The Buzz in the Backyard

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.

Male Carpenter Bee

Male Carpenter Bee

Female Carpenter Bee

Female Carpenter Bee


About Kevin

Councilmember - City of Oakley, Manager of Mainframe Operations and Optimization – USS-POSCO INDUSTRIES, Co-Founder and Board Member - Friends of Oakley A Community Foundation, Commissioner - Contra Costa Transportation Authority, Board Member - Tri Delta Transit, Transplan, San Joaquin Joint Powers Authority and RD 2137, Advisory Board – Opportunity Junction
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3 Responses to The Buzz in the Backyard

  1. Greetings! I’ve been reading your blog for some time now and finally got the courage to go ahead and give
    you a shout out from Atascocita Texas! Just wanted to mention keep
    up the fantastic job!

  2. Kevin says:

    Frank, I’ve seen the females in my backyard for a number of years, the males only recently. But I’ve never seen any damage.

  3. Frank Spinelli says:

    I have heard that these bees are as destructive as termites. I’ve seen and heard the black females over the years but never noticed wood damage. Have you?

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