Carpenter ants enter buildings to nest or forage. The are called “carpenters” because they excavate their nests in wood, creating smooth tunnels and galleries. They generally initiate colonies by excavating wood that is decayed or damaged by other insects. They also prefer wood with moisture.

The Western black carpenter ant is the most common species on the West Coast, Satellite nests may be found in structural timber, voids, under insulation, and in fibreglass or foam core insulation. Its nest excavating is often audible. Colonies can contain up to 50,000 ants.

Mature colonies consist of a parent nest and often satellite nests are established nearby whenever a need exists for more territory, more resources, or a drier, warmer nesting site for development of larvae and pupae.

In temperate regions colonies break diapause (diapause means a period of dormancy or a state of suspended animation) from January to June. When the ants become animated once again, the queen will begin her first egg-laying of the season and foraging will be heavy and intense. A second peak of activity occurs in June when the queen again lays eggs again.

Since carpenter ants are primarily nocturnal, they rely heavily on physical cues and chemical trails for orientation to and from the nest.

How to identify carpenter ants: