Great Yellow Bumblebee
Latin name: Bombus distinguendus
Notable feature: A large yellow bumblebee with a distinctive band of black hairs between its wings
Conservation Status: Data Deficient
Where in the UK: Once widespread across much of the UK, now restricted to Machair and flower-rich areas in five locations: Caithness, NW Sutherland, Orkney, Inner Hebrides, Outer Hebrides
Great Yellow Bumblebee (Bombus distinguendus) © Jamie Boyle
The Great Yellow Bumblebee (Bombus distinguendus) is one of the UK’s rarest bumblebees. This iconic species has been lost from a large proportion of its former range in the UK and is now only found along the northern coast and islands of Scotland. These remaining populations are small and fragmented and their habitat is under threat.
The Great Yellow Bumblebee is identified by its size and its yellow or yellow-brown colouring, with a distinct band of black hairs between the wings. They are restricted to machair and other flower-rich areas and may be seen from June-September. They are often found on unimproved grasslands, including autumn or winter grazed cattle pastures.
The three main requirements for an ideal habitat are:
➡ Nest site – areas of tussocky, taller grasses;
➡ Forage sites – provides a continuous supply of flowers from June-September, especially vetches, red clover and knapweeds;
➡ Hibernation site – dry in winter and out of direct sunlight.
- Size: The Queen is biggest, while workers and males are of a similar but smaller size. Queen: 19-22mm | Worker: 10-18mm | Male: 10-18mm
- Life span: Annual life cycle; from egg to adult approximately a year. Workers and males: 2-6 weeks | Queen: 1 Year
- Diet: Commonly found feeding on vetches (Vicia spp.), Red Clover (Trifolium pratense), and knapweeds (Centaurea spp.). It will feed from a range of flowers, especially those in the pea, thistle, and mint families.
- Reproduction: After mating in late summer, queen bees find suitable hibernation sites in deep plant litter, or under grass tussocks in sand dunes or soil. They will then hibernate until emerging in June the following year, when they will feed and lay eggs in a new nest. The eggs hatch into larvae which develop into worker bees until late summer, and males and daughter queens thereafter. These emerge in August-September and mating takes place with the new queens. During late August-September, and following mating, the old queen, workers and males die off and the new queens hibernate. Queens produce relatively small colonies for bumblebees, with 20-50 workers.
- When to see: June (queens emerging), July-September for worker bees, and August-September for male bees. They are most active during warm, sunny days in summer when conditions are not too windy.
- Population Trend: Unknown but likely declining
- Threats: Loss of flower-rich meadows. Intensification of farming and grazing practices. Threats associated with loss of Machair habitat, including climate change and abandonment due to increasing economic pressure on traditional crofting practices
- Fun Fact: They nest in old mouse nests, rabbit burrows and other holes under grass tussocks. The Gaelic name for the Great Yellow Bumblebee is Seillean mòr buidhe.
How you can help:
Buglife is working to increase awareness of invertebrates and the Great Yellow Bumblebee through specific projects and campaigns including Species on the Edge, but we need your help!
Buglife would like the public to help us locate, photograph, and report any sightings of the rare Great Yellow Bumblebee. Join a recording scheme and log your finds – send any records or sightings to the Bumblebee Conservation Trust or download the iRecord app and get recording!
Bees on the Edge is a project led by the Bumblebee Conservation Trust as part of the Species on the Edge. The project aims to improve the fortunes of the Great Yellow Bumblebee through habitat improvements, surveying and long-term monitoring.
Do remember that we rely on donations to continue our work. If you have searched, found and learnt about our incredible invertebrates on our website, please do consider Making a Donation, Becoming a Member or maybe even making a purchase in our shop. For more ideas on how to support our work find out how to Get Involved. Thank you 🕷