Widespread continental mtDNA lineages prevail in the bumblebee fauna of Iceland

Phylogeography and ecology of bumble bees on Kolguev Island, a remote European Arctic landmass

The bumble bee fauna of the Russian Arctic is rather poorly known. Kolguev Island, a remote insular territory in the Barents Sea, is one of the deficiently studied areas. In this study, material on Kolguev's bumble bees is re-examined, phylogeographic data analysed, putative scenarios explaining the origin of the bumble bee fauna on the island discussed, and the biology and phenology of these insular populations described. Five bumble bee species, i.e., Bombusflavidus, B.lapponicus, B.jonellus, B.pyrrhopygus, and B.balteatus, were recorded on this island. All of these species are widespread throughout the Eurasian Arctic. Bumble bee populations on Kolguev Island are characterised by a low level of molecular divergence from mainland populations. Based on paleogeographic reconstructions and phylogeographic patterns, it is hypothesised that the bumble bees appeared on this island in the Early Holocene. The lack of rodents (lemmings and voles) sharply decreases the number of available nesting places for bumble bees on Kolguev Island.

Molecular characteristics of Bombus (Alpinobombus) polaris from North Greenland with comments on its general biology and phylogeography

The bumble bee Bombus polaris (Curtis 1835) is known from the northernmost region of Greenland. But how it can survive there, where in terms of geographic origin it came from, and which species in addition to B. pyrrhopygus (Friese 1902) genetically it is most closely related to are insufficiently answered questions that have motivated us to carry out this study. On the basis of a molecular analysis of the cytochrome oxidase I gene of a B. (Alpinobombus) polaris from North Greenland (82° 48′ N; 42° 14′ W), we conclude that the female specimen we analysed was most closely related to the Canadian populations of B. polaris. Geographic proximity, occurrence of B. polaris on Ellesmere Island and wind direction are likely factors that have aided B. polaris to establish itself in northern and eastern Greenland. The presence of five haplotypes in the studied sequences from Greenland indicates a moderately high level of genetic diversity of B. polaris in Greenland, reflecting the successful adaptation of B. polaris populations. In the broader context of entomological life in the high Arctic, our results on B. polaris allow us to conclude that the survival of pollinating species in the high Arctic under the changing climate scenario depends not only on the weather but also on an individual’s opportunity to continue to locate suitable food sources, i.e. pollen and nectar in the case of B. polaris. This aspect, briefly touched upon in this study, is of relevance not just to B. polaris, but the Arctic entomofauna generally.

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

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 (1895–1925 vs. 2015–2017). Three bumble bee species inhabit the Yuzhny (Southern) Island and the southern edge of Severny (Northern) Island of this archipelago: Bombusglacialis Friese, 1902, B.hyperboreus Schönherr, 1809, and B.pyrrhopygus Friese, 1902. Bombusglacialis shares three unique COI haplotypes that may indicate its long-term (pre-glacial) persistence on Novaya Zemlya. In contrast, Bombushyperboreus and B.pyrrhopygus share 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 of Bombuspyrrhopygus based 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 (3.1 vs. 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.