Bees are insects that play a vital role in ecosystems worldwide. Their work as pollinators contributes significantly to the reproduction of flowering plants, including many crops essential for human food production. Beyond the familiar honey bee, the world of bees encompasses many species, each with unique behaviors and characteristics. This diversity is organized within a scientific classification system that provides a framework for understanding their relationships and evolutionary history.
Bees’ Broad Classification: Order and Superfamily
Bees belong to the insect order Hymenoptera, a large group that also includes ants, wasps, and sawflies. They share common physical traits, such as hind wings connected to fore wings by small hooks. Within Hymenoptera, bees are further categorized under the superfamily Apoidea. This superfamily comprises both bees and certain types of wasps, highlighting their close evolutionary ties. The defining difference is that bees primarily feed their young with pollen and nectar, while most wasps feed their young animal prey.
The Diverse Families of Bees
The superfamily Apoidea contains over 20,000 known bee species, distributed across seven recognized families. The largest family, Apidae, includes familiar bees like honey bees, bumble bees, and stingless bees, many of which are highly social. It also encompasses carpenter bees and orchid bees, displaying behaviors from solitary to highly social.
Megachilidae includes leafcutter and mason bees. These largely solitary bees carry pollen on specialized hairs on their abdomen’s underside, not their legs. Halictidae, or sweat bees, is the second-largest family. Often metallic green or blue, they show social behaviors from solitary to primitively social.
Andrenidae, or mining bees, are a large family of solitary, ground-nesting bees. They are small to medium-sized and have unique facial grooves. Colletidae, known as plasterer or cellophane bees, line their brood cells with a waterproof, cellophane-like substance. Many species are solitary, and some transport pollen internally, lacking external carrying structures.
What Defines a Bee: Shared Characteristics
Despite the diversity among bee families, all bees share common biological and behavioral characteristics. Their diet consists mainly of nectar and pollen. Nectar provides carbohydrates for energy, while pollen supplies essential proteins, lipids, and other micronutrients necessary for growth and development, especially for developing larvae. Bees possess specialized mouthparts, such as a proboscis, for collecting nectar from flowers.
Bees also have branched or feathery hairs, known as plumose hairs, on their bodies. These hairs help collect and transport pollen as bees move between flowers. This adaptation makes bees highly efficient pollinators, facilitating the transfer of pollen grains. While some bees, like honey bees, are known for their complex social colonies, the majority of bee species are solitary, with females building and provisioning their nests alone. Some solitary bees may nest in close proximity, forming aggregations, but they do not cooperate in raising young.