If you've noticed what appear to be bumblebees buzzing around the eaves of your home, you're most likely spotting carpenter bees. These aptly named insects construct their nests in the frames of wooden buildings as well as in trees.
Carpenter Bee Appearance
Carpenter bees resemble bumblebees in some ways. Both insects are up to 1 inch in length. Whereas the bumblebee has a hairy abdomen, the upper surface of the carpenter bee's abdomen is shiny and black. Bumblebees also tend to have yellow stripes, while carpenter bees don't.
Male carpenter bees are unable to sting and therefore have no stinger. They can seem aggressive because they're known to approach people and hover in front of their face. The male carpenter bees won't do any harm, though. Female carpenter bees do sting, but they're unlikely to do so. A female carpenter bee only stings if you threaten her nest or try to handle her.
Carpenter Bee Life Cycle
Carpenter bees have four life stages. These are the egg, larvae, pupae and adult. The bees move through these stages in about seven weeks. After becoming adults, the bees stay in the nest for a short period of time before leaving. Once out, they feed on pollen and nectar, and then mate.
Carpenter bees usually have one or two generations per year. Two generations are most common in southern states with milder weather, such as Florida.
Carpenter Bee Behavior
Carpenter bees aren't social creatures. Each bee constructs its own nest by tunneling into wood to lay eggs. The insect tends to construct tunnels in bare, unpainted, weathered wood. Carpenter bees are especially attracted to cedar, pine, cypress and redwood. If the wood is painted or pressure treated, carpenter bees are less likely to tunnel into it.
Common nesting sites for carpenter bees include in eaves, wooden shakes, siding, fascia boards, doors, window frames and trim, railings, outdoor wooden furniture and decks. Adult carpenter bees will overwinter in the wood within abandoned nest tunnels. They follow this by emerging in April or May and mating. The fertilized female then reenters the tunnels to lay eggs.
After laying eggs, the carpenter bee leaves behind a ball of pollen on which the larvae will feed. These larvae pupate and emerge as adults in late summer.
Signs of Carpenter Bees
If you see bees hovering around wooden structures, they're most likely carpenter bees. The insect produces perfectly round entrance holes a little bigger than the diameter of a pencil. You'll also see piles of fresh coarse sawdust near entry holes. You may also spy a yellow substance combined with a sticky solution. This is a combination of pollen and excrement.
Carpenter Bee Potential Damage
Over time, carpenter bees can do a great deal of damage to a structure. Though they don't eat wood, but instead consume pollen and nectar, their tunneling weakens wood. Woodpeckers may also cause further damage by pecking the weakened wood in pursuit of carpenter bee larvae to eat.
Carpenter Bee Control
Because of the damage they can do to wood, it's a good idea to keep carpenter bee infestations to a minimum. Your best line of defense against carpenter bees is to paint any exposed wood. The bees generally only attack wood that is bare and weathered.