Pollinators on the polar edge of the Ecumene: taxonomy, phylogeography, and ecology of bumble bees from Novaya Zemlya

Abstract

The High Arctic bumble bee fauna is rather poorly known, while a growing body of recent molecular research indicates that several Arctic species may represent endemic lineages with restricted ranges. Such local endemics are in need of special conservation efforts because of the increasing anthropogenic pressure and climate changes. Here, we re-examine the taxonomic and biogeographic affinities of bumble bees from Novaya Zemlya using historical samples and recently collected materials (1895–1925vs.2015–2017). Three bumble bee species inhabit the Yuzhny (Southern) Island and the southern edge of Severny (Northern) Island of this archipelago:BombusglacialisFriese, 1902,B.hyperboreusSchönherr, 1809, andB.pyrrhopygusFriese, 1902.Bombusglacialisshares three unique COI haplotypes that may indicate its long-term (pre-glacial) persistence on Novaya Zemlya. In contrast,BombushyperboreusandB.pyrrhopygusshare a rather low molecular divergence from mainland populations, with the same or closely related haplotypes as those from Arctic Siberia and Norway. A brief re-description ofBombuspyrrhopygusbased on the newly collected topotypes is presented. Habitats, foraging plants and life cycles of bumble bees on Novaya Zemlya are characterized, and possible causes of extremely low bumble bee abundance on the archipelago are discussed. The species-poor bumble bee fauna of Novaya Zemlya is compared with those in other areas throughout the Arctic. The mean bumble bee species richness on the Arctic Ocean islands is three times lower than that in the mainland Arctic areas (3.1vs.8.6 species per local fauna, respectively). General linear models (GLMs) indicate that this difference can be explained by specific environmental conditions of insular areas. Our findings highlight that the insularity is a significant factor sharply decreasing species richness in bumble bee assemblages on the Arctic Ocean archipelagoes through colder climate (lower summer temperatures), prevalence of harsh Arctic tundra landscapes with poor foraging resources, and in isolation from the mainland.

<p align="center">A new Norwegian Lemming subspecies from Novaya Zemlya, Arctic Russia

“…The bumble bee species Bombus glacialis Friese, 1902 is known to occur on Novaya Zemlya, and, probably, on Wrangel Island (Potapov et al 2018). This species did not cross the Kara Strait, a 56 km wide marine barrier, separating Novaya Zemlya from the Vaigach Island (Potapov et al 2019). The Arctic charr Salvelinus alpinus (Linnaeus, 1758) populations in land-locked lakes on Novaya Zemlya share unique mtDNA haplotypes that may reveal their long-term (pre-glacial) existence there (Makhrov et al 2019).…”

Widespread polytypic species or complexes of local species? Revising bumblebees of the subgenus Melanobombus world-wide (Hymenoptera, Apidae, Bombus)

“…The newer multi-rate PTP (mPTP) method fits a different model for branching rates within each species and is claimed to perform better in recognising candidate species that are more similar to the species recognised from morphology (Kapli et al 2017). However, although mPTP has been applied to bumblebees (Potapov et al 2019), it is not used here because it has been found to fail to discriminate between some bumblebee species that can be distinguished by morphology and behaviour as well as by COI coalescents using the original PTP (Williams et al 2019;Williams submitted). We estimate a metric gene tree for the subgenus Melanobombus using MrBayes (ver.…”

Bombus (Pyrobombus) johanseni Sladen, 1919, a valid North American bumble bee species, with a new synonymy and comparisons to other “red-banded” bumble bee species in North America (Hymenoptera, Apidae, Bombini)

“…The Bombus lapponicus -complex (Williams et al 2014) has been of interest to many researchers in the Old World for some time, with many taxa recognized at subspecific rank (e.g., Pittioni 1942Pittioni , 1943, but also as distinct species in the past (Svensson 1979;Pekkarinen 1982;Martinet et al 2018) and more recently (Gjershaug et al 2013;Potapov et al 2017Potapov et al , 2019. In a recent treatment of the North American members, Martinet et al (2019) recognized B. lapponicus sylvicola as a Nearctic subspecies, with the typical taxon occurring in the Palearctic, supporting previous speculation on the status of this species (e.g., Pittioni 1943, Thorp 1962Thorp et al 1983;Williams et al 2014).…”

“…One common trend exists for most of these recently treated bumble bee species in North America -they are taxa with ranges that extend into, or are restricted to, northern regions of the globe. In North America and elsewhere, northern latitudes have been one of the most poorly studied and sampled regions for bumble bees (Potapov et al 2019). Though the bee fauna of this region is typically considered much less speciose than others (for Canada, see Sheffield et al 2014), it is of interest because of the obvious connection to the Old World via Beringia (Williams 1985;Hines et al 2006;Williams et al 2019).…”