Bombus friseanus Skorikov, 1933

Figs 13, 83–90, 190

Bombus friseanus Skorikov, 1933b: 62 .

Lapidariobombus pyrrhosoma subsp. ĥnei Bischoff, 1936: 10.

Bombus pyrosoma (part) – Williams 1991: 101 (non Morawitz, 1890: 349).

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

Females show size-dependent dimorphism in the colour pattern of the hair: large queens have T2 predominantly black; whereas workers (which are smaller) have T2 yellow or light chocolate brown. Males have the thoracic dorsum and T1–2 extensively yellow and T3–5 extensively orange-red. This species is widespread and abundant, but despite variation in COI barcodes shows little geographical variation in colour pattern. Individuals from near Qianggang in Xizang (29.998° N, 91.939° E) have less black hair. One worker (ML5) from Maoshan in Sichuan (31.685° N, 103.899° E) with white bands has been confirmed as this species from a COI sequence. The males have the eye unenlarged relative to the female eye (Williams et al. 2009).

Diagnosis

Females

Queens medium-sized body length 19–22 mm, workers 10–16 mm. Can usually be distinguished in the Hengduan region by their combination of the hair of the thoracic dorsum with yellow bands, side of the thorax yellow, and T3–5 red (cf. B. tibeticus, B. qilianensis, B. miniatus, B. pyrosoma, B. tanguticus). From other often similar co-occurring species they can be distinguished by their combination of the hind tibia with the distal hairs entirely black (cf. B. (Pyrobombus) lepidus Skorikov, 1912) with the mid basitarsus with the distal posterior corner broadly rounded (cf. B. (Thoracobombus) impetuosus Smith, 1871).

Males

Body length 13–15 mm. Can usually be distinguished in the Hengduan region by their combination of the hair of the thoracic dorsum with yellow bands, side of the thorax yellow, and T3–7 red. Genitalia (Fig. 190) 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. pyrosoma); 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

Holotype

CHINA • ♀ (queen), holotype of Bombus friseanus Skorikov, 1933 by monotypy (Williams 1991); Sichuan, Songpan; [18]94; M. Berezovsky leg.; ZIN (examined PW).

Material sequenced (65 specimens)

