Bombus home | Introduction | BumblebeeID | Find species by Group, Region, Colour, A-Z | References


Find species by colour-pattern group
click on a matching bee diagram:


tail black

tail red/orange/brown

tail red/orange and

tail yellow/white


Click on the bee above that matches the predominant pale colour of the 'tail'. The 'tail' refers to the palest hair covering all or parts of gastral terga 3-5. Bumblebees with a yellow band on tergum 3 or 4, with no red on terga 3-5, and with black immediately anteriorly, are counted as yellow tailed. Bumblebees with terga 2-3 pale and terga 4-5 black are counted as black tailed. This classification was derived using worker bumblebees alone and therefore excludes Psithyrus.



Use of colour for identification
Variation within and among species
Defining colour-pattern groups
Background on colour-pattern diagrams
New colour-pattern diagrams
Key to bumblebees of the world



Use of colour for identification

Colour pattern is used here to refer only to colours of the body hair, not to the colour of the body surface (which is black or brown). Because of the pronounced variation within species and resemblance among species, colour patterns, when used alone and when considered only for the coarsely defined body regions used here, are never going to be sufficient to distinguish some species. Nonetheless, bumblebee colour patterns have been used in most keys as an important part of identifying species. The colour key below can still be used to find quickly a small number of the most likely candidates for closer morphological comparison (e.g. by examining the genitalia of the corresponding males), especially when combined with a key to subgenus.



Variation within and among species

Variation within species. The example below for the Oriental B. trifasciatus complex (redrawn from Williams, 1991 [pdf] ), shows that bumblebee colour patterns can be highly variable:

B. trifasciatus


Resemblance among species. In contrast, the table below shows that bumblebee colour patterns can be closely similar among species within the same geographical region (in this case, very similar patterns to B. trifasciatus above are shared and covary across southern Asia with co-occuring species, including B. haemorrhoidalis and B. breviceps).


W Himalaya
E Himalaya


B. (Mg.) trifasciatus



B. (Or.) haemorrhoidalis



B. (Ag.) breviceps



Convergence among species. Because these species belong to distantly related subgenera, the colour-pattern resemblances are likley to be the result of evolutionary convergence. Convergence among bumblebee colour patterns could be the result of several different kinds of processes, including selection for the advantages that particular patterns may confer for thermoregulation, cryptic protection, and mimetic protection (Williams, 2007 [pdf]). For these particular species, mimetic convergence is likely to be a major component because of the complexity and precision of the mimicry.



Defining colour-pattern groups

Geographically based colour-pattern groups similar to those shown above from southern Asia can be described among bumble bees from many parts of the world (Williams, 2007 [pdf]). A classification of colour-pattern groups needs only simple rules, which are based here on large flexibly-defined components of the colour pattern, such as (1) the colour of the 'tail' and (2) the colour of various transverse 'pale bands'.


The 'tail' refers here to the palest hair covering all or parts of the posterior metasomal terga 3-5. 'Pale bands' refer to transverse bands of any colour, surrounded by black, where the band is of a colour other than black (most often the colour is yellow or white), and where the band must cover parts of the body other than the 'tail' or head. Differences in colours other than black between adjacent colour-pattern elements are not counted as defining separate pale bands. Several other qualifications need to be recognised. First, a black bumblebee with terga 1-5 red is counted as being unbanded black with a red tail (group 100). Second, bumblebees with a yellow band on tergum 3 or 4 (with no red on terga 3-5) and with black immediately anteriorly are counted as yellow-tailed (e.g. group 332). However, if bumblebees have pale terga 2-3 with black terga 4-5, then they are counted as black-tailed (e.g. group 033).


