Bombus

Diversity

The genus Bombus, commonly known as bumble bees, includes 260 species worldwide. In North America, there are 43 species in the west, 24 in the east, and 18 in the south. (Bartlett, 2019; Colla, et al., 2011)

Geographic Range

Bumble bees are found in the temperate regions of North, Central, and South America, Europe, and Asia. They are not found in Australia, parts of India, and most of Africa. (Colla, et al., 2011)

Habitat

Bumble bees inhabit a broad habitat, including urban areas, suburban locations, and farmlands. Grasslands, forests, and marshes are also habitats of this species. Bumble bees can be found in cold temperate to warm subtropic climates. Some species of this genus may create nests underground. Others may steal nests from other bumble bees. (Colla, et al., 2011; Resh and Cardè, 2009; Stange and Fasulo, 2018)

Physical Description

Bumble bees have a distinctive yellow and black striped pattern. Some species have orange or reddish colors too. They have short, pale yellow hairs on their thoraxes and black hairs on their heads, abdomens, and legs. Females have corbicula (pollen baskets) on their hind tibiae. Males and females of some species have differing facial colors, which allows them to be differentiated. Species of bumble bees have varying tongue lengths. Members of this genus can be confused with eastern carpenter bees. Bumble bees can be differentiated from eastern carpenter bees by the pubescence on the dorsum. (Borror and White, 1970; Colla, et al., 2011; Stange and Fasulo, 2018)

  • Sexual Dimorphism
  • female larger
  • sexes colored or patterned differently

Development

Eggs are laid in individual cells and hatch after approximately 4 days. Larvae go through four instars of development. They spin cocoons and pupate in about two weeks. Pupae develop for an additional 2 weeks before emerging. (Colla, et al., 2011)

Reproduction

Bumble bees are eusocial, except for members of the subgenus Psithrys. This subgenus is made up of social parasites that utilize the nests of other bumble bees to produce offspring. (Colla, et al., 2011)

Colonies of bumble bees are annual and are founded by a single queen bee. They utilize sexual reproduction. After fertilized queens emerge from overwintering in the spring, they will build the colony alone. The first brood of worker bees hatches and they care for the next generation. Males are typically produced during midsummer. (Bartlett, 2019; Colla, et al., 2011; Stange and Fasulo, 2018)

Members of this genus utilize female parental care. (Colla, et al., 2011; Stange and Fasulo, 2018)

Lifespan/Longevity

Bumble bees produce annual generations. Queen bumble bees live for a maximum of one year. Workers and males live for a much shorter time period, typically dying with the onset of colder weather. In areas that do not get cold seasons, bumble bees may be found year-round. (Colla, et al., 2011)

Behavior

Social and colonial, bumblebees can form large colonies. Bumble bee queens live with their male and female offspring. Older generations forage for pollen during the day while younger generations care for the brood. While bees forage, they pollinate the plants from which they harvest pollen and nectar. In the nest, pollen and saliva are combined to produce honey to feed the colony. Male bees do not do any work. (Colla, et al., 2011; Eaton and Kaufman, 2007; Resh and Cardè, 2009)

Bumble bees can live in surprisingly large groups. Younger generations take care of the larvae. Older generations of bumble bees hunt for pollen during the day. While bees hunt for nectar and pollen, they pollinate the plants that they land on. In the nest, pollen and saliva are chewed together to produce honey. Male bees do not do any work. Bumble bees are active for an oddly long part of the year. (Colla, et al., 2011; Eaton and Kaufman, 2007; Resh and Cardè, 2009)

Communication and Perception

Like other social bees, bumblebees communicate using touch, vision, chemicals called pheromones, and wing vibrations. Bees communicate about the safety of the nest, where food is, and what they should do. Like other bees, bumblebees can see ultraviolet light. (Colla, et al., 2011)

Like other social bees, bumblebees communicate using touch, vision, chemicals called pheromones, and wing vibrations. Bees communicate about the safety of the nest, where food is, and what they should do. Like other bees, bumblebees can see ultraviolet light. (Colla, et al., 2011)

