Carpenter Bee 40D0012269

Eastern Carpenter Bee (Xylocopa virginica) - female, sitting on Buttonbush (Cephalanthus occidentalis)

The common Eastern carpenter bee, Xylocopa virginica, is the carpenter bee most often encountered in the eastern United States. It is often mistaken for a large bumblebee species, as they are similar in size and coloring. They can be important pollinators, especially of open-faced flowers, though they are also known to "rob" nectar by boring holes in the sides of flowers with deep corollas (thus not accomplishing pollination). They use chewed wood bits to form partitions between the cells in the nest.

The most visible physical difference (at a glance) between this species and a bumblebee is the abdomen. Eastern carpenter bees have a shiny black abdomen, with the only yellow hair present being at the base next to the thorax, while bumblebees have a very fuzzy abdomen, which in some species has large areas of yellow hair across the middle (this is visible and obvious). The female eastern carpenter bee also has a much broader head than bumblebees. Eastern carpenter bees can be sexed at a glance. Males have a patch of white cuticle on the face, as opposed to females, whose faces are black. Males are unable to sting.

Female carpenter bees make nests by tunneling into wood. They make an initial upward hole in an overhang. Then, they make one or more horizontal tunnels. Unlike termites, carpenter bees (also called woodcutters) do not eat wood. They discard the bits of wood, or use them to make partitions (walls) inside the tunnels of their nests. The tunnel functions as a nursery for brood and the pollen/nectar upon which the brood subsists.

The eastern carpenter bee is faithful to its home, preferring to lay eggs in the same hole it was born in and hibernated in. Females who leave the natal tunnel prefer to live nearby, often digging a new hole a few inches away in the same piece of wood.

Male eastern carpenter bees are curious and will investigate anyone, including humans, that comes near their nests. The curiosity is often interpreted as aggressiveness; however, the males are only aggressive to other male carpenter bees. They do not have stingers and cannot cause any real harm. The female carpenter bees tend to be busy with floral visitation and nest provisioning, but have the ability to cause a painful sting if captured.

Males spend many hours guarding their territory against other males, hovering about the nests for hours on sunny days. They sometimes attempt to mate with other insects or small birds.

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