Photo by Dr. Jeffrey K. Barnes, Curator
Arthropod Museum
University of Arkansas • Division of Agriculture

Carpenter bees cause alarm because they are large insects, up to about an inch long, heavy-bodied, blue-black to black colored with a green or purplish metallic sheen Carpenter bees are the largest native bees in the United States. They do resemble bumble bees. Carpenter bees sometimes become a nuisance outdoors when they fly hover around the heads of people. The territorial males harass humans and other animals that enter their terrain, and they are often found boring holes in structural timbers, such as rafters and fascia boards. The males lack a stinger, and while females do have stingers, they are very docile and are not known to sting people, even when disturbed.

Carpenter bees are black, and they have bright yellow, orange or white hairs on the thorax and first abdominal segment. The abdomen, especially on the top side, is black, shiny and bare without hairs. Adults differ from bumble bees in that they are not social, the upper surface of the abdomen in mostly devoid of hairs, and the females have a brush of hairs on the hind leg instead of a pollen basket. Male carpenter bees have white faces, but females have dark faces. Larvae are sac like, white and legless with brown, globular heads. The pupal stage is passed in a silent cocoon.

Photograph of carpenter bee damage by Robert G. Bellinger, Clemson University Entomology

Adult carpenter bees take pollen and nectar from a wide variety plant species. They are early morning foragers. When carpenter bees land on flower blossoms they become “living tuning forks”; they sonicate (which is the act of applying sound, usually ultrasound, energy to agitate particles - thank you Wikapedia for the definition) the dry pollen grains out of the flower.
* Okay – How cool is that? Carpenter bees use ultrasonic vibes to knock the pollen off the flower! * This type of pollination is called “buzz pollination.” With declining populations of honeybees, the carpenter bee, is becoming an important pollinator.

From time to time carpenter bees are quite ingenious in their foraging for nectar. On long, tubular flowers the carpenter bee, due to its large size, is unable to enter the flower opening. Instead they become “nectar robbers”; they use their mouth parts they cut a slit into the stem of the flower to steal away nectar.

Carpenter bees nest in tunnels in sound wood of dead trees and in structural timbers. They use both soft and hard woods, but they seem to prefer pines. Carpenter bees can get into very small areas, and will seek out the unpainted wood surfaces and bore their holes This is where people and carpenter bees come into conflict. The bees want to eat the things we build out of wood and wooden products, and we (understandably) do NOT want a bunch of bees ruining our stuff. And although carpenter bees attack fence posts, utility poles, lawn furniture and structural timbers, they do not usually cause serious structural damage, unless there are a large numbers of bees and they lengthen the same tunnels over a period of years. Woodpeckers may also damage wood in search of bee larvae in the tunnels. In the case of thin wood, such as siding, this damage can be severe. Holes on exposed surfaces may lead to damage by wood-decaying fungi or attack by other insects, such as carpenter ants.

Carpenter bee infestations are often first detected by finding large amounts of sawdust in the area of the tunnel excavation. Control can be difficult. If only a few bees are present, it is probably best to simply swat or capture them, treat the tunnels with insecticide or insert a wire probe to kill the larvae or pupae, and plug the tunnel entrances so they cannot be used by other bees. Painting or treating wood can discourage attack by carpenter bees.

Let’s be clear: If it’s wood, in the environment – it belongs to the bugs. Bearing that in mind, there are a few things you can do to reduce your insect profile.

Keep all exposed wood surfaces well painted (oil base or polyurethane) to reduce attack. Wood stains will not prevent damage. If practical, remove and replace damaged wood with chemical pressure-treated wood to discourage nest construction. Carpenter bee control can be done at any time of year.

Depending on the area you want to protect, you can use common insect screening to keep these bees from getting into areas where there may be unpainted surfaces, such as behind fascia trim boards or other places where it might be difficult or impossible to paint. Just cut strips of metal insect screening, (don't use the fabric or plastic type - they’re edible), climb on a ladder and wedge or staple them into place where the bees are working. You can do this with the bees there.

We always recommend killing them by hand, with a tennis racket. This is a two fold plan:
1) you get a great cardio workout and 2) the large face of the racket can often take out many bees at once. They just pop into pieces, and it’s eco-friendly. Carpenter bees are very much like salmon, they return to the same places every year to spawn. Killing the individuals who call you place home is the only way to keep from having a recurring problem.