Formosan Subterranean Termite

The Formosan subterranean termite is an introduced species native to southern China and Taiwan that has become established in the southeastern United States, Hawaii, and other warm regions worldwide through human transport. It is notable for forming exceptionally large colonies, sometimes numbering in the millions of individuals, and for its ability to build carton nests, moisture-retaining structures made of soil, wood fragments, and saliva, both underground and in above-ground locations such as tree cavities and building voids.

Because of its large colony sizes and rapid foraging capability, the Formosan subterranean termite is considered one of the more aggressive wood-feeding termite species where it has become established, though ecologically it functions the same as other subterranean termites, as a decomposer of cellulose material.

• Workers are pale cream-colored, soft-bodied, and similar in general appearance to other subterranean termite workers, roughly 0.5 inch (12-14 mm)
• Soldiers have an oval, orange-brown head (rounder than the rectangular head of eastern subterranean termite soldiers) with a fontanelle (pore) that exudes a defensive fluid, and long mandibles
• Winged reproductives (swarmers) are yellowish-brown with two pairs of equal-length, hairy wings
• Straight, bead-like antennae and a thick waist distinguish termites from ants, as in other termite species
• Large above-ground carton nests, made of chewed wood, soil, and saliva, are a distinguishing sign of this species when found in wall voids or tree hollows
• Swarms tend to be very large and are strongly attracted to lights at night

This species requires warm, humid climates and is established primarily in the southeastern United States (from Texas to the Carolinas), Hawaii, and other subtropical to tropical regions worldwide, having spread from its native range in East Asia. Colonies live underground in soil but can also establish satellite colonies above ground within structures or trees where sufficient moisture is available, reducing their dependence on direct soil contact compared to some other subterranean termites. Swarming activity typically occurs on warm, humid evenings, often around lights, during a defined swarming season in spring or early summer depending on region.

Formosan subterranean termites feed on cellulose in wood and other plant material, foraging extensively through underground tunnel networks that can extend a considerable distance from the central colony. Their ability to build moisture-retaining carton nests allows some colonies to persist above ground, in tree cavities or building structures, without needing constant direct soil contact, a trait less common in other subterranean termite species. Within the colony, workers forage and maintain the nest, soldiers defend against threats such as ants using both their mandibles and a defensive fluid released from a head pore, and reproductives are responsible for colony founding and growth. As with other subterranean termites, this species functions ecologically as a decomposer of dead wood and cellulose, though its large colony sizes and adaptability make it a significant nuisance pest in the regions where it has become established.

New colonies are founded by a mated pair of winged alates following a nighttime swarming flight, after which the pair sheds its wings and begins a small nest in soil, wood, or another suitable cavity. The colony grows through the production of worker and soldier offspring via incomplete metamorphosis, with nymphs developing gradually into the different castes needed by the colony. Formosan subterranean termite colonies can grow unusually large and persist for many years, periodically producing large swarms of winged reproductives, typically in spring or early summer on warm, humid nights, to disperse and found new colonies.