Subterranean Termites

What Are Subterranean Termites?

Subterranean termites are a species of termite that live and build their colonies underground. They are among the most destructive wood pests in the world, particularly in the United States, due to their aggressive foraging behavior and the size of their colonies. Here's an overview:

Are Subterranean Termites Harmful?

Subterranean termites are considered highly destructive pests due to a combination of biological, behavioral, and ecological factors that enable them to cause extensive damage to wooden structures, homes, and even non-cellulose materials. Here are the primary ways in which subterranean termites are classified as pests:

• Structural Damage to Buildings: Subterranean termites feed on cellulose-based materials, primarily wood, which makes the structural components of homes and buildings prime targets. They often go undetected for long periods, silently compromising the integrity of foundational timbers, support beams, joists, and flooring. This can result in significant repair costs and safety hazards, such as sagging floors or even structural collapse if infestations are left unchecked.
• Stealthy and Hidden Infestations: One of the most insidious aspects of subterranean termites is their ability to remain hidden. They live in underground colonies and access food sources through mud tubes that protect them from air and light exposure. Because they rarely emerge into the open, infestations can progress for years without any visible signs, making detection and timely intervention challenging.
• Rapid Colony Expansion: Subterranean termite colonies can number in the hundreds of thousands to millions of individuals. A mature queen can lay thousands of eggs per day, allowing colonies to grow rapidly. Additionally, they can establish secondary colonies or satellite nests, especially in moist conditions, which increases the spread and intensity of infestation.
• Moisture Attraction and Damage: These termites thrive in moist environments and are often drawn to buildings with water-damaged wood, poor drainage, leaky pipes, or insufficient ventilation. In turn, they exacerbate moisture problems by breaking down wood, allowing for further mold growth and decay. This not only accelerates damage but also contributes to unhealthy indoor environments.
• Economic Impact: The economic burden of subterranean termites is substantial. In the United States alone, termites cause an estimated $5 billion in damage each year, with subterranean species responsible for the vast majority. Most homeowner insurance policies do not cover termite damage, adding to the financial strain of infestations and reinforcing their status as a major pest.
• Impact on Landscaping and Trees: Subterranean termites don’t limit their feeding to manmade structures. They can also damage trees, fence posts, decks, wooden retaining walls, and landscape timbers. In orchards, vineyards, and nurseries, they can kill young trees by feeding on their roots and lower trunks, potentially resulting in loss of valuable agricultural assets.
• Reinfestation Risk: Even after treatment, subterranean termites can reinfest a property, especially if conducive conditions such as soil contact, wood debris, and moisture issues persist. Their cryptic behavior and ability to forage over long distances from the colony make complete eradication difficult without ongoing monitoring and preventive measures.
• Public Health Nuisance: Although subterranean termites do not directly spread diseases or pose health risks like some pests, their presence still creates distress for homeowners. The financial burden, fear of structural damage, and need for ongoing inspections and treatments can take a psychological toll, especially in areas where termite activity is prevalent.

Subterranean Termite Appearance

Subterranean termites have a distinct appearance that varies depending on their caste within the colony—workers, soldiers, and reproductives (also known as swarmers or alates). While they all share certain termite-specific traits such as straight antennae and soft bodies, each caste has unique characteristics that aid in identification. Here is a breakdown of their physical features:

Worker Termites

• Color: Creamy white to pale gray
• Size: Approximately 1/8 inch (3 mm) in length
• Body: Soft-bodied and wingless
• Head: Small and rounded, lacking compound eyes
• Antennae: Straight and bead-like
• Function: Workers are the most numerous caste in a colony and are responsible for foraging, feeding the colony, constructing tunnels, and grooming other members. They are the ones that cause the most structural damage, as they continuously chew through wood and other cellulose-based materials.

Soldier Termites

• Color: Similar creamy white body as workers, but with a larger, darker head—often amber or brown
• Size: Slightly larger than workers, usually about 1/8 to 3/16 inch (3–5 mm)
• Head: Large, rectangular, and hardened with powerful mandibles (jaws)
• Antennae: Straight, similar to workers
• Function: Soldiers are specialized for defense. They protect the colony from predators such as ants and other intruders using their strong mandibles. They rely on workers to feed them because their mouthparts are adapted solely for defense.

