Carpenter bees are large, hairy, black and yellow. Often mistaken for bumblebees, Carpenter bees differ in that they have a black shiny tail section. They are usually about one inch long. Male Carpenter bees do not have a stinger, and although females do have a stinger they are docile and will rarely sting.
Many Carpenter bees have a pouch inside their first metasomal tergite where mites reside as part of a commensalism relationship. Exactly what the benefit of this relationship is, is not presently known.
Carpenter Bee Habitat and Food Source
Carpenter bees inhabit every continent but Antarctica and there are approximately 500 species.
Solitary creatures, the Carpenter bee often lives alone but mother and daughter Carpenter bees may have a simple social nest in which they reside together. Although Carpenter bees tend to nest individually, several bees may build nests near each other. While other bees build hives the Carpenter bee prefers a nest. This bee truly is a “carpenter,” tunneling into the wood of a tree limb, beam, deck, porch rail, or bench. The tunnels are built with the Carpenter bee’s strong jaw as it vibrates itself through the wood. The bees do not eat the wood but reuse the particles to build individual cells or discard them. Round half-inch diameter entrance holes are the telltale sign of a Carpenter bee nest, as well as a trace of coarse sawdust.
The Carpenter bee might be starting to sound like a termite, but should not be mistaken with this pest. Whereas termites eat the wood they chew up, Carpenter bees do not eat wood. Instead the Carpenter bee feeds on pollen and nectar (similar to a honeybee). Carpenter bees are therefore excellent pollinators and a welcome part of a garden.
Carpenter Bee Life Cycle
Carpenter bees are not active year-round. Hibernating during the winter, the bees emerge from their nests in the spring. After mating the male Carpenter dies and the female begins to expand the nest in order to make room for the new addition. Once new brood cells are made, the female fills them with food (regurgitated pollen and nectar) then lays eggs in each compartment.
After the eggs are laid they hatch in a few days. The young will then feed on the provisions left by their mother before they hatched. The bee pupae will reach adulthood within a period of five to seven weeks. This new generation of adult Carpenter bees will feed on large amounts of pollen and nectar in the fall and hibernate through the winter.
Carpenter Bees and Humans
Male Carpenter Bees are thought to be the more aggressive sex, may buzz around protectively and be a nuisance if you come near the nest, but have no stinger and are therefore of no harm to people. Female Carpenter bees do have stingers, but will only sting a victim if extremely agitated or disturbed (such as being caught or squeezed). These bees, then, are not considered to be dangerous to humans.
Wood decks, overhangs, and other exposed woods on houses are a prime target for the Carpenter bee. Although they have a reputation for being “pest-resistant,” unpainted or stained redwood, cedar, and cypress wood (like shingles and siding) are also favorite materials for the Carpenter bee. The nest of the Carpenter bee does not itself cause serious damage to structures unless several nests are built next to each other over the course of successive years, but there are some secondary effects that can be quite a problem. The bees’ waste is usually eliminated before entering the tunnels, but may show up on the outside of a tunnel as a yellowish-brown fecal stain. Woodpeckers, a predator of the Carpenter bee larvae, may forage through the tunnel in search of young bees and can cause serious damage to structures. Additionally, wood-decaying types of fungi or invasion of other insects could also cause structural damage.
Carpenter Bees Sting
Even though the Carpenter bee rarely stings humans, they have been known to sting if provoked. If you know you are allergic to bee stings or experience symptoms other than localized pain, itching or swelling, seek a medical professional immediately. Stay calm and move indoors. Keep the affected area below the heart at all times and remove any stingers gently with your fingernail, a credit card, or butter knife. If the stinger is still in your skin, the venom sac most likely is too – don’t squeeze the sting or you may release more venom into the sting—ouch! Treat the sting(s) with cold compresses and use an over-the-counter pain medication. Meat tenderizer containing the ingredient Papain will relieve effects of the sting quickly and effectively as well. If symptoms persist more than a few days, see a doctor.
Symptoms of an allergic reaction to a bee sting include burning and itching, body swelling, body rash, weakness, nausea, difficulty breathing, shock, or unconsciousness. If you believe you have an allergy to bee venom, see a doctor about obtaining an anti-venom first aid kit.
Professional Carpenter bees Control
Keep in mind that the Carpenter bee is an efficient pollinator for gardens. Control of the Carpenter bee should be employed when structures are at risk or secondary problems like Woodpeckers or Carpenter ants have invaded.
Bee Identification: First a professional will positively identify the bee species to make sure they employ the proper measures of getting rid of the hive.
Insecticide: When the bees have returned to their nests, usually around nightfall, a professional will apply insecticide by spraying into the entrance to the nest. Dust pesticides containing cypermethrin are most commonly used. A dust pesticide is used so that the bee is covered but can still exit the nest during the day. When the bee cleans itself, the insecticide will be ingested and the bee will die. Over spraying the nest could cause the bees to remain inside the nest, leaving dead bees and a mess behind.
Follow Through! As a follow-up treatment, a liquid insecticide is best. In early spring before Carpenter bee nesting has occurred, a professional will apply liquid spray to the affected areas to keep the bees from returning to nest.
DIY and Green Solutions for Carpenter bee Control
If you don’t desire to use chemical compounds to control the Carpenter bee, try some homemade remedies, or consider employing a “green” pest control company. Many companies are “green shield certified,” meaning they are authorized to treat infestations with organic and natural compounds rather than dangerous chemicals.
Salad dressing or repellent? The ingredients of this all-natural bee repellent sounds a little like a vinaigrette, but has been known to ward off Carpenter bees. Where you know a Carpenter bee’s nest is, spray white vinegar in and around the nest. The cheaper the white vinegar, the more acidic, so don’t get too fancy. After applying white vinegar, mix cooking oil with several cloves of garlic and allow it to sit for a few days. Liberally spray in and around the nest. If you don’t see a significant reduction in bee numbers, apply another coat.
Bee-Proof your wood materials: Hardwoods are less likely to attract the Carpenter bee, as are painted or varnished woods. Consider these wood types when building outdoor structures like decks. On your home and other buildings, fill in cracks and depressions to make them a less attractive nesting site. Cover rough areas like ends of timber with wire screening or mesh.
Clean and Seal up! Once the nest is empty, clean the nest area thoroughly with soapy water then seal all entrances points with steel wool and caulking. Pain or stain them as necessary.
The Carpenter bee is known as an excellent pollinator, but can be a pest. If the nest is bored into wood structures like roofs and decks, damage over successive years can be substantial. Luckily control of this bee species is easy and effective, and there is little danger in do-it-yourself methods.