Food Habits

Bumble bees consume the nectar and gather the pollen of a wide variety of plants. They are generalist foragers. Adults feed on nectar from native wildflowers and crops for energy to fuel flight. Larvae feed on pollen gathered by the adults. Food plant choice varies by species and is dictated by tongue length. Species of this genus store food. Some species store pollen in vacant cocoons, while others store pollen in a pocket near larval cells. (Bartlett, 2019; Colla, et al., 2011; Eaton and Kaufman, 2007)

Bumble bees pollinate many crops, including apples, alfalfa, almonds, apricots, blackberries, beans, blueberries, cherries, chives, cranberries, cucumbers, eggplants, nectarines, peaches, peppers, plums, raspberries, rosehips, soybeans, strawberries, sunflowers, and tomatoes. (Colla, et al., 2011)

Predation

Bumble bees are preyed on by birds and other animals. (Bartlett, 2019; Colla, et al., 2011; Resh and Cardè, 2009)

Bumble bees are eaten by birds and other animals. (Bartlett, 2019; Colla, et al., 2011; Resh and Cardè, 2009)

Ecosystem Roles

Bumble bees are important pollinators. In the process of foraging, they pollinate the plants from which they harvest nectar and pollen. They are eaten by various birds and other animals. (Bartlett, 2019; Colla, et al., 2011)

Members of the subgenus Psithyrus are parasitoids of bumble bees. A few of these species are B. ashtoni, B. citrinus, B. fernaldae, B. insularis, and B. variabilis. (Bartlett, 2019)

  • Ecosystem Impact
  • pollinates

Economic Importance for Humans: Positive

Bumble bees are beneficial to humans because they are extremely important pollinators. They pollinate many types of flowers. They are used as a pollinator for crops in locations outside of their native range. (Colla, et al., 2011)

  • Positive Impacts
  • pollinates crops

Economic Importance for Humans: Negative

Bumble bees may sting when they feel threatened. (Colla, et al., 2011)

  • Negative Impacts
  • injures humans

Conservation Status

Populations of the species B. occidentalis, B. pensylvanicus, B. affinis, and B. terricola have declined dramatically. (Bartlett, 2019)

  • IUCN Red List [Link]
    Not Evaluated

Contributors

Deena Hauze (author), Animal Diversity Web Staff.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

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Neotropical

living in the southern part of the New World. In other words, Central and South America.

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Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

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bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

cosmopolitan

having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.

diapause

a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.

diurnal
  1. active during the day, 2. lasting for one day.
dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

eusocial

the condition in which individuals in a group display each of the following three traits: cooperative care of young; some individuals in the group give up reproduction and specialize in care of young; overlap of at least two generations of life stages capable of contributing to colony labor

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

internal fertilization

fertilization takes place within the female's body

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

nectarivore

an animal that mainly eats nectar from flowers

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

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pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

venomous

an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

References

Bartlett, T. 2019. "Genus Bombus - Bumble Bees" (On-line). Bug Guide. Accessed August 28, 2020 at https://bugguide.net/node/view/3077.

Borror, D., R. White. 1970. A field guide to the insects of America north of Mexico. Boston: Houghton Mifflin Company.

Colla, S., L. Richardson, P. Williams. 2011. Bumble Bees of the Eastern United States. Washington, D.C.: USDA Forest Service and the Pollinator Partnership.

Eaton, E., K. Kaufman. 2007. Kaufman Field Guide to Insects of North America. New York: Houghton Mifflin Company.

Resh, V., R. Cardè. 2009. Encyclopedia of Insects, Second Edition. Amsterdam: Elsevier.

Stange, L., T. Fasulo. 2018. "common name: bumble bees (of Florida)" (On-line). Featured Creatures Entomology & Nematology. Accessed August 28, 2020 at http://entnemdept.ufl.edu/creatures/misc/bees/bumble_bees.htm.