Carpenter Ant (Camponotus species)

Identification

Carpenter ants are among the largest ants in Texas — workers measure ¼–½ inch long, and queens can exceed ¾ inch. Most Brownsville-area carpenter ants are black, though some species are bicolored (reddish-brown thorax with black abdomen). They have a single waist node (petiole) and an evenly rounded thorax profile when viewed from the side — distinguishing them from other large dark ants.

Carpenter ants are frequently confused with termites during swarm season. The key differences: carpenter ant swarmers have elbowed antennae, a pinched waist, and forewings longer than hindwings. Termite swarmers have straight antennae, no waist constriction, and wings of equal length.

Behavior and Damage

Carpenter ants do not eat wood — they excavate it to create nesting galleries. They remove wood shavings (frass) and deposit them outside the nest, creating small piles of sawdust-like material that are often the first visible sign of infestation. They prefer wood that has been softened by moisture — around leaking windows, under bathroom tile, behind dishwashers, and in roof decking where ice dams or flashing failures have allowed water entry.

In Brownsville's humid climate, moisture-softened wood is common in older homes, especially the pier-and-beam structures across San Benito and the Valley’s historic neighborhoods. That makes carpenter ant damage a bigger risk here than in dry regions. A mature colony can hold 10,000 to 50,000 workers and cause real structural damage over several years without professional ant control.

Signs of Infestation

Small piles of coarse wood shavings (frass) beneath wooden structures or along baseboards. Large black ants seen indoors, particularly at night (carpenter ants are primarily nocturnal). Faint rustling sounds inside walls when the house is quiet. Winged carpenter ant swarmers emerging inside the home in spring — a definitive sign that a mature colony is established inside the structure.

Carpenter Ant vs Termite Damage

Carpenter ant galleries are clean and smooth with a sandpapered appearance. Termite galleries are rough, packed with mud and fecal material. Carpenter ant frass is deposited outside the nest; termites consume the wood and leave no frass. Both cause structural damage, but they require completely different treatment approaches — misidentifying the pest wastes time and money on the wrong treatment.