Bombus balteatus Dahlbom

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 : 31-34

4. Bombus balteatus Dahlbom

( Figs. 4 , 59‒76 , 132 )

B.<ombus> balteatus Dahlbom 1832:36 , type-locality citation ‘Lapponia Tornensi ad Enontekis’. Neotype queen (#5011) by designation of Nilsson 2008:3, ZMU examined PW, ‘ Sweden, Lappland’ (Norrbotten, Sweden). Proposed nomen protectum. Notes 1, 2.

B.<ombus> nivalis Dahlbom 1832:40 , type-locality citation ‘Alpium Tornensium’. Lectotype queen by designation of Milliron 1960:94, ZIL not seen, ‘Torneåträsk’ (Norrbotten, Sweden). Synonymised with Bombus balteatus Dahlbom by Thomson 1872:35). Proposed nomen oblitum. Note 2.

B.<ombus> tricolor Dahlbom 1832:41 , type-locality citation ‘Karesuando Lapponiae Tornensis’ (Norrbotten, Sweden). Holotype male by monotypy ( Ander 1967:185), ZIL not seen. Synonymised with Bombus balteatus Dahlbom by Thomson 1872:35). Proposed nomen oblitum. Note 2.

[ Bombus batteatus Dahlbom ; Etzel 1859:144, incorrect subsequent spelling.]

< Bombus nivalis> Var. Nigricans Thomson 1872:35 , no type-locality citation. Syntype female(s), not seen.

< Bombus kirbyellus > var. [subspecies] tristis [Sparre-Schneider in] Friese 1902:495 (not of Seidl 1837:69, = Bombus humilis Illiger ), type-locality citation ‘Tromsö’ (Troms, Norway). Type material not seen. Note 3.

[B.<ombus> kirbyellus var. lysholmi Friese 1905:519 , infrasubspecific. Note 4.]

B.<ombus> kirbyellus var. similis Friese 1911c:684 (not of Fabricius 1804:351, = Centris similis (Fabricius)) , replacement name for tristis Friese (1902:495) .

[ Alpinobombus kirbyellus var. subcollaris, var. appropinquans, var. subbalteatus, var. gmelini, var. pyrrhopygoideus Skorikov 1914:123‒124 , infrasubspecific.]

[< Alpinibombus balteatus > morpha nigricauda, mod. ciliatus Skorikov 1937:58, infrasubspecific.]

[B.<ombus> balteatus balteatus m. balteatus f. pleurotricolor, f. subtristis, f. pleurobalteatus, f. alexanderioides, f. analinigrescens Pittioni 1942:216, infrasubspecific.]

[B.<ombus> balteatus balteatus m. nivalis f. parvoanalis, f. pleuroparvoanalis, f. pleuronivalis Pittioni 1942:216, infrasubspecific.]

Note 1 ( balteatus ). Milliron (1960:89) designated as lectotype a worker, although Ander (1967:186) argued that this was not an original syntype, so that the designation is invalid. Nilsson (2008:3) described the unsuccessful search for an original syntype. In its absence, he designated as neotype a queen that agrees with the usual interpretation of the species (e.g. Løken 1973).

