Termites are social insects whose existence revolves around consuming cellulose, the most abundant organic polymer on Earth. While wood is a primary source of this complex carbohydrate, their digestive capabilities allow them to exploit nearly any material derived from plant matter. This fundamental dependence means a termite’s potential menu extends deep into human homes and structures, encompassing a variety of materials used in construction and everyday life.
Processed Cellulose Materials
Termites readily consume many common household items because manufacturing often concentrates cellulose into easily accessible forms. Paper products, including stored documents, books, cardboard boxes, and paper currency, are highly attractive sources of nutrition. These refined cellulose fibers are often stored in dark, humid environments like attics or basements, which are ideal habitats for a termite colony.
A particularly vulnerable component is the paper backing of drywall. Termites target this outer layer for its cellulose content, leaving the gypsum core intact. This can make the infestation difficult to detect until significant damage has occurred. Natural fabrics derived from plants, such as cotton and linen, also contain substantial cellulose and can be damaged, especially when stored in damp conditions.
Fungal Sources and Decaying Matter
Termites often seek food that has been chemically altered, preferring decaying plant matter over sound wood. In natural environments, their diet includes leaf litter, grasses, humus, and organic waste found in the soil. This preference is strategic because wood-inhabiting fungi, such as white-rot and brown-rot, predigest the wood’s tough lignin and cellulose, making the material easier for the termites to metabolize.
The presence of fungi also increases the concentration of nitrogen and protein, nutrients necessary for termite survival and colony growth. Certain species, like those in the subfamily Macrotermitinae, actively cultivate symbiotic fungi, called Termitomyces, in specialized structures known as fungus gardens. The termites feed on the fungus, which has broken down the plant material into a nitrogen-rich food source.
Structural Materials Consumed for Passage
Some materials are damaged not because they are a food source, but because they are physical obstacles blocking the path to cellulose or water. Termites have powerful mandibles that allow them to bore through materials that hold no nutritional value. This includes soft materials like foam insulation, such as expanded or extruded polystyrene (EPS or XPS).
They tunnel through foam to create pathways and shelter, using the insulation as a hidden conduit to access the wooden framing of a structure. Similarly, soft plastics, like PVC piping, and some forms of plaster or grout may be chewed through incidentally. These materials are simply removed to maintain the colony’s structural integrity or to reach a more desirable cellulose source.
The Biological Mechanism of Digestion
The ability of termites to digest a broad range of cellulose-based materials is rooted in a remarkable biological partnership. Termites themselves do not produce the necessary enzymes to break down the complex cellulose molecule. Instead, they rely on a diverse community of symbiotic microorganisms living within their specialized hindgut.
In lower termites, this microbial community is primarily composed of flagellated protozoa and bacteria. These symbionts produce cellulase, an enzyme that hydrolyzes cellulose into simpler, digestible sugars. The protozoa then ferment these sugars into short-chain fatty acids, such as acetic acid, which the termite absorbs through its gut wall as its main energy source.
This internal microbial fauna is crucial and must be transferred from one individual to another. Newly hatched nymphs and termites that have molted lose their gut lining and must repopulate their digestive tract through a process called proctodeal feeding. During this process, they consume a liquid discharged from the anus of an older termite, ensuring the next generation has the necessary microbial machinery to process its cellulose-rich diet.