Termites are a major wood-destroying pest, particularly in the southern United States and Hawaii. According to some estimates, three times as many homes nationwide are damaged by termites compared to those damaged by fire. The cost of termite damage exceeds $1 billion. In North Carolina, our most serious termite problems are caused by subterranean termites. You can reduce the likelihood of damage to your home by understanding how these termites live and how termite control requires a joint effort by you and a pest control professional.

Termite Biology
Like ants, termites are social insects, i.e., they live in a nest or colony. As their name implies, these colonies are typically found underground, often near a tree or stump. The colony contains three forms or castes of individuals:
  1. Reproductives - come in several forms, but you are most likely to see the winged, primary reproductives, which are commonly called swarmers. They are usually a brown-black to pale reddish-brown color and about 1/4 to 3/8 inch long, with pale or smoke-gray wings. They can be confused with winged ants, but there are several distinct differences between them. A typical termite colony will have a single pair of reproductives (a "king" and "queen"). They remain in the nest and are fed by worker termites. Studies have shown that reproductive pairs can live 15-25 years.

  2. Workers - lack eyes and wings. They are white to grayish-white with a round, yellow-brown head and about 1/4 to 3/8 inch long. Their main function is to maintain the nest and forage for cellulose-based foods that they provide to the rest of the colony. Their foraging and feeding activities are what result in damage to structural wood.

  3. Soldiers - are also wingless and resemble workers except that they have large, rectangular, yellowish and brown heads with large mandibles (jaws). The sole purpose of the soldier is to defend the colony against enemies such as ants

Life Cycle and Habits

A mature queen can lay thousands of eggs each year. Workers tend these eggs during their two-week incubation period. The newly-emerged nymphs are fed regurgitated food by workers ("attendants"). After molting, these new nymphs become members of the working caste, and eventually mature to become workers, soldiers, or reproductives.

As the colony grows, the workers expand the nest and their feeding area. Contrary to what was once believed to be true, a termite colony does not usually occupy a single large underground nest. As the foraging area expands the colony will split into a number of small "nesting sites". Studies have shown that a mature colony will contain 200,000 to 2,000,000 workers, although many colonies may contain as few as 50,000-60,000. A single acre of land may be supporting as many as 12 termite colonies (although this doesn't mean they are invading your home).
Termite colony "nesting sites" (courtesy of Dow Agrosciences)

Termite colonies usually mature in about 3-6 years, at which time swarmers are produced. The swarmers leave the colony through "swarm castles". Swarming from a single colony usually occurs 3-6 years after the colonyoften occurs in several bursts that may take several days. The swarmers are poor fliers and usually move only a few yards from their emergence spot. Swarmers emerging outdoors from tree stumps, railroad ties, etc., are usually not of concern and are in no way an indication that the structure is infested. After dropping to the ground, they shed their wings. Surviving males and females find compatible mates, then burrow into the ground to become kings and queens of their own new colony. In some instances, a new colony forms from secondary reproductives who may not swarm and simply move out to form their own colony.

Workers need a high humidity to survive. Unlike ants, they do not forage out in open areas. Instead, they carry soil aboveground where they construct mud tubes (see "Signs of a Termite Infestation") onto surfaces and into the wood where they are feeding to maintain a high relative humidity and to protect them from predators as they forage. Termites can also move their colony up and down in the soil to find the optimal temperature and moisture conditions.

Termite Feeding Habits

Although termites feed on wood, they actually rely microscopic organisms called protozoa in their gut to digest the cellulose, the basic component of wood. Colony workers who forage for food bring it back to the nest where they secrete material from their mouths and anuses to feed the reproductives, soldiers and newly-hatched nymphs.