Key facts
- Gaelic name: Seillean mòr buidhe
- Distribution: Restricted to Orkney, Scottish Western Isles, and Caithness and Sutherland.
- When to see: May – August
- Status: Rare
- Species on the Edge areas: Argyll and Inner Hebrides; Orkney; Outer Hebrides; North Coast
Species information
How to identify
The great yellow bumblebee is a large bumblebee species. The abdomen and thorax are entirely covered with sandy-yellow hairs, with the exception of a black band across the thorax between the wing bases. Workers are generally smaller than the queens and males are similar in size to workers.
Lifecycle
The Great yellow bumblebee is a late emerging bumblebee. Queens are usually seen from mid-June. Queens will feed on nectar and then begin to search for a suitable nest site. Great yellow queens will use old mouse nests, rabbit burrows and other holes under grass tussocks as nest sites. It is estimated that nest density is no more than one or two nests for every square kilometre of suitable habitat. Great yellow queens produce small colonies compared to other bumblebees with 20-50 workers. Workers, seen from mid-July onwards, collect nectar and pollen to support the nest. The queen will switch from producing workers to rearing males and daughter queens in late July. Males emerge from the nest in early August and daughter queens are seen from mid-August. After mating, daughter queens find suitable hibernation sites in deep plant litter or under grass tussocks in soil or sand dunes. They will not emerge again until June the following year. During late August and September the old queen, workers and male great yellow bumblebees will die.
Distribution
The great yellow bumblebee is one of the rarest British bumblebees, now restricted to machair and other flower-rich areas in Orkney, Scottish islands, and Caithness and Sutherland.
The current distribution of great yellow bumblebee reflects the distribution of flower-rich machair and locations where traditional crofting practices are still maintained.
Great yellow bumblebee UK distribution map. Credit: Bumblebee Conservation Trust www.bumblebeeconservation.org/learn-about-bumblebees/species-guide/great-yellow-bumblebee/
Habitat and feeding
This bumblebee is a specialist of highly flower-rich, open grassland habitat. They are particularly associated with machair, a rare habitat in global terms, with the majority occurring on the west coasts and islands of Scotland and Ireland. Away from machair-rich areas, they are also supported by targeted agri-environment options.
Great yellow queens will use old mouse nests, rabbit burrows and other holes under grass tussocks as nest sites.
The tongue of a great yellow is long relatively to other bees species, and they favour red clover and many wildflowers in the pea/vetch family. They also target knapweed, comfrey and field scabious.
When to see
Great yellows are a late-emerging bumblebee, generally emerging from hibernation around late May and finishing their colony cycle in mid-late August.
Conservation status
Rare
Threats
Great yellow bumblebee used to be found throughout the UK, but distribution has declined by 80% in the last century making it one of the UK’s rarest bumblebees.
Great yellows are on the edge of their natural climactic range in the UK, and a a naturally boreal species. They thrive only where a high quality of the habitat mitigates this.
The principle causes of decline are the loss of flower-rich meadows and the intensification of farming and grazing practices.
What Species on the Edge is doing
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Monitoring and surveying
- Leading BeeWalks
- Training volunteers to lead BeeWalks
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Engaging with local communities to increase awareness of bumblebees
- Engaging with farmers, crofters and land managers to advise on best management and engage in targeted work to benefit the species
- Working with local groups to build upon the success of Tiree’s great yellow bumblebee project.
Watch
Resources
- A guide to the bumblebees of Orkney and Shetland | Species on the Edge
- Bumblebee Conservation Trust
- BeeWalk
- Tiree’s great yellow bumblebee project
- Wildflowers used by great yellow bumblebees | Tiree’s great yellow bumblebee project
If you are interested in learning more about our work with bumblebees and how you can get involved, get in touch with your local Species on the Edge team.
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