Invertebrates

Great yellow bumblebee (Bombus distinguendus) - UK notable

In recent times in the UK, this bumblebee has only been recorded in western and northern Scotland. Bombus distinguendus is one of several bumblebees to have undergone a dramatic decline in range and abundance, probably because of habitat loss to modern agricultural practices.

Habitat

This bumblebee is associated with extensive areas of meadowland. This habitat supports a large number of plant species which flowers have long corolla, notably black knapweed (Centaurea nigra), red clover (Trifolium pratense) and other species belonging to the families Fabaceae, Lamiaceae and Asteraceae. These plants are generally absent from improved or intensively managed ground. Nests are constructed underground. Workers are relatively large, but the number of workers per nest is low (20 - 50). Most activity on Orkney and the mainland occurs from June to September, but may be earlier in the Western Isles.

Threats and conservation

This bee is under threat from heavy summer grazing, reduction in rotation period, fertilisation and adoption of silage and monoculture. These practices result in loss of the extensive, permanent, flower-rich meadows. Traditional Hebridean cattle-rearing regimes and rotational machair cropping provide suitable habitat for the great yellow bumblebee. It may be able to survive on small, widely scattered patches of forage, provided they supply food continuously through the season (from May or June to the end of September).

For more on this bumblebee, see the following web pages:

Source

Phillips, D. 2000. The northern bumblebee Bombus distinguendus. SNH Information Note Series.

Douglas, G. 2003. Bombus distinguendus Morawitz, great yellow bumble bee (Hymenoptera: Apidae). Invertebrate species dossier, Scottish Natural Heritage.