Carpenter bees are often mistaken for a bumblebee species, as they can be similar in size and coloration, although most carpenter bees have a shiny abdomen, while in bumblebees the abdomen is completely clothed with dense hair. Male bees are often territorial, often seen hovering near nests, and will approach nearby humans or animals. However, males are harmless since they do not have a stinger. Female carpenter bees are capable of stinging, but they are docile and rarely sting unless caught in the hand or otherwise directly provoked.
Carpenter bees are traditionally considered solitary bees, though some species have simple social nests in which mothers and daughters may cohabit. However, even as a solitary species, they will nest near each other. It has been occasionally reported that when females cohabit, there may be a division of labor between them, where one female may spend most of her time as a guard within the nest, while another female spends most of her time foraging for food.
Carpenter bees are a wood-destroying insect, making nests by tunneling into wood. Each nest has a single entrance which may have many adjacent tunnels. The entrance is often a perfectly circular hole measuring about 0.63 inch on the underside of a beam, bench, or tree limb. Carpenter bees do not eat wood. They discard the bits of wood, or re-use particles to build partitions between cells. The tunnel functions as a nursery for their young and storage for the pollen/nectar upon which the young feed. The eggs are very large relative to the size of the female, and are some of the largest eggs among all insects.