What are these bees doing hovering around my barn?

ASK THE HORT AGENT

Question What are these bees doing hovering around my barn?

Answer They are carpenter bees staking out their territory like hummingbirds. Carpenter bees resemble bumble bees. Both are great flower pollinators. Bumble bees typically nest in the ground and carpenter bees make tunnels in wood. While both are relatively large, black and yellow, there is one easy way to tell them apart. Carpenter bees can be seen hovering around barns and bumble bees do not.

Carpenter bees are often accused of chasing people. These claims are greatly exaggerated. A bull, bear or walrus will chase people, but a little old bee isn’t quite as aggressive. The male carpenter bees do chase anything small that flies through their air space. They are mostly gunning for other male carpenter bees. Male carpenter bees can easily be distinguished from females by looking at their face. Males have a large yellow (or white) spot on their face. Females have a completely black face.

The females perform a lot less aerial combat. Their job primarily consists of making a home for the baby bees. While they are called carpenter bees, they don’t actually build anything from wood. Instead, they chew tunnels. More accurate names would include miner, sculptor or sawdust bees.

The lady of the tunnel bores into the wood perpendicular to the grain for an inch or two, then makes a right angle turn and excavates along the wood grain for four to six inches. She excavates at the rate of about one inch per week. Whenever possible, carpenter bees prefer the elongation of an old tunnel as opposed to the excavation of a new tunnel.

Carpenter bees are most visible in the spring when they are fighting, mating and tunneling. They lay eggs in the tunnels. In the fall, the new bees crawl out, fly around and reenter the tunnels for the winter.

A single family of carpenter bees will not affect the stability of a wooden structure. However, multiple families over several years can have a destabilizing structural effect. The best way to deter carpenter bees is the use of paint and/or siding. Aluminum or plastic siding covers wood and prevents the bees from tunneling. Paint (not stain) will serve a similar purpose.

Other means of control consist of plugging the hole (during the summer), running a stout piece of wire into the tunnel (during the summer or winter) or swatting the bees with a tennis racquet (during the spring or fall).

For more info on carpenter bees, visit http://ohioline.osu.edu/hyg-fact/2000/2074.html If you don’t have internet access, call me at 910-893-7533 or email me at gpierce@harnett.org

Here is a test to see if you really trust what I say and understand what I’m telling you. When a male carpenter bee is hovering, you can clearly see the yellow dot on his face. Simply use your catlike reflexes to grab the male bee from the air. He will buzz in your hand, but not sting you. Ironically, they do not have stingers. The female carpenter bees have stingers and will sting you if captured. Now you know who wears the stinger around their house.

Gary L. Pierce

Horticulture Extension Agent