Bullet Western Subterranean Termites

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The subterranean termites are ground dwelling termites which nest in the soil, or in the wood or vegetable material in contact with the ground. They are able to reach wood or cellulose material above the ground level by means of earthen tubes which they build. Since these termites are dependent on moisture, they must always have a ground connection or an above ground source of moisture such as a plumbing leak. Unlike drywood and dampwood termites, their feces consist of liquid drops, not pellets, which characteristically spot their excavations in wood. In their galleries frass is found which is also characteristic. The frass consists of masticated wood and earth cemented together with saliva and liquid feces to form a mud-like cement. “Mud tubes” can come in many different looks and sizes. 

The sexually mature reproductives, known commonly as swarmers, bunch up inside near the exit hole. When the right combination of moisture, temperature, and light intensity is present, they swarm out of the colony and fly away to form a new colony. Their swarmers are not given off from a western subterranean termite colony until after the colony is 2 to 3 years old.

After the male and female reproductives (Alates) have swarmed from a colony, they pair off and attempt to establish a colony of their own. The successful pairs manage to excavate a cell. They seal the exit closed with bits of debris cemented together with the liquid fecal material. Copulation takes place only after this cell is prepared and sealed closed. The male (king) cohabits with the female (queen) throughout the life of the colony.

When a subterranean termite is hatched from the egg, it is called the First Instar Nymph. When it molts (sheds its exoskeleton) for the first time, it becomes a second instar nymph.

If the individual is destined to become a reproductive (alate), it will shed its skeleton six separate times to finally become a seventh instar stage which is the fully developed reproductive stage (swarmer or alate). After the fourth instar stage has been reached, those nymphs that are destined to become reproductives start to grow wing pads and otherwise differentiate from the worker caste. At each succeeding instar stage, the wings become more fully developed until they are quite well developed. Another molt and this individual will be a fully developed swarmer capable of mating and forming a new colony. A new colony does not produce swarmers until after its third year under good conditions. In an older colony, the transition from egg to adult usually takes from one to two years. Termites will eat anything made of cellulose. In addition to wooden members of the house, this includes books, other paper products, and furniture. Any structure with a cement slab floor can be easily invaded by subterranean termites, if it has a crack or an expansion joint running through it.

The winged reproductives are dark brown to brownish black and have two pairs of equal size wings that extend well beyond the body. Swarms are common in spring and fall, especially after a rain. After a flight, the winged males and females return to the ground and shed their wings. The wingless males and females pair off and search for sources of wood and moisture in soil. The royal couple digs a chamber in the soil near wood, enters the chamber and seals the opening. After mating, the queen starts laying eggs. The queen may live up to 25 years and lay more than 60,000 eggs in her lifetime. The eggs are yellowish white and hatch after an incubation of 50 to 60 days.

Full-grown workers are soft-bodied, wingless, blind and creamy white. In early stages, they are fed predigested food by the king and queen. Once workers are able to digest wood, they provide food for the entire colony. The workers perform all the labor in the colony such as obtaining food, feeding other caste members and immatures, excavating wood, and constructing tunnels. Workers mature within a year and live from 3 to 5 years.

Soldiers are creamy white, soft-bodied, wingless and blind. The head of the soldier is enormously elongated, brownish, hard and equipped with two jaws. Soldiers must be fed by workers because they cannot feed themselves. They are less numerous in the colony than workers and their only function is to defend the colony against invaders. Soldiers mature within a year and live up to 5 years.

Communication in the Colony

Termites communicate primarily by secreting chemicals called pheromones. Each colony develops its own characteristic odor. An intruder is instantly recognized and an alarm pheromone is secreted that triggers the soldiers to attack. If a worker finds a new source of food, it lays a chemical trail for others to follow. The proportion of termites in each caste within the colony is also regulated chemically. Nymphs or immatures can develop into workers, soldiers or reproductive adults depending on colony needs.

Sound is another means of communication. Soldiers and workers may bang their heads against the tunnels creating vibrations perceived by others in the colony and serving to mobilize the colony to defend itself. Mutual exchange of foods enhances recognition of colony members.

Evidence of Termite Infestations 
Wood damaged by termites always has remains of mud tubes attached to wood galleries or tunnels in an irregular pattern. The tunnels may contain broken mud particles with fecal materials. In the case of an active colony, white termites may be found in infested wood. The presence of flying winged males, females or their shed wings inside the building indicates an infestation. The presence of mud or shelter tubes extending from the ground to woodwork or on foundation walls also may indicate infestation. Workers travel periodically via shelter tubes to their nest to regain moisture and perform feeding duties. Each mud tube may very in size from the diameter of a lead pencil to the size of a large marker.

How Old is the Damage

Based on normal feeding activity, it takes 3 to 8 years to cause appreciable damage. There have been some predictions that, under ideal conditions, a termite colony of 60,000 workers may consume a one-foot length of 2" x 4" pine in 118 to 157 days.