The genus Xylocopa consists of over 500 species of bees, which includes carpenter bees. Bees of the genus Xylocopa use their mandibles to burrow into wood and other hard plant matter creating tunnels in which they create their nests. They do not eat the plant material they remove; it is either discarded or reused to build features like dividers within the tunnel or nest.
Types of Carpenter Bees
Carpenter bees are a broad species, having more than 500 different types of bees that are divided into 31 subgenera. Types can vary according to locations and behaviours. Some types of carpenter bees are distinguished by their unique behaviours. For example, the aforementioned carpenter bees that belong to the subgenus Proxylocopa, build their nests in soil rather than wood or plant matter.
Sometimes, types of carpenter bees can be identified primarily by their geographical location.
In the eastern United States are the Xylocopa virginica and Xylocopa micans. In the western United States are the X. sonorina, tabaniformis orpifex, and californica. The differences between these species might be as subtle as a slight variation in the wings or a subtle difference in the shape of male genitalia.
Where Can Carpenter Bees Be Found?
Carpenter bees are found in several geographical regions around the world, such as North America, South America, Africa, Australia, Europe, Asia, and some parts of the Middle East. Additionally, carpenter bees can be found throughout the island nations, sometimes referred to as Oceania.
Carpenter Bees’ Nesting Behaviour
Although Carpenter Bees are primarily solitary bees, some species are considered somewhat socially active. It is not uncommon to see several small carpenter bee nests close together. In these small nests are typically a mother and one or more daughters. Labour is divided among the resident bees, dividing up tasks such as guarding the nest, foraging, and laying eggs.
Where Do Carpenter Bees Nest?
Carpenter bees are known for creating their nests in tunnels. These solitary nesters do not require the same amount of space that a large colony would, meaning that they are able to find nesting space anywhere they identify dead plant matter, such as wood, bamboo, or even on the sides of homes with wooden siding. The exception, as mentioned above, is the subgenus Proxylocopa, that nests in soil rather than in plant matter like their counterparts.
What Is the Process of Building a Carpenter Bee Nest?
Although It is easier to say that carpenter bees build their nests out of wood, it is not entirely accurate. Rather, carpenter bees build their nests by the removal of wood and other plant matter.
To remove dead plant matter, carpenter bees use their strong mandibles, placing them against the plant matter and vibrating their bodies, causing their mandibles to rasp away the material. They do not eat the plant debris that is created as a byproduct of this process, but it is often repurposed to construct forms and dividers within the tunnels.
What Is a Carpenter Bee Tunnel?
A carpenter bee tunnel is usually between 4-6″ into the surrounding material, and from this singular tunnel are more sections called ‘galleries.’ Female carpenter bees can drill roughly an inch of new depth every week. When galleries are added to a new tunnel, it is not uncommon for the tunnels to grow up to 10 feet in length.
Inside these tunnels are egg cells where the female will lay her eggs.
Lifecycle of a Carpenter Bee
A female carpenter bee begins the reproductive process by boring a new tunnel and opening up larger areas within the tunnel, which serve as cells for the brood. Each tunnel is stocked up with what is called “bee bread,” which is a mixture of regurgitated nectar and pollen. When the eggs hatch, they rely on the bee bread to sustain them as they grow from a larva into pupae. This process takes around 36 days.
If the pupae grow into a young adults and survive the summer months, the bee will return to the nest to hibernate, surviving on small amounts of nectar and pollen that is stored in the nest.
The Lifespan of a Carpenter Bee
Carpenter bees hibernate, and unlike some other bees, can survive for more than a single season. In some species, it has been observed that a female that survives through winter will live in the same nest with the females from the previous year’s brood. When this occurs, Carpenter bees begin the process of elongating the original tunnel and distribution of roles within the nest.
Although carpenter bees have a longer lifespan than many other bees, they do have natural predators, including birds such as woodpeckers and shrikes, as well as insects such as mantises and predatory flies. Also, a natural predator to the Carpenter Bee is the parasitoidal bee fly, whose maggots feed on Carpenter Bee larvae.
How Do Carpenter Bees Reproduce?
All species of carpenter bees participate in one of two mating systems.
Sight
When a carpenter bee uses the mating system based on sight, the male searches for females by hovering and patrolling until they find a passing female carpenter bee to pursue. The species of carpenter bees employing this mating system have developed large, compound eyes.
Scent
The male carpenter bees in species that employ a scent-based mating system have very small heads and large, hypertrophied glandular reservoirs in their mesosoma that release pheromones into the airstream behind them during flight. These pheromones alert females to their presence.
