Bombus

.

B. religiosus worker visiting Aconitum.

Megabombus ecology and behaviour   HABITAT: Grassland, mountain meadow, and forest, including tropical montane forest.   FOOD-PLANTS: Medium to long tongue-length bumblebees visiting medium to deep flowers. This group includes the longest-tongued bumblebees worldwide (e.g. photo left). These species usually specialise in a narrow range of bilaterally symmetrical long-corolla flowers and may even form narrowly oligolectic relationships (best known for B. consobrinus: Løken, 1973, Huang et al., 2015), particularly for pollen foraging.   NESTING BEHAVIOUR: Nests underground or sometimes on the surface. Pocket-makers.   MATE-SEARCHING BEHAVIOUR: Males patrol circuits of scent marks.

Subgenus MEGABOMBUS Dalla Torre
Bombus (Megabombus) Dalla Torre, 1880:40, type-species Bombus ligusticus Spinola (= Bombus argillaceus (Scopoli)) by monotypy
Bombus (Megalobombus) Schulz, 1906:267, unjustified emendation
Hortobombus (as a subgenus of Bombus) Vogt, 1911:56, type-species Apis hortorum Linnaeus (= Bombus hortorum (Linnaeus)) by subsequent designation of Sandhouse, 1943:559
Bombus (Diversobombus) Skorikov, 1915:406, type-species Bombus diversus Smith by subsequent designation of Sandhouse, 1943:546
Bombus (Odontobombus) Krüger, 1917:61,65 (proposed as a section name but stated by Milliron, 1961:53, to be equivalent to his concept of the subgenus Megabombus Dalla Torre), type-species Apis argillacea Scopoli (= Bombus argillaceus (Scopoli)) by subsequent designation of Williams, 1995:339
[Nortobombus Skorikov, 1922:map 3, incorrect subsequent spelling]
Bremus (Senexibombus) Frison, 1930:3, type-species Bombus senex Vollenhoven by original designation
Hortibombus Skorikov, 1938a:146, unjustified emendation
Diversibombus Skorikov, 1938b:1, unjustified emendation
[Bombus (Senecibombus) Kruseman, 1952:101 incorrect subsequent spelling]

TAXONOMIC STATUS: For a discussion of why several former subgenera have been synonymised within this subgenus see Williams et al. (2008 [pdf]) .

Part of the bumblebee phylogenetic tree including available Megabombus species from an analysis of DNA sequence data for five genes (Cameron et al. 2007 [pdf]). Values above branches are Bayesian posterior probabilities, values below branches are parsimony bootstrap values. Alternative resolution from parsimony analysis is shown with dotted lines.

trifasciatus-group of species

Bombus (Mg.) diversus Smith
diversus Smith, 1869:207, examined
tersatus Smith, 1869:207, examined
6 names

NOMENCLATURE: Tkalcu (1965) first explicitly regarded B. diversus and B. tersatus as conspecific and, following the Principle of First Reviser (ICZN, 1999: Article 24), chose B. diversus as the valid name for the species.

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental, Japanese, Palaearctic Regions.

Bombus (Mg.) ussurensis Radoszkowski
Ussurensis Radoszkowski, 1877b:196
[ussuriensis Morawitz, 1881:254, incorrect subsequent spelling]
7 names

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental, Japanese, Palaearctic Regions.

Bombus (Mg.) longipes Friese
longipes Friese, 1905:511
hummeli Bischoff, 1936:18, examined
3 names

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental Region, Palaearctic border.

Bombus (Mg.) montivagus Smith
montivagus Smith, 1878:168, examined
montivagus Smith, 1879:131, redescribed
maxwelli Pendlebury, 1923:67, examined
9 names

TAXONOMIC STATUS: This species is now recognised as a separate species from gene data by Hines & Williams (2012) and by Huang et al. (2015).

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental Region.

Bombus (Mg.) albopleuralis Friese
albopleuralis Friese, 1916:108, examined
mimeticus Richards, 1931b:529, examined
?atropygus (Tkalcu, 1989:58 [Megabombus]) examined
9 names

TAXONOMIC STATUS: This species is now recognised as a separate species from gene data by Hines & Williams (2012) and by Huang et al. (2015).

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental Region.