A summary of the rules for classifying colour-pattern groups by three criteria are shown in the table below:



A Tail colour

0 black
1 brown / red / orange
2 brown / red / orange followed by yellow / white
3 yellow / white

B Pale band colour 0 pale bands absent (black)
1 olive
2 brown / red / orange
3 yellow
4 white
C Pale band position 0 pale bands absent
1 one pale band only, on gaster
2 one pale band only, on part of thorax
3 at least two separated pale bands, on thorax or thorax and gaster
4 all pale, at least on thorax


The three criteria and 14 values for discriminating colour-pattern classes in the table above permit 68 possible classes to be distinguished. Of these, 44 classes are actually observed among the worker colour patterns coded, as shown below. Consequently, 24 possible classes in this colour-pattern 'space' have not been observed and are 'missing'. Another 12 of the 44 classes cannot be considered to be groups of similar or convergent colour patterns because each class includes just a single species:

Several of the 32 colour-pattern groups above have easily recognised subgroups of, for example, darker and paler colour patterns, bringing the number of groups recognised back up to 38. These remaining colour-pattern groups have been tested to assess whether the bumblebees sharing each colour pattern within a group tend to occur together in the same parts of the world (at least at the coarse spatial scale of the equal-area grid map, Williams, 2007 [pdf]). Significant geographical association was found for the 24 largest groups, which are presented here on separate pages (e.g. all-black bees, group 000). The most common colour pattern world-wide consists of yellow stripes with black between the wings and a red tail (group 133, e.g. B. keriensis):

B. keriensis




Background on colour-pattern diagrams

Early illustrations of bumblebees were attempts to portray the insects more or less naturalistically e.g. Harris's (1776) B. terrestris:

B. terrestris


This tradition continued with improving techniques and illustrations showing more subtle colour variations by many authors e.g. Friese & Wagner's (1904) B. pascuorum:

B. pascuorum


In contrast, some authors realised the value of reducing colour patterns to small multiples of simplified diagrams that summarise aspects of the colour variation considered important both for studying variation and for identifying taxa. Early examples were rendered in black and white, e.g. Vogt's (1909) B. terrestris:

B. terrestris

or in colour, e.g. Friese & Wagner's (1910) B. soroeensis:

B. soroeensis


Colour patterns have been used before to identify British bumblebees. Many keys have used colour as well as morphology (e.g. keys by Richards, 1927; Yarrow, in Free & Butler, 1959; Alford, 1975). Alford's key was first published in six separate parts between 1970-1972. After an introduction and a part on cuckoo bees, there were separate parts for each of four major colour-pattern groups (see Alford, 1973). Prys-Jones & Corbet (1987, 1991) included a slightly modified form of the combined larger key, but added (page 55) a text-based key to the seven species common in southern Britain, based on similar colour-pattern groups (their book also contains excellent colour illustrations of bumblebees by Anthony Hopkins). Subsequently, several similar simple and effective guides to a few species have been compiled along with colour-pattern diagrams. One example is Murdo Macdonald's guide to the bumblebees of the Scottish Highlands, which works by matching colour-pattern diagrams separately for the thorax and gaster:

Highland species


Any diagrammatic summary is a compromise between, on the one hand, selecting the most important components and, on the other, precision in representing the details of the pattern. Both the pattern elements (regions of the body) and the colours (hues) are reduced to just a few classes. The choice of compromise will depend on the purpose of the study.



New colour-pattern diagrams

The colour-pattern diagrams used here were designed for an analysis of colour-pattern groups among bumblebees of the world (Williams, 2007 [pdf]). Each diagram represents a particular individual specimen. Areas of the body with no hair (eyes, top of head, wing bases) or with only short hair (metasomal segment 6) are shown in white. Otherwise, these diagrams have coded the dorsal aspect of 27 regions (elements) of the female body (excluding the legs and wings) into at least 7 colour (hue) classes. For simplicity, the coded body regions are more or less rectangular and show only the colour that predominates within each e.g. for British B. pascuorum:

B. pascuorumB. pascuorum



Key to bumblebees of the world

A Lucid multi-access key is available to help in identifying females (queens and workers) of all of the world's bumblebees to species using colour-pattern diagrams. This is a test version. At present the illustrations are incomplete, but as a work in progress it may still be useful. Comments and suggestions are welcomed.


Click here for a colour key to female bumblebees of the world


research publications | books on British bumblebees | links and credits


top top of page