.

Concrete poured around a wood post
This post that supports a lanai roof was siting on a concrete slab. Another slab was poured around it and ground termites entered through a the small crack visible at the left and infested the post. The homeowner was completely unaware of the extensive damage since the termites stayed in the center of the post and did not expose themselves.

The right way
This is the proper way to support a wood post. There is a termite shield under the post, a ‘tofu’ block under the shield and a concrete foundation that sits about eight inches above grade. The post is pressure treated lumber. All this makes this post impregnable to termites.

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IV Predators
Termites have many predators. Perhaps the most dangerous enemies to non-swarming termites in Hawaii are ants, several species of which attack termites whenever there is an opportunity. Pheidole megacephala is particularly likely to inflict heavy casualties. However, under normal circumstances the termites are well protected from attacks by ants. It is usually only when some accident befalls a colony that it is exposed to attack by ants in Hawaii. Ground termite colonies that are well established often have too many individuals to adversely affected even by constant predation by ants. At the time of swarming reproductives are most vulnerable to attack. If swarming takes place in daylight (as it does occasionally, although it normally takes place at night), dragon-flies, skinks, mynah birds bulbuls and sparrows gorge themselves on the flying termites. At night geckoes and Bufo toads take over the slaughter. Geckoes are particularly helpful in reducing the numbers which might enter houses by taking up their hunting stations on windows, screens and ceilings and capturing with insatiable appetites the swarming termites which are attracted to lights. The singe native Hawaiian bat is rare and local in habit and is not regularly attracted to the lowlands where termites are abundant. Pemberton (1928:147) found a lepismatid, a type of silverfish, living in the nests and galleries of certain termites in Borneo and feeding upon the termite eggs and nymphs. A single attempt to introduce the species into Hawaii did not succeed because of the death of the small colony before the specimens could be released. There have been no really effective methods of biological control of termites found. There was some work done with nematodes on the Mainland but did not prove to be effective and to the best of my knowledge was never tried here. The small Hawaiian snake, Ramphotyphlopsw braminus, is capable of eating large quantities of termites and is small enough to enter the ground termite nests. For those not familiar with it the snake is usually four to six inches and is a shiny dark gray, almost black. They are quite thin and at first glance some people think they are an earthworm. They have no eyes but can be recognized as a snake by the tongue that constantly flits out to detect prey or predators. Interestingly, all of the species is parthenogenic. All females and they can reproduce without being fertilized by a male which helps insure their survival.

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V Geographical Distribution
Termites are exceedingly abundant, they are found throughout the tropical and sub-tropical areas of the world, and in some areas extending into the temperate regions. Two species, Reticulitermes lucifugus and Kalotermes flavicollis, are found in Europe but they do not appear to thrive farther north than Paris in France, except that a third species, Reticulitermes flavipes, a few colonies of an introduced termite, still maintain themselves in the basements of warehouses in Hamburg. Another species, Zootermopsis angusticollis, is found extensively on the Pacific coast of Canada. The nearer to the equator one travels so the number of species and the total number of termites increase, so that in very large areas of the world cellulosic materials (all material of vegetable origin) are being constantly destroyed by termites (Hickin, 1971).
Millions of tons of wood are utilized annually world-wide. The developed countries use far more wood than underdeveloped countries. Since a substantial proportion of the people in developed countries enjoy a higher standard of living with the majority of residences and various buildings constructed of lumber, a higher magnitude of problems occur with termites. The following countries are just some of the many that are battling termite infestation: Australia, Bahamas (Nassau), Barbados, Hong Kong, Kenya (Nairobi), Malaysia (Kuala Lumpur and throughout West Malaysia), New Zealand, Philippines (Manila), Singapore, Trinidad (Port of Spain) and the United States. Elaborate as to which states.

Throughout the Pacific Rim there are countries and islands that have been infested with the Formosan subterranean termite. Pan American World Airlines used Midway as a refueling point from 1935 through 1947 on its Trans-Pacific route from San Francisco to Honolulu, Midway, Wake, Guam and Manila. Part of Pan Am's beautification program was the introduction of 100 tons of soil from Guam in 1935. Although the soil was certified to be free of "parasites, animals or vegetables," it was undoubtedly the start of the Formosan Subterranean termite on Midway. Termite infestations have spread to most of the structures on both islands. The battle of Midway June 4-6, 1942, severely damaged and destroyed most of the above ground facilities. However, following this battle and through 1945, the facilities greatly increased and new construction started.(Beal, 1985)
In 1957, a $40,000,000 building program was started on Midway with little or no preventive termite treatments. This, of course, led to a large build-up of termite problems. As early as 1970, extremely large flights of alates were disrupting outdoor lighted recreation events on warm May and June evenings. Infestations of Coptotermes formosanus could be found in most wooden structures during the 1960's and 1970's, and when high winds broke off or blew over ironwood trees, evidence of C. formosanus could be found in the center of the trees. Many trees in the housing area are under attack as is evidenced by the mud tubing coming to the surface of scars on the trees. In May 1984, Navy personnel conducted a thorough inspection of approximately 50 usable buildings on Sand Island. C. formosanus was found infesting 85 percent of the buildings in varying degrees. Some infestations are so severe that major structural repair may be required (Beal, 1985).

