What Do Termites Eat? Wood, Cellulose and Gut Microbes

Termites are recyclers of dead plants

Termites are detritivores, meaning they feed on dead and decaying plant material. Wood, dry grass and leaf litter are rich in cellulose, but few animals can use it because it is very hard to break down. Termites are one of the main groups of animals that can, which makes them some of the most important decomposers on Earth, especially in the tropics.

About 3,000 termite species are known, and their food depends on the species:

Some species also eat dung, lichens or mosses. Wood-feeding termites often prefer wood that fungi have already started to soften, because it is easier to chew and slightly richer in nitrogen.

How termites digest wood

Wood is mostly cellulose, plus hemicellulose and lignin, a woody glue that very few organisms can break down. The termite starts the process itself. Its jaws cut wood into tiny pieces, a muscular gizzard grinds them, and enzymes from the salivary glands and midgut begin to break down the cellulose.

The rest happens in the hindgut, an enlarged, oxygen-free chamber that works like a fermentation tank. In the eastern subterranean termite and other “lower termites”, this chamber is packed with single-celled protists, along with bacteria and archaea. The protists swallow wood particles and break the cellulose into simple compounds, especially acetate, which the termite absorbs as its main source of energy. The eastern subterranean termite carries about a dozen kinds of these protists, first described in 1877.

The “higher termites” of the family Termitidae, which include most species, have lost the protists. They rely on bacteria in the gut and, in some groups, on fungi.

Sharing microbes and food

Newly hatched termites have no gut microbes. They get them by feeding on droplets of fluid from the hindgut of older nestmates, a form of food sharing called proctodeal trophallaxis. Every time a termite molts, it loses the lining of its hindgut and must restock its microbes the same way.

Workers also feed the soldiers, the young and the king and queen, which cannot feed themselves on wood. This constant exchange spreads nutrients, microbes and chemical signals through the whole colony, and it helps explain why termites are always social: a lone termite could not keep its gut partners alive. Read more about the colony’s roles in do termites have a queen?

Getting enough nitrogen

Wood is rich in energy but very poor in nitrogen, which animals need to build proteins. Termites have several solutions. Some of their gut bacteria can fix nitrogen from the air, turning it into a usable form. Termites also recycle waste nitrogen within the colony, eat fungus-infected wood that contains more protein, and sometimes eat dead nestmates and shed skins.

Fungus-farming termites

Some of the most remarkable termites are the fungus growers of Africa and Asia, in the subfamily Macrotermitinae. Workers gather dead wood, grass and leaves, eat them quickly and deposit the partly digested material as a spongy comb inside the nest. A fungus of the genus Termitomyces grows on this comb, breaking down the plant matter, and the termites then eat the fungus and the enriched comb.

This partnership is thought to have begun about 30 million years ago, long before people invented farming. In parts of the African savanna, fungus-growing termites break down a large share of the dead wood and grass. Their nests are often hidden inside huge earth mounds, as explained in how do termites build mounds?

Why termite diets matter to ecosystems

By eating dead plants, termites return carbon and nutrients to the soil and the air. Their tunnels mix and loosen the soil and help rain soak in, and soil around termite nests is often richer than the surrounding ground. In dry tropical regions, termites can do much of the decomposition work that earthworms and fungi do in cooler climates.

Termite digestion also produces methane, a greenhouse gas. Termites are a natural source of a small share of global methane emissions, a few percent according to most estimates, far less than human activities.

Termites are also food for many animals. Ants are their main predators, and aardvarks, aardwolves, pangolins, anteaters, echidnas and many birds depend on them. See what do aardvarks eat?

Myths and facts

Myth: termites eat only wood. Many species never touch wood. They eat grass, leaf litter, soil, fungus or dung instead.

Myth: termites can digest wood by themselves. Termites make some of their own enzymes, but they depend on their gut microbes, or on fungus gardens, to extract most of the energy from plant fiber.