Small garden bumblebee (Bombus hortorum)
|Size||Length of males: 13-15 mm (2)|
Length of queens: 17-22 mm (2)
Length of workers: 11-16 mm (2)
Abundant throughout Britain (3).
This is a large bumblebee, which has a fairly 'scruffy' appearance with long hair (3). It is a yellow, black and white banded species (2), with a long head. The tongue, which is as long as the body, is the longest of all bumblebees found in central Europe (4). Three 'castes' occur within bumblebee nests, a 'queen' (the reproductive female), 'workers' (non-reproductive females) and males (5). All three castes are broadly similar in appearance, but males can be distinguished as they lack stings and have longer antennae than females (5).
This species is one of the commonest and most widespread of bumblebees in Britain (1). It is found throughout the Palaearctic region, and has been introduced to New Zealand and Iceland (6).
Found in a range of habitats, including the edges of woodlands and scrubby areas, and is common in gardens (1).
The exceptionally long tongue of this species allows it to obtain nectar from plants with deep-tubed flowers, which honeybees and other bumblebees cannot exploit (5). It is an important pollinator of fruit trees and clover, and also visits deadnettle, foxgloves, cowslips and a range of other plants (4).
Colonies contain between 50 and 120 insects, and are present between late April and early October (2). The queen is the only member of a colony to survive the winter, they emerge in April and begin to search for a suitable place in which to establish a nest (7). Nests are typically made underground, in banks and among tree roots (2), or occasionally above ground in bird boxes (7). The queen creates a circular chamber in which she builds a wax egg cell, and she lays her first batch of eggs inside. The eggs are laid on a layer of pollen, which is collected by the queen, and then covered with a layer of wax (5). After hatching, the white larvae are fed on honey and pollen by the queen. When they are fully-grown, the larvae cease to feed and develop into pupae after spinning a protective silk cocoon around themselves. During the pupal stage, the larvae undergo complex changes, and develop into adult workers. Throughout their development, the queen incubates this first brood by lying over the cell in which they grow, keeping them warm with the heat of her body. After emerging, the workers undertake the duties of foraging and nest care, and the queen remains inside the nest, producing further batches of eggs. When the colony reaches its peak, males and new queens are produced. Males develop from unfertilised eggs; after leaving the nest they fly around in search of new queens with which to mate. In this species, males are present between June and October, but their numbers peak towards the end of July (2). After mating, these new queens search for a place to hibernate. The colony and the old queen gradually die, and the newly mated queens emerge the following spring, to establish new colonies (5).
Many British bumblebee species have undergone a worrying decline, largely as a result of changes in agricultural practices leading to a loss of open habitats and important food plants (8).
Specific conservation action has not been targeted at this species.
For details of how to help bumblebees see the English Nature leaflet 'Help save the bumblebee...get more buzz from your garden' available on-line from:
http://www.english-nature.org.uk/news/news_photo/savegardenbumbl esweb.pdf or ring the English Nature Enquiry Service: 01733 455101
For more on bumblebees see The Natural History Museum's Bombus site:
Benton, T. (2000) The Bumblebees of Essex. Lopinga Books, Wimbish, Essex.
Sladen, F.W.L. (1912, republished 1989) The Humble-Bee. The Logaston Press, Woonton, Herefordshire.
Information authenticated by Robin Williams.
- Antennae: pair of sensory structures on the head of invertebrates.
- Caste: 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.
- Colony: a group of organisms living together, individuals in the group are not physiologically connected and may not be related, such as a colony of birds. Another meaning refers to organisms, such as bryozoans, which are composed of numerous genetically identical modules (also referred to as zooids or 'individuals'), which are produced by budding and remain physiologically connected.
- Hibernate: 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.
- Palaearctic: the region that includes Europe, the part of Asia to the north of the Himalayan-Tibetan barrier, North Africa and most of Arabia.
- Pupae: stage in an insect's development when huge changes occur, which reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
- Pupal stage: stage in an insect's development, when huge changes occur that reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
- 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 (March 2003):
- Williams, R. British bumblebees with particular emphasis on the county of Somerset (3rd edition revised 3/2003). Vanellus Publications, Wedmore, Somerset.
- Chinery, M. (1986) Collins guide to the insects of Britain and Western Europe. William Collins sons and Co Ltd., London.
- Zahradnik, J. & Severa, F. (1999) A field guide in colour to bees and wasps. 2nd Edition. Blitz Editions, Leicester
- Free, J. B. & Butler, C. G. (1959) The New Naturalist: Bumblebees. Collins, London.
Natural History Museum Bombus (March 2003):
- Prys-Jones & Corbet (revised 1991) Bumblebees, Naturalists Handbooks 6, published for the Company of Biologists by Richmond Press, Slough.
Natural History Museum: Distribution and decline of British bumblebees. (March 2003):