Bombus (Mg.) malaisei (Skorikov)
malaisei (Skorikov, 1937b:2 [Diversibombus])
1 name

TAXONOMIC STATUS: This species is now recognised as a separate species from gene data by Hines & Williams (2012) and by Huang et al. (2015).

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental Region.

Bombus (Mg.) trifasciatus Smith
trifasciatus Smith, 1852a:43, examined
wilemani Cockerell, 1911:100, examined
11 names

TAXONOMIC STATUS: This species is now recognised as a separate species from gene data by Hines & Williams (2012) and by Huang et al. (2015).

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental Region.

senex-group of species

Bombus (Mg.) bicoloratus Smith
bicoloratus Smith, 1879:132, examined
kulingensis Cockerell, 1917:266, examined
tajushanensis Pittioni, 1949:244
12 names

TAXONOMIC STATUS: B. kulingensis has been regarded as a species separate from B. bicoloratus (e.g. Williams, 1998).

B. bicoloratus and B. kulingensis show variation in the pattern of the teeth on the inner process of the gonostylus and on the outer margin of the penis valve head, and more especially in how pronounced is the outer lateral shoulder on the penis valve just anterior to the ventro-lateral process. However, from the material examined, I believe that B. kulingensis and B. bicoloratus are morphologically closely similar. Furthermore, evidence from comparisons of DNA sequences from five genes is consistent with the two taxa being conspecific (Cameron et al., 2007 [pdf]).

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental Region.

Bombus (Mg.) irisanensis Cockerell
irisanensis Cockerell, 1910a:416, examined
1 name

DISTRIBUTION: Oriental Region.

IUCN CONSERVATION STATUS: Preliminary assessment as VULNERABLE (Williams & Osborne, 2009) by criterion A2 (IUCN, 2001, 2008) that no records are known since 1983.

Bombus (Mg.) senex Vollenhoven
Senex Vollenhoven, 1873:229
4 names

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Sumatran Region.

hortorum-group of species

Bombus (Mg.) supremus Morawitz
supremus Morawitz, 1887:196
linguarius Morawitz, 1890:351
3 names

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental Region.

Bombus (Mg.) gerstaeckeri Morawitz
Gerstäckeri [gerstaeckeri] Morawitz, 1881:242
Gerstaeckeri Hoffer, 1883:55, mandatory correction (ICZN, 1999: Article 32.5.2.1)
4 names

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Palaearctic Region.

Bombus (Mg.) argillaceus (Scopoli)
Argillacea (Scopoli, 1763:305 [Apis])
ligusticus Spinola, 1806:29

TAXONOMIC STATUS: See comments on B. ruderatus.

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Palaearctic Region.

Bombus (Mg.) ruderatus (Fabricius)
ruderata (Fabricius, 1775:380 [Apis]) examined
Perniger (Harris, 1776:131 [Apis])
villarricaensis Asperen de Boer, 1992a:133

TAXONOMIC STATUS: B. argillaceus and B. ruderatus are similar in most characters and differ principally in the colour patterns of the queens (e.g. Reinig, 1939). Scholl, Obrecht & Zimmermann (1992) found that hybrid queens between B. argillaceus and B. ruderatus do occur in parts of southeastern France, but are very rare. Whether or not the taxa on either side of this hybrid zone are considered to be separate species therefore depends on which species concept is preferred. Because Scholl, Obrecht & Zimmermann (1992) estimated that only slight gene flow is occurring, I shall continue to treat them as separate species.

MORPHOLOGY: photos of male genitalia.

INTRODUCTIONS: This species has been introduced into New Zealand (e.g. Gurr, 1957; Macfarlane & Gurr, 1995) (see the comments on B. hortorum, B. subterraneus and B. terrestris) and Chile (Arretz & Macfarlane, 1982; Asperen de Boer, 1993b; Thorp, 2003)). B. ruderatus also occurs on the Azores (which have never had a continental connection), where it may be presumed to be an introduction (Yarrow, 1967).

DISTRIBUTION: Palaearctic Region.

NOTES on this species in Britain.

