Extra-Mediterranean glacial refugia in a Mediterranean faunal element: the phylogeography of the chalk-hill blue Polyommatus coridon (Lepidoptera, Lycaenidae)

Abstract

Most warm-adapted Central European species are thought to have survived ice ages exclusively in Mediterranean refugia. During recent years, this point of view has been questioned. Therefore, we tested the hypothesis that extra-Mediterranean refugia also played a role in warm-adapted insect species and selected the chalk-hill blue, Polyommatus coridon. We sequenced two mitochondrial loci (COI, CR) in 150 individuals from 30 populations covering nearly the complete range. Minimum spanning networks and other statistical analyses concordantly revealed four genetic lineages with strong phylogeographic signal: a western group in Italy, France and western/central Germany, an eastern lineage in the Balkan Peninsula, the Carpathian Basin and eastern Central Europe, an Alpine group with populations in the Alps and southern Germany and a Pyrenean group. Our results are generally consistent with previous analyses for P. coridon based on allozymes and DNA sequences, but provide additional insights. We propose that these four lineages have evolved during allopatry in different glacial refugia, two in typical Mediterranean refugia (Apennines and Balkan Peninsulas), but two in extra-Mediterranean areas south of the Alps and Pyrenees. This supports survival of warm-adapted organisms in these regions in close geographic proximity to the refugia of high mountain species.

Wing morphology of the butterflyCoenonympha arcaniain Europe: Traces of both historical isolation in glacial refugia and current adaptation

“…Also, the level of differentiation among haplotypes was low with only seven mutational steps among the most diverged ones. Both are less than typically observed for butterfly species with Mediterranean refugia (e.g., Habel et al, 2017;Junker et al, 2015;Kühne et al, 2017) and also mountain species (e.g., Vila, Marí-Mena, Guerrero, & Schmitt, 2011 us assume that population sizes during refugial phases were greatly reduced and/or that refugia were restricted to smaller geographic areas. It also indicates a young evolutionary root of the species.…”

“…A large proportion of the thermophilic European species survived the last glaciation in Mediterranean refugia situated in the three large Mediterranean peninsulas (Iberia, Italy, and Balkans), Anatolia, and the Maghreb (de Lattin, 1949;Schmitt, 2007). This picture is, for example, supported by the phylogeographic patterns of European butterflies (e.g., Habel, Dieker, & Schmitt, 2009;Habel, Lens, Rödder, & Schmitt, 2011;Habel, Schmitt, & Müller, 2005;Habel et al, 2017;Junker et al, 2015;Kühne, Kosuch, Hochkirch, & Schmitt, 2017;Schmitt, Röber, & Seitz, 2005;Schmitt, Varga, & Seitz, 2005;Wahlberg & Saccheri, 2007). Despite the refugial areas differing in their environmental and climatic characteristics, knowledge about historical selection on current phylogenetic patterns and morphological variation is scarce (Habel et al, 2017).…”

Wolbachia affects mitochondrial population structure in two systems of closely related Palaearctic blue butterflies

“…Species-rich radiations seem to be common in other Polyommatinae (e.g. the Polyommatus coridon group 82 , 83 and Agrodiaetus species with chromosomal fissions 84 ). Wolbachia and other symbiotic bacteria are suspected drivers of arthropod evolution 85 .…”

Polyploid evolution: The ultimate way to grasp the nettle

“…Second, the Po river diploids regularly occur both in a wide range of highly synanthropic types of habitats and in semi-natural alluvial vegetation. Diploid populations might have survived the last glaciation in an refugium extending along the lower elevations of the southern Alps and in adjoining areas, as demonstrated for many alpine plants as well as for beech ( Fagus ) and some insect species [129–132]. Alternatively, diploids might have survived in more southerly located refuges in the Apennine Peninsula [133, 134].…”