carpenter bee nest

Carpenter Bee Nests

Most people probably don’t want to think about carpenter bees nests. Still, knowing where to look, how to identify one, and what to do if you find one can be useful. Here you’ll learn what the exterior and interior of carpenter bees nests look like.

I’ll tell you where these bees commonly make their nests. You’ll also learn what to do in the event that you find a carpenter bee nest.

What Does the Outside of a Carpenter Bee Nest Look Like?

Carpenter bees belong to the subfamily Xylocopinae. They are a solitary species, meaning they don’t live in colonies. There are two genera—Certina and Xylocopa. Their name is derived from their nesting habits.

Certina

Bees belonging to the genus Certina nest inside plant stems. The adults of this species reach roughly a quarter-inch long.

Xylocopa

The larger genus Xylocopa is the more common. These bees are between half-inch and one inch in size, and are generally considered to be a pest. These bees can target natural or manmade wooden structures.

They don’t modify the exterior of the wooden structure they pick. Rather, they tunnel inside it and build their nests internally. Unfortunately, this means it isn’t easily apparent that a nest is in the vicinity. Unlike a beehive, you won’t see a visible structure.

wood bee (carpenter) in nest

You may see tunnels on the outside of a tree or wooden structure. If there are piles of yellow dust below these tunnels, it’s likely carpenter bees.

These piles are chewed wood and waste. Burrowing carpenter bees push these materials out of the tunnel as they work. Next, check for the presence of carpenter bees. If there are carpenter bees in the vicinity, a nest may be nearby.

You might actually see the bees entering the nest through tunnels. Or, witness carpenter bees creating brand new tunnels. Bees will always congregate at some point or another by the entrances. Bees belonging to Xylocopa pubescens species leave pheromone signals around their nests. Foraging bees are guided straight back to the nest by these scents.

These bees are sometimes mistaken for bumblebees. This is likely due to their rounded, large bodies.

bumble bees inside some wood
CC Image courtesy of allan_harris

However, compared to bumblebees, carpenter bees aren’t hairy. Their abdomens are not fuzzy-looking like those of bumblebees. Carpenter bees aren’t as yellow as bumblebees either. The bulk of their hairless abdomens are black in color.

Male carpenter bees fly around the nest, protecting their territory. The males are defensive and can dart at approaching people or animals.

You’ll be relieved to know that the males aren’t built with stingers. Females have the ability to sting but don’t engage territorial posturing.

Woodpeckers can also signal the location of carpenter bees nests. These birds like to eat the larvae of carpenter bees and will peck at the wood to get to them.

What Does the Inside of a Carpenter Bee Nest Look Like?

Carpenter bees nests can consist of one tunnel or hundreds. It all depends on how long the nest has been in existence.

The bees use the wood itself to make the nest. Unlike other species of bees, they don’t produce wax to make combs or cells.

The purpose of a carpenter bee nest is for rearing young and overwintering. Solitary bees don’t rear their young in the same way as social bees.

Carpenter bee females are the nest-builders of the species. Males aren’t responsible for this task. Remember, their job is to patrol outside the nest to keep potential intruders away.

carpenter bee

An established carpenter bee nest has many tunnels. Future generations of bees return to these tunnels and expand on them. They widen and lengthen tunnels as needed to make them easier to use.

Entry tunnels are bored into the wood by females. These entrances are small, not more than half an inch in diameter. Carpenter bee tunnels always follow the wood’s natural grain. The bee will bore itself into the wood until it hits the natural grain. Then, she will direct the new tunnel accordingly.

The end of the tunnel is where the carpenter bee female lays her eggs. First, she packs this small chamber with nectar and pollen. Once this is done, she’ll lay one egg in the packed nectar and pollen. Using chewed wood, the female forms a seal between the egg cell and the tunnel. The newly adult bees eventually chew free of these cells, emerging from the nest.

During the winter, adult bees return to the nest to enter a state of hibernation. They come back out again when the weather warms up.

Where Are Carpenter Bee Nests Commonly Found?

Aside from trees, carpenter bees make nests in buildings and other man-made constructions. Carpenter bees can be attracted to wood that is either new or decayed.

If the wood is badly maintained, carpenter bees will take advantage of it. Holes, cracks, and splinters are inviting to these bees. These are signs that the wood will be easy to tunnel through.

You can find carpenter bee nests in wooden decks, fence posts, or picnic tables. Even doors and window sills can fall victim to carpenter bees under the right circumstances.

Like all bees, carpenter bees subsist off nectar and pollen. Ideal nesting sites are near to their favorite food source—flowers.

What Should You Do If You Find a Carpenter Bee Nest?

Carpenter bee tunnels can do significant damage. The more tunnels in a structure, the more likely that structure is to be compromised.

If you find a carpenter bee nest in or near your home, don’t panic. Call a pest control expert with experience of removing bees to come and assess the situation.

Using insecticides to kill the carpenter bees should be a last resort. These insects are beneficial and shouldn’t be destroyed. The only exception is if the infestation is severe.

Generally, existing tunnels will be plugged up or otherwise blocked. This should be done during the day when the bees are out of the nest.

Take note, however, that sealing an active nest requires effort. Remaining eggs, larvae, or pupae will mature into adults. These adults will be able to chew out of the sealed tunnels. In this case, you’ll have to keep sealing the tunnels until the bees move on.

Summary

Forewarned is forearmed when it comes to invasive insects. Carpenter bees are useful pollinators, but they can also be destructive pests.

Carpenter bees nests should be left alone if you come across them in nature. These bees pollinate vegetables like eggplants as well as flowers. If you find a nest around your home and it’s causing a problem, call an expert. Don’t try and deal with it yourself.

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