Photo: Eastern Carpenter Bee female showing mandibles , Judy Gallagher
Judy Gallagher is an ASNV board member and a regular surveyor of local wildlife who also captures photos of what she sees, in particular the less common species.
Most of us appreciate bees, especially for their role in pollination. But there is one bee that homeowners love to hate, the carpenter bee. They make nests by tunneling into wood, and this is not good if the wood is part of your house or deck. The entrance is a circular hole, frequently on the underside of a beam, bench, or tree limb. The bee makes a tunnel with various chambers, one for each of its larvae. The nest may have several adjacent tunnels. There are about 500 carpenter bee species worldwide, including large and small varieties, but the most commonly seen carpenter bee in our area is the Eastern Carpenter Bee, which is about 3/4 inch long.
The Eastern Carpenter Bee is visually similar to a bumble bee, but the carpenter bee’s abdomen is black, bare, and shiny. Bumble bee abdomens are fuzzy, usually with yellow markings.
Eastern Carpenter Bee female showing mandibles, Judy Gallagher
Carpenter bees have particularly strong mandibles (jaws) and they vibrate their bodies while rasping their mandibles against the wood. They don't eat wood, but they often use wood shavings to create walls between the chambers. A carpenter bee can excavate about one inch of tunnel in a day, so it takes a while to create a large nest.
Eastern Carpenter Bee female going into nest with a lot of pollen, Judy Gallagher
When the nest is complete, the bee provisions each chamber with a ball of pollen and nectar, and lays an egg in each chamber. Carpenter bee eggs are known for their size, larger relative to the size of the female than for most insects.
Eastern Carpenter Bee male guarding its nest, Judy Gallagher
Female carpenter bees can sting, but it's unlikely that they would sting you unless you picked one up. So don't try that! Male bees can be a bit aggressive when protecting their nest. They dive bomb, which is intimidating because of the size of the bee and the buzzing, but they don't have stingers so they can't hurt you. You can tell the difference between a female and a male Eastern Carpenter Bee by the face. Males have a white face, and females do not.
Male Eastern Carpenter Bee guarding a flower, Judy Gallagher
Male carpenter bees find mates visually while flying, and also by guarding flowers, hoping that a female will appear. Eastern Carpenter Bees are solitary bees, but females sometimes make tunnels close to other females. They tolerate each other but aren't social like Bumble Bees or Honey Bees, and they don't have worker bees to help with pollen collection.
Eastern Carpenter Bee nectar-robbing Virginia Bluebells, Judy Gallagher
Carpenter bees are good pollinators, so they play an important role in the ecosystem. They employ a technique called buzz pollination, where the bee grasps the flower with its legs or mouthparts and vibrates its flight muscles to make the pollen fall from the flower's anthers. The tongues of carpenter bees are of medium length, so they can't easily get nectar from flowers with long tubes. But they've found a way around that. The bee drills a hole near the base of the flower and gets nectar through that hole, bypassing the pollen. This is called nectar robbing.
Tiger Bee Fly, Judy Gallagher
Eastern Carpenter Bees have some natural predators, including woodpeckers. Sadly, the woodpeckers can do further damage to your house or deck by drilling into the wood to get at the bees. Large mantises and robber flies also eat carpenter bees. The Tiger Bee Fly will lay eggs in or near the bee's nest, and its larvae will eat the bee larvae.
Bedraggled Eastern Carpenter Bee, Judy Gallagher
You may be wondering how you can make your house and deck less attractive to carpenter bees. First, treat or paint the wood. Carpenter bees usually won't drill in treated or painted wood. Spraying citrus fruit spray (water with citrus or citrus essential oils) or almond oil around bee nests usually repels the bees. Finally, scientists have discovered that playing loud music, especially music with vibration, disturbs the bees. So, crank up the heavy metal and enjoy a home free of carpenter bees!
View more of Judy’s Observations from Meadowood articles here.