WHY WE NEED NOT KILL CARPENTER BEES

by Whit Gibbons

March 22, 2015

I received the following question about a fascinating insect more than a decade ago. The answer bears repeating as I am asked the question every spring.

Q: We have an unpainted back porch we like to sit on. About this time in the spring, sawdust begins to fall from the underside of the roof where black bumblebees actually burrow into the eaves and wood frame. Also, one will occasionally threaten me by hovering in front of my face. How can I get rid of them?

A: The short answer is don't. Instead of eradicating the shiny black wood-burrowing bees on our own back porch, we watch them, listen to them and otherwise enjoy them. They are carpenter bees, which get to be about an inch long but do not have the fuzzy yellow appearance of bumblebees. Carpenter bees can sometimes sport a two-tone look when carrying a supply of yellow pollen.

The ecology of carpenter bees is relatively straightforward. During spring, throughout much of the country, carpenter bees emerge from holes in natural or man-made wood and seek mates. Males sometimes appear aggressive; they may even seem to threaten someone by buzzing loudly and flying in front of the 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. This in-your-face behavior of the males may just be curiosity instead of aggression. Male carpenter bees have a distinctive light-colored spot on the face.

Female carpenter bees literally chew a tunnel into wood. I know they work at night as well as day because I recently watched a steady stream of sawdust trickle from the ceiling an hour after dark. The females often choose an already created hole, but 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 can be entertaining - at least to the host.

Carpenter bees are valuable pollinators - females gather pollen, store it in the burrows, and lay their eggs so that the pollen serves as a source of nutrition for the larvae. The adult bees die during the summer and the recently born ones spend the winter in the previously completed holes.

The response of some people to carpenter bees confirms that the control mentality of humans is sometimes unnecessary and unreasonable. Many cooperative extension units associated with universities provide information on how to control carpenter bees with pesticides. Come on! Haven't we learned by now that pesticides never kill just the target organism but many other harmless creatures as well? Besides just how harmful is a carpenter bee?

Sure, bad things might happen. A female carpenter bee could sting you. But a person generally has to grab one to be stung. Of course, the possibility exists that a female carpenter bee could fly up someone's shirt sleeve or get under another piece of clothing and sting when it gets trapped. But is that enough of a problem to take invasive action and destroy the species in the area?

It's also possible that enough burrowing over the years could cause structural damage that might weaken a porch roof. But since carpenter bees tend to 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.

To me the potential hazards of carpenter bees, and a lot of other animals that some people are paranoid about, are not worth eliminating, especially with pesticides. Why lose the opportunity to watch and hear a live-action nature show produced by an industrious pollinator just because of a little sawdust?

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