Carpenter Bees: Xylocopa Virginica

Photo of a carpenter bee

Description Of The Carpenter Bee

The carpenter bee is a robust and large insect. The upper surface of their abdomen appears shiny black and is mostly bare. Their thorax is covered with hair that is yellow, orange, or white. Its head is nearly as broad as the thorax. There is a completely blackhead for the female, while the male has yellow or white markings. The carpenter bees have a thick hairbrush on their hind legs.

Carpenter bees resemble bumblebees because they are similar in size, but the bumblebee’s head is much smaller than the width of the thorax. Unlike carpenter bees, Bumblebees have a very hairy abdomen with yellow markings, and on their hind legs, they also have large pollen baskets. Bumblebees are social insects living in colonies typically located on the ground with nests and carpenter bees nest within wood structures. 1Go To Source ohioline.osu.edu -“Carpenter Bees”

Learn More: List Of Stinging Insects

Carpenter Bee Behavior

Only on warm days do Eastern carpenter bees leave their nests. They can be social or solitary, meaning that they nest alone or in groups. Male eastern carpenter bees are territorial, and their nests will be protected.

It is the responsibility of females of this species to construct nests. A single female, typically on dead trees, logs, or stumps, will choose a nesting site and begin to chew a hole. She will create a nesting tunnel with a diameter of 15 mm, known as a gallery. Female carpenter bees are capable of chewing up to 15mm a day. The gallery will be constructed vertically if the grain of the wood is vertical.

Similarly, if the wood grain is horizontal, then the gallery will be horizontally constructed. Completed, newly-built galleries are about 35-45 mm in length. Alternatively, it is possible to expand on and reuse old nesting sites. They’re considerably longer than the new galleries. 2Go To Source animaldiversity.org -“Xylocopa virginica carpenter bee”

Reproduction Cycle Of Carpenter Bees

Image of carpenter bee chewing on wood

Carpenter bees do not live like honeybees or bumblebees in colonies. The adults, often live within previously constructed brood tunnels, overwinter individually. Those who survive the winter emerge in the following spring and mate. The female carpenter bees fertilize and then bore into wood, digging a tunnel to lay their eggs. The entrance hole in the wood’s surface is perfectly round and about a pinky finger’s diameter. Below the opening, coarse sawdust may be present, and tunneling sounds within the wood are sometimes heard.

The bee makes a right angle turn after boring within a short distance and continues to tunnel parallel to the wood surface. Around five or six cells are constructed inside the tunnel for the housing of individual eggs. The bee supplies each cell with pollen and a single egg, working back to front, sealing each successive chamber with regurgitated wood pulp.

Hatching and maturation take place over several weeks, with the pollen serving as a source of food for the developing larvae. The new generation of adult bees emerge later in the summer and forage on flowers, returning to wood for hibernation in the fall. 3Go To Source entomology.ca.uky.edu -“Carpenter Bees”

Carpenter Bee Habitat

Carpenter bees look to establish their nests in dry, coniferous woods, stumps, logs, or other dead trees. They dig into the wood and develop long tunnels to nest up to a length of 47 cm. Carpenter bee nests are typically found in pine, cypress, and juniper genera trees. The preferred nesting site is unpainted or barkless wood in well-lighted areas. This species often nests for generations in the same location.

These habitual requirements often lead to carpenter bees living in close proximity to humans. The bees will invade wooden structures such as sheds or even houses. Their nesting habits weaken the structures causing headaches for homeowners.

Range & Distribution Of Carpenter Bees

Image of carpenter bee attempting to extract nectar

Numerous species of carpenter bees inhabit a wide range of tropical, subtropical, and temperate ecosystems. In the United States, from Arizona to Florida and in the eastern United States, north to New York, carpenter bees can be found across the southern United States. 4Go To Source fs.fed.us -“Carpenter Bees (Xylocopa spp.)”

Carpenter Bee Diet

Adults feed on nectar from flowers to “rob” the nectar without pollinating, sometimes biting a hole in the petals’ base. However, they pollinate many flowers, including passionflowers (maypops). With nectar and pollen, the female provides her nest tunnels, then lays eggs on this food, which nourishes the young as they develop. In spring and summer, carpenter bees are busy furnishing their nests. 5Go To Source nature.mdc.mo.gov -“EASTERN CARPENTER BEE Xylocopa virginica”

Natural Predators Of The Carpenter Bee

  • Ratels
  • Bee-eaters
  • Shrikes
  • Predatory Flies
  • Large Mantises
  • Woodpeckers

Carpenter Bees And Humans

Picture of carpenter bee pollinating flower

Carpenter bees sometimes intimidate individuals because the males are territorial and will patrol an area in the springtime where female bees can emerge. Males buzz, giving the impression that they are guarding a nest and are ready to sting. Because they look like stinging bees, they evoke a great deal of concern among many humans.

Males are harmless because they lack a stinger and cannot sting. In addition, carpenter bees are solitary and do not have a communal colony and a queen. As such, as they have no queen or nest to protect, they are not aggressive. Female carpenter bees possess a stinger, but unless handled or provoked, they rarely use it.

The potential structural and aesthetic damage that bees can cause as they bore into wood is the most concern to homeowners, especially if the wood is part of a home, deck, or wooden furniture. Carpenter bees do not eat wood. They feed mainly on flowers’ pollen, where they play a valuable role as pollinators. Due to the relatively small tunnel created, structural damage only occurs after many years of the bees boring new or enlarging tunnels in the same location.

Occasionally, carpenter bees’ larvae attract vertebrate predators such as woodpeckers, which compound the carpenter bees’ damage. Eye-sore controls may be justified if either of these situations occur or if the holes themselves or the stains (bees typically defecate around their tunnels) are unacceptable. 6Go To Source extension.entm.purdue.edu -“CARPENTER BEES”

Carpenter Bee Species

  • Eastern Carpenter Bee Xylocopa virginica
  • California Carpenter Bee Xylocopa californica
  • Orchard Mason Bee

 

Sources:

  1. Jones, Susan. “Carpenter Bees.” Ohioline, The Ohio State University, 3 July 2017, ohioline.osu.edu/factsheet/hyg-2074.
  2. Hauze, D. 2020. “Xylocopa virginica” (On-line), Animal Diversity Web. Accessed February 09, 2021 at https://animaldiversity.org/accounts/Xylocopa_virginica/
  3. Potter, Michael. “Carpenter Bees | Entomology.” UK College Of Agriculture, Food, And Environment, University Of Kentucky, 7 Sept. 2018, entomology.ca.uky.edu/ef611.
  4. Buchman, Steve. “Carpenter Bees.” U.S. Forest Service, USDA, www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/carpenter_bees.shtml#:%7E:text=There%20are%20numerous%20species%20of,States%2C%20north%20to%20New%20York. Accessed 9 Feb. 2021.
  5. “Eastern Carpenter Bee.” MDC Discover Nature, Sate Of Missouri, nature.mdc.mo.gov/discover-nature/field-guide/eastern-carpenter-bee. Accessed 9 Feb. 2021.
  6. Gibb, Timothy. “Carpenter Bees.” Purdue University, Purdue Extension Entomology, extension.entm.purdue.edu/publications/E-252/E-252.html. Accessed 9 Feb. 2021.