Following the cold: geographical differentiation between interglacial refugia and speciation in the arcto‐alpine species complex Bombus monticola (Hymenoptera: Apidae)

Abstract

Abstract. Cold-adapted species are expected to have reached their largest distribution range during a part of the Ice Ages whereas postglacial warming has led to their range contracting toward high-latitude and high-altitude areas. This has resulted in an extant allopatric distribution of populations and possibly to trait differentiations (selected or not) or even speciation. Assessing inter-refugium differentiation or speciation remains challenging for such organisms because of sampling difficulties (several allopatric populations) and disagreements on species concept. In the present study, we assessed postglacial inter-refugia differentiation and potential speciation among populations of one of the most common arcto-alpine bumblebee species in European mountains, Bombus monticola Smith, 1849. Based on mitochondrial DNA/nuclear DNA markers and eco-chemical traits, we performed integrative taxonomic analysis to evaluate alternative species delimitation hypotheses and to assess geographical differentiation between interglacial refugia and speciation in arcto-alpine species. Our results show that trait differentiations occurred between most Southern European mountains (i.e. Alps, Balkan, Pyrenees, and Apennines) and Arctic regions. We suggest that the monticola complex actually includes three species: B. konradini stat.n. status distributed in Italy (Central Apennine mountains), B. monticola with five subspecies, including B. monticola mathildis ssp.n. distributed in the North Apennine mountains ; and B. lapponicus. Our results support the hypothesis that post-Ice Age periods can lead to speciation in cold-adapted species through distribution range contraction. We underline the importance of an integrative taxonomic approach for rigorous species delimitation, and for evolutionary study and conservation of taxonomically challenging taxa.

Local adaptation across a complex bioclimatic landscape in two montane bumble bee species

“…For many insects, the association between minimum tolerable temperature and the minimum temperature at which species are found suggests an especially important role for cold tolerance (Hazell, Groutides, Neve, Blackburn, & Bale, 2010;Kellermann et al, 2012;Kimura, 2004). This is true for bumble bees, especially in montane regions (Hines & Williams, 2012;Martinet et al, 2018;Williams, 1985;Williams et al, 2018). Facultative endothermy makes bumble bees well suited for low temperatures, with several mechanisms to generate heat that include activation of muscles for nonflight thermogenesis ("shivering") (Esch & Goller, 1991;Heinrich, 1975;Heinrich & Kammer, 1973;Masson, Hedges, Devaux, James, & Hickey, 2017).…”

“…We investigated local adaptation to climate variation using bumble bees ( Bombus ) from montane regions of western North America. Temperature, in particular, has been instrumental in the evolution of Bombus (Hines, ; Martinet et al, ; Williams, ; Williams, Lobo, & Meseguer, ). Their abundance in cool temperate, arctic, and alpine zones, largely driven by a capacity for facultative endothermy, suggests temperature is an important selective pressure (Heinrich, ).…”

BumbleKey: an interactive key for the identification of bumblebees of Italy and Corsica (Hymenoptera, Apidae)

“…However, recent revisions and phylogeographic studies have led to several taxonomic changes (Rasmont et al 2005, Williams et al 2008, Lecocq et al 2011, Lecocq et al 2015, Martinet et al 2018). Moreover, possible faunal changes can result from the increase of species ranges due to climate change (Neumayer 2004, Jenič et al 2010, Šima and Smetana 2012, Martinet et al 2015) or from the introduction of species or subspecies from other regions as a consequence of the commercialization of bumblebee colonies for pollination (Ings et al 2010).…”

“…The key includes all the 45 species of bumblebees that have been recorded for the study area (Rasmont and Adamski 1995, Intoppa et al 1995, 2009, Lecocq et al 2015, Martinet et al 2018). A few species, i. e. Bombusconfusus Schenck, B.pomorum (Panzer), B.veteranus (Fabricius), have not been collected in the last several decades and their presence in Italy is doubtful and should be confirmed by new records.…”

Non-Pessimistic Predictions of the Distributions and Suitability of Metasequoia glyptostroboides under Climate Change Using a Random Forest Model

“…In the past few decades, by using a species distribution model and systematic geographical surveys, some speculations about the location of glacial refugia have been confirmed, such as in Northern Europe [67], the mountains of Southern Europe (i.e., the Alps, Balkans, Pyrenees, and Apennines) [68], and Southeast Asia [69]. Phylogenetic analysis has also been used to support such hypotheses that some refugia were located in the Arctic or beyond during Pleistocene glaciation [70].…”