Many people think they have stinging bumblebees when they see large, black bees hovering in the air near wooden buildings. These probably are not bumblebees but male carpenter bees, also called wood bees. Male carpenter bees do not have stingers, but the females do.
The good news is that the female bee "must be extremely provoked (i.e. handled) before she will sting," according to Steve Jacobs, Sr., of the Penn State entomology department. The bad news is that female carpenter bees carve circular holes as entrances to tunnels they excavate inside unpainted wood.
The Differences Between Carpenter Bees and Bumblebees
Carpenter bees usually have a small band of yellow around their heads, but their abdomens (the large rear part of the body) are smooth and shiny and virtually all black. Bumblebees' abdomens are usually not shiny and have a large band of yellow or white hairs. Also, while carpenter bees nest in their tunnels in wood, bumblebees build their nests in burrows in the ground.
Therefore, if you see a large, shiny, black bee hovering near a wooden structure, especially one with bee-sized, circular holes, it is almost certainly a carpenter bee. However, if you see a somewhat similar, large, yellow-banded bee hovering continuously over an area of ground away from wood, it is likely to be a bumble bee. Avoid it.
How Carpenter Bees Behave
It is the male of both these bee species that hovers. He is protecting the nest from intruders and will chase away any flying creature, including butterflies and tiny gnats. He may also try to chase away humans. Carpenter bees may bump up against you, presumably hoping to scare you away. If you're sure they are carpenter bees, you can ignore them.
If you're not sure which species of bee you are dealing with, stay away from them and certainly keep children away from them. If you have to go near either bee, move slowly and do not wave your hands in the air. Both species will respond aggressively to rapid movements.
Both carpenter bees and bumblebees are useful animals, especially as pollinators of many types of plants. They often are as effective for this purpose as the honey bee that seems to be disappearing from so many parts of the world, as, incidentally, are bumblebees. However, carpenter bees and bumblebees do not produce honey.
Getting Rid of Carpenter Bees
Carpenter bees can eventually seriously weaken wood they tunnel into. To prevent them from starting their tunnels, paint the wood with a thick coat of pigmented paint. Do not use wood stain, which rarely discourages tunneling bees.
If you have to eliminate existing bees, you can plug the holes with wood putty, dowels or even steel wool. Check beneath any holes for fresh wood sawdust. This is a sign of an active nest.
To avoid being stung, do this plugging on a cool night using a flashlight with its lens covered with transparent, red plastic. Red light is invisible to the bees.
The bees inside will die, but you will still need to paint the wood to keep other carpenter bees from carving tunnels into the same wood.
However, if the wood they are tunneling into is not a structural support, you can just live with the carpenter bees as bumptious but not really such bad neighbors. Some gardners deliberately set up pieces of a soft, unpainted wood in or near their garden so the carpenter bees will nest there and pollinate their flowers.
Sources:
- Carpenter Bees by Steve Jacobs, Sr. Extension Associate, Penn State Entomology Department Fact Sheet
- Carpenter Bees by Susan C. Jones, Ohio State University Department of Entomology
