Unexpected layers of cryptic diversity in wood white Leptidea butterflies

Abstract

uncovering cryptic biodiversity is essential for understanding evolutionary processes and patterns of ecosystem functioning, as well as for nature conservation. As European butterflies are arguably the best-studied group of invertebrates in the world, the discovery of a cryptic species, twenty years ago, within the common wood white Leptidea sinapis was a significant event, and these butterflies have become a model to study speciation. Here we show that the so-called 'sibling' Leptidea actually consist of three species. The new species can be discriminated on the basis of either DnA or karyological data. such an unexpected discovery challenges our current knowledge on biodiversity, exemplifying how a widespread species can remain unnoticed even within an intensely studied natural model system for speciation. G iven the global biodiversity crisis [1][2][3] , cataloguing the earth's species has become a race against time. Several studies have highlighted the presence and importance of cryptic biodiversity, which might represent a substantial proportion of Earth's natural capital. An estimate of cryptic species diversity is important to better understand evolutionary processes and patterns of ecosystem functioning, while also having deep implications for nature conservation 4,5 . The recent increase in the number of reported cryptic species is, in large part, owing to an increasing amount of studies incorporating DNA-based techniques, including large-scale approaches such as DNA barcoding 6 , which often provide resolution beyond the boundaries of morphological information. However, documenting cryptic diversity based on DNA data alone is generally not sufficient, prompting calls for integrative morphological, ecological and molecular approaches 7,8 . Recent estimates on the distribution of cryptic diversity are contradictory, and are based on a thin empirical foundation 4,9 . In any case, it is to be expected that the highest number of yet-to-be-discovered cryptic species is concentrated in the most biodiverse and least explored regions of our planet (that is, tropical areas). In temperate regions such as Europe, it is assumed that the level of unrecognized diversity is low, not only because of lower species richness, but also because taxonomic research has been intense for many groups of organisms. Such a case is represented by butterflies, probably the best-studied group of invertebrates, which have become a flagship for insect conservation efforts in Europe 10,11 .The discovery of a new European species of wood white (Leptidea sp.) at the end of the twentieth century was an important event in butterfly systematics. Leptidea sinapis (Linnaeus, 1758), a common butterfly with Palaearctic distribution was found to 'hide' a cryptic species, Leptidea reali (Reissinger, 1989) 12,13 . After the two species were shown to be separable based on their genitalia-but not on their wing morphology 13 -several studies revealed that L. reali is often sympatric with L. sinapis and that its distribution is almost as wide as that ...

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

“…A proportionally great number of "double" (in one case triple) species have been identified by these methods and butterflies may be second only to amphibians, or sometimes mammals, in this respect. Porter et al 1997;Dapporto 2010;Dincă et al 2011aDincă et al , 2011bZinetti et al 2013), to cite some of the most recently demonstrated, do not fit well into the ESU paradigm. These species, irrespectively of their generally strong genetic differentiation, apparently show too little ecological distinctness, within the same pair, to allow us to classify them as separate ESUs.…”

Butterfly fauna (Insecta, Lepidoptera, Papilionoidea) of northern Moslavina (Croatia)

“…However, the analysis of mitochondrial and nuclear DNA markers of Leptidea genus by Dinca et al (2011) revealed that L. sinapis -L. reali, previously understood to be a cryptic pair, are really part of a triplet of species that also includes L. juvernica. Shtinkov et al (2016) …”

Indobiosys – Dna Barcoding as a Tool for the Rapid Assessment of Hyperdiverse Insect Taxa in Indonesia: A Status Report

“…Based on that premise, the Indonesian Biodiversity Discovery and Information System Even in well studied areas, DNA barcoding has uncovered many cases of overlooked, misinterpreted, cryptic, or even new species (Dincă et al 2011, Hendrich et al 2014, Morinière et al 2014, Schmidt et al 2015. The Swedish Malaise trap program has so far increased the country's insect fauna by more than 1,900 species, including several hundred species new to science (Ronquist 2010, Karlsson 2017.…”