Bumblebees in decline

Of the 16 species of Bumblebee in the British Isles only 6 species remain widely distributed and common. Nest densities of some threatened species may be as low as one or two per square kilometre.

The most critical change in the farmed landscape appears to be limited availability of forage flowers especially those with long corollas and high nectar loads, although many such plants may be common e.g. red clover and bird’s-foot trefoil they may not be present in sufficient quantity over wide areas during the summer. Modern seed mixes often contain white or hybrid clovers – these lack the long corolla/high nectar load required by bumblebees.

Current agri-environment schemes may offer limited opportunities to enhance habitats e.g. heathlands, but most schemes are too short-term and not extensive enough. Many bumblebees require tall, tussocky but open swards for nesting. These may be harmed by intensive winter grazing which also reduces the small mammal population, holes of which are used as nest sites by ground nesting species. Surface nesting carder bees require a more open sward with tussocks and moss, short grazed or regularly cut areas are not suitable. Several species use tussocky vegetation or clumps of moss for hibernation. These may be lost during extensive winter grazing.

There is an urgent need for large-scale changes to the farmed landscape with a reversion to more extensive systems.

Species included in the UK Biodiversity Action Plan:

Great Yellow Bumblebee Bombus distinguendus  – confined to Scottish islands. Classified as Nationally Scarce, cause of decline loss of extensive, herb-rich grasslands.

Brown Banded Carder Bee Bombus humilis  – widespread but declining. Classified as Local, cause of decline loss of extensive, herb-rich grasslands through agricultural intensification, possible threat from non-native forms of Bombus  used for pollination in glasshouses. 

Large Garden Bumblebee Bombus ruderatus  – on the verge of extinction. Classified as Nationally Scarce, cause of decline loss of extensive, herb-rich grasslands through agricultural intensification, possible threat from non-native forms of Bombus  used for pollination in glasshouses. 

Short Haired Bumblebee Bombus subterraneus  – last seen in 1996. Classified as Nationally Scarce, cause of decline loss of extensive, herb-rich grasslands through agricultural intensification, possible threat from non-native forms of Bombus  used for pollination in glasshouses. 

Shrill Carder Bee Bombus sylvarum  – on the verge of extinction. Classified as Local, cause of decline loss of extensive, herb-rich grasslands through agricultural intensification. 

How to identify the six common bee species 

Bombus terrestris   

Largest species of bumblebee in the UK, usually the first to emerge, also one of the most widespread. 

Very similar to B. lucorum but yellow hairs duller with brownish orange tip to abdomen. 

Workers impossible to separate from B. lucorum, Males have more yellow hairs and distinctive yellow nose, emerge in August. 

Nests underground, usually in old mouse nests. 

Have comparatively short tongue so tend to forage on flowers with short corollas and daisy-type flowers. 

Will bite into the corolla of plants too deep to reach the nectar source. 

Bombus lucorum 

Slightly smaller than B. terrestris, widespread and common. 

Queen has lemony yellow hairs on thorax and abdomen and white tip to abdomen, males have pale yellow hairs on top of head and front of thorax. 

Hairier than most other common species. 

Nests in old mouse nests. 

Bombus lapidarius 

Common and widespread in much of lowland Europe, probably the easiest species to recognise with its black body and bright orange tail. 

Males similar to queens and workers but have band of yellow hair on thorax. 

Could be confused with smaller and rarer B. ruderarius  – has reddish rather than black hairs fringing the pollen basket. 

Nests on the ground, often under large stones or at the base of dry stone dykes. 

Comparatively short-tongued species often feeding on daisies, dandelions and thistles. 

Bombus pratorum 

Common and widespread relatively small bee. 

Queens and workers have yellow bands at front and rear of thorax with yellow band on abdomen with tail red in queen white in workers black in males, although shows much variation. 

Short tongued but visits a variety of flowers e.g. white clover, lavender, sage, allium, thistles and daisy type flowers. 

Nests in variety of sites above and below ground, colonies established in early spring, worker numbers often peak well before other species. 

Colony cycle short often ending by mid-summer although a second cycle can occur. 

Bombus hortorum 

Common and widespread in Europe but never abundant. 

Has white tail but distinguished from B. terrestris/lucorum by two yellow bands on thorax, also has longer head and slimmer body. 

Longest tongue of any British species so can visit flowers with long corollas e.g. foxglove, vetches. 

Colony small often with 30-80 workers, cycle short, second cycle may be completed. 

Nest usually among plant roots and litter just above or below the surface. 

Bombus pascuorum 

Common and widespread species, commonest of the ‘ginger’ species, queens, workers and males almost entirely covered by ginger hairs although there is much variation. 

Medium tongue length, forages on clovers, vetches, blackberries and, later in the year, thyme, sage and lavender. 

Often nests at the base of a grass tussock where it combs adjacent plant material around the nest. 

Colony has long cycle, often lasting into October.