Carpenter Bees

Facts

The carpenter bee is one of the largest bees found in the United States.

Appearance & Identification

What do carpenter bees look like?

profile shot of carpenter bee
Image credit: Univ. of Missouri
carpenter bee from top
dark carpenter bee

Carpenter bees resemble the widely recognizable bumble bee in appearance.

Size & Color
Both types of bees grow to as long as an inch in size and have round, black bodies covered in stripes of yellowish hair.

Body / Abdomen
However, while bumble bees are hairy over the entire body, the abdomen of a typical carpenter bee remains hairless and has a glossy black sheen.

Male vs Female
Carpenter bees also exhibit slight physical differences between males and females within the species. The head and face of adult male specimens feature white markings, while females have an entirely black head.

General Information

Though several different types of carpenter bees live throughout the U.S., Xylocopa virginica is the most prevalent species in eastern regions of the country. Like other bee species that inhabit the area, carpenter bees facilitate the growth of vegetation by pollinating flowers and other plants. Carpenter bees are generalist pollinators that pollinate many different kinds of plants , but the beneficial insects often serve as particularly capable pollinators of vegetable crops like eggplant and tomatoes. As their common name suggests, carpenter bees are also capable of boring into wood and causing aesthetic, and sometimes even structural, damage to homes.

Habitat

Where do they live?

Unlike the social bee species (bumble bees and honey bees), carpenter bees are solitary and do not establish large colonies nor live according to a caste system. The insects live up to their name by excavating galleries from trees and other wood structures to carve out sites for nesting and overwintering. Taking advantage of their powerful jaws, or mandibles, female carpenter bees construct the galleries by selecting a suitable piece of wood, creating a distinctively round entrance hole, and drilling through the material to produce a tunnel. Carpenter bees then use chewed wood to create walls and partition the gallery into individual sections, each of which eventually houses an individual egg.

The eastern carpenter bee generally prefers to make galleries out of softer woods, such as cedar, cypress, fir, and pine. While females construct the galleries and lay the eggs, male carpenter bees are often seen hovering outside the nest site and chasing trespassers away. Though males cannot sting, they defend the nest with vigor and frequently fly in the personal space of humans, commonly inciting undue panic. Only female carpenter bees have functional stingers, which the they rarely use.

Diet

What do carpenter bees eat?
Adult carpenter bees do not actually ingest the wood they excavate and instead feed on the nectar of flowers. Due to their large size relative to other bees, carpenter bees cannot fit into the openings of certain flowers and instead use their strong jaws to make a slit and access the nectar at other points on the plant. The excavating insects also combine pollen with regurgitated nectar to create a food source for newly hatched eggs and subsequent larvae to feed on through all the stages of development.

Life Cycle

Reproduction
After mating with young males in the spring, female carpenter bees construct wood galleries and lay eggs within the resulting tunnel. Carpenter bees lay a single egg on top of the mixture of nectar and pollen in each section of the partitioned gallery.

Larvae
Larvae hatch from the eggs and begin consuming the food source to gain the nourishment necessary for complete development.

Pupae
Like other bee species, carpenter bees develop into pupae after the larval stage and eventually become fully grown adults roughly seven weeks after hatching. Newly matured carpenter bees emerge from the excavated gallery during late summer to feed and return to the tunnel to overwinter through the winter.

Problems / Dangers

While carpenter bees rarely sting or live in groups large enough to pose a dangerous threat to humans, the insects can cause problems by excavating galleries out of wood.

Although trees often make adequate nesting sites, carpenter bees frequently lay eggs and overwinter in the wood of decks, outdoor furniture, and houses. The excavating insects mainly create cosmetic damage by chewing entrance holes into the wood and staining the area below the entryway with excrement and pollen. However, carpenter bees can also cause structural damage when multiple generations of the insects inhabit and enlarge the same wood gallery over an extended period of time.

Signs of Infestation

Holes in Wood
The entrance hole is a telltale sign of carpenter bee activity. Entrance holes are roughly a half-inch in diameter and almost perfectly round.

Stains
Carpenter bees may also leave yellowish or brownish stains of pollen and excrement in the vicinity of the entrance hole.

Hovering Behavior
Males often hover, an action typically not performed by other bee species. In fact, if a large fuzzy bee is seen hovering under the eaves of a house, chances are the insect in question is a carpenter bee.

Prevention

One of the easiest ways to prevent carpenter bees from nesting is to reduce the attractiveness of the wood.

Painting Wood
As the flying insects generally prefer to excavate bare and untreated wood, home owners should consider painting or staining exposed wood structures around the outside of the house.

Hard Wood vs Soft Wood
Homeowners should also keep in mind that carpenter bees most often select softer woods for nesting and overwintering, making hardwoods perhaps a better choice for completing any kind of construction or project.

Sealing Old Wood
Carpenter bees like to reuse previously excavated wood galleries, as well. Area residents should therefore locate and seal all entrance holes while making sure not to trap any carpenter bees inside, as the excavating insects will simply chew new tunnels and escape.

Control

How to Get Rid of Them

Insecticides

If carpenter bees have been active around the home, each tunnel should be treated with insecticide. The objective is to apply something that will eliminate the female bees immediately. The insecticide should also remain effective so it can eliminate the bees that hatch in a few months.

Dust insecticide is usually the most effective and practical treatment for carpenter bees. The dust will not soak into the wood, so it will remain effective. A wettable powder insecticide can also be effective. It is applied as a liquid, and then when it dries, it leaves a powder on the surface.

Application
Insecticide injection requires special equipment. Safety is a concern to prevent insecticide splashing into the face of the person making the treatment. Many people prefer to contact a pest control professional to do these treatments.

Sealing Tunnel Holes
After the insecticide has been applied, do not seal the holes for a few days. After the female carpenter bees have been exposed to the insecticide, the holes can be plugged with putty or wooden dowels.

Homeowners can protect exterior wood by applying paint or a similar durable sealer. Scientists believe that carpenter bees are less likely to attack wood that has been painted or sealed.

Due to the risks associated with pesticides and the high heights at which the insects often live, carpenter bee traps are a frequently used alternative to other methods of pest management.

A typical carpenter bee trap is constructed of wood and generally resembles a birdhouse with a transparent bottle or container attached to the bottom.

While the effectiveness of carpenter bee traps remains open for discussion among experts, the devices prove easy to use largely because of the way they work.

How They Work
Carpenter bee traps take advantage of the insects natural tendencies. Made of the very material carpenter bees are most attracted to, the traps feature an opening roughly the same size and shape as the holes the insects produce when boring through wood. Carpenter bees then enter the trap willingly as if the device were an ideal nesting place. Once inside, the insects are attracted to the light shining through the transparent receptacle connected to the underside of the wood. The carpenter bees fly in to the receptacle and become trapped.

Despite the ease of using carpenter bee traps, homeowners should still seek out the services of a pest control expert to ensure the safe and complete removal of all carpenter bees. Carpenter bees are often difficult to control without professional assistance, as the insects often nest in high places and will sting when threatened.

Furthermore, because carpenter bees do not actually eat the wood they excavate, the use of protective insecticide sprays and other preventative measures frequently proves ineffective. Even when private residents successfully trap carpenter bees, additional steps must be taken for the issue to become totally resolved.

Homeowners must ensure complete displacement of all carpenter bees before sealing the holes created by the destructive insects. Otherwise, any carpenter bees left behind will simply bore new holes and cause additional damage. An experienced pest control professional has the knowledge, equipment, and ability to deal with carpenter bees properly and effectively.

For the best and safest results in managing and preventing carpenter bees, contact a professional pest control service.