carpenter bee

carpenter bee, (genus Xylocopa), any of a genus of about 400 species of bees that are found in most areas of the world. Like most bees, carpenter bees do not produce honey, and they do not sting unless provoked. Although bees in Xylocopa are often considered pests because of their tunneling in structural wood such as that of buildings and fences, they are also important native pollinators that coevolved with the flowering plants in the areas in which they live. This makes them well adapted to the climates, flower structures, and other ecological relationships in their habitats, and it makes them essential to the perpetuation of many wild species.

Physical description

Carpenter bees somewhat resemble bumblebees (Bombus) but differ in having a nonhairy abdomen. Most are all black or nearly so and may feature white or yellow hairs on the thorax. Males sometimes have a white or yellow face and often have larger compound eyes than females. Only the females have a stinger, which is a modified ovipositor for egg-laying.

Natural history

Most carpenter bees are solitary, meaning that each female builds and provisions her own brood nest. The bees are so named for their habit of nesting in a tunnel excavated within solid wood. A few species are ground nesting. Under certain environmental conditions, some species form simple social colonies of mothers and daughters and divide the labor of foraging and egg-laying among themselves.

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Animal Group Names

Commonly built into tree branches, wooden beams, or even park benches, carpenter bee nests each have a single entrance, often a circular hole, that typically branches into a number of adjacent tunnels. Although the female uses her strong mandibles to carve a new nest or to adapt an existing nest, the wood is not eaten. Once the nest is established, the female lays her eggs in individual cells in the tunnels. The eggs, which are among the largest insect eggs known, are each provisioned with food before the cell is sealed with a mixture of wood pulp and saliva. The larvae take several weeks to reach maturity and pupate within their cells. Adults typically hibernate over the winter in the nest in which they matured and emerge the following spring to mate and produce their own offspring. Carpenter bee larvae and adults are an important food for woodpeckers.

Unrelated species

Another group of bees, commonly called small carpenter bees, form the genus Ceratina (tribe Ceratinini). Adults are typically about 6 mm (0.2 inch) long and metallic in coloration. Most are solitary and nest in plant stems, which the female first hollows out and then packs with pollen and eggs. A number of individual cells are placed in a row, separated by thin partitions of wood debris mixed with saliva.