Pestipedia

Destructive Wood Ants

**Destructive Wood Ants** is a general term often used to describe species of ants that cause structural damage to wood, most commonly referring to **Carpenter Ants** (*Camponotus* species). Unlike termites, Carpenter Ants do not *eat* the wood; rather, they **excavate** tunnels and galleries within the wood to create nesting sites. This tunneling weakens the structural integrity of homes, decks, and trees, making them significant structural pests.

Taxonomy and Classification

Carpenter Ants belong to the family Formicidae (ants) in the order Hymenoptera. They are **social insects**, forming large colonies with distinct castes (queen, workers, soldiers, reproductives). The *Camponotus* genus is characterized by a smoothly arched thorax (top part of the body) when viewed from the side and a single, distinct node (petiole) connecting the thorax and abdomen. They undergo complete metamorphosis.

Physical Description

Carpenter Ants are some of the largest ants in North America, with workers ranging from $1/4$ to $5/8$ inch long. They are typically black, but some species are red and black, or entirely red or brown. Key identification features for workers include:

  • **Single Node:** One distinct segment separating the thorax and abdomen.
  • **Antennae:** Elbowed antennae.
  • **Winged Reproductives (Alates):** Large, winged forms that swarm to mate, possessing two pairs of unequal-sized wings (forewings are larger than hindwings).

The larvae are legless, white, grub-like, and live only inside the nest.

Distribution and Habitat

Carpenter Ants are found worldwide, particularly prevalent in forested and suburban areas. Their primary nesting habitat is **moist, damaged wood**, such as rotting tree stumps, firewood, leaky window sills, decaying deck posts, or wall voids near plumbing leaks. The ants often establish a **parent colony** in soft, wet wood outdoors and several smaller **satellite colonies** inside dry structural wood, which can be difficult to locate.

Behavior and Life Cycle

A colony is established by a single mated queen and can take 3–6 years to mature. Workers forage widely, primarily at night, seeking sweet substances (honeydew, sweets) and protein (dead insects).

  • **Excavation:** Workers use their mandibles to shred wood, creating smooth, clean tunnels and galleries. A key sign of their presence is the presence of **frass**—a mixture of shredded wood (looks like sawdust or wood shavings) and dead insect parts, often pushed out of a small slit in the wood near the nest.
  • **Swarming:** Winged reproductives emerge in late spring or early summer, usually indoors, signaling a mature indoor colony.

    • Feeding and Damage

    Carpenter Ants do not consume wood; they feed on sugar (nectar, honeydew) and protein. Their damage is entirely mechanical. The excavation of galleries weakens the integrity of the wood, which can be structurally compromising over time. Galleries typically follow the wood grain and are distinguished from termite damage by their **clean, sandpapered appearance** (termite galleries are dirty and often packed with mud).

    Management and Prevention

    Control is challenging and requires eliminating both the parent and satellite colonies.

    • **Moisture Control:** The most crucial preventative step is finding and eliminating all sources of excess moisture (leaky roofs, plumbing, poor drainage) that create soft, susceptible wood.
    • **Remove Wood Contact:** Ensure no structural wood, firewood, or debris is in direct contact with the ground or foundation.
    • **Baiting:** Non-repellent, slow-acting baits are the most effective control. Workers consume the bait and carry it back to feed and ultimately eliminate the queen and the entire colony.
    • **Residual Treatment:** Applying a residual, non-repellent liquid insecticide into voids where the colony is suspected to reside (often identified by frass piles) can also provide immediate control.

    Conservation and Research

    Carpenter Ants are primarily pests in urban settings but are important decomposers in natural forests. Research focuses on refining bait matrix formulas to increase acceptance and developing non-chemical methods to deter nesting in structural wood.