Bombus alpinus (Linnaeus)

Williams, Paul H., Berezin, Mikhail V., Cannings, Sydney G., Cederberg, Björn, Ødegaard, Frode, Rasmussen, Claus, Richardson, Leif L., Rykken, Jessica, Sheffield, Cory S., Thanoosing, Chawatat & Byvaltsev, Alexandr M., 2019, The arctic and alpine bumblebees of the subgenus Alpinobombus revised from integrative assessment of species’ gene coalescents and morphology (Hymenoptera, Apidae, Bombus), Zootaxa 4625 (1), pp. 1-68 : 23

1. Bombus alpinus (Linnaeus)

( Figs. 1 , 15‒21 , 129 )

< APIS > alpina Linnaeus 1758:579 , type-locality citation ‘Lapponiae alpibus ’. Neotype queen by designation of Løken 1963:187, ZIL not seen (identity not in doubt), ‘Lule Lappmark’ (Norrbotten, Sweden).

Bombus rufescens Lepeletier de Saint-Fargeau [1835] :460, type-locality citation ‘Forêt de Saint-Germain-en-Laye’. Holotype female by monotypy, not seen. Note 1. Synonymised with Bombus alpinus (Linnaeus) by von Dalla Torre 1896:509.

Bombus Helleri von Dalla Torre 1882:16 , type-locality citation ‘alpine’ (probably Tyrol, Austra). Syntypes not seen (identity not in doubt). Synonymised with Bombus alpinus (Linnaeus) by von Dalla Torre 1896:509).

< Bombus helleri> var. collaris von Dalla Torre 1882:16 (not of Scopoli 1763:306, = B. pratorum (Linnaeus)) , type-locality citation ‘alpine’ (probably Tyrol, Austra). Syntype female and male, not seen (identity not in doubt). Considered conspecific with Bombus alpinus (Linnaeus) by von Dalla Torre 1896:509.

[B.<ombus> alpinus alpinus m. alpinus f. scutellaris Pittioni 1942:216, infrasubspecific.]

Note 1 ( rufescens ). The type-locality citation appears false because it refers to a location on the western edge of Paris, where this species is very unlikely to have occurred. The explanation is not pursued further here because it is unlikely to affect the valid name for this or any other Alpinobombus species.

Taxonomy and variation. A species coalescent in the COI gene ( Fig. 9 ) and divergence in the PEPCK gene characterising B. alpinus have been demonstrated by Williams et al. (2015). Morphometric differences between B. alpinus and B. pyrrhopygus (as B. polaris ) have been demonstrated graphically by Løken (1973) and Pekkarinen (1979).

Variation in colour pattern is primarily in the extent of yellow hairs on the dorsum of the thorax. Extensive yellow hair is rare in females ( Fig. 16 ) but more frequent in males ( Fig. 18 ).

Variation in COI sequences between the samples from the Alps and samples from Scandinavia shows divergence at only one base position ( Figs. 9 , 14 ).

Material examined. 15 queens 54 workers 19 males (plus 28 females with caste undetermined), from France, Switzerland, Austria, Italy, Romania, Norway, Sweden, and Russia ( Fig. 15 : FO INHS NHMUK PW ZISP), with 15 specimens barcoded.

Habitat and distribution. Flower-rich arctic/alpine tundra in the Old World from the far north of Scandinavia, east only to the Kola Peninsula, extending southwards into the subarctic region in the alpine zone of the southern Scandinavian mountains, as well as disjunctly in the alpine zone into the temperate region of the Alps and western Carpathian mountains. Regional distribution maps ( Skorikov 1931; Pittioni 1942; Løken 1973; Pekkarinen et al. 1981; Rasmont & Iserbyt 2012; Cederberg et al. 2013a; Ødegaard et al. 2015; Rasmont et al. 2015).

