Bombus (Thoracobombus) humilis Illiger

An, Jiandong, Huang, Jiaxing, Shao, Youquan, Zhang, Shiwen, Wang, Biao, Liu, Xinyu, Wu, Jie & Williams, Paul H., 2014, The bumblebees of North China (Apidae, Bombus Latreille), Zootaxa 3830 (1), pp. 1-89 : 38-39

25. Bombus (Thoracobombus) humilis Illiger

( Figs 52, 53 )

Apis fulve ∫cens [fulvescens] Schrank, 1802:367. Nomen oblitum (Williams et al., 2009). Bombus humilis Illiger, 1806:171 . Nomen protectum (Williams et al., 2009).

Bombus (Agrobombus) helferanus var. subbaicalensis Vogt, 1911:42 , 54.

Material examined. 3 queens, 137 workers, 12 males (IAB).

Distribution in North China. Primarily in northeastern Neimenggu, on the loess plateau and the west Qinling mountains. Common at low elevations of the Nenjiang river valley in northeastern Neimenggu, at medium elevations of the Kongdongshan nature reserve and the Maijishan forest park in Gansu, at medium elevations of the Liupanshan nature reserve in southern Ningxia, and the west Qinling mountains in Shaanxi. Rare at medium elevations of the Baihuashan nature reserve and the Lingshan nature reserve in Beijing, at medium elevations of the Xiaowutaishan nature reserve in Hebei, at medium elevations of the Taihangshan mountains and Lvlaingshan mountains in Shanxi, and at medium to high elevations on the edge of the east Qinghai-Tibetan plateau in Gansu. 51 localities ( Fig. 52 ) between 315–3130 m (IAB).

Variation in North China. This species shows strong variation in the colour pattern of the hair across its global distribution but shows little variation in North China ( Fig. 53 ).

Similar species in North China. This species is very similar in its grey colour pattern to B. deuteronymus and B. pseudobaicalensis (see the key; Figs 51 , 53 , 61 ).

Distribution in China. Beijing, Hebei, Shanxi, Neimenggu, Heilongjiang, Sichuan, Xizang, Shaanxi, Gansu, Ningxia, Xinjiang (IAB).

Forage plants. ASTERACEAE : Cirsium leo , C. monocephalum , C. setosum , Cosmos bipinnatus , Helianthus annuus ; CAMPANULACEAE : Adenophora divaricata ; CONVOLVULACEAE : Calystegia hederacea ; FABACEAE : Astragalus bhotanensis , Trifolium pratense , Trifolium repens ; LAMIACEAE : Caryopteris tangutica , Dracocephalum heterophyllum , Elsholtzia densa , Mentha canadensis ; MALVACEAE : Hibiscus trionum , RANUNCULACEAE : Clematis tangutica ; TILIACEAE : Grewia biloba .

Figures

FIGURES 52 – 53. 52. Map showing the distribution of B. humilis in North China with records as black spots, the province boundaries in dark grey, and all sites with records of all bumblebee species in light grey. 53. B. humilis worker visiting Trifolium pratense (Fabaceae) in Shaanxi.

FIGURE 51. B. deuteronymus worker visiting Cirsium leo (Asteraceae) in Gansu (PW).

FIGURES 60 – 61. 60. Map showing the distribution of B. pseudobaicalensis in North China with records as black spots, the province boundaries in dark grey, and all sites with records of all bumblebee species in light grey. 61. B. pseudobaicalensis worker from Neimenggu.