Drywood termites live in wood which has a relatively low moisture content. These differ from the subterranean termites, in that they do not have to have contact with the ground or other moisture sources. They are typically found in humid regions. These areas include the coastal and subtropical regions of the united states. There is a species that is in the desert southwest.
Drywood termites eat across the grain of the wood. Subterranean termites typically follow the grain of the wood. They make galleries connected by tunnels, and these tunnels are very clean and smooth inside. One of the major signs of drywood termite infestation is the fecal pellets, which are kicked out of the gallery and are easily seen. Pellets tend to accumulate on surfaces located below the kick holes and are usually the first evidence of a drywood termite infestation. There is no soil associated with these termites, and therefore there are no mud tubes tunnels ever seen.
Often times, drywood termite damage is localized to a specific area, however, if left untreated, re-infestations ca occur and compound the problem. Swarming drywood termites fly into structures and infest the wood directly. They often attack exposed wood such as window/door frames, eaves, and attics. When drywood termites swarm, they will often re-infest the same structure several times.
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.
The reproductives are winged (alates or swarmers) or wingless males and females that produce offspring. They 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.
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. Certain environmental conditions, such as heat, light (time of day), rainfall and moisture conditions, wind, atmospheric pressure (especially rapid changes in pressure) and the electrical properties of the atmosphere (associated with thunderstorms) trigger the emergence of alates, and each species has a definite set of conditions under which swarming will occur. The number of alates produced will be proportionate to the age and size of the colony, while environmental conditions regulate the number of swarms emerging from the colony.