Carpenter ants are a common concern for homeowners, often recognized by their noticeable size. They are among the largest ant species found in residential areas. This article explores their typical sizes, identification features, and preferred nesting locations.
Understanding Carpenter Ant Size
Carpenter ants exhibit a range of sizes within a single colony. Worker ants, which are sterile females, vary significantly in length. Minor workers can be as small as 6 mm (0.25 inches), while major workers can reach up to 12 mm (0.5 inches) long. This variation means that different-sized ants indicate different roles within the same carpenter ant colony.
The reproductive members, including winged males and queens, are typically larger than the workers. Winged males generally measure 5 to 13 mm. The queen is the largest individual, often ranging from 13 to 20 mm (up to 0.75 inches) in length. Their large size makes them a preliminary indicator of their presence.
Identifying Carpenter Ants Beyond Size
While their size is a prominent feature, other distinct physical characteristics are important for accurate identification, especially to differentiate them from termites. Carpenter ants possess a clearly defined, constricted waist, with a single node between their thorax and abdomen. This is a key difference from termites, which have a broad, undefined waist.
Their antennae feature a noticeable bend or “elbow,” unlike the straight antennae of termites. When winged reproductive ants (swarmers) are present, carpenter ants have two pairs of wings where the front wings are significantly longer than the hind wings. Termite swarmers, however, have wings of roughly equal size and length and tend to shed them quickly after swarming.
Where Carpenter Ants Reside and Their Activities
Carpenter ants are named for their habit of excavating wood to create nests, rather than consuming it as a food source like termites do. They use their strong mandibles to chew through wood, forming smooth, clean tunnels and galleries for their colony. The wood shavings and debris, often referred to as “frass,” are typically pushed out of small openings in the wood, forming piles that resemble sawdust.
These ants prefer to establish their nests in wood that is moist, decaying, or softened. Common outdoor nesting sites include dead trees, stumps, logs, and firewood piles. Indoors, they often target areas with water damage, such as wood around windows, door frames, roof eaves, or structural timbers compromised by leaks.
They may also establish satellite nests in drier wood once a primary nest is well-established. The presence of carpenter ants often indicates potential moisture issues within a structure, given their preference for damp wood.