Polyommatus dorylas

Bartoňová, Alena Sucháčková, Konvička, Martin, Marešová, Jana, Bláhová, Dana, Číp, David, Skala, Pavel, Andres, Miloš, Hula, Vladimír, Dolek, Matthias, Geyer, Adi, Böck, Oliver, Kadlec, Tomáš & Fric, Zdeněk Faltýnek, 2021, Extremely Endangered Butterflies of Scattered Central European Dry Grasslands Under Current Habitat Alteration, Insect Systematics and Diversity (AIFB) 5 (5), pp. 1-18 : 13

Polyommatus dorylas Biogeography

Inference of P. dorylas biogeography based on COI is problematic due to the presence of double peaks in the alignment. If erased, the species shows only a low level of populations’ structuring. Still, the populations could be sorted into three clusters, a western ( Spain, southern France, Italy), a central (from the Balkans to Central Europe), and an eastern ( Anatolia and Transcaucasia), although only the samples from Turkey were highly separated ( Fig. 4 ). In the climatic models ( Fig. 6 ), P. dorylas displays oceanic preferences, following maritime climates in the last interglacial, shifting to the proximity of continental glaciers during the LGM, contracting during the arid Younger Dryas stadial, and expanding to mainland Western and Central Europe in the Holocene. Combining the molecular evidence and climatic models suggests that P. dorylas colonized Central Europe from the Balkans, whereas the western cluster did not expand outside the Mediterranean.

More than in the previous two species, areas climatically suitable for P. dorylas match the Holocene distribution of the temperate forests ( Prentice et al. 2000). Notwithstanding that the woodlands would be more open if humans were absent and the interglacial megafauna present ( Vera 2000, Sandom et al. 2014, Riesch et al. 2020), the species’ host plant, Anthyllis vulneraria , occupies, besides dry grasslands, also disturbed-ground road verges, woodland clearings, elevated embankments, and fallows amidst arable lands. The forb is rather drought-sensitive, drought waves can be detrimental for associated herbivores, including another lycaenid butterfly, Cupido minimus (Fuessly, 1775) ( Lepidoptera : Lycaenidae ) ( Piessens et al. 2009). These observations reveal that specialized open grassland butterflies may persist even in relatively humid climates suitable for tree growth, if open patches appear frequently enough for colonization by dispersal (cf. Hodgson et al. 2009, Johansson et al. 2017).

Figures

Fig. 4. Phylogeographic analyses for the butterfly P. dorylas: (a) distribution range (shaded) with locations of samples colored and symbolized by COI BAPS groups, (b) TCS haplotype network, (c) Maximum Likelihood tree (COI + wingless). Branch labels show bootstrap values higher than 50%. Sequences in the network and the tree were assigned to geographical or political regions (described by the legend). Question marks on the map stand for uncertainty in the species distribution and EX. for extinct populations.

Fig. 6. Species Distribution Models (MaxEnt) for three steppe butterflies, (a) C. briseis, (b) P. damon, (c) P. dorylas. Diagrams show BIOCLIM variables selected by jackknife procedure and their contribution to the model (explained variation) (x-axes: the value of the variable, y-axes: predicted values).The climatic niche is modelled for the last interglacial period (–130 ky), the glacial maximum (–21 ky),Younger Dryas (–12 ky), mid Holocene (–6 ky), current situation, and the future (2050) with an RCP4.5 climate change scenario.Purple colors show the suitability,including the least suitable training record (minimum training presence threshold), and orange colors the suitability of 90% of the training data (tenth percentile training presence threshold).The glacial sheet was adopted after Ehlers et al. (2011).