Bees are flying insects belonging to the clade Anthophila, nested within the superfamily Apoidea. This diverse group includes over 20,000 known species globally, inhabiting every continent except Antarctica. While the domesticated honey bee is the most familiar, it represents only a tiny fraction of the enormous variety. The vast majority of these insects exhibit lifestyles and physical features far removed from the familiar image of a hive-dwelling insect. Understanding this diversity requires examining their social structures, unique family traits, and specialized nesting habits.
Categorizing Bees by Social Structure
Bee life is categorized by social organization, which falls into two broad categories. Solitary bees represent approximately 90% of all species, where a single female is responsible for reproduction and nest construction. She builds a nest, provisions each cell with pollen and nectar, lays an egg, and seals the cell, never interacting with her offspring. This life cycle means there is no cooperative brood care, division of labor, or overlapping generations, as seen in species like the Mason or Leafcutter bees.
Social bees exhibit varying degrees of communal living, culminating in eusociality. Eusocial species, such as honey bees, are characterized by three distinct traits: a reproductive division of labor, cooperative care of the young, and multiple generations living together. This complexity results in specialized castes, typically a single reproductive queen and a large number of non-reproductive female workers. This social organization allows for the creation of large, highly structured colonies.
Major Bee Families and Defining Characteristics
Understanding bee diversity requires examining the major taxonomic families, each defined by unique physical and behavioral traits.
Apidae (Long-Tongued Bees)
The family Apidae, often called the long-tongued bees, includes recognizable groups such as Honey Bees (Apis) and Bumble Bees (Bombus). Bees in this family typically collect pollen using specialized structures on their hind legs called corbiculae, or pollen baskets. The Apidae family also contains the large Carpenter Bees (Xylocopa), which bore into wood to create nesting galleries.
Megachilidae (Mason and Leafcutter Bees)
Another prominent group is the Megachilidae, commonly known as Mason bees and Leafcutter bees. Instead of carrying pollen on their legs, these insects possess a dense patch of stiff hairs on the underside of their abdomen called a scopa. This unique method of pollen transport makes them highly visible as they fly with their abdomens dusted yellow. Mason bees are named for their use of mud or clay to construct partitions within their nest tunnels, while Leafcutter bees utilize precisely cut pieces of leaves.
Halictidae (Sweat Bees)
The Halictidae, or Sweat Bees, represent the second-largest bee family globally and are characterized by their bright metallic coloration, which can range from vivid green to blue. Their social structure is highly varied, with some species being solitary, others communal, and many exhibiting a primitive form of eusociality.
Andrenidae (Mining Bees)
The Andrenidae family consists entirely of solitary, ground-nesting species abundant in temperate regions. Mining bees are often among the earliest species to emerge in the spring, making them important early-season pollinators for fruit trees.
How Bees Choose and Build Nests
Bee nesting preferences are categorized by the physical location and the materials used to construct the brood cells.
Ground Nesters
The majority of native bees, estimated to be around 70%, are ground nesters, digging burrows in the soil. These solitary bees, including most Mining bees and many Sweat bees, prefer sunny, well-drained, and often bare patches of ground for excavating their tunnels. The female digs a network of shafts and cells, sometimes lining the cells with a waterproof secretion to protect the developing young.
Cavity Nesters
A significant portion of species are cavity nesters, relying on pre-existing voids rather than excavating their own tunnels in the earth. This group includes Leafcutter and Mason bees, which use hollow plant stems, abandoned beetle tunnels in dead wood, or man-made bee houses. Inside these linear tunnels, the female builds a series of individual cells, separating them with materials like mud, resin, or plant matter. Bumble bees also fall into the cavity-nesting group, often selecting sheltered, pre-existing spaces like abandoned rodent burrows or dense grass tussocks.
Wood Borers
A specialized subset of cavity nesters are the Wood Borers, exemplified by the Carpenter Bees. Unlike many other bees that use existing holes, the large female carpenter bee uses her mandibles to drill clean, smooth tunnels into soft or dead wood. Within the excavated galleries, she creates partitions between the developing larvae using a mixture of chewed wood pulp and sawdust. This nesting habit is distinct from other groups, as it involves the physical creation of the tunnel itself.