Termites: Isoptera

Physical characteristics: This is the largest and most primitive termite in North America. Winged kings and queens measure 1.0 to 1.2 inches (25.4 to 30.5 millimeters) from head to wingtips, with a wingspan up to 1.9 inches (48.3 millimeters). Their bodies are dark yellowish. Soldiers measure 0.6 to 0.9 inches (15.2 to 22.9 millimeters) in length. The flattened head is widest at the back, and they have very long and roughly toothed jaws. Workers, soldiers, and other castes are whitish yellow or cream in color.

Geographic range: In the United States these termites are found from central and southeastern Arizona to southern New Mexico and western Texas; they also live in Chihuahua and Sonora, Mexico.

Wide-headed rottenwood termite are found inside the rotten cores of logs and large branches of living willows, cottonwoods, sycamores, oaks, alders, ash, walnuts, hackberries, and other hardwoods. (Illustration by Barbara Duperron. Reproduced by permission.)

Habitat: This species lives in dry habitats between 1,500 and 5,500 feet (457 and 1,676 meters) along canyons and river valleys. The termites are found inside the rotten cores of logs and large branches of living willows, cottonwoods, sycamores, oaks, alders, ash, walnuts, hackberries, and other hardwoods.

Diet: Wide-headed rottenwood termites feed only on rotten hardwoods. Unlike many other termites, this termite is not known to feed on completely dead and rotten logs or on pines, firs, and their relatives.

Behavior and reproduction: Colonies are found in galleries and open chambers in rotten wood. The chambers eventually become filled with masses of termite waste. The termites sometimes gain access to a rotten tree core through a knothole. These and other knotholes are plugged with termite waste in the form of hardened pellets. Inside, the galleries are usually quite damp. Soldiers with powerful jaws defend the colony against ants and other predators.

Kings and queens fly in the middle of the night from late June through early August. Mated pairs look for tree scars, knotholes, or small pockets of rot or other wounds in trees, where they can gain access to the rotten core. A single king and queen usually head each colony, but there may be additional termites that can reproduce and contribute broods to the colony. Colonies are small and rarely have more than one thousand individuals.

Wide-headed rottenwood termites and people: This species attacks living trees, quickening their collapse and death from rot on the inside. However, they are not considered pests because the trees they attack are not used for lumber.

Conservation status: This species is not endangered or threatened. ∎