How harmful are carpenter bees?

Carpenter bees appear and become active beginning in mid-spring through summer. These bees live up to their name because they drill perfectly round holes in exterior wood structures, dead trees, woodpiles, fences, and decks.  Homeowners may overlook a simple round hole, but as more appear, it becomes evident that carpenter bees are present.

What are carpenter bees?

Carpenter bees got their common name from their habit of boring into wood. Carpenter bees do not eat wood but cause damage to structures by drilling circular holes to create tunnels inside the wood. Unlike other common bees, such as honeybees and bumble bees that live in colonies, carpenter bees are not social insects and build individual nests in trees outdoors or into the frames, eaves, or sides of buildings. (Pestworld.org)

The male carpenter bee is territorial and protects its nesting sites, hovering nearby and attacking intruders. Although the male behaves aggressively, it does not have a stinger, making it harmless. The female has a stinger but is not defensive and rarely stings. Males have a white or yellow blaze on their faces, while females have a dark face.

Female carpenter bees chew circular holes through the wood to make individual galleries to lay eggs and protect their larvae as they develop. They are particularly inclined to build their galleries in soft, unpainted, and worn wood, although some species may prefer hardwood. As a female creates tunnels, she will bore larger, open areas into the tunnel, called cells, where her young will develop. She will provision each gallery cell with a mass of pollen and regurgitated nectar upon which she will lay a single egg. The female then seals this portion of the gallery with chewed wooden pulp. The eggs the female lays take approximately 36 days to develop into adulthood.

Do carpenter bees sting?

Male carpenter bees do not sting, but they are territorial and often the gender that most people come into contact with. The males will hover closely to people, especially attracted to sudden movements, but do no more than create unnecessary fear. Female carpenter bees sting; however, it is rare and requires provocation.

Are carpenter bees pollinators?

Yes, carpenter bees are indeed pollinators. Here are some interesting facts from the U.S. Forest Service:

• In our vegetable and flower gardens, carpenter bees are generalists and may be found foraging on several different species. They, like bumblebees, are early-morning foragers. Carpenter bees land on flower blossoms; they become living tuning forks. Using their powerful thoracic muscles, carpenter bees sonicate the dry pollen grains from the flower’s anthers. This type of pollen gathering is called “buzz pollination.” Carpenter bees are excellent pollinators of eggplant, tomato, and other vegetables and flowers.
• From time to time, carpenter bees are quite ingenious in foraging for nectar. Due to its large size, the carpenter bee cannot enter the flower opening on salvias, penstemons, and other long, tubular flowers. Instead, they become nectar robbers. Using their mouthparts, they cut a slit at the base of the corolla and steal away with the nectar without pollinating the flower.

We are very mindful of the value of pollinators for plants and crops, including backyard gardens, and make every effort possible to relocate them.

Carpenter bees and damage to your home

Unfortunately, bees can be pests around homes, causing considerable structural damage when they repeatedly colonize exposed wood. An early sign of carpenter bee damage is coarse sawdust that collects beneath excavated cavities during the spring of the year. Unsightly stains caused by falling bee waste around the entrance hole may also develop. Homeowners often notice a buzzing or burrowing sound coming from within the wood. The excavating bee will bore directly into the wood with her mouth parts for about an inch, then turn sharply and bore at a 90-degree angle, usually along the grain of the wood.

Usually, the gallery will extend about four to six inches, but with repeated use, galleries have measured ten feet long. Nest sites by a single bee result in slight damage, but repeated colonization over several years may result in considerable damage. In addition, the open holes allow water intrusion that also can create significant moisture damage over time. Also, woodpeckers feeding on the developing bee larvae will tear into the galleries, further damaging the wood to the point where it needs replacing.

Can I prevent a carpenter bee infestation?

Carpenter bees prefer unpainted and untreated wood, which is an option, but is usually not preferred by homeowners. Diligence is the best practice for homeowners, no matter the pest or nuisance wildlife issues. Make the areas in and around your house unwelcoming:

• Seal cracks and gaps along the property’s foundation and walls with a silicone-based caulk.
• Inspect regularly and repair any tears in screens or gaps in windows.
• Keep all doors closed, including the garage doors.
• Remove dead wood and yard debris, and keep firewood stored away from your home and never in the garage!

I need help getting rid of bees!

Getting rid of bees is more than one size fits all approach. Contact us for professional bee removal. Our technicians are licensed by the DEC and certified by New York State. Visit our FAQ page to learn more about us and our services.

Please note: Please seek immediate medical attention if you have been stung by a bee, wasp, or yellowjacket and are unsure of your reaction. Please do not delay.

Resources: Clemson Cooperative Extension, pestworld.org, U.S. Forest Service