Bombus


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B. asiaticus
Mate-searching male of B. asiaticus.
 

Introduction

 

 

Bumblebee checklists
Patterns of description
Sample of names
WWW checklist history
WWW checklist development

 

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Aims for this site. The aim for these web pages is to give an overview of all of the world's bumblebee species. The list of species has to be one person's interpretation, but where possible, alternative interpretations are presented in the comments on each species. Updates are added frequently.

 

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Bumblebee checklists

Bumblebees are relatively well known. Bumblebees have long been popular with field biologists. As with butterflies and birds, part of the attraction lies in their bright colours, large body size, activity during daylight hours, and abundance in the north-temperate regions where most collectors and authors have lived. As a result, large collections of bumblebee specimens have been assembled, not only from countries like Britain, but even from the more remote parts of their range, such as north-east Asia. The rate of discovery of new species is now low, as shown by the histogram below (Williams, 1998 [pdf]: new descriptions in grey, cumulative in white). Therefore bumblebees are a particularly well described group of organisms with well recorded distributions.

rate of decsription of species

Where are bumblebees found? The map below shows the distribution of bumblebee diversity as counts of species richness around the world. The number of indigenous species of bumblebees (excluding introductions) is recorded within each large equal-area (611,000 km²) grid cell. Equal-area grid cells are important for reducing bias from species-area effects when comparing regional richness (otherwise richness tends to be affected strongly by the size of an area). An equal-area colour scale is used to emphasise the differences among regions. Red shows the richest regions, with a white spot showing the primary global hotspot in Sichuan/Gansu. In the Old World, bumblebees are particularly species rich in the southern Tertiary mountains that run from the Qinghai-Tibetan Plateau and Himalaya westwards to the Alps and Pyrenees, with another area of high richness in the north-temperate forest-steppe zone running eastwards from the Baltic to Inner Mongolia. In the New World, bumblebees are particularly species-rich in the western mountains, from the Rockies southwards to the Andes. Note that many erroneous records and introductions have been excluded. For comparison, see the richness maps for honey bees and stingless bees.

 

species richness

 

These grid cells can also be classified by differences in their faunal composition to recognise different biogeographic regions specifically for bumblebees (rather than using the traditional biogeographic regions based largely on birds):

 

bumblebee regions

 

Bumblebees prefer cool, open, flower-rich habitats, often with one long but predictable adverse season (usually cold winters). These conditions characterise subalpine meadows and north temperate grasslands (see the map above). The photo below shows high grasslands (3500 m) grazed by nomadic yak herds in the global hotspot for bumblebees at the eastern (wetter) end of the Qinghai-Tibetan Plateau in Sichuan:

 

PHW on E Tibetan Plateau
Photo by S Cameron.

 

Why is there no recent revision of bumblebees? A problem for biologists trying to identify bumblebee species, all the more apparent because of the large amount of material available, is that while bumblebees have been described as morphologically relatively 'monotonous' or 'homogeneous' compared to other bees (Michener, 1990, 2000, 2007), they are often extraordinarily variable within species in the colour patterns of their pubescence (hair). This is shown for one exemplary species complex in the map below. As well as differing within species in colour pattern in different parts of the world, there is also a confusing tendency for species to resemble one another between species in their colour patterns locally (Plowright & Owen, 1980; Williams, 2007 [pdf]). Faced with this variation, generations of taxonomists since the starting point of Linnaean nomenclature (in 1758) have described differing individuals under a plethora of more than 2800 names (unpublished catalogue: see Williams, 1998 [pdf]). Most of these names are for taxa below the rank of species, and just 246 taxa are interpreted here as separate species. Arguably, this nomenclatural burden of more than 11 names per species (median 5, maximum 186) has slowed progress towards a complete revision of the group. The situation is made more difficult because most of the type specimens for all of these names are in institutions in Europe and North America, whereas the least well known bumblebees (requiring comparison with more types) are in Asia and South America.

