Bees

Carpenter bees resemble large bumblebees but have very different nesting behavior. They bore long tunnels into wood and divide these tunnels into cells where individual larvae will develop. While several to many females may be nesting in wood of same structure or other site, each is acting in a solitary fashion, as these are nonsocial bees.
The common eastern species resembles many of the bumblebees closely enough that it is often confused on casual observation. The carpenter bee is black in color and marked with areas of yellow hair, but the dorsal sides of the abdominal segments have no areas of yellow hair. In bumblebees at least some of the abdominal segments will have yellow hair on their dorsal segments. Other species of carpenter bees, from other genera, may be black, green, or somewhat marked with whitish, yellowish or reddish hair. The dorsal surface of the abdomen is also generally bare in these species. The typical carpenter bee gallery has an entrance hole on the wood surface and continues inward for a short distance. It then turns sharply upward and runs in the same direction as the grain of the wood. The female provisions the gallery by inserting a ball of pollen on which an egg is laid. Live preys, such as insects or spiders, are not used. The female then closes the cell by placing a mass of wood pulp in the gallery. A series of cells are constructed as the bee works backward, out of the gallery. Females often enlarge existing galleries or use old ones, so very complex gallery systems can be developed over a number of years. These galleries are often made in the siding or window trim of homes, and in such cases the structural strength of tunneled timbers may be reduced.
Carpenter bees nests are usually not difficult to locate. Some of the more common sites chosen within buildings include siding, eves, wooden shakes, porch ceilings, windowsills, doors and so forth. They will also nest in telephone poles, fence railings or posts, and even lawn furniture. Many types of wood are selected for nesting, but the softer woods are preferred. Unpainted or well weathered wood is much more susceptible to attack than hardwood or well painted timbers. Another sign to look for in locating carpenter bee galleries is the yellowish or brownish excrement stains created on the side of the home, below entrance holes to the galleries.
Carpenter bees complete one generation per year in most areas of the United States. Tunnels are prepared and eggs are laid in the spring. Larvae and pupae develop in the closed cells in the early summer. Adult bees emerge in late summer and return to the same tunnels to hibernate for the winter. In the spring the adults mate and the females lay eggs, completing the cycle. The abandoned nests of carpenter bees are frequently infested by any number of secondary pests, including dermested beetles, dried fruit moths, and other scavengers that will feed on the unused pollen and nectar. Certain wasps, ants, and bees will also be found in old galleries, using them as shelter and nesting sites.