Note 2 ( balteatus , nivalis , tricolor ). Richards (1931) believed B. balteatus Dahlbom and B. nivalis Dahlbom to be conspecific and selected the name B. balteatus Dahlbom to have precedence because it was published on an earlier page (page priority is not a mandatory part of the Code). However, Thomson (1872:35) had already chosen the name B. nivalis Dahlbom in precedence to both B. balteatus Dahlbom and B. tricolor Dahlbom. Following the Principle of the First Reviser ( ICZN 1999: Article 24.2.2), Thomson’s action should now stand, so that the valid name for this species would be B. nivalis Dahlbom. However , we propose that in this case it is appropriate to maintain the prevailing usage of the name B. balteatus Dahlbom ( ICZN 1999: Article 23.9.2), because as far as we are aware neither the name B. nivalis Dahlbom nor the name B. tricolor Dahlbom has been used in subsequent publications as the valid name for this species after 1899 ( ICZN 1999:Article 23.9.1.1), except for a few early references to this species under the name B. nivalis ( Lie-Pettersen 1901, 1907; Bengtsson 1908). In contrast, the name B. balteatus Dahlbom has been the name in common use for this species in more than 25 works, published by at least 10 authors in the preceding 50 years ( ICZN 1999: Article 23.9.1.2) (since 1968: e.g. Løken 1973; Plowright & Stephen 1973; Sakagami 1976; Svensson & Lundberg 1977; Pekkarinen 1979; Pekkarinen et al. 1981; Reinig 1981; Rasmont 1983a; Ito 1985; Ito & Sakagami 1985; Pekkarinen & Teräs 1993; Chen & Wang 1997; Williams 1998; Koulianos 1999; Pedersen 2002; Hines et al. 2006; Cameron et al. 2007; Holmström 2007; Nilsson 2008; Gjershaug 2009; Goulson 2010; Ebmer 2011; Berezin & Tkacheva 2012; Mossberg & Cederberg 2012; Rasmont & Iserbyt 2012; Potapov et al. 2014; Ødegaard et al. 2015; Rasmont et al. 2015). If challenged, the matter should be referred to the Commission for a ruling under its plenary power ( ICZN 1999: Article 81). While the case were under consideration, use of the name B. balteatus Dahlbom would need to be maintained ( ICZN 1999: Article 82). Bombus balteatus Dahlbom is the prosposed nomen protectum, in place of the unused names and prosposed nomina oblita, B. nivalis Dahlbom and B. tricolor Dahlbom. Therefore we consider Bombus balteatus Dahlbom to be the valid name for this species.

Note 3 ( tristis ). The name tristis is published by Friese (1902) for a taxon as a variety alongside taxa given subspecific rank, so that infrasubspecific rank is clearly intended for the taxon tristis ( ICZN 1999: Article 45.6.1). However, Skorikov (1937) uses tristis Friese for the name of a species, so that the taxon tristis Friese must be treated as having subspecific rank from the date of its original publication ( ICZN 1999: Article 45.6.4.1). The name tristis was first published for an Alpinobombus taxon by Friese (1902), who described the taxon in a key couplet with the name attributed to Sparre-Schneider ‘i. l.’ (in litt.). Therefore Sparre-Schneider may have been the first to recognise the taxon as undescribed and may have supplied the name tristis . However, there is no evidence from Friese’s original publication that Sparre-Schneider was responsible for satisfying the other minimum criterion for availability ( ICZN 1999: Article 12.1), that Sparre-Schneider supplied a description or diagnosis. Therefore the author of the nomenclatural act is deemed to be Friese ( ICZN 1999: Article 50.1.1), not Sparre-Schneider.

Note 4 (lysholmi). The name lysholmi was published by Friese (1905) for a taxon as a variety alongside other taxa given subspecific rank, so that infrasubspecific rank is clearly intended for the taxon lysholmi ( ICZN 1999: Article 45.6.1). Subsequent references to this taxon before 1985 (e.g. Richards 1931; Skorikov 1937; Løken 1973) make no change to this status ( ICZN 1999: Article 45.6.4.1).

Taxonomy and variation. Bombus balteatus has often been considered to include B. kirbiellus but has recently been recognized as separate from evidence of a species coalescent in the COI gene ( Williams et al. 2015; Fig. 9 ). Bombus balteatus is vicariant with B. kirbiellus across the Bering Strait ( Figs. 59 , 77 ).

Variation in the colour pattern has been analysed previously ( Williams et al. 2015). Colour variation is primarily in whether the pale hair of T4‒5 is white ( Figs. 60‒61, 67‒69, 71‒73, 76 ) or orange-red ( Figs. 62‒66, 74‒75 ) and whether the yellow bands on the thorax and on T1‒2 are present ( Figs. 60‒64, 71‒74 ) or absent ( Figs. 66, 69‒70, 75 ). The banded ‘white-tailed’ colour pattern ( Figs. 60‒61, 71‒73 ) is more prevalent in Scandinavia (often with a pinkish anterior margin on T4: Fig. 73 ) and the banded ‘orange-tailed’ colour pattern ( Fig. 64 ) is the only one known from Mongolia. The unbanded orange-tailed colour pattern ( Figs. 66, 75 ) is recorded from Norway and the unbanded (or weakly banded) white-tailed colour pattern ( Figs. 69, 76 ) is more frequent from Kamchatka, especially from Karaginsky Island. One queen from Karaginsky Island is extensively black ( Fig. 70 ).

