Eastern carpenter bee

Species of insect

Xylocopa virginica, sometimes referred to as the eastern carpenter bee, extends through the eastern United States and into Canada. They are sympatric with Xylocopa micans in much of southeastern United States. They nest in various types of wood and eat pollen and nectar. In X. virginica, dominant females do not focus solely on egg laying, as in other bee species considered to have "queens". Instead, dominant X. virginica females are responsible for a full gamut of activities including reproduction, foraging, and nest construction, whereas subordinate bees may engage in little activity outside of guarding the nest.

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. in the subgenus Xylocopoides, which contains only 5 New World species, including Xylocopa californica, which also occurs in the U. S.

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.

X. virginica build their nests in wood, bamboo culms, agave stalks, and other comparable materials, but they prefer to nest in milled pine or cedar lumber. The nests are built by scraping wood shavings off of the wall. These shavings are then used to create partitions between nesting cells. The entrance cuts into the wood perpendicular to the grain, but they are built parallel beyond the entrance. These nests may be either social, containing groups of two to five females, or solitary. Social nests are more common, despite the fact that brood productivity is actually lower when females choose to nest together. X. virginica is the most common large carpenter bee in eastern North America, and it nests in small groups, so nests are fairly commonly encountered.

Female X. virginica can have solitary nests, but they usually nest in social groups. The social order of X. virginica is broken into three groups: primary, secondary, and tertiary. Primary females act as the dominant within a nest and are in charge of reproduction, providing food for the larvae, and laying all the eggs. This is different from many bee species in which there is a queen that focuses her energy solely on laying eggs while relying on provisions provide by subordinate bees. Secondary females may sometimes participate in oviposition, and they reinforce this potential role by helping provide for the larvae or performing nest maintenance. Tertiary females rely on the provisions provided by primary females and quietly await overwintering while remaining inactive. Males often spend long periods of time hovering, flying, or in fast pursuit of intruders, while female flight activity is usually very directed, such as flights to flowers and food sites. Larger females have an advantage because they can carry larger amounts of pollen or nectar back to the nest and can fly longer distances. The ability of X. virginica to recognize nestmates allows primaries and secondaries to exclude tertiary bees from their nests. Tertiary bees are a burden on resources because they do not perform any useful activities, but they benefit from the food and shelter provided by the primary females. As the stinger is not barbed, a female can sting multiple times.

X. virginica visits many different kinds of flowers in order to gather pollen and nectar to bring back to the nest for larvae. Most of the plants they visit are wild grown or grown for decorative value; Their active seasons are quite long, and they forage on a wide variety of plant species. Also, because the start of their activity season is dependent on temperature, it is easy for greenhouse workers to manipulate the beginning of foraging activity.

Because X. virginica builds its nests in various types of wood, it presents the disadvantage of weakening wood in manmade structures. They are also able to produce an excrement upon exiting their tunnels that may splash on the sides of buildings and negatively affect the aesthetic appeal of that structure. However, when weighed against the benefits X. virginica have as pollinators, the costs of its destructive behavior are insignificant. X. virginica offer benefits in the form of pollination for fruits, vegetables, legumes, and flower crops. Although the pollination strengths of X. virginica are secondary to that of the bumblebees and honey bees, the contribution is great enough to overlook destructive tendencies.