Buzz-pollination
Guides
Bombini
bumblebees
Bombini is a tribe of large, densely hairy apid bees containing the single living genus Bombus, the bumblebees, plus several extinct genera. The tribe includes both social species that form annual or perennial colonies of up to a few hundred individuals, and brood-parasitic species (formerly classified as Psithyrus) that invade and exploit nests of social species. Bumblebees are distinguished by their ability to perform buzz pollination and to forage in cooler temperatures and lower light conditions than most other bees.
Bombus
bumble bees, bumblebees
Bombus is the sole extant genus in the tribe Bombini, comprising over 250 species of bumble bees. These bees are distinguished by their ability to forage in cooler temperatures and lower light conditions than many other bees, including honey bees. They perform buzz pollination—vibrating their flight muscles to dislodge pollen from flowers—a behavior critical for crops such as tomatoes, peppers, and cranberries. Multiple Bombus species face significant population declines due to habitat loss, pesticide exposure, climate change, and pathogen transmission from commercial bee operations. Four California species (B. franklini, B. suckleyi, B. occidentalis, B. crotchii) are under endangered species protection consideration, with B. franklini feared extinct since 2006.
Bombus crotchii
Crotch's bumble bee, Golden State bumble bee, Crotch's bumblebee
Bombus crotchii, commonly called Crotch's bumble bee or the Golden State bumble bee, is a short- to medium-tongue bumble bee endemic to California and adjacent regions. The species is classified as endangered under the California Endangered Species Act and listed as imperiled globally by the IUCN. It has experienced severe population declines attributed to habitat loss, pesticide exposure, climate change, and inbreeding depression. The species is a dietary generalist and important pollinator of native plants and agricultural crops.
Bombus fervidus
golden northern bumble bee, yellow bumblebee
Bombus fervidus is a North American bumble bee distinguished by its predominantly yellow coloration on the abdomen and thorax. The species is a long-tongued specialist that forages on flowers with deep corollas, and has been documented visiting over 20 plant genera including milkweeds, goldenrods, and blueberries. It exhibits complex social behavior including coordinated nest defense and worker-queen conflict over male production. Populations have declined significantly across most of its range, with habitat loss to agricultural intensification identified as the primary threat; it is currently classified as Vulnerable by the IUCN.
Bombus occidentalis
Western bumble bee, white-bottomed bee
Bombus occidentalis, the western bumble bee, is a medium to large bumble bee species native to western North America. Once among the most common bumble bees in its range, it has experienced severe population declines since the late 1990s, with losses exceeding 40% in some areas and near-disappearance from parts of California, Oregon, and Washington. The species was listed as endangered under the California Endangered Species Act in 2019. It is a generalist forager and effective pollinator of crops including tomatoes, peppers, and berries through buzz pollination.
Bombus terricola
Yellow-banded Bumble Bee, Yellow-banded Bumblebee
Bombus terricola, the yellow-banded bumble bee, is a North American bumble bee native to southern Canada and the eastern and midwestern United States. The species has experienced significant population declines since the late 1990s, with range contractions particularly severe in its southern distribution. It is now classified as vulnerable on the IUCN Red List and listed on the Xerces Society Red List of endangered bees. The species exhibits complex behavioral traits including thermoregulation for cold-weather flight and adaptive responses to queenless nests.
Bombus vancouverensis
Vancouver Bumble Bee, Vancouver Island Bumblebee
Bombus vancouverensis is a eusocial bumblebee of subgenus Pyrobombus, widespread across mountainous regions of western North America. The species was long treated as synonymous with Bombus bifarius, with most historical literature on bifarius actually referring to vancouverensis. Genetic studies completed in 2020 confirmed their distinct status, with true B. bifarius being exclusively red-tailed and geographically restricted, while B. vancouverensis is polymorphic and broadly distributed. It is one of only two bumblebee species known to use pheromones for kin recognition.
Habropoda laboriosa
Southeastern Blueberry Bee, Blueberry Digger Bee
Habropoda laboriosa is a solitary ground-nesting bee in the family Apidae, native to the eastern United States. It is an oligolectic specialist pollinator of blueberries (Vaccinium spp.), for which it is the most efficient known pollinator due to its buzz pollination behavior. The species is active for only 3-5 weeks annually, synchronized with early spring blueberry bloom. It nests in aggregations in sandy soils and has been estimated to provide $20 per individual in blueberry pollination services.
Nomiinae
Nomiine bees
Nomiinae is a subfamily of sweat bees (Halictidae) comprising approximately 11 genera and at least 550 described species. These bees are morphologically diverse, particularly in males, which often exhibit modified hind legs and metasomal sterna. The subfamily has a global distribution with significant diversity in tropical and subtropical regions. Nomiine bees are ground-nesting pollinators, with documented nesting biology in several genera including Nomia, Dieunomia, and Hoplonomia. They exhibit varied social systems ranging from solitary to communal nesting.
Ptiloglossa
Ptiloglossa is a genus of large, hairy bees in the family Colletidae, endemic to the Americas. The genus is notable for being among the most common nocturnal colletid bees, with activity restricted to very low light conditions. Species possess enlarged ocelli that facilitate flight in dim light. The genus contains approximately 55 species, with highest diversity in South and Central America.
Xylocopa
Large Carpenter Bees, Carpenter Bees
Xylocopa is a large genus of bees comprising approximately 500 species in 31 subgenera, commonly known as carpenter bees for their distinctive nesting behavior in wood and bamboo. The genus exhibits remarkable diversity in size, coloration, and social organization, ranging from solitary to incipiently social species. Recent research has revealed that Xylocopa species harbor gut microbiomes remarkably similar to those of eusocial bees like honey bees and bumble bees, challenging assumptions that advanced sociality is required for such microbial communities. Carpenter bees are important pollinators of wild plants and crops, with some species demonstrating greater pollination efficiency than honey bees for certain large-flowered crops such as passion fruit.
Xylocopa californica arizonensis
Arizona Carpenter Bee
Xylocopa californica arizonensis is a subspecies of carpenter bee in the family Apidae, recognized as the Arizona Carpenter Bee. It belongs to a genus of large, robust bees known for nesting in wood and exhibiting incipient social behavior. Research on related Xylocopa species has revealed surprising microbiome similarities to highly social bees like honey bees and bumble bees, suggesting that advanced sociality is not required for maintaining complex gut bacterial communities.
Xylocopa micans
Southern Carpenter Bee
Xylocopa micans, the southern carpenter bee, is a large solitary bee in the subgenus Schonnherria. It excavates nests in dead wood but, unlike the sympatric X. virginica, has not been documented nesting in structural timbers. The species exhibits a unique polymorphic mating strategy, shifting from resource defense polygyny in early spring to lek polygyny in mid-summer. It is an important generalist pollinator capable of buzz pollination.