Reproductive Termites (Swarmers/Alates)

• Color: Dark brown to almost black
• Size: Larger than workers and soldiers, typically 3/8 to 1/2 inch (10–12 mm) in length
• Wings: Two pairs of equal-length wings that are long, translucent, and veined; the wings are about twice the length of the body and are shed soon after swarming
• Eyes: Well-developed compound eyes
• Antennae: Straight, but sometimes appear slightly curved
• Function: Swarmers are the winged, reproductive members of the colony. Their sole purpose is to leave the nest during a swarming event (typically in spring or after rainfall) to mate and establish new colonies. Finding discarded wings near windowsills or light fixtures is often one of the first signs of an infestation.

Primary and Secondary Queens and Kings

• Queens: Initially similar to alates, but once established, they become enormously swollen with eggs, reaching lengths of 1 inch or more. Their abdomens become distended and dark-colored.
• Kings: Resemble swarmers but remain smaller and do not undergo abdominal enlargement.
• Function: The queen and king are the central reproductive figures of the colony. The queen lays thousands of eggs per day, while the king remains by her side for life to ensure ongoing reproduction.

Subterranean termites may be small, but their physical characteristics—particularly the winged swarmers and distinct castes—can be identified by a trained eye or pest control professional. Recognizing their unique traits is essential for early detection and effective treatment, especially since their cryptic nature allows them to cause significant damage before obvious signs appear.

Subterranean Termite Habitat

Subterranean termites are among the most destructive types of termites, and they are found across a wide geographic range, thriving in areas that offer warmth, moisture, and a source of cellulose-based material (such as wood). Their distribution can be broken down by region and environmental conditions:

United States

Subterranean termites are widespread throughout the continental U.S., though their prevalence and destructive potential vary by region:

• Southeastern U.S. – This is the most termite-prone area in the country. States like Florida, Georgia, Alabama, Louisiana, and the Carolinas experience extremely high termite pressure due to the warm, humid climate that supports year-round activity.
• Southwestern U.S. – Arizona, New Mexico, Texas, and Southern California are also home to subterranean termites, particularly species that are adapted to arid conditions, such as the desert subterranean termite(Heterotermes aureus).
• Mid-Atlantic and Gulf Coast States – These areas also see significant termite activity, especially in the spring and summer when swarming occurs.
• Northern States – While less common, subterranean termites can still be found in parts of the Midwest and Northeast, including states like Illinois, Ohio, Pennsylvania, and New York. Activity tends to be seasonal due to colder winters.
• Pacific Northwest – States like Oregon and Washington do have subterranean termites, though moisture and dampwood termites are often more of a concern here.

Globally

• Asia – Countries like India, China, Indonesia, and the Philippines report widespread subterranean termite infestations. Tropical climates and heavy rainfall provide ideal nesting conditions.
• Australia – Subterranean termites (often called "white ants") are a major pest problem, particularly in Queensland and New South Wales. Species like Coptotermes acinaciformis are extremely aggressive.
• Africa – Termites are prevalent throughout sub-Saharan Africa, where they play a major role in natural ecosystems but also damage structures and crops.
• Central and South America – These regions experience heavy termite activity due to consistently warm and humid conditions.
• Europe – Termites are less common in most of Europe, but some southern areas (like parts of Spain, Italy, and Portugal) have known populations. Subterranean species like Reticulitermes lucifugus are present in Mediterranean zones.

Habitat Preferences

Subterranean termites require moisture to survive and build their colonies underground, usually in soil. They build mud tubes to access food sources above ground while maintaining humidity. Their ideal environments include:

• Soil near and beneath foundations
• Landscaped areas with wood mulch or tree stumps
• Leaky plumbing or poorly ventilated crawlspaces
• Areas with frequent rainfall or high groundwater