Bombus simillimus Smith, 1852

Williams, Paul H., Altanchimeg, Dorjsuren, Byvaltsev, Alexandr, Jonghe, Roland De, Jaffar, Saleem, Japoshvili, George, Kahono, Sih, Liang, Huan, Mei, Maurizio, Monfared, Alireza, Nidup, Tshering, Raina, Rifat, Ren, Zongxin, Thanoosing, Chawatat, Zhao, Yanhui & Orr, Michael C., 2020, Widespread polytypic species or complexes of local species? Revising bumblebees of the subgenus Melanobombus world-wide (Hymenoptera, Apidae, Bombus), European Journal of Taxonomy 719, pp. 1-120 : 51-52

Bombus simillimus Smith, 1852

Figs 2 , 13 , 46–49 , 184

Bombus simillimis Smith, 1852a: 48 .

Bremus oculatus Frison, 1933: 335 .

Sibiricobombus tonsus Skorikov, 1933a: 248 ( Skorikov 1923, 1931: published without description). Bombus oculatus var. [subsp.] haemorrhous Richards, 1934: 87.

Bombus similis – Smith 1854: 403, incorrect subsequent spelling.

Bombus simillimus – von Dalla Torre 1896: 548, justified emendation.

Our PTP analysis ( Fig. 10 ) of coalescents in the COI gene within the rufofasciatus -group supports nine species including B. simillimus , corroborated by differences in morphology (see the Diagnosis).

Females show pronounced size-dependent dimorphism in the colour pattern of the hair: large queens have the thorax and T1–2 black (taxon simillimus s. str.); whereas workers (which are smaller) have the thorax grey-white and T1–2 dark chocolate brown ( Fig. 2 : taxon haemorrhous). Males have the thoracic dorsum and often T1–2 grey-white (taxon oculatus ). Unsurprisingly, the queens, workers, and males were first described as separate species. That these castes and sexes are conspecific has been confirmed from examining variation within one colony excavated in Kashmir ( Williams 1991). The male is distinctive for its unusually large eyes ( Frison 1933; Williams 1991).

Diagnosis

Females

Queens large body length 25–27 mm, workers 12–17 mm. Can be distinguished by the combination of the hair of the thoracic dorsum either entirely black (queen) or entirely white (worker: Fig. 2 ) with the wings dark brown (cf. B. lapidarius , B. eriophorus , B. pyrosoma ).

Males

Body length 16–18 mm. Can be distinguished by the combination of the hair of the thoracic dorsum entirely white with the wings dark brown, similarly coloured to the worker, but the hair of T1 and usually T2 is white; hair of T3 almost entirely black and without a yellow posterior fringe (cf. other rufofasciatus -group species except B. richardsiellus ). Genitalia ( Fig. 184 ) with the gonostylus robust, about half as long on its outer side as broad, with the distal edge concave and the inner distal corner and the inner proximal corner both broad and nearly 90° (cf. all other Melanobombus ); volsella with the inner distal corner broadly rounded and without a narrow hook ( cf. festivus -group, other rufofasciatus - group); antenna short and eye strongly enlarged relative to female eye.

Material examined

Lectotype

INDIA • ♀ (queen), lectotype Bombus simillimus Smith, 1852 by designation of Williams (1991); “N.[orth]”; NHMUK (examined PW).

Material sequenced (5 specimens)

INDIA • 4 ♀♀ (workers); Kashmir ; 34.16° N, 74.90° E; Sep. 1980; P. Williams leg.; NHMUK seq: NHMPW17 to NHMPW20; PW: ML182 , ML314 to ML316 • 1 ♂; Himachal Pradesh, Jalori pass; 31.5370° N, 77.3729° E; 10 Sep. 2004; R. Raina leg.; BOLD seq: 6877B09; RR: ML384 .

Global distribution

(West Himalayan mountain species) Himalaya: PAKISTAN, INDIA: Kashmir, Himachal Pradesh, Uttaranchal. (IOZ, NHMUK, PW, ZIN, ZMHB.) The species is narrowly distributed but locally common and not rare in collections.

