Eastern Carpenter Bee

The bee is similar in size to bumblebees, but has a glossy, mostly black body with a slight metallic purple tint. X. virginica males and females have generally the same mass, but can be differentiated visually by the male's longer body and the female's wider head. The males also have a white spot on their face. Additionally, the males have larger thoracic volumes for given masses. Females of different social standing can also be told apart based on morphology. Primary females are larger than secondary or tertiary females, and also have more mandibular and wing wear. X. virginica have distinctive maxillae that are adapted to performing perforations on corolla tubes to reach nectaries. Their maxillae are sharp and wedge-shaped, allowing them to split the side of corolla tubes externally to access the nectar. Eastern carpenter bees also have galeae on their maxillae that are shaped like large, flat blades. Bees with sharp galeae can use these to further aid in penetrating the corolla tubes.

X. virginica is found throughout much of North America east of the Rocky Mountains and at least as far north as Nebraska, southern Ontario, and Maine.

In X. virginica, mating occurs only once a year, in the spring. Eggs are laid in July, starting farthest from the exit hole, and by about August and mid-September, larval development has completed and all the pupae have become adults. Researchers suggest that there is a mechanism that synchronizes the emergence time of young that are laid at different times by causing the younger eggs to develop faster. This mechanism prevents bees that would emerge sooner from removing their siblings and decreasing their potential competition. Bees that have newly emerged have a soft cuticle and white wings. The wings later transition to brown, then to a bluish black. They can fly 3–4 days after emergence, but they remain in their nest for at least two weeks, consuming nectar but not pollen. The juveniles begin the next mating cycle the following spring, so one generation develops in a year. Females begin to exhibit signs of senescence around July. The indicative behavior includes resting in flowers, remaining in the nest, or even just falling to the ground from flight. Older individuals also crawl, avoid taking flight, and do not struggle when handled by humans. The old bees die by early August, the same time that juveniles emerge from brood cells. …

X. virginica gathers pollen and nectar to bring back to the nest for larvae from many different kinds of flower. Most are wild grown or decorative; however, it can be a good pollinator of commercial crops, such as the blueberry. Its active seasons are quite long, and it forages on a wide variety of plant species. Also, because the start of its seasonal activity is temperature dependent, it is easy for greenhouse workers to manipulate the beginning of foraging activity. However, in comparison to species such as the honey bee, the species’ smaller nest makes it less powerful as a pollinator.