CARPENTER BEES ARE HERE AT LAST

by Whit Gibbons

April 4, 2010

After the coldest and most prolonged southern winter in recent memory, I enjoy getting questions about courting animals and flowering plants. I have answered the following question many times about a frequent visitor to decks and other wooden structures at this time of year.

Q. We start sitting on our unpainted back porch about this time each year, and we notice that sawdust is falling from the underside of the roof. Do we have termites or are the black bumblebees that fly around responsible? We think they burrow into the eaves and wood frame. One will occasionally threaten me by hovering in front of my face. Should we get rid of them, or are they important pollinators?

A. The short answers are don't get rid of them, and yes they serve a significant role as pollinators. Instead of eradicating the wood-burrowing, shiny black bees, watch them, listen to them, and otherwise enjoy them. They are carpenter bees, which are about an inch long. They do not have the yellow, fuzzy appearance of bumblebees, but carpenter bees sometimes sport a two-tone look when carrying a supply of yellow pollen.

The life cycle of carpenter bees is relatively straightforward. From early to late spring throughout much of the country, they emerge from holes in natural or man-made wood and seek mates. Males sometimes appear aggressive by buzzing loudly and flying in front of a person's face. But it's just an act. Male carpenter bees are completely harmless. Like other bees and wasps, only the females have stingers.

Male carpenter bees have a distinctive light-colored spot on the face that is presumably a signal to other males during mating season to watch their manners and back off. To enjoy a particularly impressive show, have someone (in my case it was a grandson) wear a bright yellow shirt at the height of carpenter bee mating season. Male bees buzzed right up to the front of the shirt, apparently challenging what they thought was the biggest bee on the block. You can bring the adventure to another level when one hovers in front of you. Grab it and hold it in your hand. It will be mad when you let it go but will not sting. Be sure you grab a male and not one of the females, which have black faces with no yellow spot, but also have a stinger.

Female carpenter bees literally chew a tunnel into wood. The females prefer an already created hole, but some additional excavation and reorganization may be part of the process, much like someone moving into a new apartment might paint the walls or rearrange the furniture. Having a visitor sit in the chair beneath a carpenter bee reconstruction project with a steady stream of sawdust trickling from the ceiling can be entertaining--at least to the host. Female carpenter bees gather pollen, store it in the burrows, and lay their eggs. The pollen serves as a source of nutrition for the larvae. The adult bees die during the summer; the recently born ones spend the winter in the previously completed holes.

Some people's response to carpenter bees is unreasonable, particularly those who recommend using pesticides to eliminate them. No pesticide kills just the target organism. Many other harmless creatures die as well. Besides, just how harmful are carpenter bees? It's possible that enough burrowing over the years could cause structural damage that might weaken a porch roof. But since carpenter bees make it simple on themselves by using holes that have already been constructed instead of making new ones, demolishing an entire structure would take a lot of burrowing. Maybe our porch will eventually fall down from the annual attack of the carpenter bees, but we will have gotten considerable entertainment from these fascinating creatures before that happens.

The potential hazards of many animals are overstated. This is certainly true of carpenter bees. If we eliminated them, we would lose not only an industrious pollinator but also the opportunity to watch and hear a live-action nature show.

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