22 interesting facts about carpenter bee nests


Carpenter bees are intriguing insects, particularly known for their unique nesting habits. Here are 22 interesting facts about carpenter bee nests:

  1. Wood preference: Carpenter bees prefer nesting in softwoods such as cedar, pine, redwood, and cypress, though they can also be found in hardwoods.
  2. Nesting sites: They often choose weathered, unpainted, and untreated wood, making decks, eaves, wooden siding, and outdoor furniture common targets.
  3. Entrance holes: The entrance to a carpenter bee nest is typically a perfectly round hole about 1/2 inch in diameter.
  4. Tunneling depth: The tunnels created by carpenter bees can extend up to 10 inches or more into the wood, though they usually average about 6 to 8 inches.
  5. Branching tunnels: Within the main tunnel, carpenter bees create lateral branches, which serve as individual brood chambers for their offspring.
  6. Reuse of nests: Carpenter bees often reuse and expand old tunnels, which can lead to more extensive damage over time.
  7. Construction process: Female carpenter bees use their mandibles to chew wood, creating tunnels without consuming the wood. The resulting sawdust, known as frass, is pushed out of the entrance.
  8. Sound of drilling: The sound of carpenter bees drilling into wood can often be heard, especially in quiet environments.
  9. Nesting timeline: Nest construction typically occurs in the spring when adult bees emerge from hibernation.
  10. Egg-laying: Females lay eggs inside the nest tunnels, providing each egg with a food supply of pollen and nectar known as a bee bread.
  11. Brood chambers: Each tunnel is divided into several brood chambers, each housing a single egg.
  12. Development stages: Eggs hatch into larvae, which feed on the provided bee bread before pupating and eventually emerging as adult bees.
  13. Nesting behavior: Carpenter bees are solitary nesters, meaning each female creates and tends to her own nest rather than sharing communal living spaces like honeybees.
  14. Nesting cycles: Carpenter bee nests may be used by successive generations, with each new generation expanding the tunnels.
  15. Structural damage: While the initial damage from a single nest might be minimal, extensive tunneling and reuse of nests can weaken wooden structures over time.
  16. Entrance orientation: The entrance holes to carpenter bee nests are often found on the underside of wooden surfaces, protecting the nest from rain and predators.
  17. Nest marking: Female carpenter bees may mark their nest entrance with a scent, which helps them navigate back to their nest after foraging.
  18. Defensive behavior: While females can sting if provoked, they are generally non-aggressive. Males, which cannot sting, may aggressively guard nest entrances.
  19. Nest detection: Look for signs such as perfectly round holes, sawdust (frass) beneath entry points, and bees hovering near wooden surfaces.
  20. Nesting deterrents: Painted or stained wood surfaces are less attractive to carpenter bees, as are hardwoods which are more difficult to excavate.
  21. Chemical treatments: Insecticidal dust can be applied to nest entrances to kill adult bees and prevent further use of the tunnels.
  22. Filling tunnels: After ensuring bees are no longer active in the nest, tunnels can be filled with wood putty or caulk to prevent reuse by future generations.

These facts provide a comprehensive overview of the nesting habits of carpenter bees and the implications of their behavior for wooden structures.

Carpenter bee eating hole in wood