Bombus sonorus

Say, 1837

Sonoran Bumble Bee

Bombus sonorus is a large native to southwestern North America and Mexico. It was historically treated as a of Bombus pensylvanicus but is now recognized as a distinct species based on lack of hybridization across their zone of geographic overlap. The species has experienced regional declines, notably disappearing from the Central Valley of California around 2010 while persisting in southern California and Arizona. It is currently under review for federal protection under the Act, with the broader B. pensylvanicus sensu lato complex listed as Vulnerable by the IUCN.

Bombus sonorus by (c) Andrew Meeds, some rights reserved (CC BY), uploaded by Andrew Meeds. Used under a CC-BY license.

Bombus (Fervidobombus) sonorus by the Smithsonian. Used under a CC0 license.

Pronunciation

How to pronounce Bombus sonorus: /ˈbɒmbəs soʊˈnɔɹəs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from Bombus pensylvanicus by non-hybridizing where ranges overlap. May be confused with the yellow form of Bombus crotchii and with Bombus nevadensis; the deep golden yellow coloration and specific thoracic banding pattern aid separation.

Images

Appearance

A large with deep golden-yellow coloration. Females have yellow hairs on the pronotum, , and scutellum, with a distinct black band between the wing bases. Abdominal segments T1-T3 are entirely yellow in females; males have T1-T4 yellow.

Habitat

Occurs in diverse across its southwestern range. Nests underground, frequently in abandoned pocket gopher burrows. Found in areas supporting its documented pollen plants.

Distribution

Western North America from California east to central Texas, and south to southern Mexico. Range overlaps with Bombus pensylvanicus in western Texas, parts of New Mexico, and Mexico.

Diet

Collects pollen from Gossypium (cotton), Viguiera, Helianthus (sunflowers), Linaria, Chrysothamnus, and Kallstroemia flowers.

Life Cycle

Nests underground, typically in pre-existing burrows such as old pocket gopher tunnels. Colony cycle follows typical pattern with solitary initiation, production, and late-season male and new queen .

Ecological Role

of native wildflowers and agricultural crops within its range. Documented pollen collection from multiple plant indicates foraging with established plant associations.

Human Relevance

Subject of conservation concern due to regional declines. Under federal review for Act protection. sequenced to support conservation genetics research and future population monitoring.

Similar Taxa

Bombus pensylvanicusHistorically treated as but now recognized as distinct based on lack of hybridization across broad geographic overlap in Texas, New Mexico, and Mexico
Bombus crotchii (yellow form)Similar yellow coloration; distinguished by specific thoracic banding pattern and abdominal segment coloration
Bombus nevadensisOverlapping range and similar appearance; separation requires attention to thoracic hair pattern and color shade

Misconceptions

The 'Sonoran ' likely derives from a mistranslation of the Latin specific epithet sonorus (meaning 'noisy' or 'loud,' referring to the 's loud buzz). A name intended to reference the Mexican state of Sonora would have been formed as sonorensis.

More Details

Conservation Genetics

High-quality assembly generated using Pacific Biosciences HiFi long reads and Dovetail Omni-C data, with -length scaffolds available to support resequencing and genetic diversity assessment.

Population Status

Noted by Robbin Thorp to have disappeared from California's Central Valley around 2010, while remaining relatively common in southern California and Arizona. This pattern of regional decline without rangewide collapse parallels other experiencing geographic range contractions.