Genetic divergence and evolution of Polyommatus coridon gennargenti (Lepidoptera: Lycaenidae) in Sardinia

Abstract

Electrophoretic analysis of 17 enzyme loci was carried out to assess the genetic differentiation and isolation of the Sardinian Polyommatus coridon gennargenti from R c. apennina of peninsular Italy and the related taxon P caelestissimus from central Spain. I? c. gennargenti is represented by a small, strongly inbred population, restricted to the central mountains of Sardinia, and probably derived from mainland populations as indicated by the reduction of genetic variation (P 17.6 per cent, H 0.024) with respect to the continental populations (P>52 per cent, H 0.170). Absence of gene flow is indicated by the presence of alternative fixed alleles at the Aat, Gpi and Pgm loci and significant differences in allele frequencies at other loci, which distinguish the Sardinian population from 1? C. apennina and P caelestissimus. The genetic differentiation of P c. gennargenti, as measured using Wright's FST values and Nei's genetic distances, suggests the evolution of the Sardinian taxon along an independent lineage, facilitated by isolation and the strict dependence of the butterflies on specific biotopes, thus confirming its taxonomic status.

Strongly diverging population genetic patterns of three skipper species: the role of habitat fragmentation and dispersal ability

“…Graur 1985;Packer et al 1998;Vandewoestijne et al 1999;. None of the parameters analysed reached the average diversities found in the highly diverse butterfly family of the Blues (Lycaenidae) (e.g., Leliè vre 1992;Peterson 1995;Marchi et al 1996;Brookes et al 1997;Schmitt and Seitz 2001;Schmitt et al 2003), but the observed values were considerably higher than in genetically impoverished taxa as species of the genus Yponomenta (Menken 1987) or Aglaope infausta (Schmitt and Seitz 2004). In comparison with Nymphalids, the studied Thymelicus species showed population genetic diversities that were little less than in common and widespread species of this family (e.g., Vandewoestijne et al 1999;Schmitt et al 2005), but considerably higher than in rare and very localised taxa (e.g., Debinski 1994;Britten et al 1994Britten et al , 1995Pelz 1995).…”

Evaluating hypotheses about dispersal in a vulnerable butterfly

“…The butterfly has very low genetic variation (mean heterozygosity, H=0.024, vs. H=0.185 of the mainland P. coridon) and significant genetic differentiation from mainland populations (Nei's coefficient of genetic distance D=0.434), suggesting that the Sardinian taxon is evolving independently from the mainland taxa (Marchi et al 1996). Larval stages feed exclusively on the perennial Hippocrepis comosa (L.) (Fabaceae), have extended development time, and hibernate.…”

“…Indeed, the European P. coridon and other species of the former Lysandra group are thought to be sedentary (Shreeve 1992), and P. c. gennargenti adults have been observed flying only in the immediate vicinity of larval food plants (Casula et al 2004). Due to its strong specialization, low genetic variability, low mobility, and narrow and fragmented distribution, P. c. gennargenti has been considered vulnerable to extinction (Casula et al 2004;Grill et al 2002;Marchi et al 1996).…”

“…Due to its strong specialization, low genetic variability, low mobility, and narrow and fragmented distribution, P. c. gennargenti has been considered vulnerable to extinction (Casula et al 2004;Grill et al 2002;Marchi et al 1996). This taxon shows life-history traits that are usually associated with low mobility (Dennis et al 2004).…”

Biology and biogeography of the chalk-hill blue Polyommatus coridon – insect of the year 2015 for Germany, Austria and Switzerland

“…While the former is mostly accepted as being just a subspecies of P. coridon, the latter is frequently assumed to be a good species, as supported for example by genetic analysis and rearing experiments (Marchi et al 1996, Jutzeler et al 2003. Polyommatus corydonius is another morphologically similar species distributed in Turkey and the Caucasus region, but which never occurs in sympatry with P. coridon (Tshikolovets 2011).…”