Lepidoptera: Nymphalidae)
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View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Repository of the Academy's Library Biological Journal of the Linnean Society, 2017, XX, 1–15. With 5 figures. Mito-nuclear discordance helps to reveal the phylogeographic patterns of Melitaea ornata (Lepidoptera: Nymphalidae) JÁNOS P. TÓTH1,*, ZOLTÁN VARGA2, RUDI VEROVNIK3, NIKLAS WAHLBERG4, ALEX VÁRADI2 and JUDIT BERECZKI2 1MTA-DE ‘Lendület’ Behavioural Ecology Research Group, 4032 Debrecen Egyetem tér 1, Hungary 2Department of Evolutionary Zoology and Human Biology, Institute of Biology and Ecology, University of Debrecen, 4032 Debrecen Egyetem tér 1, Hungary 3Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000 Ljubljana, Slovenia 4Department of Biology, Lund University, 223 62 Lund, Sweden Received 6 September 2016; revised 7 November 2016; accepted for publication 1 December 2016 Periodical changes of glacial and interglacial conditions have influenced the distribution of most living organisms and shape the separation of different genetic lineages significantly. We investigated the phylogeography of a nym- phalid butterfly Melitaea ornata. Our main aim was to explore the existence, the origin, and the variability of differ- ent genetic lineages based on a multilevel approach. M. ornata and its close relatives (with a focus on M. phoebe) from the Palearctic were analysed based on five gene regions (COI, EF-1a, MDH, RPS5, and wingless) using Bayesian methods to infer the phylogeographic history. The DNA-based analyses have been complemented with species dis- tribution modelling (SDM) and Wolbachia screening. The Bayesian inference analysis showed mito-nuclear discord- ance in M. ornata, which is split into an eastern and a western clade. Based on mitochondrial DNA , the western clade of M. ornata clusters together with M. phoebe, while the eastern clade is well-separated. In contrast to this, the combined nuDNA-based analysis revealed that M. ornata forms a monophyletic group which is clearly separated from M. phoebe. The timing of divergence analyses suggest that the split between M. ornata and M. phoebe is about 6 million years old based on both the COI and the concatenated nuclear genes. SDM predicted considerably larger area shifts for M. phoebe than for M. ornata. LGM refugia were predicted for both species to the Mediterranean pen- insulas in Europe and several Middle-East and Asian localities. The prevalence of Wolbachia infection was 88.9% in M. phoebe and only 7% in M. ornata. Our results clearly indicate a lack of ongoing hybridization between M. phoebe and M. ornata, but argue for an ancient hybridization event in the Apennine Peninsula which strongly influenced the observed split between the two clades of M. ornata. ADDITIONAL KEYWORDS: hybridization – Last Glacial Maximum – species distribution modelling – Wolbachia. INTRODUCTION of Earth’s climate sensitivity to CO2-based radiative forcing which was half as strong during the warm The Earth’s climate has shown a general cooling Pliocene as during the cold late Pleistocene epoch (0.8– trend that began around 45 Mya in the Eocene with 0.01 Mya) (Lisiecki & Raymo, 2007; Martínez-Botí strong oscillations from the Miocene (Zachos, Dickens et al., 2015). These periodical changes of glacial and & Zeebe, 2008). Various records from the Quaternary interglacial conditions have influenced the distribu- show increasingly severe ice age cycles with shorter tion of most living organisms significantly. According and shorter warm interglacials driven by the change to the classic refugia paradigm for Europe, the bulk of temperate species could survive in southern Europe *Corresponding author. E-mail: [email protected] during the glaciations, mostly in climatically buffered © 2017 The Linnean Society of London, Biological Journal of the Linnean Society, 2017, XX, 1–15 1 2 J. P. TÓTH ET AL. parts of the Mediterranean peninsulas (de Lattin, mtDNA-based analyses could be misleading. Thus, a 1967; Hewitt, 1996; Schmitt, 2007), although this phylogeographic or a phylogenetic study using only paradigm has been greatly refined by the growing mtDNA is unreliable without Wolbachia screening. amount of new information. Past distributions of spe- Multiple gene analyses are strongly recommended cies are essentially inferred from four types of evi- not only for phylogeography but also for phyloge- dence (Tzedakis, Emerson & Hewitt, 2013): (1) plant netic studies in general (e.g. Wiemers & Fiedler, 2007; and animal macrofossils; (2) pollen records; (3) genetic Wahlberg et al., 2009). Moreover, the combined use of data; and (4) species distribution models. different data sets and methods – for example mul- The most comprehensive coverage comes