Colour-pattern variation of B. balteatus within Scandinavia has been mapped by Løken (1973: her figure 69). Within Scandinavia, B. balteatus shows a tendency towards an increased frequency of darker colour patterns in the more southern mountains. Entirely black individuals are not present in our sample. Pekkarinen (1979) recorded ‘almost completely black’ Scandinavian males of B. balteatus .

Material examined. 59 queens 61 workers 113 males (plus 425 females with caste undetermined), from Norway, Sweden, Finland, Russia, and Mongolia ( Fig. 59 : AB BP FB FO INHS MB MNHU NHMUK PW SD SEMC YPM ZISP), with 23 specimens barcoded. Several records are questionable. A record for four Russian females in the ZISP collection from near the southern border with Kazakhstan (#905‒908) needs confirmation because the temper- ate low-elevation steppe habitat appears climatically unsuitable (cf. the Maxent climatic suitability model in Fig. 7 ). Similarly, southern records from near Krasnoyarsk (#683, farmland/forest) and Khabarovsk (#909, town/forest) appear to be from unsuitable low-elevation habitat and need to be confirmed.

Habitat and distribution. Flower-rich arctic/alpine tundra and subalpine meadows in the Old World from the north of Scandinavia and Taymyr (but absent from Novaya Zemlya and Wrangel Island), extending southwards into the subarctic region in the alpine zone of the Kamchatka, Magadan-Sakha, Altay, Ural, and southern Scandinavian mountains. Regional distribution maps ( Pittioni 1942; Løken 1973; Pekkarinen et al. 1981; Rasmont & Iserbyt 2012; Ødegaard et al. 2015; Rasmont et al. 2015). The records of this species by Milliron (1973) from Alaska and northern Canada are believed to be misidentifications (specimens examined resembling B. balteatus from Ellesmere Island have all proved to be dark individuals of B. kirbiellus ).

Food plants. ( Richards 1931; Berezin & Tkacheva 2012; Mossberg & Cederberg 2012)

Behaviour. ( Løken 1973; Svensson & Lundberg 1977; Berezin & Tkacheva 2012)

Conservation status. This species has been assessed in part for Red List threat status using IUCN criteria (2001). Cederberg et al. (2013b) assessed the Red List status of this species in Europe as ‘Least Concern’ because of its broad distribution, its presumed large overall population described as stable, with no major threats. Subsequently, Rasmont et al. (2015) have assessed the risk from climate change to this species in Europe as ‘very high climate change risk’ (HHR), projecting that it will suffer considerably from global warming.

Figures

FIGURE 7. Sample sites and climatic suitability for all Alpinobombus species combined estimated using Maxent from climate variables for the year 2000. Bright yellow and brown areas show where the logistic prediction of occurrence is p> 0.5 (the outlier records with exceptionally low probabilities of suitability were excluded in step-wise iterations); brown spots show all consistent Alpinobombus site records; ‘?’ shows the five records that are in climatically outlying sites. Polar projection, North Pole (starred) at the centre of the map, international boundaries and the Arctic Circle shown as narrow grey lines.

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).

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 59‒76. 59: Bombus balteatus global distribution (as for Fig. 15). 60‒76 colour patterns (as for Figs.16‒21): 60 (#540) Russia-Krasnoyask; 61 (#119) Sweden; 62 (#541) Russia-Krasnoyarsk; 63 (#542) Russia-Krasnoyarsk; 64 (#117) Mongolia; 65 (#534) Russia-Kamchatka; 66 (#3841) Norway; 67 (#738) Russia-Kamchatka; 68 (#971) Russia- Kamchatka; 69 (#535) Russia-Kamchatka; 70 (#973) Russia-Kamchatka; 71 (#880) Russia-Kamchatka; 72 (#536) Russia-Kamchatka; 73 (#228) Norway; 74 (#392) Sweden; 75 (#3843) Norway; 76 (#538) Russia-Kamchatka.

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).

FIGURES 77‒88. 77: Bombus kirbiellus global distribution (as for Fig. 15). 78‒88 colour patterns (as for Figs. 16‒21): 78 (#556) Canada-Nunavut; 79 (#294) Canada-Nunavut; 80 (#100) Canada-Nunavut; 81 (#3791) USA-Colorado; 82 (#3790) USA-Colorado; 83 (#3765) Canada-Nunavut; 84 (#3792) USA-Colorado; 85 (#3797) USA-Colorado; 86 (#4915) USA Alaska; 87 (#3768) Canada-Nunavut; 88 (#3812) USA-Colorado.