Carpenter bees look like big bumblebees and are well known for their ability to drill holes in wood. These flying insects become a nuisance in spring when they start buzzing around looking for places to lay their eggs. During this time the males can become especially aggressive and cause panic when they seem to attack people.
What can you do if you are bothered by carpenter bees? Do carpenter bees serve any useful purpose as pollinators? In this article, you will find out all you need to know about carpenter bees.
How to Identify a Carpenter Bee
Carpenter bees are a species of insect called Xylocopa virginica that belong to the bee family Apidae. They grow up to 1” (2.5 cm) long, although some species can be somewhat smaller. It can be difficult to identify these bees because of their resemblance to the common bumblebee. However, there are a few differences that can help with bee identification.
According to researchers at Penn State University, you can identify carpenter bees by their hairless abdominal area and shiny black color. Male carpenter bees may differ in appearance from the females because they have a fuzzier appearance. Because of this, they are sometimes called “teddy bears.”
Another difference between the male and the female species is their stinging ability. Males don’t have stingers even though they tend to behave more aggressively. The females can sting, but usually, only do so when threatened.
Do They Pollinate?
Yes! Like other native bees, carpenter bees play an important role in pollinating our native wildflowers.
Unlike honey bees, they pollinate via “buzz pollination” and this enables them to access shallow or open-faced flowers that other bees cannot. The female lands on the flower and curls herself around the anthers. She buzzes loudly while vibrating her wings vigorously; this loosens the pollen so it flows, as a very fine mist, onto the bee’s body. This is a critical pollination technique for various native wildflowers, introduced flowers including wisteria and jasmine, as well as food plants such as passion fruit, tomatoes, kiwifruit, blueberries, cranberries, chili, capsicum, and eggplant.
The females use the pollen they collect to create plugs in their nesting tunnels. After drilling out a long tunnel, they lay an egg at the far end of the tunnel. She then creates a pollen plug that the larva feeds on as it grows. There can be up to six such chambers in a single tunnel.
Are they Destructive?
Though they are gentle, docile creatures, these bees nest in soft, dead or decaying timber, carving their nest burrows using their incredibly strong jaws. Female bees burrow tunnels within nests from a single entrance point, laying eggs on honey and pollen mounds and sealing them with particles of chewed wood. The same bee family occupies the same nest for generations.
Male bees mate with females and help protect the nest; they do not bore.
They are renowned for nesting in dead branches on frangipani, mango, and jacaranda trees, dead banksias and eucalypts, dead grass tree flower stalks, and across an array of environments including urban, agricultural, and open forest areas. So, they can be destructive.
Unlike termites, they don’t eat wood, but they do cause damage with their boring of circular holes for their tunnels, building individual family nests into not only trees but building frames, eaves, posts, beams, sidings, and trims.
A carpenter bee infestation is identifiable by the smooth round holes in the wood that they create. Damage is usually very minor and only aesthetic – they don’t damage the structure of your home like a termite infestation does. Over time, however, minor damage triggered by these bees can lead to moisture retention, rot, and decay.
How to Keep them Away from your house
Many researchers say that the benefits of carpenter bees outweigh the destruction that these flying insects cause. However, that is probably of no comfort to homeowners who see a number of large round holes appearing in their building.
The best ways to keep them away and prevent them from damaging your property is:
First of all, it’s important to realize that staining wood won’t prevent them from damaging it. The females will easily bore through stained wood to create their nests. Researchers at Ohio State University recommend treating exterior wood with an oil or polyurethane-based coating.
Some people claim that they hate the smell of citrus oils. So, you could try slicing up the rinds of a few lemons and lime and simmering them in some water for 15 minutes. Wait until the bee repellent citrus mixture cools and then spray around the holes. This may help prevent bees from returning to their nest.
Extracts from some plants may also help to keep them away. For example, flowers such as chrysanthemums and tansies contain a chemical called pyrethrum. The National Pesticide Information Center (NPIC) says that pyrethrum is highly toxic to bees and may have a repellent action. So, you could try a natural insecticide containing pyrethrum to get rid of these bees for good.
In most cases, the only way to prevent them from causing damage is to plug up their nesting tunnels. As they hibernate in their nest during winter. So, it is best to block up the hole in fall or winter when bees emerge from their nest and there is less chance of being stung. Stuff some steel wool into the hole and then plug it with a wooden dowel. This will prevent them from chewing their way out of their nest in springtime and creating more damage to your property.
Do your best to encourage carpenter bees to relocate away from your house – don’t kill them! They are friendly little critters that play a critical role in our environment – and you can coexist quite happily with a little planning and management.