To achieve these conditions, they build airtight tunnels or passages from their nest to their feeding places. The tunnels are made by the workers from wood or soil particles cemented together with saliva and fecal material. A knowledge of these behavioral characteristics of termites is fundamental in achieving effective control. These termites are extremely tenacious. Even when metal caps and termite shields are placed over piers and foundation walls to prevent them from reaching the wood, they have been known to exude an acid which eats away the metal so that they can proceed.
Subterranean termites are social insects living in colonies in the soil.
The members of these colonies are divided into several castes. The wingless and sterile worker caste constitutes the largest number of individuals in a colony. In doing so, they construct tunnels over masonry and form galleries in the wood in which they are feeding. Another sterile caste in the colony are the soldiers, which are fed by the workers and must protect the colony from attack by invaders such as ants. Once a year, usually in the spring, a winged reproductive caste develops.