What Are Wood Bees?

Carpenter bee. Image source: Wikimedia Commons.

Wood bees, also known as carpenter bees, are a type of bee named for the way they make their home: by burrowing into wood. With all of the buzzing and flitting around, it is not always easy to differentiate between different types of bees.

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What Do Wood Bees Look Like?

Carpenter bee. Image source: Wikimedia Commons.

There are two genera of carpenter (wood) bees, called Xylocopa and Ceratina; the Xylocopa carpenter bees are large while the Ceratina carpenter bees are small. The more commonly encountered carpenter bee is from the genera Xylocopa. The large carpenter bee tends to be one to two and a half centimeters in length, while the small carpenter bee is generally less than one centimeter in length. Both genera are darkly colored (black or dark green) and can have a somewhat metallic coloring as well, ranging from blue to purple. The back of the abdomen of the large carpenter bee is smooth rather than hairy although there tend to be yellow hairs on the legs and thorax of the bees.

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What Is The Difference Between Wood Bees and Bumblebees?

Both large carpenter bees and bumblebees are approximately the same size and can be similar in color. The easiest way to distinguish between the two types of bees is by looking at the abdomen. In carpenter bees, the abdomen is more clearly pronounced, likely due to the lack of fuzzy hair covering the dark and shiny abdomen. Bumblebees, however, are covered in thick fuzzy hair and have black and yellow bands of hair.

Bumblebee. Image source: Wikipedia.

Carpenter bees and bumblebees also differ in their pattern of flying. When not out pollinating, solitary male carpenter bees tend to hover while searching for a mate, and then to dive abruptly and chase the female of interest. Bumblebees, however, tend to travel in loose clusters and fly seemingly aimlessly around while they land on different flowers and pollinate.

Carpenter bees live in holes that they have bored out of wood, whereas bumblebees tend to nest in burrows that they build underground. These underground nests can be found in burrows that had been previously constructed and inhabited by animals, or in small gaps beneath stones or planks of wood, or even in compost heaps. As social bees, bumblebees live together in their nests and are ruled by one queen who is the only female capable of reproducing.

What Is The Difference Between Carpenter Bees and Mason Bees?

Unlike honeybees or bumblebees, carpenter bees are solitary bees. Solitary bees live near one another but tend to make nests of their own, rather than hives. Other solitary types of bees are mason bees, miner bees, and leafcutter bees.

Female red mason bee. Image source: Flickr.

Carpenter bees and mason bees are often confused for one another, not because of their similarities in appearance, but due to their similar habits both in living solitary lives and for where they make their homes. However, unlike carpenter bees, mason bees do not create any holes in wood to form their homes. Mason bees find preexisting small gaps and holes in structures and make small nests within those gaps or holes. They do not perform any further excavations, but rather add bits of collected materials such as clay or mud to transform their found space into a suitable home.

How Do Wood/Carpenter Bees Make Their Homes?

Wood bees make their wooden homes for two reasons, protecting the eggs that they have laid, and hibernation during winter.

Female carpenter bees make round holes that are approximately one half of an inch in diameter in untreated softwood such as redwood, cedar, pine, or cypress. The female carpenter bee uses her mandibles to drill the hole and excavate a tunnel that is usually an inch long which then turns at a ninety-degree angle to run parallel along the length of the wooden structure for approximately six inches.

Carpenter bee tunnels in wood. Image source: Wikipedia.
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In this tunnel, she will make small cells that she will fill with some pollen and nectar in the shape of a ball called “bee bread”. She will lay her eggs on the bee bread, and seal each cell with some wood pulp from the sawdust she has generated in boring out her tunnel.

When the eggs hatch and the larvae emerge, they eat the bee bread on which their eggs were laid. The larvae then enter the pupal stage, during which they become adult carpenter bees.

Adult carpenter bees use their new mandibles to emerge from their cells in their burrow, approximately seven weeks after having been laid as eggs and go to explore the outside world. It is summer when the new adult carpenter bees emerge, so they spend the summer pollinating and preparing for winter.

During winter, carpenter bees hibernate. They choose old burrows and clean them out so that they can spend the winter safely protected from the cold. When spring returns, the carpenter bees leave their hibernation burrows and seek a mate, usually in April or May. Females whose eggs have been fertilized begin to make their burrows or return to an old burrow and expand it for their eggs.

What Do Wood Bees Eat?

Despite common belief, carpenter bees do not eat wood. As described above, carpenter bee larvae eat a mixture of pollen and nectar called bee bread. Adult carpenter bees eat nectar during the summer before they hibernate for the winter.

Like honeybees and bumblebees, when carpenter bees feed on nectar, they collect pollen in their legs hairs and spread that pollen around to each different flower on which they land. With the many different ways in which bees may be lost, including fungal diseases, mites, insecticides, and changes to the ecosystem, it is more important than ever that all pollinators be supported.

Are Wood Bees Pests?

Many people worry about being stung by bees. While that can be a danger, it is not one that typically needs to be worried about concerning carpenter bees. The males may seem aggressive during the mating season when they hover and dive, but the male carpenter bees do not possess a stinger, so their aggressive behavior is nothing more than posturing. Female carpenter bees do possess stingers, but very rarely use them (unless she has been assaulted in some way).

Another major concern about carpenter bees is of course damage to wooden structures such as homes due to the tunnel excavation performed by the bees. It is important to keep in mind, however, that these tunnels are generally only made in untreated softwood, including rotting wood. It is usually better to try to prevent carpenter bees from boring nests into your wooden structures than to kill them.

How To Prevent Carpenter Bees From Making Your Home Their Home Too

The best way to prevent carpenter bees from making your home into their home is to prevent the bees from being able to bore into wood. Use hardwoods or wood that has been pressure-treated when building. Keep wood well painted or varnished or stained. Use vinyl or plastic siding on the exterior of your house.

Bee kind.

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Cite this article as:
Jessica McGregor, PhD. What Are Wood Bees?, Science Trends, 2018. Available at:
http://doi.org/10.31988/SciTrends.25115
*Note, DOIs are registered Friday weekly and therefore may not work until then.

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