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Let’s bee neighbors

VIC LEIPZIG AND LOU MURRAY

When we first moved to Southern California, I was afraid of the giant

black bees that hovered around the eaves of our house. They looked

more like Chinook cargo helicopters than insects. Vic reassured me

that they were merely harmless carpenter bees.

California carpenter bees (Xylocopa californica) have large plump

bodies with shiny black abdomens with no yellow markings. They can be

found in natural areas like Shipley Nature Center, the Jack Green

Nature Area, Bartlett Park, the Bolsa Chica mesa as well as your own

yard.

Males can be quite aggressive in defending their territory. If

they have decided that the wood under your eaves would be a good

place to nest, look out. They’ll get right in your face and scare the

living daylights out of you. But it’s all bluff. The males have no

stingers.

The females do have stingers but are quite docile. According to

bee literature, they don’t sting unless you try to confine them with

your bare hands. We’re not stupid enough to test that theory.

Unlike social honeybees, carpenter bees are loners. Individual

males will hang around likely nesting sites in the spring and defend

this territory hoping to snag a female. A female mates with him and

then builds her nest by herself, having nothing further to do with

the male. She’s as much of a loner as he is.

Usually she chooses a dead log for her nest, but in our urban

setting of many wooden houses and few dead logs, she takes the next

best thing. This is often the eaves of your house or your deck.

The female carpenter bee is quite the little construction worker.

Once she has found some wood that appeals to her maternal instincts,

she begins drilling. Lacking a cordless, variable speed drill like

the one I use for home repair projects, she chews a perfectly round,

bee-sized hole with her mouthparts. She doesn’t eat the wood; she

just chews it and spits it out.

Her instincts tell her to drill a hole straight in, about an inch

or two deep, which takes her about six days. Then she turns and chews

a hole at right angles to the entry hole. She burrows parallel with

the wood grain for about 4 to 6 inches, leaving a pile of coarse

sawdust below the entry hole. I proudly pointed out to Vic that the

female of the species does the carpentry work, but he countered that

it’s really just destruction. Harrumph. That’s the last time I’ll let

him use my power tools.

The next step is construction of the galleries. She lays an egg

and leaves behind a ball of “bee bread,” which is pollen and

regurgitated nectar. After sealing that section of the gallery, she

lays an egg in the next gallery cell, continuing until she has laid

six to eight eggs.

The larvae hatch from the eggs, eat the bee bread left behind for

their nourishment, then form pupae in about 30 to 40 days. The full

transformation to adulthood takes about three months. The new adult

bee chews its way out of the wooden nurse chamber and emerges in

August. These adults feed throughout the fall in preparation for

their winter hibernation. They generally hibernate in the galleries

in which they were raised. In the spring, they emerge to continue the

cycle of mating, and then die in the fall.

One carpenter bee doesn’t do much damage to a house or deck. But

unfortunately, the bees like to return to sites used in previous

years and enlarge the galleries. Often, several bees will use the

same entry hole, each building its own gallery off the main tunnel.

Eventually the tunnels may extend 10 feet back from the entry hole,

with many branches. With only one entry hole, a homeowner can only

guess by the pile of sawdust how extensive the hidden damage might

be.

Plugging up the dime-sized carpenter bee holes while there are

bees inside does no good. The bees just tunnel out through a new

opening. If you are concerned about an infestation of carpenter bees,

they can be controlled with relatively safe insecticides such as

boric acid or pyrethrins. However, prevention is the better approach.

Carpenter bees prefer unpainted woods, so keeping wood painted will

discourage these insects from setting up housekeeping in the first

place.

Since carpenter bees are local natives and act as pollinators,

they are a useful component of the natural environment. They will

live happily in nature if they can find suitable nesting sites, which

for them are generally dead logs. This is one reason why it is

important to leave some dead wood in parks and natural areas.

It’s hard to think of a dead tree as habitat, but in fact dead

trees are important components of the ecosystem. When they are still

upright, dead trees provide food for woodpeckers and perches for

raptors. Great blue herons like to nest in them. And when they fall,

they provide food for decomposers.

I’m no longer afraid of carpenter bees. They are just one more

interesting creature that shares the space around us here in

Huntington Beach.

* VIC LEIPZIG and LOU MURRAY are Huntington Beach residents and

environmentalists. They can be reached at [email protected].

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