CHINA – Sichuan Province • 1 ♀ (worker); Maoxian; 31.6853° N, 103.8994° E; 10Aug. 2002; P.Williams leg.; BOLD seq: 1550E09; PW: ML5 • 1 ♀ (worker); same collection data as for preceding; BOLD seq: 3262F02; PW: ML7 • 1 ♀ (worker); same collection data as for preceding; BOLD seq: 3263F02; PW: ML199 • 1 ♀ (worker); Hongyuan; 32.6403° N, 102.3286° E; 4 Aug. 2002; P. Williams leg.; BOLD seq: 3262F01; PW: ML8 • 1 ♀ (worker); Haikou; 27.3271° N, 102.4651° E; 19 Aug. 2005; P. Williams leg.; BOLD seq: 1555G07; PW: ML297 • 10 specs; Hongyuan; 32.3282° N, 102.4543° E; 2017; YD seq: DYX48.2, DYX16.1, DYX40.2, DYX7.2, DYX20.1, DYX6.1, DYX7.4, DYX43.1, DYX6.2, DYX7.1; YD: ML428 to ML437 • 1 ♀ (worker); Ganzi county; 31.62916° N, 100.22675° E; 5 Aug. 2018; Z. Ren leg.; KIB seq: GZM106001; KIB: ML533 • 1 ♀ (worker); Hailuogou; 29.93515° N, 101.96387° E; 7 Aug. 2018; Z. Ren leg.; KIB seq: GGSL101019; KIB: ML534 • 1 ♀ (worker); Xinduqiao; 30.06679° N, 101.76088° E; 7 Aug. 2018; Z. Ren leg.; KIB seq: XDQM101028; KIB: ML535 • 1 ♀ (worker); Daofu county; 30.78966° N, 101.30716° E; 5 Aug. 2018; Z. Ren leg.; KIB seq: DFM101018; KIB: ML537 • 1 ♀ (worker); Ganzi county; 31.62916° N, 100.22675° E; 5 Aug. 2018; Z. Ren leg.; KIB seq: GZM102003; KIB: ML540 • 1 ♀ (worker); same collection data as for preceding; KIB seq: GZM101002; KIB: ML541 . – Yunnan Province • 1 ♀ (worker); Lijiang; 27.0069° N, 100.1751° E; 26 Jul. 2017; A. Moss leg.; BOLD seq: 1555C10; PW: ML241 • 1 ♂; same collection data as for preceding; BOLD seq: 1555G06; PW: ML296 • 1 ♀ (queen); Lijiang; 27.0156° N, 100.1714° E; 1 Aug. 2016; H. Liang leg.; KIB seq: 24; KIB: ML368 • 1 ♂; same collection data as for preceding; 6 Sep. 2016; H. Liang leg.; KIB seq: 40; KIB: ML369 • 1 ♀ (worker); same collection data as for preceding; 1 Aug. 2016; H. Liang leg.; KIB seq: 52; KIB: ML370 • 1 ♀ (queen); same collection data as for preceding; 14 Jun. 2012; Y. Zhao leg.; KIB seq: 304432147; KIB: ML371 • 1 ♀ (worker); same collection data as for preceding; 26 May 2012; Y. Zhao leg.; KIB seq: 40241082; KIB: ML372 • 1 ♀ (worker); same collection data as for preceding; 2 Aug. 2016; H. Liang leg.; KIB seq:42; KIB ML373 • 1 ♀ (worker); same collection data as for preceding; 26 Jul. 2015; Z. Ren leg.; KIB seq: 2018045; KIB: ML374 • 1 ♀ (worker); same collection data as for preceding; 22 Aug. 2016; H. Liang leg.; KIB seq: 2018071; KIB: ML375 • 1 ♀ (worker); same collection data as for preceding; 15 Jul. 2016; H. Liang leg.; KIB seq: 2018038; KIB: ML376 • 1 ♀ (worker); same collection data as for preceding; 19 Jul. 2016; H. Liang leg.; KIB seq: 53; KIB: ML377 • 1 ♂; same collection data as for preceding; 5 Sep. 2016; H. Liang leg.; KIB seq: 84; KIB: ML378 • 1 ♀ (worker); same collection data as for preceding; 1 Sep. 2016; H. Liang leg.; KIB seq: 107; KIB: ML379 • 1 ♀ (worker); Cangshan; 25.88991° N, 100.02974° E; 14 Jul. 2018; Z. Ren leg.; KIB seq: CSL201011; KIB: ML514 • 1 ♀ (worker); Cangshan; 25.88001° N, 100.02691° E; 14 Jul. 2018; Z. Ren leg.; KIB seq: CSL301005; KIB: ML515 • 1 ♀ (worker); same collection data as for preceding; KIB seq: CSL301016; KIB: ML516 • 1 ♀ (worker); Cangshan; 25.89461° N, 100.02125° E; 14 Jul. 2018; Z. Ren leg.; KIB seq: CSL101008; KIB: ML517 • 1 ♀ (worker); Baima Snow Mountain; 28.39838° N, 98.99286° E; 18 Jul. 2018; Z. Ren leg.; KIB seq: BMXSM301021; KIB: ML518 • 1 ♀ (worker); same collection data as for preceding; KIB seq: BMXSM301049; KIB: ML519 • 6 ♀♀; Baima Snow Mountain; 28.3373° N, 99.0771° E; 14–19 Aug. 2019; M. Orr leg.; IOZ seq: 14F2, 14F4, 14F19, OR20, OR24, OR27; IOZ: ML584 to ML589 . – Xizang Autonomous Region • 1 ♀ (worker); Milashan; 29.85301° N, 92.33378° E; 27 Jul. 2018; Z. Ren leg.; KIB seq: MLSM101027; KIB: ML520 • 1 ♀ (worker); same collection data as for preceding; KIB seq: MLSM101002; KIB: ML521 • 1 ♀ (worker); same collection data as for preceding; KIB seq: MLSM101034; KIB: ML522 • 1 ♀ (worker); Ranwu Lake; 29.4849° N, 96.64252° E; 23 Jul. 2018; Z. Ren leg.; KIB seq: RWM101017; KIB: ML523 • 1 ♀ (worker); same collection data as for preceding; KIB seq: RWM101057; KIB: ML524 • 1 ♀ (worker); same collection data as for preceding; KIB seq: RWM101001; KIB: ML525 • 1 ♀ (worker); Dongdashan; 29.57184° N, 98.18467° E; 20 Jul. 2018; Z. Ren leg.; KIB seq: DDSM303001; KIB: ML526 • 1 ♀ (worker); Dongdashan; 29.62259° N, 97.89246° E; 20 Jul. 2018; Z. Ren leg.; KIB seq: DDSM203003; KIB: ML527 • 1 ♀ (worker); Sejilashan; 29.64141° N, 94.69818° E; 26 Jul. 2018; Z. Ren leg.; KIB seq: SJLSM101009; KIB: ML528 • 1 ♀ (worker); Dongdashan; 29.69073° N, 98.11641° E; 20 Jul. 2018; Z. Ren leg.; KIB seq: DDSH301056; KIB: ML529 • 1 ♀ (worker); Sejilashan; 29.77619° N, 94.74278° E; 26 Jul. 2018; Z. Ren leg.; KIB seq: SJLSL301011; KIB: ML530 • 1 ♀ (worker); Galonglashan; 29.78346° N, 95.69765° E; 24 Jul. 2018; Z. Ren leg.; KIB seq: GLLSM103018; KIB: ML531 • 1 ♀ (worker); Anjiulashan; 29.9229° N, 96.67203° E; 23 Jul. 2018; Z. Ren leg.; KIB seq: AJLSM101004; KIB: ML532 • 1 ♀ (queen); Yelashan; 30.16394° N, 97.2860° E; 22 Jul. 2018; Z. Ren leg.; KIB seq: YLSH101083; KIB: ML536 • 1 ♀ (worker); Zhujiaolashan; 31.11821° N, 97.01749° E; 2 Aug. 2018; Z. Ren leg.; KIB seq: ZJLSM101015; KIB: ML538 • 1 ♀ (queen); Zonglashan; 31.2922° N, 97.59554° E; 3 Aug. 2018; Z. Ren leg.; KIB seq: ZLSM201011; KIB: ML539 • 1 ♂; Galonglashan; 29.82189° N, 95.71101° E; 24 Jul. 2018; Z. Ren leg.; KIB seq: GLLSL301020; KIB: ML542 • 1 ♀ (worker); Xizang; 29.5032° N, 95.8980° E; 8 Aug. 2015; IBK seq: BB12; IOZ: ML582 .

Global distribution

(Hengduan mountain species) East Asia: CHINA: Xizang, Qinghai, Sichuan, Yunnan, Guizhou. (AMNH, IAR, IOZ, KIB, KIZ, NHMUK, PW, SAC, USNM, YD, ZIN, ZMHB, ZMUM.) The species is widely distributed within the Hengduan region and often one of the most abundant.

Behaviour

A colony of this species has been found underground in a coniferous forest at 3300 m in Yunnan (ZR unpublished). Food-plant generalists (Williams et al. 2009). Male mate-searching behaviour appears to resemble patrolling of B. eurythorax (PW pers. obs.).