Eastern Subterranean Termite: Facts, Castes and Colonies

What does an eastern subterranean termite look like?

Like all termites, the eastern subterranean termite lives in a colony divided into castes, and each caste looks different. Termites have straight, beaded antennae, a broad waist and soft bodies, which separates them at a glance from ants.

• Workers are about 3–4 mm (1/8 in) long, creamy white to grayish, soft-bodied, wingless and blind. They make up most of the colony.
• Soldiers look like workers but have a large, long, yellowish-brown head with powerful black jaws called mandibles. They make up only about 1–2% of the colony.
• Swarmers, or alates, are the winged males and females. They are dark brown to black, about 8.5–10 mm (0.3–0.4 in) long including their wings, and have working eyes. Their pale, translucent wings are of equal length and extend well beyond the body. The species name flavipes means “yellow feet”, after the yellowish feet of the alates.
• Kings and queens are former swarmers that have shed their wings and founded a colony.

Habitat and range

The eastern subterranean termite is native to North America, probably originating in the southeastern United States. Today it lives throughout the eastern half of the country, from Florida and Texas north to New England and the Great Lakes, and into southern Ontario in Canada. It has also been recorded in Oregon on the West Coast.

People have carried it overseas in wood and soil. Termites long known in western France as Reticulitermes santonensis turned out to be the same species, and it is now also established locally in Germany, Italy and other parts of Europe, as well as in Chile, Uruguay and the Bahamas.

The species needs moisture. It nests in damp soil and in wood that touches the ground, such as fallen logs, stumps and roots, in forests, fields, parks and gardens. Unlike the big mound builders of Africa, it does not build a visible nest above ground, as explained in how do termites build mounds?

Diet and digestion

Eastern subterranean termites are detritivores: they eat dead plant material, especially wood, and the cellulose it contains. They also eat roots, leaf litter and other plant debris, and they can feed on paper, cardboard and cotton, which are made of cellulose too. They prefer wood that is already softened by fungi, and in forests they work through fallen branches, stumps and old roots that would otherwise take many years to rot away.

Cellulose is hard to digest, and the termite cannot do it alone. Its hindgut contains a dense community of single-celled protists, bacteria and archaea. The protists, first described from this species by the American naturalist Joseph Leidy in 1877, break down wood particles into simple compounds that the termite can absorb. Young termites are not born with these partners; they get them by feeding on droplets from the hindgut of older nestmates, and they must restock after every molt. Read more in what do termites eat?

Colony life and behavior

An eastern subterranean termite colony is not a single nest but a network of tunnels and chambers in the soil linking several feeding sites, sometimes spread over tens of meters. The colony moves its activity according to food, moisture and temperature, going deeper in winter and closer to the surface in warm, damp weather. There is no fixed central nest, and every caste can be found at many feeding sites.

Workers do almost all the work. They dig tunnels, gather food, feed and groom the other castes, care for eggs and young, and build shelter tubes: narrow mud tunnels that let them cross open surfaces while staying in the dark and humid air they need. Workers pass food mouth to mouth, a behavior called trophallaxis, which shares nutrients and chemical signals through the colony.

Soldiers guard the tunnels. They block breaches with their heads and bite intruders, especially ants, which are the termites’ main enemies. Like other advanced termites, they also have a pore on the forehead, the fontanelle, that releases defensive chemicals. When alarmed, soldiers knock their heads against the tunnel walls, sending vibrations that warn the rest of the colony.

Reproduction and swarming

New colonies start with a swarm. On warm days in late winter and spring, usually from about February to May depending on the latitude and often after rain, mature colonies release thousands of winged alates in daytime. They flutter up weakly, fall back to the ground, shed their wings and pair up.

Each pair, now a king and queen, digs a small chamber in moist soil or wood, mates and starts laying eggs. The first workers are reared by the royal pair themselves. Unlike ant queens, the termite queen keeps her king for life, and he goes on mating with her. The primary queen of a mature colony has been estimated to lay several thousand eggs a year.

Eastern subterranean termite colonies also produce supplementary or neotenic reproductives, which develop from nymphs inside the colony. These can lay eggs alongside or in place of the founders and allow the colony to grow very large. The different roles are explained in do termites have a queen?

Termites develop by incomplete metamorphosis, molting several times. A young termite usually becomes a worker, but depending on the colony’s needs it may turn into a soldier or a nymph with wing buds that later becomes an alate.

Colony size and lifespan

Mature colonies are usually estimated at tens of thousands to several million workers, though counting termites in the soil is difficult and estimates vary widely. Colonies take several years to reach the size at which they produce swarmers.

Individual workers are thought to live about one to two years. Kings and queens live considerably longer, several years or more, and because neotenic reproductives can replace them, a colony may outlive its founders.

How it compares with other termites

About 3,000 termite species are known worldwide, but most live in the tropics. Europe has only about 10 species and North America about 50. Biologists sort them into three broad ecological groups, and the eastern subterranean termite is a typical member of the first:

Compared with the giant mound-building termites of Africa, whose queens can grow longer than a human finger, Reticulitermes is modest. Its queens swell only slightly, and the colony spreads its egg-laying among many reproductives. It belongs to the “lower termites”, which rely on protists in the gut to digest wood, while the large family Termitidae, the “higher termites”, has lost these protists and depends on bacteria and, in some species, on cultivated fungus gardens.

In the eastern United States, several close relatives look almost identical, including the dark southeastern subterranean termite and Hagen’s subterranean termite. Experts separate them mainly by the swarmers’ size, color and swarming season, and by details of the soldiers’ heads.

Predators and threats

Ants are the most important predators of eastern subterranean termites, raiding exposed termites and attacking tunnels. Swarming alates are snapped up by birds, lizards, toads, spiders, dragonflies and many other animals, and only a tiny fraction survive to found a colony. Fungi and nematodes infect termites too.

The species is abundant and is not considered at risk. It has not been assessed by the IUCN, so its Red List category is Not Evaluated.

Myths and facts

Myth: termites are white ants. Termites are not ants. Genetic studies show that termites belong within the cockroach order Blattodea, while ants are related to bees and wasps.

Myth: a winged insect in spring is always a flying ant. Termite swarmers have straight antennae, a thick waist and four wings of equal length; flying ants have elbowed antennae, a pinched waist and front wings longer than the back ones.

Fact: termites help forests. By breaking down dead wood and leaf litter, termites return nutrients to the soil, and their tunnels aerate it and help water soak in.

Relationship with people

Because they eat cellulose, eastern subterranean termites can also feed on wood in buildings, and they are one of the most economically important wood-eating insects in the United States. In nature, though, they are valuable recyclers. Scientists also study their gut microbes, which turn tough plant fiber into sugars and other simple compounds, for ideas on producing biofuels from wood and straw. They are also food for many other animals, just as termites in Africa feed aardvarks, pangolins, aardwolves and chimpanzees. Chimpanzees even fish termites out of their mounds with carefully trimmed sticks, as described in do chimpanzees use tools?