Subterranean termites are one of the most common termite species found in the United States, and they can be particularly tricky to detect. These insects tend to stay hidden underground or inside walls, which makes their presence difficult to notice until visible signs of damage may appear. Their colonies can grow rapidly and may include hundreds of thousands of termites.
Each member has a specific role – some forage for food, others defend the colony, and others help care for young termites and maintain the nest.
Subterranean termites come in different forms, depending on their role within the colony. Workers are soft, pale, and usually small, often going unnoticed because they stay hidden while performing most of the foraging and feeding.
Soldiers, while similar in size to workers, have large, darker heads and powerful jaws. Their job is to protect the colony from threats like ants.
Swarmers, also known as alates, are the reproductive termites. They look quite different from workers and soldiers. These termites are darker in color, usually brown or black, and have two pairs of wings that are the same length and extend beyond the body. After they take flight during a swarm, they shed their wings, which can often be found near windowsills, door frames, or light fixtures.
One of the most obvious signs of subterranean termites is the presence of mud tubes. These narrow tunnels, about the width of a pencil, are often found on walls, foundations, or crawlspaces. Subterranean termites use these tubes to move safely between their underground nest and a food source like wood inside a building. They prefer damp soil and are often found around the base of buildings, near leaking pipes, or under porches.
You may also notice other signs, such as shed wings, wood that sounds hollow when tapped, blistering or bubbling paint, sagging floors, or small dark spots on walls. In some cases, the damaged wood may look intact on the outside but be completely eaten out from within.
Knowing how subterranean termites live, what they eat, and how they behave helps you better understand why they may appear in certain areas and how to reduce your risk. Here are some subterranean termite facts:
These termites typically nest underground, building their colonies in moist, dark soil. If there’s enough moisture available, subterranean termites may create above-ground nests in places like attics, wall voids, or basements. Areas with water leaks, poor airflow, or high humidity provide the ideal environment for these insects to expand their colonies.
Subterranean termites feed on cellulose, a material found in wood, cardboard, paper, and some fabrics. Once a food source is located, the worker termites continue feeding on it and may return to it repeatedly until the material is gone.
This feeding behavior can gradually weaken important parts of a structure, such as wall studs, floor joists, or wooden beams. Over time, this may lead to noticeable damage, especially if the infestation goes undetected.
Subterranean termites begin life as eggs, which are laid by a queen. These eggs hatch into small, pale nymphs. As they grow, the nymphs develop into workers, soldiers, or swarmers depending on what the colony needs most at the time.
Colonies can grow quite large over time, with thousands or even up to 2 million termites working together. Swarming usually takes place in the spring, particularly after a warm rain. This is when the winged swarmers leave the nest in search of a new place to build a colony. If they succeed, the cycle begins again with a new queen and king establishing a nest and laying eggs.
These termites remain active throughout the year, working day and night to support their colony. Although they may slow down slightly in colder months, they don’t hibernate or go dormant like some pests. Their secretive behavior and ability to stay hidden make them especially difficult to detect.
Most of their activity happens behind walls, under floors, or inside other hidden areas. They rarely come out into the open, relying on their mud tubes and hidden tunnels to stay safe and maintain the moisture they need to survive. Because of this, homeowners may not realize they have a termite issue until significant damage has occurred.
Subterranean termites don’t bite or sting, and they aren’t known to carry diseases that harm people or pets. Still, they may create problems over time by feeding on wooden parts of a structure. When left alone, a large colony may weaken important supports, such as beams, floorboards, and wall studs.
This kind of damage may be costly to fix if not addressed. Because the signs aren’t always easy to spot early, the termites may continue feeding for months or years before being discovered. That’s why regular inspections and early action are so important.
While you can’t always stop these termites from appearing, there are steps you can take to reduce the chances of an infestation. Keep your home or building as dry and sealed as possible by following these tips:
You should also schedule yearly termite inspections with a professional technician, especially if you’ve had problems in the past or live in an area where termites are common. These check-ups can catch early signs of termite activity and may help you avoid costly repairs later. Learn more about everything you need to know about identifying and treating termites in our homeowner's guide.
Subterranean termites can stay hidden while they feed, making them hard to spot until damage has already begun. Western Exterminator offers a variety of termite protection plans that are specifically designed for your property. Our termite plans focus on preventing future infestations and eliminating active ones. No amount of termite activity is too big or small for our termite experts.
Learn more about Western Exterminator's termite protection services.
Yes, some subterranean termites can fly. These are called swarmers or alates, and they have wings so they can fly off in groups to start new colonies. If you see flying termites or shed wings indoors, it might be a sign of a colony within your structure.
Yes, they feed on cellulose, which is found in wood and other plant-based materials. Over time, their feeding may lead to damage if the colony grows large or goes untreated.
They do. Swarming usually happens in the spring after a warm rain. During this time, winged termites leave their nest to find a place to start a new colony. Seeing swarmers can be one of the first signs of a termite issue.
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