Bombus (Mg.) portchinsky Radoszkowski
Portchinskij Radoszkowski, 1883:208
Porchinsky Radoszkowski, 1883:208[210]
Portchinsky Radoszkowski, 1883:209[211]
Portschinsky Radoszkowski, 1883:209[211], 210[212]
4 names

NOMENCLATURE: Radoszkowski (1883) published four different spellings of B. portchinsky, repeating this third form twice (page numbers 207 and 208 are repeated twice for different pages). Williams (1998) was the first author who cited all names (there are many incorrect subsequent spellings, e.g. Dalla Torre, 1896) and, following the Principle of First Reviser (ICZN, 1999: Article 24), chose B. portchinsky as the name for the species. This form is a simple noun in apposition and so retains the same ending whatever the gender of the generic name with which it is combined (ICZN, 1999: Article 31).

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Palaearctic Region.

Bombus (Mg.) hortorum (Linnaeus)
hortorum (Linnaeus, 1761:424 [Apis]) examined
meridionalis Dalla Torre, 1879:13
hispanicus Pittioni, 1939c:244, not of Friese, 1911:571 (= B. monticola Smith)
asturiensis (Tkalcu, 1975:181 [Megabombus]) replacement name for hispanicus Pittioni, 1939c:244
?reinigiellus (Rasmont, 1983:43 [Megabombus])
46 names

TAXONOMIC STATUS: The Spanish B. asturiensis has been considered a separate species from B. hortorum by Rasmont (1983, 1988), although they have been treated as conspecific by Pittioni (1939c), Tkalcu (1975), Ornosa (1986a, 1986b, 1991), Castro (1988, 1993) and, more recently, by Rasmont et al. (1995). The two taxa are closely similar.

The Spanish B. reinigiellus has also been considered both as conspecific with B. hortorum (Castro, 1987) and as a separate species (e.g. Rasmont, 1983; Castro, 1988; Ornosa, 1991). The two taxa are allopatric (Rasmont, 1983), with B. reinigiellus being narrowly restricted to the Sierra Nevada of Spain, possibly as a disjunct peripheral population. B. reinigiellus is closely similar to B. hortorum, although subtle differences in characters of colour and morphology have been described (e.g. Rasmont, 1983; Castro, 1988; Ornosa, 1991). From the material I have examined, the morphological differences appear to be analogous to the variation between mainland and island populations of B. terrestris (see the comments on B. terrestris).

Depending upon the species concept embraced, such subtle differences as those between B. reinigiellus and B. hortorum might be expected even within a single population and I shall treat all three taxa as conspecific for the present. More evidence is awaited.

INTRODUCTIONS: B. hortorum has been introduced into New Zealand (e.g. Gurr, 1957; Macfarlane & Gurr, 1995) (see the comments on B. ruderatus, B. subterraneus and B. terrestris). It occurs in Iceland, where it has also probably been introduced (Prys-Jones et al., 1981) (see the comments on B. lucorum).

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Palaearctic Region.

NOTES on this species in Britain.

Bombus (Mg.) securus (Frison)
securus (Frison, 1935:346 [Bremus]) examined
yuennanicus Bischoff, 1936:23, examined
2 names

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental Region.

Bombus (Mg.) religiosus (Frison)
religiosus (Frison, 1935:344 [Bremus]) examined
1 name

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental Region.

Bombus (Mg.) czerskii Skorikov
czerskii Skorikov, 1910b:413, examined
4 names

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental, Palaearctic Regions.

Bombus (Mg.) tichenkoi (Skorikov)
[saltuarius (Skorikov, [1923]:156 [Hortobombus]) published without description]
[tichenkoi (Skorikov, [1923]:156 [Hortobombus]) published without description]
tichenkoi (Skorikov, 1926:115 [Hortobombus])
[pseudoligusticus (Skorikov, 1926:116 [Hortobombus]) infrasubspecific]
saltuarius (Skorikov, 1931:235 [Hortobombus])
sushkini (Skorikov, 1931:235 [Hortobombus]) examined
kurilensis Sakagami, 1954:92
pseudoligusticus Lelej & Kupianskaya, 2000:9
9 names

TAXONOMIC STATUS: B. sushkini and B. saltuarius have been regarded both as conspecific (Bischoff, 1936) and as separate species (Skorikov, 1931; Tkalcu, 1974a). B. saltuarius is said to be differentiated by the morphology of the male genitalia (Skorikov, 1931), although I have seen no males of this species. More evidence is awaited.

