Drywood Termites
In nature, termites function as decomposers that breakdown dead wood that accumulates in and on the soil. The beneficial products of this breakdown process are returned to the soil as humus. Drywood and subterranean termites are the most destructive insect pests of wood, causing more than $1.7 billion in damages and cost of control each year in the U.S. alone. Their presence in structures is seldom noticed until damage is discovered or the termites swarm within the building.
Drywood termites are found in the southern tier of states, from North Carolina through the Gulf Coast and into the coastal areas of California.
Drywood termites are social insects that live in colonies in sound, dry wood. Each colony consists of offspring from an original pair (male and female). There are three growth stages – eggs, immatures and adults. Drywood termites are larger than local, southwestern subterranean species.
In comparison to other termites, drywood colonies are rather small (a few thousand individuals), and the colony develops relatively slowly. They neither live in the ground nor maintain contact with the soil, and they do not build mud tubes.
Subterranean termites produce liquid feces, whereas drywood termites produce characteristic pellets. These pellets are eliminated from the galleries through “kick holes”. Pellets tend to accumulate on surfaces located below the kick holes and are usually the first evidence of a drywood termite infestation.
Drywood termites tend to cut across wood grain destroying both the soft spring wood and the harder summer growth. Subterranean termites typically follow the grain of the wood, feeding primarily on the soft spring wood.
The reproductive’s are winged (alates or swarmers) or wingless males and females that produce offspring. The primary reproductive’s, also called swarmers or alates, vary in body color from dark brown to light yellowish tan. Their wings may be almost clear to smoke gray, and have few distinct veins in them. Swarmer drywood termites are about 7/16 inch long, including the wings. If the primary reproductives die, they are replaced by immatures that can become capable of reproductive activity. They are known as replacement or secondary reproductives.
In most drywood species there is no true worker caste (subterranean termites do have a true worker cast); this function is taken over by immatures. These immatures are wingless, white to beige in color, 1/4 to 3/8 inch long and make up the largest number of individuals within a colony. They gather food, enlarge the nest and feed and care for the queen, younger immature forms and others in the colony.
Soldiers resemble immatures in color and general appearance. However, they have large, brownish to yellowish-brown heads with enlarged, heavily sclerotized mandibles (jaws). Soldiers defend the colony against invaders, primarily ants. Soldiers are about 5/16 inch long.
After a drywood termite colony has matured (several years), winged alates (swarmers) are produced that leave the colony to establish new colonies. Swarming activity (nuptial flights) generally occurs at dusk or during the night and they tend to fly towards areas of greatest light intensity, gathering around lights or illuminated windows. However, the dark western drywood termite (Incisitermes minor) is a daytime swarmer. Swarming of Arizona species occurs in early to late summer with certain species swarming during the winter months of January and February also.