Termites are social insects recognized globally as significant structural pests that cause billions of dollars in damage annually. These organisms operate in highly organized colonies and are driven by a single nutritional requirement: a source of energy derived from plant matter. Understanding their diet reveals why they are so destructive to human dwellings, where they find their sustenance, and what materials offer a natural defense. The core purpose of their diet is to extract energy from cellulose, the complex organic compound that forms the structural component of plant cell walls.
The Primary Fuel Source Cellulose
The life cycle of a termite colony revolves around the acquisition and digestion of cellulose, the most abundant organic polymer on Earth. Wood, whether from a fallen tree in a forest or a two-by-four in a home, is the primary source of this molecule. Termites cannot produce the enzymes necessary to break down this tough, fibrous material on their own.
They overcome this challenge through a mutualistic relationship with microscopic organisms, primarily protozoa and bacteria, residing within their hindgut. These symbionts produce cellulase enzymes that chemically dismantle the long cellulose chains into simple sugars, such as glucose, which the termite absorbs for energy. This allows them to thrive on a diet indigestible to most other animals.
In nature, termites prefer wood that is already decaying, often softened by moisture or infested with fungi, which makes the cellulose more accessible. When they target a home, the worker termites will consume both softwoods like pine and hardwoods, though they often prefer the softer, less dense springwood within lumber. They are cultivating their internal microbial partners to process the cellulose into life-sustaining nutrients.
Hidden Household Diets
While wood forms the bulk of their diet, any item containing cellulose is a potential food source, leading to unexpected damage within a home. Paper products are particularly vulnerable because they are processed wood fibers. Items like books, stored documents, and cardboard boxes are readily consumed when termites are foraging inside walls or storage areas.
The paper backing on drywall, which provides a layer of gypsum plaster with a cellulose-based covering, is also a common target. Termites will often strip this paper layer, sometimes leaving the plaster core intact but structurally weakened. Certain fabrics, such as cotton and linen, are composed of plant fibers and can be damaged by termites seeking nutrition.
These secondary food sources, while not providing the long-term structural sustenance of lumber, offer quick energy that supports colony growth. Finding damage to these materials often serves as the first visible sign of an infestation, indicating that the pests are actively foraging beyond the main structural timbers. Termites have been observed consuming non-traditional items like currency, dictionary bindings, and fast-food wrappers due to their cellulose content.
What Termites Cannot Eat
Termites are limited by their digestive capabilities and physical ability to consume certain materials, which provides homeowners with natural defenses. They cannot derive nutrition from inorganic materials such as stone, metal, and concrete. While they cannot eat concrete, subterranean termites are adept at exploiting small cracks, sometimes as narrow as 1/32 of an inch, to gain access to the wood above or behind the foundation.
Most plastics are indigestible, as they lack the cellulose necessary for microbial breakdown. Materials like cement fiber board and composite lumber made with plastic components are resistant because they do not offer a viable food source. These inorganic items act as physical and nutritional barriers.
Chemically treated wood is infused with preservatives that contain toxins, making it unappetizing to termites. This wood acts as a strong deterrent, making it far more resistant than untreated lumber. However, the protection is not absolute; if the treated wood is cut or weathered, termites may tunnel through the treated layer to reach untreated wood nearby.