They fill the ecological role of primary decomposition of plant material. Tunnels are clean, and do not contain dirt as do termite's tunnels. When they enter homes they may make rustling noises in side walls loud enough to be heard when listening near to the source. Carpenter ants use wood as a nest site, but do not eat the wood. Although the ants may damage sound wood, the majority of excavations occur in damp or decaying wood.
Bumble bees have yellow hairs on the other abdominal segments as well.
They frequently re-use old tunnels for pollen storage and overwintering chambers. They prefer rotten or seasoned wood. Their name refers to the adults boring into seasoned wood reducing it to powder. The exit hole is so small a ball point pen tip can barely fit in. Although a few species in the western states have readily visible heads with large mandibles.