Food plants. ( Richards 1931; Løken 1973; Mossberg & Cederberg 2012)

Behaviour. ( Løken 1973; Svensson & Lundberg 1977)

Conservation status. This species has been assessed for Red List threat status using IUCN criteria (2001). Cederberg et al. (2013a) assessed the Red List status of this species as ‘Vulnerable’ because its known area of occupancy (AOO) is small (1,288 km ²) and because it is experiencing a continuing decline due to climate warming. Subsequently, Rasmont et al. (2015) have assessed the risk from climate change to this species as ‘very high climate change risk’ (HHR), projecting that it will be on the verge of extinction by the year 2100.

Figures

FIGURE 9. Estimate of the metric gene tree for the 54 longest unique COI-barcode alleles of the subgenus Alpinobombus from MrBayes combined with the Bayesian Poisson-tree-process (PTP) solution with the highest support with spots showing the nodes with the strongest support as coalescents for candidate species (outgroup B. ignitus not shown). Values above the nodes are Bayesian posterior probabilities showing branch support for groups; values below the nodes are PTP Bayesian support values that all daughter alleles are parts of a single species (probabilities within candidate species are all ≤ 0.44). The scale bar is calibrated in substitutions per nucleotide site. Each unique allele is represented by one of the longest available sample sequences, labelled with: the sequence length in number of nucleotides, a taxon name or name describing an unpublished colour pattern, and then a code that consists of a specimen identifier (AL#n) from the project database and (after the hyphen) a sample identifier from BOLD or GenBank, followed with its geographic origin (for simplicity Greenland is included without Denmark).

FIGURE 14. Assigning names to candidate species in a COI gene tree for the 235 specimens of the subgenus Alpinobombus with sequences. Based on the MrBayes analysis of all of the 54 longest unique alleles in Fig. 9, with the remaining sequences interpolated back into the tree with 0 branch lengths from their matching samples (where a sequence matches more than one longer sequence within a species in the Collapse results, it is arbitrarily added after the first matching sequence). The sequence labels follow the format used in Fig. 9. Lineages with high probabilities of representing candidate species in the Poisson-tree-process (PTP) results (Fig. 9) are shown as thick branches with the most recent common ancestors (coalescents) of each candidate species shown with a black spot, the branches within candidate species shown as thin branches. Asterisks mark samples used as informal proxies for the type specimens of each of the taxon names in Table 2. The proxy sample for the type specimen for the oldest available name (the valid name) for each candidate species (from Fig. 9) is marked in bold.

FIGURES 1‒6. Lateral views of foraging females (queens) of species of the subgenus Alpinobombus (with photo credits): 1, B. alpinus, Norway (A. Staverløkk); 2, B. pyrrhopygus, Sweden (G. Holmström); 3, B. polaris, Canada (B. Heinrich); 4, B. balteatus, Sweden (G. Holmström); 5, B. kirbiellus, USA (D. Wilson); 6, B. hyperboreus, Sweden (L.-I. Larsson). Some images reversed.

FIGURES 15‒21. 15: Bombus alpinus global distribution shown with: grey spots for specimens examined; black spots for samples with COI barcodes; question marks for uncertain records at low elevation and low latitude; and grey crosses for records of all species of Alpinobombus combined (Alpinobombus species are unknown from the southern hemisphere). Relief map with hill shading, Polar projection, the international boundaries and the Arctic Circle are shown as narrow grey lines, and the northern tree line shown as a broad grey line. Image created in ArcGIS using World_Shaded_Relief basemap which is Copyright: © 2014 Esri. 16‒21: simplified colour-pattern diagrams for the dorsal hair, with olive indicating a mixture of black and yellow. Figure (AL#n) country: 16 (#14) Sweden; 17 (#113) Sweden; 18 (#3785) Austria; 19 (#3787) Austria; 20 (#3788) Austria; 21 (#141) Norway.

FIGURES 129‒137. Morphology of the male genitalia for species of the subgenus Alpinobombus from the dorsal aspect, anterior to the left of the image, posterior to the right: 129 B. alpinus (#3824); 130 B pyrrhopygus (#3833); 131 B. polaris (#73); 132 B. balteatus (#3843); 133 B. kirbiellus (#3768); 134 B. neoboreus (#4387); 135 B. kluanensis (#4876); 136 B. natvigi (#81); 137 B. hyperboreus (#3821).