Behaviour

A colony of this species has been described from underground in a deciduous forest at 1700 m a.s.l. in Kashmir ( Williams 1991). Food-plant generalists ( Williams 1991). The male mate-searching behaviour is expected to resemble the territoriality of B. rufofasciatus ( Williams 1991) .

Figures

Figs 1‒6. Individuals of the subgenus Melanobombus von Dalla Torre, 1880 (with photo credits). 1. Bombus eximius Smith, 1852, queen, Thailand (CT). 2. B. simillimus Smith, 1852, worker, India- Kashmir (RR). 3. B. prshewalskyi Morawitz, 1880, worker, China-Gansu (PW). 4. B. eriophorus Klug, 1807, queen, Georgia (I. Popov). 5. B. semenovianus (Skorikov, 1914), male, India-Kashmir (PW). 6. B. ladakhensis Richards, 1928, male, China-Gansu (PW). Some images reversed.

Figs 12‒13. Maps of sequenced samples. 12. The rufipes-group and festivus-group. 13. The rufofasciatus- group as recognised as species from the UHF-PTP analysis in Fig. 10. Keys to the coloured symbols are shown on the left (in some cases symbols on the map for one species may overlie symbols for another). Maps projected onto a sphere in ArcGIS using World_Shaded_Relief basemap © 2014 ESRI and showing boundaries between countries as recognised by the UN.

Figs 25–63. Simplified diagrams for the colour patterns of the hair on the dorsum for the species from the integrative analysis. The dorsum is divided into regions, each of which shows only the predominant or most apparent colour for that region using a simplified colour palette, with olive indicating a mixture of black and yellow hair, and grey indicating a mixture of black and white hair. The rufipes-group. 25. Queen, China-Taiwan. 26. Queen, China-Guangdong. 27. Worker, China-Sichuan. 28. Worker, Thailand. 29. Queen, Nepal. 30. Male, China-Sichuan. 31. Male, China-Sichuan. 32. Male, Thailand. 33. Male, Nepal. 34. Male, Nepal. 35. Queen, Indonesia-Sumatra. 36. Queen, Indonesia-Java. 37. Male, Indonesia-Java. The festivus-group. 38. Queen, Nepal. 39. Queen, China-Sichuan. 40. Worker, China- Sichuan. 41. Worker, China-Xizang. 42. Worker, China-Yunnan. 43. Male, Nepal. 44. Male, China- Yunnan. 45. Male, China-Yunnan. The rufofasciatus-group. 46. Queen, India-Kashmir. 47. Worker, India-Kashmir. 48. Male, India-Kashmir. 49. Male, India-Kashmir. 50. Queen, India-Arunachal Pradesh. 51. Queen, Bhutan. 52. Worker, Bhutan. 53. Worker, Bhutan. 54. Male, Bhutan. 55. Queen, India-Kashmir. 56. Queen, India-Kashmir. 57. Worker, India-Kashmir. 58. Worker, India-Kashmir. 59. Worker, India- Kashmir. 60. Worker, Pakistan. 61. Male, India-Kashmir. 62. Male, India-Kashmir. 63. Male, Nepal.

Figs 181‒189. Morphology of the male genitalia for species of the subgenus Melanobombus von Dalla Torre, 1880 from the dorsal aspect, anterior at the bottom of the image, posterior at the top. 181. Bombus eximius Smith, 1852, China-Guangxi. 182. B. rufipes Lepeletier, 1835, Indonesia- Java. 183. B. festivus Smith, 1861, Nepal. 184. B. simillimus Smith, 1852, India-Himachal Pradesh. 185. B. miniatus Bingham, 1897, Bhutan. 186. B. eurythorax Wang, 1982 stat. rev., India-Kashmir. 187. B. prshewalskyi Morawitz, 1880 stat. rev., China-Sichuan. 188. B. rufofasciatus Smith, 1852, India- Kashmir. 189. B. richardsiellus (Tkalců, 1968), Burma (left volsella distal part missing). Scale bars = 1 mm.

Fig. 10. October 2019 (Fig. 8) Bayesian PTP analysis of MrBayes tree of unique COI barcodes (UHF- PTP). Symbols as in Fig. 9.