Bombus pyrosoma Morawitz, 1890

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 : 64-66

Bombus pyrosoma Morawitz, 1890

Figs 13 , 91–97 , 191

Bombus pyrosoma Morawitz, 1890: 349 .

Bombus rufus Friese, 1905: 511 (non Villers, 1789: 328 = B. pascuorum (Scopoli)) .

Pyrobombus wutaishanensis Tkalců, 1968: 39 .

Bombus pyrrhosoma – von Dalla Torre 1896: 544, unjustified emendation.

Our PTP analysis ( Fig. 10 ) supports relatively strongly two coalescents in the COI gene for sister species within a pyrosoma -complex: the north Chinese B. pyrosoma s. str. and the Taiwan endemic B. formosellus . The two coalescent groups differ in COI barcode sequences for at least 12 diagnostic nucleotide positions (1.8% of the barcode region). These nucleotide differences are all synonymous, making no difference to the amino acid sequences at translation.

From morphology, B. pyrosoma s. str. has a more extensively black colour pattern than B. formosellus for the females on the thoracic dorsum and T1 (larger workers and queens).

Females show size-dependent dimorphism in the colour pattern of the hair: large queens have the thorax and T1 black and T2–5 orange-red; whereas workers (which are smaller) have the anterior and posterior thoracic bands and T1 white, T2 chocolate brown, and T3–5 orange-red. Males have the anterior and posterior thoracic bands and T1–2 yellow and T3–5 orange-red.

Diagnosis

Females

Queens medium-sized body length 20–23 mm, workers 12–15 mm. Can be distinguished in North China by their combination of the hair of the thoracic dorsum and T1 either black or with white bands with T3–5 red (cf. B. sichelii ).

Males

Body length 13–17 mm. Can usually be distinguished in North China by their combination of the hair of the thoracic dorsum with yellow bands, side of the thorax yellow, and T3–7 red. Genitalia ( Fig. 191 ) 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 possible exceptions of B. prshewalskyi , B. friseanus ); volsella with the inner distal corner produced as a narrow curved hook ( cf. rufipes -group, B. simillimus , lapidarius -group, sichelii -group, keriensis -group); eye unenlarged relative to female eye.

Material examined

Syntype

CHINA • ♀ (queen), syntype of Bombus pyrosoma Morawitz, 1890 ( Williams 1991) ; “Kan-ssu” (= Gansu); Jun. 1884; G. Potanin leg.; ZIN (examined PW). The specimen bears a label “Schanji / M. Utai”, which could be a corruption of Mt Wutai in the province of Shanxi, where this species does occur ( PW pers. obs.).

Material sequenced (10 specimens)

CHINA – Qinghai Province • 1 ♀ (worker); Ping’an ; 36.3594° N, 102.1173° E; 19 Aug. 2013; P. Williams leg.; BOLD seq: 1555C04; PW: ML235 . – Gansu Province • 1 ♀ (worker); Xiahe ; 35.3644° N, 102.881° E; 27 Aug. 2009; P. Williams leg.; BOLD seq: 1555G08; PW: ML298 • 1 ♀ (worker); Diebu ; 34.2401° N, 103.1547° E; 29 Aug. 2009; P. Williams leg.; BOLD seq: 1555G09; PW: ML299 . – Beijing Municipality • 1 ♂; Lingshan ; 39.9755° N, 115.4803° E; 20 Apr. 2007; reared from a queen; BOLD seq: 3262E11; PW: ML3 • 1 ♂; same collection data as for preceding; BOLD seq: 3262E12; PW: ML6 • 1 ♀ (queen); Beijing ; same collection data as for preceding; BOLD seq: 3263E11; PW: ML211 • 1 ♀ (queen); same collection data as for preceding; BOLD seq: 3263E12; PW: ML212 . – Neimenggu Province • 1 ♀ (worker); Majiazi ; 43.2176° N, 117.3153° E; 10 Sep. 2007; P. Williams leg.; BOLD seq: 1555C03; PW: ML234 . – Ningxia Autonomous Region • 1 ♀ (worker); Liupanshan ; 35.77438° N, 106.18371° E; 27 Jul. 2018; K. Li leg.; KIB seq: NX03; KIB: ML561 • 1 ♀ (worker); same collection data as for preceding; KIB seq: NX04; KIB: ML562 .

Global distribution

(North Chinese mountain species) East Asia: CHINA: Qinghai, Sichuan, Chongqing, Hubei, Henan, Shandong, Gansu, Neimenggu, Ningxia, Shaanxi, Shanxi, Hebei, Beijing, Tianjin, Liaoning. (IAR, IOZ, NHMUK, PW, ZIN, ZMHB.) The species is widely distributed in North China and often one of the most abundant.

Behaviour

Food-plant generalists ( An et al. 2014). Male mate-searching behaviour appears to resemble patrolling of B. eurythorax (PW pers. obs.).

Figures

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 190‒198. 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. 190. Bombus friseanus Skorikov, 1933, China-Yunnan. 191. B pyrosoma Morawitz, 1890, China- Beijing. 192. B. formosellus (Frison, 1934), China-Taiwan. 193. B. eriophorus Klug, 1807, Russia- North Ossetia. 194. B. lapidarius (Linnaeus, 1758), UK. 195. B. incertus Morawitz, 1881, Turkey. 196. B. semenoviaus (Skorikov, 1914), India-Kashmir. 197. B. sichelii Radoszkowski, 1859, Austria. 198. B. ladakhensis Richards, 1928, China-Sichuan. 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.