Bombus prshewalskyi Morawitz, 1880

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 : 56-58

Bombus prshewalskyi Morawitz, 1880 stat. rev.

Figs 3 , 13 , 64–70 , 187

Bombus Prshewalskyi Morawitz, 1880: 342 .

Bombus rufocinctus Morawitz, 1880: 343 (non Cresson, 1863: 106 = B. rufocinctus Cresson ). syn. nov.

Bombus chinensis von Dalla Torre, 1890 [Jun. 25]: 139 (non Morawitz, 1890 [April 30]: 352), replacement name for rufocinctus Morawitz, 1880: 343 . syn. nov.

Bombus prshewalskii – von Dalla Torre 1896: 548, incorrect subsequent spelling.

Bombus przewalskii – Friese 1918: 84, incorrect subsequent spelling.

Kozlovibombus przewilskii – Skorikov 1933a: 245, incorrect subsequent spelling.

Bombus rufofasciatus (part) – Williams 1991: 105; 1998: 133 (non Smith, 1852a: 48).

Bombus prshewalskyi was described by Morawitz (1880) without reference to Smith’s (1852a) closely related taxon rufofasciatus , apparently without knowledge of it. Bombus prshewalskyi is listed as a species (as Kozlovibombus przewalskii ) separate from B. rufofasciatus by Skorikov (1923), although the latter was listed by him as “ Bombi incertae sedis ”. The two were synonymised by Richards (1930). Here, B. prshewalskyi is revised as an eastern species separate from the western B. rufofasciatus s. str. because of their unique and strongly divergent species coalescents in the COI gene ( Fig. 10 ), corroborated by morphology. These morphological differences between the two are subtle, but do appear to support that the two taxa are separate species within a morphologically more distinctive complex of rufofasciatus s. str. + prshewalskyi .

Our PTP analysis ( Fig. 10 ) supports relatively strongly two coalescents in the COI gene for the west Himalayan B. rufofasciatus s. str. and B. prshewalskyi of the eastern QTP. The two coalescent groups differ in COI barcode sequences for at least 22 diagnostic nucleotide positions (3.3% of the barcode region, although some sequences are incomplete). These differences are all synonymous, making no difference to the amino acid sequences at translation. In contrast, examination of sequences for the slower-evolving PEPCK gene (although it also includes faster-evolving intron regions) shows no diagnostic nucleotide changes.

From morphology, B. prshewalskyi has a slightly darker colour pattern of the hair than B. rufofasciatus s. str. for the females (larger workers and queens), with the white bands appearing dark greyish because of many black hairs intermixed, especially on the scutellum, and with black hair more extensive on the body generally. T2 has yellow hair conspicuously replaced by black posteriorly.

Current restrictions on collecting and sequencing in the areas where the two candidate species are most likely to occur in proximity ( Fig. 13 ) make clarifying their status difficult. However, more evidence is needed to increase confidence in any interpretation of the status of the candidate species rufofasciatus s. str. and prshewalskyi and it remains possible that with more sampling from the Himalaya the two taxa could still prove to be parts of a single broader species, B. rufofasciatus s. lat. Speciation between B. rufofasciatus s. str. and B. prshewalskyi may have arisen through vicariance between populations of the western and eastern Himalaya caused by a period of altered climate (cf. B. miniatus / B. eurythorax ).

Females show size-dependent dimorphism in the colour pattern of the hair: large queens have T2 predominantly black and T4 white; whereas the workers (which are smaller) have T2 extensively yellow and T4 red. Males have a similar colour pattern to the workers.

Diagnosis

Females ( Fig. 3 )

Queens medium-sized body length 19–23 mm, workers 10–15 mm. Can be distinguished by their combination of the hair of T5 white and the hair on the side of the thorax white only in the dorsal half (cf. B. ladakhensis ), closely similar to B. rufofasciatus but tending to have T2 with less yellow hair and the scutellum with more black hair.

Males

Body length 13–17 mm. Can be distinguished reliably at present only by their COI sequence, but tending to have T2 with less yellow hair and the scutellum with more black hair (cf. B. rufofasciatus ). Genitalia ( Fig. 187 ) with the gonostylus much reduced, less than a quarter as long on its outer side as broad, with the distal edge concave and the inner distal corner with two almost equally pronounced adjacent acute teeth (cf. other rufofasciatus -group species with the exceptions of some B. friseanus , B. pyrosoma ); volsella with the inner distal corner produced as a narrow curved hook ( cf. rufipes -group, B. simillimus , lapidarius -group, sichelii -group, keriensis -group); antenna short and eye enlarged relative to female eye.

Material examined

Syntypes

CHINA • 1 ♀ (worker, not a queen), 1 ♂ ( Williams 1991:10), syntypes of Bombus prshewalskyi Morawitz, 1880 ; “Gan-su” [= Gansu in a much broader sense than currently: the specimen is probably from modern Qinghai]; N. Przhevalsky leg.; ZIN (not seen but identity not in doubt).