How Do Carpenter Bees Behave Towards Other Bees?
Although considered “bossy” bees due to their tendencies for both males and females to stake out and lay claim to preferred blossoms, carpenter bees are not typically viewed as aggressive to other beings. However, when a carpenter bee has chosen a blossom, it will dive-bomb or bump into any perceived threats.
Male carpenter bees are known to hover around the nest and use similar behaviours to ward off anything that they perceive as a threat. This behaviour can seem aggressive and cause concern for humans but the fact that males lack a stinger means that it is harmless posturing.
Do Carpenter Bees Pollinate or Produce Honey?
Carpenter bees do pollinate, but they do not produce honey.
Carpenter bees have short mouthparts which make ideal pollinators for open-faced and shallow flower blossoms. Some flower species rely on the carpenter bee alone for pollination, such as the passionflower and the Orpheum. Flower species that have ‘lids,’ such as some members of the Fabaceae family, depend heavily on carpenter bees.
What Do Carpenter Bees Feed On?
Carpenter bees feed on nectar. They gain access to the nectar despite their short mouthparts by drilling a hole into the corolla of the flower. This process is called “robbing” nectar.
What Is the Difference Between Carpenter Bees and Bumblebees?
Without close examination, it is difficult to distinguish one species from another due to their similarities in shape and size. The easiest way to discern bumblebees and carpenter bees is to look at their abdomen. Carpenter bees have a smooth and shiny abdomen whereas bumblebees are adorned with thick, dense hair. Male carpenter bees have a white or yellow face while females lack the bare corbicula of bumblebees.
If you can get a close look, the most prominent difference between carpenter and bumblebees are the structures of their facial features. Carpenter bees have short mandibles that conceal their labrum, whereas bumblebees do not.
What’s The Difference Between Carpenter Bees and Honey Bees?
There are key differences between carpenter bees and honey bees, the most important difference being that honey bees make honey, whereas carpenter bees do not.
Other distinct differences include social activity and nest building. Honey bees live in colonies with up to 80,000 other bees in complex societies with distinct roles. Honey bees tunnel in dead plant matter to make their nests with a select few daughter bees, while carpenter bees prefer gregarious nesting (meaning bees located in solitary nests within close proximity to each other). Although carpenter bees work cooperatively with one another, their social structures are far less complex than that of the honey bee.
Similar to honey bees, carpenter bees gather pollen and nectar, which are used to provide for their young. However, honey bees turn the pollen and nectar that they collect into a sugary solution utilized by the entire colony, and carpenter bees only use nectar and pollen to make “bee bread”.
What is the Difference Between Carpenter Bees and Giant Resin Bees?
Giant resin bees are members of the genus Megachile and do not dig tunnels the way carpenter bees do. Giant resin bees make their nests in abandoned wood cavities in trees or timbers such as those created by carpenter bees. Giant resin bees do behave aggressively toward other bee species. They are known to attack carpenter bees by covering them in a sticky resin that immobilizes them and leaves them defenceless against subsequent attacks. Giant resin bees are not known to sting humans unless threatened, but they are considered a nuisance or pest species due to their impact on other native species.
Do Carpenter Bees Sting?
Bees are associated with stinging, which can cause unease when being near to one. Like other bee species, the males of the genus Xylocopa are not stingers. While unable to sting, males are incredibly territorial and react to perceived threats by hovering close to the threat to seem menacing. Females of this genus are capable of stinging, but they do so only under extreme circumstances.
How to Care for Carpenter Bees?
Often, homeowners are under the impression that carpenter bees are pests and take steps to eliminate them from their properties out of concern that the bees will make tunnels into their homes. While this concern is legitimate, most modern homes are using alternative materials to wood, which is both more sustainable and less attractive to carpenter bees and other boring insects.
It is important to consider the important role that carpenter bees play in pollination and to not take measures to destroy nests and to encourage bees by planting gardens and wildflowers. If carpenter bees nests are nearby children or pets, calling a pest control professional to relocate the bees is the best option.
For those who wish to attract carpenter bees, setting out a “bee post,” which is untreated softwood, will lure in the bees as this is an ideal spot to build their nests. Homeowners who choose to install bee posts reap the benefits of having pollinating bee species in their yards while helping sustain bee populations as a whole.
Along with a bee, a post should include an adequate water source. A shallow dish with freshwater will work. Placing pebbles or other perches inside the dish above the waterline will give the bees away to drink without falling into the water and drowning.
