Carpenter ants are one of the most beneficial predators in the forest ecosystem. They feed on small insects and honeydew and they scavenge dead insects and decaying material. They are particularly prolific in the moderate climate and high humidity of coastal British Columbia. For brief periods in the spring and early summer the winged Carpenter ants swarm into the air on mating flights. The queens are easy to see as they settle, shed their wings and search for crevices in decaying wood to begin their nest.
Carpenter ants make two types of nests.
If the queen finds moist, decaying wood, she tunnels into it to begin the main nest. This site must be permanently moist or the eggs and younger larvae cannot survive. Old nests can contain thousands of ants, but it takes several years for a new nest to build up to a few hundred individuals. Main nests are usually outdoors in rotting stumps, trees or in decaying landscape timbers. They can become established in houses where wood in the structure has begun to decay.