Bombus eximius 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 : 39-47

Bombus eximius Smith, 1852

Figs 1 , 12 , 25–34 , 181

Bombus eximius Smith, 1852a: 47 .

Bombus latissimus Friese, 1910: 404 .

Bombus rufipes var. [subsp.] tonkinensis Friese, 1914: 11.

Bombus latissimus var. [subsp.] detritus Friese, 1916: 109.

Bombus latissimus var. [subsp.] segmentarius Friese, 1916: 109.

Bombus latissimus var. [subsp.] tricoloratus Friese, 1916: 109.

Bombus rufipes var. [subsp.] lutescens Friese, 1918: 517 (non Pérez, 1890: 154 = B. flavidus Eversmann ).

Bombus discrepans Pendlebury, 1923: 64 .

Bombus geei subsp. nigribasis Cockerell, 1931: 5 .

Bombus eximius var. [subsp.] fulvobrunneus Chiu, 1948: 65.

Bombus eximius var. [subsp.] pallidus Chiu, 1948: 66 (non Cresson, 1863: 92 = B. pensylvanicus (DeGeer)) .

Bombus rufipes var. tonkininsis – Friese 1918: 527, incorrect subsequent spelling.

Bombus latiszimus – Friese 1931: 304, incorrect subsequent spelling.

Bombus eximius and B. rufipes have a distinctive morphology and previously were placed in a separate subgenus, Rufipedibombus ( Skorikov 1923) . A close relationship with other species of the subgenus Melanobombus was supported by an analysis of five genes by Cameron et al. (2007) and these subgenera were then synonymised by Williams et al. (2008).

Our PTP analysis ( Fig. 10 ) of coalescents in the COI gene within the rufipes- group supports two species B. eximius and B. rufipes , corroborated by differences in morphology. It supports as conspecific within B. eximius s. lat. the individuals from Taiwan that may have much of the hair of T2–6 orange (taxon latissimus ), the individuals from southern China and Southeast Asia that often have T2–3 predominantly black and T4–6 orange, and the individuals from the Himalaya that have T2–4 black and T5–6 either orange or black (taxon eximius s. str.).

Diagnosis

Females ( Fig. 1 )

Queens very large body length 23–30 mm, workers 13–20 mm. Can be distinguished by their combination of wings yellow with the veins orange (cf. B. rufipes ), the hair and integument of mid and hind tibiae and of all barsitarsi orange (cf. some B. rufipes ). The labral lamella has the anterior edge broad and nearly straight (cf. B. (Pyrobombus) flavescens Smith, 1852 , B. (Alpigenobombus) genalis Friese, 1918 ).

Males

Body length 16–19 mm. Can be distinguished by their combination of wings yellow with the veins orange (cf. B. rufipes ), similarly coloured to the worker but with the hair of the face black intermixed with grey (cf. B. rufipes ) and the thoracic dorsum black or sometimes intermixed with grey (cf. B. festivus ). Genitalia ( Fig. 181 ) with the gonostylus reduced to a transverse ‘S’-shaped band (cf. non- rufipes -group), the proximal inner projection not broadened distally and simple (cf. B. rufipes ); volsella projecting beyond the gonostylus by ca 6 × its breadth at its midpoint (cf. B. rufipes ), and without an obvious inner distal process or hook (cf. non- rufipes -group); penis valve head with the outer flange greatly expanded as a triangular projection (cf. non- rufipes -group); eye unenlarged relative to female eye.

Material examined

Holotype

BANGLADESH • ♀ (queen), holotype of Bombus eximius Smith, 1852 by monotypy ( Williams et al. 2009); “ Silhet ” [= Sylhet]; NHMUK (examined PW).

Material sequenced (7 specimens)

THAILAND • 1 ♀ (worker); Chiang Mai, Doi Inthanon ; 18.553º N, 98.48º E; 2 Feb. 2007; Y. Areeluck leg.; BOLD seq: 3773E10; PCYU: ML180 • 1 ♀ (worker); same collection data as for preceding; 16 Feb. 2007; Y. Areeluck leg.; BOLD seq: 3773E11; PCYU: ML195 • 1 ♀ (worker); Chaiyaphum, Tat Tone NP; 15.988º N, 102.041º E; 12 Oct. 2006; Y. Areeluck leg.; BOLD seq: 3261H06; PCYU: ML196 .

CHINA • 1 ♀ (queen); Guangdong; 22.2933º N, 111.2061º E; 16 Jan. 2013; BOLD seq: 1555A07; PW: ML178 • 1 ♀ (worker); Chongqing; 30.13º N, 108.1018º E; Aug. 2010; BOLD seq: 1555A08; PW: ML179 .

TAIWAN • 1 ♀ (queen); Taichung, Dashuishan road; 24.2561º N, 121.0108º E; 18 Jun. 2004; C. Dietrich leg.; BOLD seq: 1555A06; PW: ML177 .

BURMA • 1 ♀ (worker); Chin, Natmataung ; 21.2198º N, 93.9401º E; 2 Jun. 2010; D. Zimmermann leg.; BOLD seq: 6880E04; NHMW: ML502 .

Global distribution

(Himalayan, south Chinese and southeast Asian mountain species including some of the northern islands) East Asia: CHINA: Xizang, Sichuan, Yunnan, Chongqing, Jiangxi, Guizhou, Fujian, Guangdong, Guangxi, Taiwan. – Himalaya: INDIA: Sikkim, Darjiling Bengal, Arunachal Pradesh, Meghalaya; NEPAL, BHUTAN. – Southeast Asia: BANGLADESH, BURMA, THAILAND, VIETNAM. ( IAR, IOZ, KIZ, NHMUK, NHMW, NME, PCYU, PW, RMNH, SEHU, SMNS, USNM, ZMHB, ZMUM.) The species is widely distributed but not common in collections.

Behaviour

Expected to be food-plant generalists ( Kjellsson et al. 1985).

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.