Suckley’s Cuckoo Bumble Bee (Threatened)
Bombus suckleyi
This bumble bee once ranged across Canada, more frequently in the west than in the east, and always much less common than its hosts. Specimens were first collected in Prince Edward Island in 1909 and 1930, but no further records are known. Suckley’s Cuckoo Bumble Bee is a nest parasite of other bumble bees and depends on its hosts to rear its young. It is/was found in all provinces and territories except Nunavut. Despite increased search effort for bumble bees in Canada over 20 years, fewer individuals of this species have been found than in the past. There has been a decline of more than 30% in relative abundance compared to all bumble bees (indicating a population decline) and a decline in area of occupancy. It has not been recorded on the island of Newfoundland since 2010 and not elsewhere in Canada east of Manitoba since 1978. Recent declines have been severe in areas where the species was historically more frequent, as in British Columbia and Alberta.
The immediate threat to this species is the steep decline of host bumble bees in British Columbia and Alberta. Major threats to the hosts are the escape of pathogen-infected bumble bees from managed colonies in commercial greenhouses, pesticide use and climate change.