Large garden bumblebee (Bombus ruderatus)
|Also known as:||Ruderal bumblebee|
|Size||Male length: 15-16 (2)|
Queen length: 21-23 mm (2)
Worker length: 11-18 (2)
Classified as Nationally Scarce in Great Britain (3).
In comparison with other bumblebee species, the large garden or ruderal bumblebee, has a long face and tongue; these are adaptations for feeding on long-tubed flowers (4). They are black, with two yellow bands on the thorax, a single yellow band on the abdomen and a white tail (6). In Britain, a totally black form known as variety harrisellus may arise (4). All castes are similar in appearance to the garden bumblebee (Bombus hortorum), but tend to have a much 'neater', short-haired appearance (2).
This is one of a number of our native bumblebees that has undergone a dramatic and sustained decline in both numbers and range. This bee was very common in southern England at the beginning of the 20th century, but by the 1970s it was scarce. Recent research has only identified populations in East Anglia (5). It has not been recorded in Wales since 1960, and is absent from Scotland. Although widespread throughout Europe it is in decline (3). It was introduced to New Zealand from Britain, and has also been introduced to South America (6).
Found in a range of open, flower-rich habitats, including coastal dunes, saltmarsh margins and shingle, grasslands, and occasionally gardens. In all cases, it requires very large expanses of suitable habitat to support viable populations (4).
The large garden bumblebee makes its nest underground, in the burrows of mice and voles (2). Nests are typically amongst vegetation on banks and slopes. Colonies may contain over 250 workers and often remain active until September (2). The cells in which larvae will be housed are lined with pollen before the eggs are laid (4). Queens hibernate through the winter, probably underground in disused mammal burrows, and emerge the following spring (2). They feed on long-tubed flowers, and show a particular preference for common toadflax (Linaria vulgaris), white dead-nettle (Lamium album), woundworts (Stachys spp.), and red clover (Trifolium pratense) (4).
The main cause of the decline of this species (and indeed, many other species of bumblebee) is the widespread loss of large tracts of flower-rich unimproved habitat as a result of agricultural intensification, forestry, and development (4).
This bumblebee is a UK Biodiversity Action Plan (UK BAP) priority species, and a Species Action Plan has been produced in order to guide its conservation (3). Some known populations occur on Sites of Special Scientific Interest (SSSIs).
For details of how to help bumblebees, see the English Nature leaflet 'Help save the bumblebee...get more buzz from your garden' available here:
Information supplied and authenticated by Bryan Pinchen (independent ecologist).
- Abdomen: in arthropods (crustaceans, insects and arachnids) the abdomen is the hind region of the body, which is usually segmented to a degree. In crustacea (e.g. crabs) the limbs attach to the abdomen; in insects the limbs are attached to the thorax (the part of the body nearest to the head) and not the abdomen. In vertebrates the abdomen is the part of the body that contains the internal organs (except the heart and lungs).
- Castes: in social insect colonies, a group of individuals that are structurally and/ or behaviourally distinct, performing certain tasks. Examples are the soldier caste of termites and ants, and the workers of bees.
- Hibernation: a winter survival strategy characteristic of some mammals in which an animal's metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer. In insects, the correct term for hibernation is 'diapause', a temporary pause in development and growth. Any stage of the lifecycle (eggs, larvae, pupae or adults) may enter diapause, which is typically associated with winter.
- Larvae: stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Thorax: part of the body located near the head in animals. In insects, the three segments between the head and the abdomen, each of which has a pair of legs.
National Biodiversity Network Species Dictionary (August 2002)
- Pinchen, B.J. (2003) Pers. Comm.
UK BAP Species Action Plan (August 2002):
- Falk, S. (1991) A review of the scarce and threatened bees, wasps and ants of Great Britain. Nature Conservancy Council, Peterborough.
- Prys-Jones, O. E. & Corbet, S. A. (1987) Bumblebees. Cambridge University Press, Cambridge.
- Edwards, M (2002) Bumblebee Working Group Report.