Differentiation in the marbled white butterfly species complex driven by multiple evolutionary forces

Abstract

Aim Genetic and phenotypic data may show convergent or contrasting spatial patterns. Discrepancies between markers may develop in response to different evolutionary forces. In this study we analyse inter-and intraspecific differentiation of closely related taxa in the marbled white butterfly species group. Based on genetic and phenotypic characters we test for potential evolutionary drivers and propose a taxonomic revision.Location Western Palaearctic (including north-western Africa).Methods We compared distributions of mitochondrial cytochrome c oxidase subunit I gene (COI) sequences, of several allozyme loci, and of the shape of wings and genitalia obtained by applying landmark-based techniques for the three butterfly species Melanargia galathea (central and eastern Europe), M. lachesis (Iberia) and M. lucasi (North Africa).Results All studied markers showed a strong spatial structure, although discordance among their patterns was detected. COI sequences, wing shape and genitalia indicated a main split between M. galathea and M. lucasi. A lower differentiation between M. galathea and M. lachesis was found in wing shape and reflected in two mutations of the COI gene, while allozymes indicated a strong divergence. Within M. galathea, allozyme data and COI, but not morphology, revealed the existence of a slightly differentiated lineage in the Italian Peninsula, France and Switzerland. Based on COI, Melanargia lucasi was split into two subgroups, a western and an eastern Maghreb lineage.Main conclusions Long-term isolation of Melanargia populations between North Africa and Europe led to divergence between M. galathea and M. lucasi. This was followed by a recent differentiation among populations isolated during the cold periods of the Pleistocene, such as M. lachesis in Iberia. These lineages are characterized by a tendency not to overlap in secondary sympatry. The different patterns of the four markers may arise from divergent evolutionary processes and pressures: wings may be mainly affected by natural selection, genital structures by sexual selection, whereas long-term isolation and drift may have driven divergence of mitochondrial DNA and allozymes.

Integrative analyses on Western PalearcticLasiommatareveal a mosaic of nascent butterfly species

“…In recent years, several studies that DNA‐barcoded the butterfly species occurring in the Mediterranean and in other regions of Europe highlighted the presence of deep mitochondrial lineages within generally accepted species, suggesting ongoing differentiation or even the presence of cryptic species (Dincă, Dapporto, & Vila, 2011; Dincă, Lukhtanov, & Talavera, 2011; Dincă et al, 2015; Dincă, Zakharov, Hebert, & Vila, 2011; Hausmann et al, 2011). Some of these cases have been subsequently studied in more detail by using integrative approaches and occasionally revealed that species diversity is higher than expected even in intensively studied areas such as Europe (Dapporto, Vodă, Dincă, & Vila, 2014; Dincă, Zakharov, et al, 2011; Habel et al, 2017; Hernández‐Roldán et al, 2006).…”

Use of genetic, climatic, and microbiological data to inform reintroduction of a regionally extinct butterfly

“…A recent study on Melanargia showed that some taxa of this genus differentiated at the species level possess very low divergence at COI (Habel et al. ). From this perspective, in‐depth analyses of multiple genetic and morphological markers are needed to test the potential existence of cryptic species within M. russiae .…”

“…Such loss may be particularly relevant in a genus in which small levels of COI diversification can correspond to high overall diversification (Habel et al. ). These findings also emphasize the value of museum collections which, in combination with continuously advancing DNA techniques, can reveal past genetic diversity with important implications for fields such as phylogeography, taxonomy, and conservation (Strutzenberger et al.…”

“…It has been hypothesized that such checkered distributions are caused by a combination of factors, such as reproductive interference, reduced dispersal, density-dependent phenomena, and differences in climatic niches (Vodȃ et al 2015). A recent study on Melanargia showed that some taxa of this genus differentiated at the species level possess very low divergence at COI (Habel et al 2017). From this perspective, in-depth analyses of multiple genetic and morphological markers are needed to test the potential existence of cryptic species within M. russiae.…”

Phylogeography

“…Habel et al . () combined morphological data with genetically informed phylogeographical methods to evaluate the divergence in the marbled butterfly species group in the Western Palaearctic. The documentation of the phylogeographical patterns in starfish in the Atlantic and Mediterranean Pérez‐Portela et al .…”