When the Rule Becomes the Exception. No Evidence of Gene Flow between Two Zerynthia Cryptic Butterflies Suggests the Emergence of a New Model Group

Although most conservationists claim to protect "species", the conservation unit actually and practically managed is the individual population. As resources are not unlimited, we need to focus on a restricted number of populations. But how can we select them? The Evolutionarily Significant Unit (ESU), first conceptualised by Ryder in 1986, may offer some answer. Several definitions have been proposed for the ESU, but all make reference to units "whose divergence can be measured or evaluated by putting differential emphasis on the role of evolutionary forces at varied temporal scales". Thus, an ESU might be fully identical with a "species", or a "species" could be composed of multiple ESUs. On the other hand, an ESU might comprise single/multiple populations exchanging a degree of gene flow, such as meta-populations. In an attempt to show strengths and weaknesses of ESU concepts, we present here, among several others, some case studies on the myrmecophilous butterflies of the genus Maculinea. In particular, we analyse the apparently everlasting debate about Maculinea alcon and M. rebeli, whose separation into separate species has been accepted by many authors, on mainly ecological criteria, but has not been fully supported by molecular analyses. We also discuss how the tight association with host ants may have driven selection for increasingly more strictly adapted Maculinea populations, arguably deserving specific taxonomic identity. Finally we discuss how current DNA analyses may fail to detect critical information on differences between taxa recently originated by the action of separate adaptive processes, which non-molecular studies can sometimes reveal. We conclude by discussing some current and often conflicting taxonomic trends, in their relationships with conservation policies.

Section: Basic Conceptmentioning

confidence: 96%

The “Evolutionarily Significant Unit” concept and its applicability in biological conservation

Casacci

Barbero

Balletto

2013

“…We followed the nomenclature used in the Red data book of European butterflies (van Swaay et al 2010) and on the fauna europaea web site (www.faunaeur.org). Zerynthia cassandra Geyer, 1828 was not listed, since it was only recently separated from Z. polyxena (Denis & Schiffermüller, 1775) (Dapporto 2010;Zinetti et al 2013). …”

Section: Survey Methodsmentioning

confidence: 99%

Short-term effects of fire on Papilionoidea (Lepidoptera) communities: a pilot study in Mediterranean maquis shrubland

Scandurra

Magliozzi

Aria

et al. 2014

In the Mediterranean landscape fires are common, sometimes arising due to human activity. Fire influences the amount of sunlight that reaches the ground, thus affecting the diversity and distribution of animal and plant species. In this study, we analysed the effect of fire on butterfly diversity at the Site of Community Importance (SCI) "Monti di Lauro" (IT8040013) in southern Italy (Campania). The area covers 7040 ha and is mainly characterised by Mediterranean maquis and woody vegetation. We compared the flight activity of butterflies before and after a fire Our results show that after fire in the Mediterranean maquis, a rapid change in butterfly community structure occurred, increasing both species and individual abundance. Nevertheless, a lower evenness indicates a less balanced butterfly community after fire. Notably, Melanargia arge, a protected species by the Habitats Directive, was not observed following the fire.

“…Additionally, recent experiments have demonstrated some effects of directs interactions between L. sinapis and L. juvernica, especially in courtship behaviour . Moreover, analyses carried out on other cryptic systems of butterflies have suggested that other stochastic demographic processes may concur with climatic factors and competitive interactions in explaining the observed pattern of parapatric distributions (Zinetti et al 2013;Vodă et al 2015).…”

Section: Climatic Niche Separation Between Leptidea Speciesmentioning

confidence: 99%

“…Also for European butterflies, evidence is accumulating that phenotypically similar species that have remained hitherto undistinguished, may nevertheless differ significantly in ecological tolerance, particularly with respect to climatic factors (e.g., Friberg et al 2008a;Zinetti et al 2013;Vodă et al 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Differences in climatic niches between cryptic species of European butterflies have been investigated mainly by contrasting parapatric species (e.g., Zerynthia polyxena and Z. cassandra, Zinetti et al 2013; Aricia agestis and A. cramera, Polyommatus icarus and P. celina, Vodă et al 2015), because cryptic species rarely coexist in broad areas and are mutually exclusive on islands (Vodă et al 2014). Pairs of cryptic species in the genus Leptidea, however, are sympatric in wide regions, and often syntopic, offering the possibility to test whether differences in climatic tolerance play a role in maintaining a sympatric scenario.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Partial separation of climatic niche between two cryptic species ofLeptidea(Lepidoptera: Pieridae) in the Alpine–Adriatic region

Gallo

Beretta

Salogni

et al. 2015

Many cryptic species have been recently recognized in the European butterfly fauna, and climatic determinants have been investigated to explain the usually parapatric distribution of these species. Cryptic species of Leptidea, however, are often sympatric throughout Europe, with variable ecological interactions and segregation patterns. Focusing on the highly diverse landscape between the Alps and the Adriatic Sea, we evaluated the climatic and geomorphological correlates of the fine distribution of L. sinapis and L. juvernica, by means of discriminant analysis on 151 sites in a representative region. In addition to reliable records selected from collections and from the literature, we identified 104 specimens from 89 sites by analysing the morphometric variation of male and female genitalia and filtering for consistency between all alternative identification methods hitherto developed for this species complex. We found that L. sinapis is widespread from the coastal plain to the inner mountains, up to 1800 m above sea level (a.s.l.), whereas L. juvernica is restricted to the mountainous areas, inhabiting also the bottom of pre-alpine valleys, as low as 200 m a.s.l. Despite that the two species are often syntopic, L. juvernica is more frequent in areas with more intense rainfall and steeper slopes, whereas L. sinapis may occur in a broader range of conditions, also in warmer sites with a wider temperature range.