A termite inspector usually discovers the approximate location of a colony of Subterranean Termites by the presence of earthlike tubes. These are called shelter tubes and usually are the color of the soil type. These tubes allow the workers to seek food while remaining somewhat protected. Tubes may be constructed for other purposed. Besides the working tubes, there are swarming tubes and exploratory tubes. The swarming tubes are usually found free standing in a warm location such as below a floor furnace. The exploratory tubes are made in an attempt to reach soil without returning to the working tube which may have reached a great length, These tubes are lighter in color than the working or swarming tube.
The damage to wood created by Subterranean Termite attack always follows the grain of the wood. This termite obtains its food from the cellulose which is digestible. The lignin is indigestible therefore is avoided. This accounts for the pattern created by subterranean Termite attack. The sapwood is more attractive as food than the heartwood. The sapwood contains more starch and sugar, and the heartwood more lignin. The texture of the surface of the wood damaged by Subterranean Termites appears roughly scarred. There is also present a fecal smear on the surface of the tunnels within the wood. This is caused by liquid droplets contained by the feces of the termites. This fecal smear always spots the surface of the wood fed upon.
Dependant on soil moisture, therefore they nest in soil of wood in contacts with soil, they reach wood not in contact with soil through earthen tubes.
Subterranean Termite colonies may reach several million. Swarms cannot be expected before the end of the third year.
The Subterranean Termite Alate (swarmer) has a black body with two pair of light grey wings. The wings are longer than the body. Upon emergence the flight of alates is short and weak. The male and female are attracted to each other only after the wings are shed.
The Subterranean Termite worker is soft bodied, creamy white and maggot like in appearance. The case is blind and wingless. It may be male of female and often when a colony is opened there may be some individuals which appear to be longer than the workers and have small wing pads beginning to form. These are premature reproductives. The workers performs all of the work in a colony including constructing tubes, excavating chambers, obtaining food, feeding the young, soldiers and the queen. It also grooms the queen and cares for the eggs.
The Subterranean Termite soldier has an elongated head. It is longer than the rest of the thorax and abdomen. The head is pigmented but is slightly paler in color than the Drywood Termite soldier. The head is equipped with 2 large mandibles having curved tips. Their sole purpose is to defend the colony against invasion. The hard head may be used to plug up an opening in a broken tube. They are expendable and may be sealed off outside the tube while they are performing their duties of defending the colony.
The mandibles of the soldiers are designed to fighting other insects which may invade the colony. They can actually cut another insect in half. When handling these soldiers, one may experience a pinch of the skin of the hand. This pinch can be felt quite plainly when handling the soldier of the Dampwood species.