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Palaearctic, Oriental Regions, Arctic borders.

Bombus (Mg.) consobrinus Dahlbom
consobrinus Dahlbom, 1832:49
yezoensis Matsumura, 1932:pl. 1
przewalskiellus (Skorikov, 1933a:59 [Hortobombus]) examined
39 names

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental, Japanese, Palaearctic Regions, Arctic border.

Bombus (Mg.) koreanus (Skorikov)
koreanus (Skorikov, 1933a:59 [Hortobombus])
pekingensis Bischoff, 1936:21, examined
?notocastaneus Tkalcu, 1961a:52
4 names

TAXONOMIC STATUS: B. notocastaneus was described from a single male from Hubei. From the description, it appears most likely to be conspecific with B. koreanus. For a description of the variation in this species see Huang et al. (2014).

MORPHOLOGY: photos of male genitalia.

DISTRIBUTION: Oriental, Palaearctic Regions.

Bombus (Mg.) melanopoda Cockerell
melanopoda Cockerell, 1910a:416, examined
1 name

TAXONOMIC STATUS: B. melanopoda is known from a single female specimen (labelled 'Sumatra', reverse '92.182.') in the NHM collection in London.

According to the accessions catalogue, the number on the label of this specimen refers to 8 Hymenoptera presented in November 1892 by H. O. Forbes. The area of origin is given as Borneo, although this has been crossed out and Sumatra added. Forbes' (1885) account of his travels of 1878-1883 in Indonesia shows that he did not visit Borneo, although he did visit the mountains of southern Sumatra. There is no direct account of the collection of this specimen, although he recorded bees from at least three possible localities at higher altitudes: first, in late 1880 he climbed Gunung Tenggamus, where he recorded (p. 159) 'a few bees' at 7200 ft (2160 m); second, in 1881 he visited Gunung Dempa, where he recorded (p. 208) 'a fine grey-haired humble-bee (Bombus senex)' (identification by Forbes) between 7000-7700 ft (2100-2310 m); and later in the same year, near the summit of Gunung Kaba (1983 m), he recorded again (p. 228) 'A large humble-bee (Bombus senex)'.

B. melanopoda appears to be a morphologically distinct species. It can be distingished from the only other long-tongued bumblebee species known from Sumatra, B. senex, by the longer oculo-malar area of B. melanopoda, which is more than 1.5 times longer than the basal breadth of the mandible. Otherwise, the most closely related long-tongued bumble bee in any neighbouring area is B. trifasciatus from the Cameron Highlands of Peninsular Malaysia. However, like most queens of the subgenus Megabombus, the holotype of B. melanopoda is easily distinguished by its narrow longitudinal median groove subapically on gastral tergum VI (for B. trifasciatus this area is uniformly convex). The colour pattern of the B. melanopoda female is predominantly black, but the hairs of terga IV-V are very slightly paler, so there is some similarity to the darkest queens of B. koreanus, which have this pubescence brownish cream. However, unlike the few queens of B. koreanus available to me, the type of B. melanopoda has the unpunctured areas around the ocelli extending to less than half the ocello-ocular distance; the dorsal furrow of the gena (between the vertex and the post-ocular area) is strongly marked anteriorly; and the dorsal face of the labral tubercles (the face adjacent to the clypeus) is more sharply separated from the anterior ventral face and more densely marked by moderate-sized punctures.

Since no further individuals have been found, the possibility that the holotype of B. melanopoda is a mislabelled melanic specimen of another species of the subgenus Megabombus ought to be explored, perhaps initially through a morphometric analysis.

PHOTOGRAPH: Only a single specimen is known, in the NHM collection, London.

DISTRIBUTION: Sumatran Region.

IUCN CONSERVATION STATUS: Preliminary assessment as presumed EXTINCT (Williams & Osborne, 2009) because it is unrecorded (IUCN, 2001, 2008) since Cockerell (1910) from the specimen of probably 1878-1883. Like most other Sumatran bumble bees (with the notable exception of the extensively greyish-white queens of B. senex, see Sianturi et al., 1995), the holotype of B. melanopoda is almost entirely black. It is likely that females of this species would be particularly easily mistaken for black individuals of B. senex (although males of B. melanopoda might be paler, as for B. koreanus).