Bumblebee (Bombus spp.)

BeePollinatorBuzz pollination

Overview

Bumblebees are robust, densely hairy bees of the genus Bombus, a group of roughly 250 to 260 described species placed in the family Apidae. They are best known as large, fuzzy, often black-and-yellow (sometimes orange, red, or white-banded) insects that visit flowers in gardens, meadows, woodlands, and mountains across much of the Northern Hemisphere and parts of South America. This page is a group-level overview of the genus; traits, ranges, and conservation status differ from species to species.

Most bumblebees are social, forming small annual colonies founded each year by a single overwintered queen. They are widely regarded as important flower visitors and pollinators of many wild plants and some crops, in part because of a behavior called buzz pollination (sonication), in which a bee vibrates its flight muscles to shake pollen loose from certain flowers. Their tolerance of cool, cloudy, and high-elevation conditions makes them especially prominent in temperate and montane systems where some other bees are less active.

Because Bombus contains many species, generalizations should be made carefully. Some bumblebee species remain common and are assessed as Least Concern, while others have declined and a few are formally assessed as threatened. Statements here describe the genus broadly; for any single species, the specific ecology and conservation status should be checked against authoritative sources such as the IUCN Red List.

Taxonomy and animal group

Bumblebees make up the genus Bombus within the family Apidae, the same broad family that includes honey bees, carpenter bees, and orchid bees. The genus is divided into a number of subgenera and contains roughly 250 to 260 described species, including the cuckoo bumblebees (formerly separated as Psithyrus), which are social parasites that take over the colonies of other bumblebees rather than building their own. Bumblebees are true bees in the clade Anthophila and should not be confused with similarly fuzzy flower-visiting flies or with carpenter bees (mostly genus Xylocopa), which are often larger and have a shinier, less hairy abdomen.

Appearance and recognition

Bumblebees are typically stout-bodied and covered in dense, plush hair (setae), which helps insulate them and lets them stay active in cooler weather than many other bees. Body length varies by species and caste, with queens generally the largest, workers smaller, and males intermediate. Color patterns are commonly black with bands of yellow, but many species show orange, red, brown, or white markings, and several species look similar enough that reliable identification often depends on subtle features and regional knowledge. Like other bees, females carry pollen; many bumblebees collect it in a smooth, concave area on the hind leg known as the corbicula or pollen basket.

Habitat & Range

Bumblebees occur across much of the temperate Northern Hemisphere — including large parts of North America, Europe, and Asia — and extend into cooler and high-elevation parts of South America; a number of species reach into Arctic and alpine zones, and they are generally absent or naturally scarce in lowland tropical regions. They are associated with habitats that offer flowers for forage and suitable nesting sites, such as meadows, grasslands, forest edges, gardens, farmland, and mountain slopes. Many species nest at or below ground level, often in abandoned rodent burrows, tussocks, or cavities, though nesting habits vary. Some bumblebees have been moved beyond their native ranges through commercial use, so the distribution of a given species should not be assumed; consult authoritative range maps for specifics.

Diet

Adult bumblebees feed on nectar for energy and collect pollen as a protein source, primarily to provision developing larvae. A colony's workers forage on a wide variety of flowering plants, and bumblebees are often described as relatively generalist foragers, though individual species can show preferences for particular flower shapes or plant groups. Their relatively long tongues in some species allow them to reach nectar in deep or tubular flowers that shorter-tongued bees cannot easily access. Larvae are fed pollen and nectar brought back to the nest; bumblebees do not store large honey reserves the way honey bees do, keeping only small amounts of nectar in wax pots.

Behavior

Most bumblebees follow an annual social cycle. A mated queen overwinters alone, emerges in spring, and founds a colony, rearing the first workers herself; the colony then grows through the season as workers take over foraging and brood care. Later in the cycle the colony produces new queens and males, which leave to mate; new queens seek overwintering sites while the founding colony, including the old queen and workers, typically dies off as conditions cool. Colonies are generally far smaller than honey bee hives, often numbering from dozens to a few hundred individuals depending on species and conditions. Cuckoo bumblebees break this pattern by invading host colonies and relying on host workers to rear their offspring. Bumblebees can regulate their body temperature by shivering their flight muscles, which helps them fly in cool conditions and at high elevations.

As abundant flower visitors in temperate and montane systems, bumblebees contribute to the pollination of many native plants, supporting the seed and fruit production on which other wildlife depends, and they form part of the food web as prey for birds and other predators. Their tolerance of cool weather makes them ecologically important in places and seasons when other pollinators are less active, such as early spring, cloudy days, and cold mountain habitats. Because different bumblebee species partition flowers, habitats, and elevations in different ways, the genus as a whole interacts with a broad range of plant communities; the precise ecological role of any one species is best understood at the species and regional level rather than generalized across all bumblebees.

Human Interaction & Conservation

Bumblebees are generally not aggressive toward people and are typically encountered simply foraging on flowers. Only female bumblebees possess a sting; males cannot sting, and females usually sting only when handled roughly or when a nest is threatened. Unlike honey bees, bumblebees can generally sting more than once. This page is educational and does not provide medical, first-aid, or pest-control guidance: anyone concerned about a sting or an allergic reaction should consult a qualified medical professional, and anyone needing to address a nest or a wildlife conflict should contact local authorities or qualified professionals rather than attempting removal.

More photos of the bumblebee