Because of its relatively warm climate, the south-western part of Japan is a suitable habitat of the Formosan subterranean termite. The oldest reliable record, dated 300 years ago, state that is termite was called "Do-toos" (temple or shrine destroyer) due to its enormous destructivety. Before World War II, the Formosan subterranean termite was found in only 2 areas of Japan; one facing the Pacific (Shizouka Pref.), the other on the Sea of Japan (Yamaguchi Pref.). The status of the latter has not changed since the war, however, several new Pacific outbreaks associated with U.S. military bases in Kanagawa have occurred. These sudden and sporadic introductions were probably all started by humans who unknowingly transported lumber containing live termites. This is conceivable since the present law only requires logs imported into Japan be fumigated with methyl bromide, while cut lumber may be brought in without fumigation. Beside Kanagawa Prefecture, the Formosan subterranean termite also appeared after the war in Chichijima in the Bonin Islands, where it is presently thriving and has spread to nearby Hahajima (Mori, 1985).

Termite damage in Japan is severe because many building are made of wood. However, when compare with the Japanese termite, Reticulitermes speratus (Kolbe), the number of cases caused by the Formosan subterranean termite are rather few. No nation-wide data are available, but according to a survey conducted by our agency between 1971-73, about 94% of the incidents of termite infestation were cause by the Japanese termite and only 5.8% were by the Formosan subterranean termite. This may be due to the fact that most of the buildings surveyed were located inland distant from the coast. In terms of damage severity, however, the Formosan subterranean termite is a far more serious pest and lives up to its ancient reputation. That is, there are many buildings which have been destroyed by the Formosan subterranean termite, but none destroyed by
R. Speratus (Mori, 1985).

Species of the genus Coptotermes are widely distributed in China; with a northern boundary line in Jianhu County, Jiangsu Province (N.33 0 44'), the southern in Shanhu Island, Xisha Islands, Guangdong Province, the eastern in Taiwan Province, and the western in the Cichuan Basin. Although several Coptotermes species are known in China, most infestations are attributed to C. formosanus. Populations of C. formosanus colonies are so large that serious damage results from attacks on goods in storage, railroad cars, boats, ships, buried communication cables, crops, and forest trees, etc. Species of the genera Odontotermes and Macrotermes are the main pests attacking earth dams of reservoirs, but C. formosanus also occasionally builds nests in earth dams. The cavities and galleries formed within a dam may result in its failure (Gao, 1985).

Although the identified termite species in China has been increased from 17 to 201 between 1935 and 1983, among then Coptotermes has always been the most severe pest to human economic activities. According to a survey of 23 cities in China, the infested area has reached 22,200,000 m2, causing a loss of about 0.33 billion Chinese yuan. In addition, many famous wooden monuments and relics are attacked by Coptotermes to some extent. Furniture, clothes, sleepers, boats, landscape gardens, cables, rubber, agricultural crops as well as metal products also suffer attacks from Coptotermes. The Chinese government has considered termite damage a serious problem. In addition to the southern provinces of the Yangzhi River, the main regions with termite distribution, termite control units have been formed in the larger cities of the northern China such a Beijing, Tianjin, Dalian, and Qingdao. Provincial termite control societies have also been formed in Guangdong, Anhui, and Zhejiang provinces in the south. Termite control research stations have become common at a county level in some provinces. In 1983, the National Cooperation Center for Termite Control and Research was formed. The first issue of "Science and Technology of Termites" edited by the center was published in 1984. There are four termites research groups belonging to the Center which organize the cooperation research and solve the problems of common interest with 18 research institutes of the cities. In general, the progress of the termite control and research program has paralleled the economic development of China (Lin, 1985).

Some of our country's southern states in the Gulf of Mexico region have reported termite infestations. In 1980, a well-established colony of the Formosan subterranean termite, Coptotermes formosanus was confirmed in a condominium in Hallandale, Florida. Following this discovery, 7 nearby condominiums and 1 house were also found infested. During 1982-83 survey, C.R. Thompson used light and sticky traps to collect alates of C. formosanus. Swarmers were taken over an area bordering 155 km2 in Broward and Dade counties. In 1984, two remote infestations surfaced in Orange and Escambia counties of Florida. A large swarm was reported from the Escambia infestation in May 1985, however, the active infestation could not be located by stake survey. The newest citing in April 1985, occurred on a wooden boat docked in Palm Beach county. This infestation was located ca.100 km north of Port Everglades, the northeast boundary of the C. formosanus survey conducted by C.R. Thompson. Because no land infestation had been reported in the West Palm Beach area, this incident implies a maritime mode of introduction for C. Formosanus (Su and Scheffrahan, 1985).

The Formosan subterranean termite, Coptotermes formosanus, was first discovered in Louisiana by pest-control operators in the spring of 1966. Two widely separated but apparently well-established infestations were found in Lake Charles and New Orleans suggesting that two independent introductions had occurred several years earlier. Because these infestations had become locally widespread and were found near or on military installations, I speculate that C. formosanus may have entered Louisiana near the end of the Second World War on military transport ships returning from the Orient. Although additional infestations have been reported in the state, none has become as serious as the original ones (Fage, 1985).

Other then when wood is used to satisfy human needs, termites, together with other wood-destroying organisms play a wholly beneficial role. They then function as scavengers, boring into, breaking up, and digesting woody tissue. The products of their activity are available, either directly or indirectly through the activities of other organisms as a contribution towards the nutritional requirements of a succeeding generation of trees.

If we examine the total bio-system of tropical and sub-tropical areas, the number of termites present is of the greatest magnitude and their activity and effect are likewise immense. This great importance of the termites in the bio-deterioration of woody tissue in the areas of the world where they abound is not always apparent to the untrained observer, due to their light-avoiding behavior, except in the brief period of their nuptial flight (Hickin, 1971).

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