Scientific Name: Bombus occidentalis mckayi
Taxonomy Group: Arthropods
Range: Yukon, Northwest Territories, British Columbia
Last COSEWIC Assessment: May 2014
Last COSEWIC Designation: Special Concern
SARA Status: No schedule, No Status
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
Western Bumble Bee, Bombus occidentalis Greene, is one of five North American members of the subgenus Bombus sensu stricto. It is a medium-sized (1 – 2 cm) bumble bee with a short head. The abdomen is colour variable, but all individuals have a transverse band of yellow hair on the thorax in front of the wing bases, and the tip of the abdomen is almost always white.
Bumble bee taxonomy is widely debated, including the taxonomic history of Western Bumble Bee. The species was once considered synonymous with Yellow-banded Bumble Bee; however, recent genetic work confirms these two species as separate. Additional recent taxonomic work further splits Western Bumble Bee into two separate subspecies: Bombus occidentalis occidentalis and Bombus occidentalis, based on genetic, morphological and distributional information.
This subspecies ranges in Canada from northern British Columbia (north of approximately 55-57ºN) through southern Yukon and westernmost Northwest Territories; at least 50% of its global range is in Canada. Recent surveys in northwestern Canada and Alaska suggest that it is still common. However, the southern subspecies of the Western Bumble Bee is experiencing a serious, apparently northward-moving decline, and because the causes of this decline are unknown, the northern subspecies faces an uncertain future. Recent studies in Alaska suggest that this subspecies has among the highest parasite loads (particularly the microsporidian Nosema bombi) of any bumble bee species in North America. Other potential threats include the unknown transmission of disease from exotic bumble bee species introduced for pollination in greenhouses (ongoing in the Yukon), pesticide use (including neonicitinoid compounds), and habitat change.
Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to "assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species".
COSEWIC held two Wildlife Species Assessment Meetings in this reporting year (October, 2013 to September, 2014) from November 24 to November 29, 2013 and from April 27 to May 2, 2014. During the current reporting period, COSEWIC assessed the status or reviewed the classification of 56 wildlife species.
The wildlife species assessment results for the 2012-2013 reporting period include the following:
Special Concern: 20
Data Deficient: 0
Not at Risk: 1
Of the 56 wildlife species examined, COSEWIC reviewed the classification of 40 that had been previously assessed. The review of classification for 25 of those wildlife species resulted in a confirmation of the same status as the previous assessment.
The Government of Canada is committed to preventing the disappearance of wildlife species at risk from our lands. As part of its strategy for realizing that commitment, on June 5, 2003, the Government of Canada proclaimed the Species at Risk Act (SARA). Attached to the Act is Schedule 1, the list of the species provided for under SARA, also called the List of Wildlife Species at Risk. Extirpated, Endangered and Threatened species on Schedule 1 benefit from the protection of prohibitions and recovery planning requirements under SARA. Special Concern species benefit from its management planning requirements. Schedule 1 has grown from the original 233 to 521 wildlife species at risk.
Please submit your comments byApril 15, 2015, for terrestrial species undergoing normal consultationsand byOctober 15, 2015, for terrestrial species undergoing extended consultations.For a description of the consultation paths these species will undergo, please see:Species at Risk Public Registry website