The story of endurance: Biogeography and the evolutionary history of four Holarctic butterflies with different habitat requirements

Abstract

Aim: Biogeographical studies on the entire ranges of widely distributed species can change our perception of species' range dynamics. We studied the effects of Pleistocene glacial cycles on current butterfly species distributions, aiming to uncover complex biogeographic patterns in the Holarctic, a region dramatically affected by Cenozoic climate change. Location: Eurasia and North America. Taxon: Boloria chariclea, Agriades optilete, Carterocephalus palaemon, Oeneis jutta. Methods: We reconstructed the biogeographic history of four butterfly species differing in habitat preferences (B. chariclea-tundra, A. optilete-bogs, C. palaemontemperate grasslands, O. jutta-taiga), using one mitochondrial and two nuclear DNA markers and species distribution modelling. Results: Except for B. chariclea, all species originated in Eurasia. The open habitat species A. optilete and C. palaemon formed widely distributed east-west genetic clusters in continental Asia and clusters separated from them in Europe. Genetic clusters of the taiga species O. jutta were not geographically separated in Eurasia, suggesting Pleistocene fragmentation and recent reconnection. The glaciated North America was recolonized from Beringian and southerly situated refugia by all four species. Main conclusions: The Pleistocene mammoth steppe allowed a widespread continuous distribution of open habitat butterflies, while in contrast the distribution of a taiga-specialist species was more limited. In the mostly flat and continental North Asia, the butterflies of various types of open habitats survived ice age in widely distributed east-west belts. In the mountainous and oceanic regions of Europe, Beringia and west North America, all four species persisted in contracted areas during the glacials. After deglaciation, they expanded their ranges and formed contact zones among populations. To conclude, the harsh climate of the glacials did not represent an obstacle for butterflies. Instead, different habitat specialists selected their own ways to thrive in the dynamic conditions of Quaternary glacial periods. | 591 MARESOVA Et Al.

The opposed forces of differentiation and admixture across glacial cycles in the butterfly Aglais urticae

“…Moreover, all the specimens studied from Scandinavia show substantial admixture between the European and the Eastern lineage, and this region possibly represents another secondary contact zone. Scandinavia and north‐eastern Europe were previously found to harbour contact zones between eastern and southern recolonization routes after Glacial Maximum deglaciation for multiple organisms (Maresova et al., 2021). Furthermore, cytoplasmic incompatibility caused by Wolbachia should not limit gene flow in any part of the distribution, as no individual seems to be infected.…”

“…Nevertheless, in the case of A. urticae, a similar pattern is visible with both types of markers, albeit it is more gradual in the nuclear genome. In addition, using genomic data, we can capture and Glacial Maximum deglaciation for multiple organisms (Maresova et al, 2021). Furthermore, cytoplasmic incompatibility caused by Wolbachia should not limit gene flow in any part of the distribution, as no individual seems to be infected.…”

Czech Republic butterfly barcoding reveals that distribution of genetic lineages depends on species traits

“…These were species of open habitats and habitat specialists. Many genetic lineages could have inhabited the Palearctic continent alongside the same temperature belt (Maresova et al, 2021), with no barriers to dispersal in the east-west direction. These species might follow the east-west oceanic-continental gradient of glacial-interglacial faunal interchange related to moisture (Stewart et al, 2010).…”

“…An important step towards this goal was building world-wide databases covering as many species as possible (e.g., Ratnasingham & Hebert 2007; Geiger et al, 2014; Hendrich et al, 2015; Galimberti et al, 2021; Dincă et al, 2021). The barcode widely used in various animal groups, mitochondrial gene cytochrome c oxidase subunit I (COI), proved effective not only for species identification (Hebert, Ratnasingham, & de Waard, 2003), but also for uncovering cryptic diversity including discovery of new species (Hernández-Roldán et al, 2016), and phylogeographic and population genetic studies (Kühne, Kosuch, Hochkirch, & Schmitt, 2017; Maresova et al, 2021). The existence of large database data allowed testing the barcoding performance across large scales on entire faunal groups, summarizing genetic diversity and uncovering biogeographic patterns (e.g., Meier et al, 2006; Weigand et al, 2019; Dincă et al, 2021; D’Ercole et al, 2021; Dapporto et al, 2022).…”

Perishing rich, expanding poor: Demography and population genetic patterns in two congeneric butterflies

“…Spatial extension of sampling to the entire Palaearctic range (cf. Korb et al, 2016; Maresova et al, 2021) is desirable to elucidate whether the low genetic diversity is a regional phenomenon or holds further across the vast range of the two species.…”