Carpenter Ants
Carpenter ants are the #1 wood-destroying pest in the Pacific Northwest. Left unchecked, carpenter ant colonies can cause significant damage to sound wood, possibly compromising the structural integrity of a building.
Carpenter ants are fairly easy for an untrained person to identify with the naked eye. The easiest way is by size and color. The most common local species (Camponotus modoc), is “a big black ant” by anyone’s definition. Although workers vary in size somewhat within a colony, even the smaller workers are larger than most other ants one is likely to have encountered. Insects have three body segments, and in C. modoc the head, thorax, and abdomen are all black – the abdomen may have some silvery bands. The legs are reddish. The second most common species (Camponotus vicinus) has a black head and abdomen; the thorax is lighter, usually reddish.
Before attempting to deal with carpenter ants, it’s important to know that there are two types of colonies – primary colonies and secondary colonies. A primary colony contains the queen, eggs, and early stages in their larval development. It is nearly always located outside the structure, and most likely in the ground, since the queen, eggs, and early larvae need to be kept wet. Late-stage larvae and pupae, however, must be kept in a drier place.
Satellite colonies are established by worker ants. They find an appropriate place above grade (a hollow tree, a post – or a house), prepare the area (possibly by digging tunnels and chambers in good wood), and then carry many larvae into the area. The larvae then pupate, and new workers emerge.
A carpenter ant colony in a structure, in nearly all cases, will be a satellite colony. Therefore, after it has been eliminated, it is essential to keep up a barrier treatment with a proper insecticide, lest the primary colonies outside simply restock the area and therefore allow the wood damage to continue. Finding primary colonies can be very difficult, since carpenter ants will trail hundreds of feet. And even if the primary colony is found and successfully killed, there is probably another primary colony within range of the building.
Carpenter ants may be eliminated by a wide range of products and methods, selection of which depends on the colony location, time of year, and many other factors. In cases where the carpenter ants being sighted in a structure are coming from a satellite colony (and not just foraging in from a primary colony), it is probably best to contact an experienced professional exterminator.