Material sequenced (57 specimens)

CHINA – Gansu Province • 1 ♀ (worker); Gahai ; 34.1743° N, 102.5577° E; 28 Aug. 2009; P. Williams leg.; BOLD seq: 6876H09; PW: ML1 • 1 ♂; Hezuo ; 34.9027° N, 102.8445° E; 27 Aug. 2009; P. Williams leg.; BOLD seq: 1555E03; PW: ML251 . – Sichuan Province • 4 specs; Hongyuan ; 32.3282° N, 102.4543° E; 2017; YD seq: DYX9.1, DYX56.2, DYX22.2, DYX32.2; YD: ML424 to ML427 • 1 ♀ (worker); Hailuogou ; 29.89546° N, 102.01324° E; 7 Aug. 2018; Z. Ren leg.; KIB seq: GGSM102001; KIB: ML555 • 1 ♀ (worker); Que’er shan; 31.89688° N, 99.14853° E; 4Aug. 2018; Z. Ren leg.; KIB seq: QESM202003; KIB: ML560 . – Yunnan Province • 1 ♀ (worker); Lijiang ; 27.0156° N, 100.1714° E; 27 Aug. 2012; Y. Zhao leg.; KIB seq: 402646105; KIB: ML366 • 1 ♂; same collection data as for preceding; 21 Sep. 2012; Y. Zhao leg.; KIB seq: 402648064; KIB: ML367 • 1 ♀ (worker); Baima Snow Mountain ; 28.34827° N, 99.05771° E; 17 Jul. 2018; Z. Ren leg.; KIB seq: BMXSM102034; KIB: ML548 • 1 ♀ (worker); Baima Snow Mountain ; 28.37252° N, 98.99982° E; 16 Jul. 2018; Z. Ren leg.; KIB seq: BMXSH101052; KIB: ML549 • 26 ♀♀, 8 ♂♂; Baima Snow Mountain ; 28.3373° N, 99.0771° E; 14–17 Aug. 2019; M. Orr leg.; IOZ seq: 14F2 to 14F7, 14F9, 14F11 to 14F16, 14F18, 14M1 to 14M5, 16F1, 16M1, 16M2, 16M4, 17F1 to 17F4, 17M1, OR4, OR6 to OR8, OR14, OR16, OR19, OR21, OR25; IOZ: ML599 to ML632 . – Xizang Province • 1 ♀ (worker); Anjiulashan ; 29.6509° N, 96.71712° E; 23 Jul. 2018; Z. Ren leg.; KIB seq: AJLSM103002; KIB: ML550 • 1 ♂; Galonglashan ; 29.78346° N, 95.69765° E; 24 Jul. 2018; Z. Ren leg.; KIB seq: GLLSM201092; KIB: ML551 • 1 ♂; same collection data as for preceding; KIB seq: GLLSM201104; KIB: ML552 • 1 ♀ (queen); same collection data as for preceding; KIB seq: GLLSM101006; KIB ML553 • 1 ♀ (queen); Milashan ; 29.85301° N, 92.33378° E; 27 Jul. 2018; Z. Ren leg.; KIB seq: MLSH101029; KIB: ML554 • 1 ♀ (worker); Honglashan ; 29.92411° N, 92.77629° E; 19 Jul. 2018; Z. Ren leg.; KIB seq: HLSM101103; KIB: ML556 • 1 ♀ (worker); Dangxiong County; 30.21253° N, 90.62821° E; 30 Jul. 2018; Z. Ren leg.; KIB seq: DXH101006; KIB: ML557 • 1 ♀ (worker); Zhujiaolashan; 31.10878° N, 96.88469° E; 2 Aug. 2018; Z. Ren leg.; KIB seq: ZJLSM 101045; KIB: ML558 ; 1 ♀ (worker); Ailashan ; 31.61421° N, 98.48028° E; 1 Aug. 2018, Z. Ren leg.; KIB-ALSM 102002 ( KIB ML559 ) • 1 ♀ (worker); Milashan ; 29.8530° N, 92.3338° E; 27 Jul. 2018; Z. Ren leg.; KIB seq: MLSH109001; KIB: ML578 • 1 ♀ (worker); Galongashan ; 29.7669° N, 95.6991° E; 24 Jul. 2018; Z. Ren leg.; KIB seq: GLLSM104005; KIB: ML579 .

Global distribution

(Qinghai-Tibetan-Plateau and East Himalayan species) Himalaya: INDIA: Sikkim, Arunachal Pradesh. East Asia: CHINA: Xizang, Qinghai, Gansu, Sichuan, Yunnan. – Southeast Asia: BURMA. (AMNH, IAR, IOZ, KIB, KIZ, MNHN, NHMUK, NME, NMS, PW, SEHU, UAP, YD, ZIN.) The species is widely distributed within its range and often abundant.

Behaviour

A colony of this species has been found underground in a meadow at 3900 m a.s.l. in Yunnan (ZR unpublished). Food-plant generalists ( Williams et al. 2009; An et al. 2014). Male mate-searching behaviour appears to resemble the true territoriality of B. rufofasciatus with collisions between males in flight and replacement in perch occupancy (PW pers. obs.).

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 64–102. 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 rufofasciatus-group. 64. Queen, China-Yunnan. 65. Queen, China-Sichuan. 66. Worker, China-Xizang. 67. Worker, China- Xizang. 68. Worker, China-Gansu. 69. Male, China-Yunnan. 70. Male, China-Xizang. 71. Queen, India- Kashmir. 72. Queen, India-Kashmir. 73. Queen, Pakistan. 74. Worker, India-Kashmir. 75. Worker, India- Kashmir. 76. Male, Pakistan. 77. Male, India-Kashmir. 78. Queen, Burma. 79. Worker, Burma. 80. Worker, China-Xizang. 81. Worker, China-Xizang. 82. Male, Burma. 83. Queen, China-Sichuan. 84. Worker, China-Sichuan. 85. Worker, China-Sichuan. 86. Worker, China-Sichuan. 87. Worker, China-Sichuan. 88. Worker, China-Xizang. 89. Male, China-Sichuan. 90. Male, China-Sichuan. 91. Queen, China-Beijing. 92. Queen, China-Beijing. 93. Worker, China-Shanxi. 94. Worker, China-Beijing. 95. Worker, China- Beijing. 96. Male, China-Beijing. 97. Male, China-Beijing. 98. Queen, China-Taiwan. 99. Worker, China- Taiwan. 100. Worker, China-Taiwan. 101. Worker, China-Taiwan. 102. Male, China-Taiwan.

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.