The only external sign of a carpenter ant infestation other than the presence of workers and/or swarmers is the appearance of small openings on the surface of wood. Through these, the ants expel debris, which consists of sawdust-like shavings and/or fragments of insulation and insect body parts. The accumulation of this debris below the holes is a good indication of an active infestation. The gallery walls that carpenter ants create are smooth, with a sandpapered appearance. Active galleries are kept clean of debris.
Carpenter ants prefer to attack wood softened by fungus and are often associated with moisture problems, so homeowners should keep an eye out for excess moisture and soft, rotting wood around the home
By: Pest World