Carpenter bees are large, yellow and black (or blue-black) bees that become active in early spring. This bee is commonly 2/3 to 1 inch long, usually with a shiny abdomen and a yellow thorax. Its look-alike cousins (bumblebees) have a fuzzy abdomen. Although it is rare to be stung by one, their sheer size is scary and people generally stay clear of them. Bumblebees do not bore into wood, as do carpenter bees.
Carpenter Bee Biology
Carpenter bees get their name from their ability to drill through wood and nest in the hole. Their drilling creates a near-perfect hole, approximately 1/2 inch in diameter. The hole is usually located on the underside of the wood surface; including siding, soffits, decks, overhangs, fence posts and window frames. Although the hole appears to be only an inch or two deep, it rarely ends there.
- The female carpenter bee will turn 90 degrees and bore a channel from 6 inches to as long as 4 feet. This channel serves as the main corridor from which she will drill small chambers a few inches deep. These chambers become egg holders. She will deposit an egg, bring in a mass of pollen for the newly hatched larvae to feed on, and then seal it all off to ensure it’s development before she repeats the process for the next egg.
- The male spends most of his time flying around the nest playing guard. This is ironic as nature has left him ill-prepared: he has no stinger! Only the female can sting. Simply killing the male will not solve your problem. You must treat the nest.
Identification & Physical Description
Size: These hairy bees are usually larger than the honey bee in size
Sound: Their wings make a buzzing sound while flying
Colour & description: Xylocopa male and female individuals look different in colouration, which makes most farmers believe they are different species.
Aggressive behaviour: Female Xylocopa bees are capable of stinging and the sting can be quite painful, but they are docile and rarely sting unless captured or provoked.
Carpenter bees are large, solitary creatures. They get their name from their interesting nesting habits; females excavate a burrow in wood in which to lay her eggs. There are four stages of a carpenter bee’s life cycle: egg, larva, pupa and adult. The whole transformation from egg to adult takes roughly seven weeks.
Carpenter bees are traditionally considered solitary bees, though some species have simple social nests in which mothers and daughters may cohabit. When females cohabit, a division of labour between them may occur. In this type of nesting, multiple females either share in the foraging and nest laying or one female does all the foraging and nest laying, while the other females guard the nest.
Solitary species differ from social species. Solitary bees tend to be gregarious and often several nests of solitary bees are near each other. In solitary nesting, the founding bee forages, builds cells, lays the eggs, and guards. Normally, only one generation of bees lives in the nest.
Carpenter bees make nests by tunnelling into wood, bamboo, and similar hard plant material such as peduncles, usually dead. They vibrate their bodies as they rasp their mandibles against hardwood, each nest having a single entrance which may have many adjacent tunnels. As a subfamily, they attack a wide range of host plants, but any one species may show definite adaptations or preferences for particular groups of plants. The entrance is often a perfectly circular hole measuring about 16 mm on the underside of a beam, bench, or tree limb. Carpenter bees do not eat wood. They discard the bits of wood or reuse particles to build partitions between cells. The tunnel functions as a nursery for brood and storage for the pollen/nectar upon which the brood subsists. The provision masses of some species are among the most complex in the shape of any group of bees; whereas most bees fill their brood cells with a soupy mass and others form simple spheroidal pollen-masses, Xylocopa species form elongated and carefully sculpted masses that have several projections which keep the bulk of the mass from coming into contact with the cell walls, sometimes resembling an irregular caltrop.
The eggs are very large relative to the size of the female and are some of the largest eggs among all insects. Carpenter bees can be timber pests and cause substantial damage to wood if infestations go undetected for several years.
Two very different mating systems appear to be common in carpenter bees, and often this can be determined simply by examining specimens of the males of any given species. Species in which the males have large eyes are characterized by a mating system where the males either search for females by patrolling, or by hovering and waiting for passing females, which they then pursue. In the other mating system, the males often have very small heads, but a large, hypertrophied glandular reservoir in the mesosoma releases pheromones into the airstream behind the male while it flies or hovers. The pheromone advertises the presence of the male to females.
Male bees often are seen hovering near nests and will approach nearby animals. However, males are harmless, since they do not have a stinger. Female carpenter bees are capable of stinging, but they are docile and rarely sting unless caught in the hand or otherwise directly provoked.
Woodpeckers eat carpenter bees, as do various species of birds, such as shrikes and bee-eaters as well as some mammals such as ratels. Other predators include large mantises and predatory flies, particularly large robber-flies of the family Asilidae. Woodpeckers are attracted to the noise of the bee larvae and drill holes along the tunnels to feed on them.
Apart from outright predators, parasitoidal species of bee flies (e.g. Xenox) lay eggs in the entrance to the bee’s nest and the fly maggots live off the bee larvae.
Signs of a Carpenter Bee infestation
Half-inch, round holes appear, and piles of sawdust are found underneath. Along with the coarse frass (sawdust) found underneath the nest entrance, there are usually dirty-yellow streaks of faecal matter staining the wood below the hole. If you are near a nest, you will likely be buzzed by the male carpenter bee on guard. He is loud and aggressive but remembers that he does not have the ability to sting you. The female can sting but she is normally very docile. A single pair (male and female) occupies each nest. It is not uncommon to find several pair of carpenter bees nesting in one structure. They frequently nest near each other and often in the same area year after year, causing extensive damage. You may find old holes near newer ones. Sometimes the female will renovate an old nest gallery and reuse it.
Methods for treating carpenter bees
Carpenter bees predominantly bore holes into ones external eaves of your roof trusses and use those cavities to breed in. The Flick technician would spray an insecticide within the nest to flush the larvae and adult out. A spray is applied to all infested eaves to deter others from boring into those. The Flick technician will then seal the holes up with wood filler, or if the damage is too severe the owner would need to replace the damaged beams.