Although hundreds of distinct carpenter bee species exist, the term "carpenter bee" is generically used as the common name for the eastern carpenter bee that is native to the eastern portion of North America. Carpenter bees are most known for their nesting habits; all but one species of carpenter bee burrows into wood, bamboo or other plant materials to make nests. Although many people think that these bees are pests, they play an important role in the environment.
Carpenter bees are large, black-and-yellow insects that are simple to confuse with bumblebees. Unlike bumblebees, carpenter bees don't have hairy abdomens, though a few stray hairs may be present. Carpenter bees are 3/4 to 1 inch in length and have a metallic sheen to their bodies that is more prevalent in males. Male carpenter bees also have yellow or white hair on their faces; the females lack that facial hair, making the males a bit more colorful than their female counterparts.
While male carpenter bees don't have stingers, females do and sting if threatened. If you are unable to tell the male and female bees apart, treat any carpenter bee you see like a female to avoid painful stings.
Contrary to popular belief, carpenter bees don't actually eat the wood into which they burrow. The burrowed holes are nests that female bees create to lay eggs inside. These nests, known as "galleries," typically begin straight and then turn to prevent potential predators or other invaders from easily accessing the bee eggs and larvae. Females dig out galleries using their strong jaws and often seek existing galleries to expand instead of creating a new nest from scratch. Even though individual galleries aren't overly destructive, multiple large galleries built over time can damage and weaken wood. This damage is sometimes made worse by woodpeckers that are attracted to the sounds of bee larvae within the nests.
Carpenter bees hatch from eggs in late summer and grow large enough to fly and seek food on their own by August or early fall. When winter comes, they return to the tunnels in which they were born and hibernate there until the next spring. The bees emerge from hibernation in April and May, with the males usually appearing first and each one seeking territory away from its siblings. Mating occurs in spring and early summer. Adult males often die soon after mating, and the females live long enough to lay about six to 10 eggs in their nests. In warmer climates, the life cycle is often longer and mating can occur twice within the same year.
Like other bee species, carpenter bees act as pollinators within their environment. The bees eat nectar and leave both nectar and pollen in their nests to feed the young bees that hatch in late summer. Unlike some insects, carpenter bees don't have a preference for specific plants; they collect pollen from a wide range of flowers, trees and other plants in the area around their nests.