 

geographical variation

 

Which summaries are available? There have been few attempts to present complete revisions, catalogues or checklists of all bumblebee species from which to see summaries of past views. Latreille (1809) included 13 species in his genus Bombus. Most early lists included just those species seen by the authors, usually from particular collections, and often from just one region. For example, Smith (1854) catalogued 87 bumblebee species (79 Bombus + 8 Apathus [= Psithyrus]) in the collection of the British Museum. The only truly synoptic catalogue of bumblebees was published by Dalla Torre (1896), with 255 (non-fossil) species (228 Bombus + 27 Psithyrus). His catalogue included many varietal names, synonyms and early references. The reason why Dalla Torre's species count exceeds the total recognised here as described before 1899 (159 species) is that many of his species are now treated as synonyms or subspecies. Later, Skorikov ([1923]) listed 237 species (plus 70 'Bombi incertae sedis'), but with few synonyms and without including Psithyrus. Skorikov's list is also interesting because it arranged most of the known species within his genera and subgenera, which form the basis of the subgeneric system, which has recently been revised.

 

Why do we need a new overview? Nearly half of the c. 2800 bumblebee names have been published since the last world-wide checklist in 1923. Consequently, there has been a need for a new overview. The checklist on these web pages begins to address this need. This checklist cannot be expected to solve all biological and nomenclatural problems so it is bound to require revision. However, it is hoped that it provides an improved framework to support more detailed regional studies, and that by identifying some of the major problems it will stimulate further research.

 

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Patterns of description

When seeking to interpret patterns in diversity, ecology and biogeography, any regional or taxon-based bias in patterns of taxonomic description needs to be understood.

 

The geographical range size of a species has had an effect on when it was first described and (directly or indirectly) on how many names it has attracted. Below is a scatterplot showing the relationship for the presently accepted bumblebee species between the dates of their first description (x axis), their global range sizes (y axis: number of occupied 611,000 km² grid cells world-wide, see the map above), and their numbers of synonyms and subspecific names (z axis: infrasubspecific names are excluded). The British fauna is distinguished as filled triangles, the nearly circumpolar fauna (B. hyperboreus, B. balteatus, B. polaris and B. lapponicus) as squares, and some British and widespread European species are labelled individually (B. hypnorum has recently joined the British fauna, Goulson & Williams, 2001 [pdf]).

 

patterns of description

 

For an analysis of patterns of description, including rates of discovery of new species, see Williams (1998 [pdf]).

 


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Selective sample of names

This checklist is based on a complete unpublished catalogue of over 2800 names. As a checklist, it is not required to include the full list of names, so names are selected primarily where they help to clarify the identity and scope of the species (including the subspecies included by some authors), and particularly where those names have been in most common use in the literature since 1960. Misidentifications are not included and are discussed only where they are needed to clarify the application of problematic names.

 

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WWW checklist history

The first version of this checklist was drafted in 1980. First-hand experience of many bumblebee species has been gained through field work in various parts of the world (1971-2010):

 

PHW fieldwork sites

 

A version of the checklist was circulated for comment in 1985 (this version is shown in Williams, 1985a). Many specialists have offered helpful comments and suggestions. These web pages are based on the resulting publication (see the checklist introduction [pdf]) with updates, so it is suggested that any reference to these web pages should also refer to this:

 

Williams, P. H. 1998. An annotated checklist of bumble bees with an analysis of patterns of description (Hymenoptera: Apidae, Bombini). Bulletin of The Natural History Museum (Entomology) 67: 79-152.

 

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WWW checklist future

These web pages are a work in progress and are expected to be updated frequently. Future plans for development include:

 

  • adding photographs of live bees
  • an application to ICZN to resolve nomenclatural problems
  • adding a complete catalogue of all names, providing full database-searching facilities.

 

research publications | books on British bumblebees | links and credits

 

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