from plant tiple gene analyses complemented with Wolbachia macrofossils and pollen spectra. These indicate that screening, morphometric data, and species distribu- many species respond individually to climatic oscil- tion modelling (SDM) predictions – enables us to bet- lations (Bhagwat & Willis, 2008; Stewart et al., 2010) ter understand how the various factors together shape depending on differential responses to various ecological the evolutionary relationships among taxa. factors. These species-specific reactions produce a vari- SDM could be useful to estimate the potential dis- ety of distributional patterns by speeding up or slowing tribution at different time scales, thus it could provide down range expansion and contraction, thus they can insight into area dynamics even for fossil-deficient result in a significant difference in species composition species. Therefore, SDM has become an important of communities that could be essentially different from tool for historical biogeography usually combined with those observed today (Schmitt & Varga, 2012). Obviously, molecular methods or morphometry (e.g. Habel et al., the change of vegetation has also an effect on the animal 2011; Schorr et al., 2012; Rajaei et al., 2013; Zinetti assemblages, although the fossil record is poor or not et al., 2013; Tóth, Varga & Bereczki, 2016). available for the majority of animal species, especially The demand for such multilevel approach has arisen for insects. For these fossil-deficient groups, molecular in the case of the Melitaea phoebe species group, which methods and distribution modelling techniques could has been studied intensively in the last few years. It help us to infer their biogeographic history. The disjunct became clear that a cryptic species, namely M. ornata glacial distribution patterns have regularly resulted in Christoph, 1893, was concealed within the morphologi- the separation of different genetic lineages in the three cally similar species M. phoebe from which it was first major Mediterranean peninsulas, Anatolia (Comes distinguished based on larval morphology (Russell & Kadereit, 1998; Taberlet et al., 1998; Hewitt, 1999, et al., 2005; Varga, Szabó & Kozma, 2005). 2000; Schmitt, 2007), North Africa, large Mediterranean M. phoebe ([Denis & Schiffermüller, 1775]) is dis- islands, and also some microrefugial areas (Provan & tributed widely in the Palearctic, although it seems Bennett, 2008; Dapporto, 2010; Husemann et al., 2014). less abundant under Mediterranean climate condi- Mitochondrial DNA (mtDNA) proved to be suitable tions. M. ornata also has a relatively large distribu- for barcoding animal life and highly informative in tion but the most northern localities are found in the phylogenetic and phylogeographic studies (Hebert, Carpathian Basin and in the Volgograd Region in Ratnasingham & de Waard, 2003). Nevertheless, the Russia (Kuznetsov & Stradomsky, 2010). Owing to the use of nuclear (nuDNA) markers in addition to mtDNA application of geometric morphometrics and phyloge- improves the power of phylogenetic and phylogeo- netic methods, two more Melitaea species have been graphic hypothesis tests significantly and highlights identified in this group, namely M. telona Fruhstorfer, the limitations of studies using only mtDNA markers. 1908 and M. abbas Gross & Ebert, 1975, and the Results based solely on mtDNA could be very differ- relationships between these taxa have become much ent from those which are inferred from nuDNA (e.g. clearer through a series of recent studies (Leneveu, Wahlberg et al., 2009); a phenomenon known as mito- Chichvarkhin & Wahlberg, 2009; Tóth & Varga, 2011; nuclear discordance. According to Toews & Brelsford Tóth et al., 2014, 2016). One of the most surprising (2012) the most frequent explanations of mito-nuclear discoveries was that M. telona from the Levant region discordance are incomplete lineage sorting, adaptive appears to be a distinct species also based on molecu- introgression of mtDNA, demographic disparities lar data (Tóth et al., 2014). Additionally, a more focused and sex-biased asymmetries, hybrid zone movement, study on Iranian Melitaea specimens (Tóth, et al., human introductions, and Wolbachia infection. 2016) from several localities showed that M. ornata is Recently, it has become clear that patterns of a rare species in this region and found exclusively in mtDNA inheritance could be highly manipulated the north-eastern part of the country, while the widely by the maternally inherited, intracellular bacteria distributed sister species in Iran is M. abbas. genus Wolbachia. This microorganism could induce The distribution of M. ornata at different time scales ‘two barcodes – one species’ (Kodandaramaiah et al., has already been studied using the Maximum Entropy