My backyard has been buzzing with a wide variety of bees. The loudest was also the largest.
Carpenter bees (members of the genus Xylocopa) are the largest bees found in California, measuring up to an inch in length. They are solitary bees, and do not have a social structure like that of the honeybee. The females do have the capability of stinging but are generally not aggressive if left undisturbed. The females of this species are a metallic black while the males are a pale yellowish brown. As with other bees, the males cannot sting. Carpenter bees get their name because of their ability to tunnel through wood.
They are most active during the spring and summer. In the spring female carpenter bees bore into non-painted, usually sound but sometimes decaying wood to make their nests. The tunnels are usually about ½ inch in diameter and from 6 to 10 inches deep. The sawdust coming from the hole is called “frass.” The tunnels are divided into several chambers, with each chamber containing one egg. The female will place a supply of pollen into each chamber to feed the newly hatched larvae. When the brood finishes developing the nests will be abandoned. Sometimes these old nests may be reused by overwintering adults or for nesting the following year.
This bee is an excellent pollinator for tomatoes and has an unusual way of performing this task. At a point on the stem just below the flower, the bee gets itself carefully positioned. Then it hugs tightly to the stem and vibrates, an action known as buzz pollination. The pulsations from the vibrating bee cause the pollen grains to fall from the flower’s anthers.