140 research outputs found

    Discovery of mass migration and breeding of the paintedlady butterfly Vanessa cardui in the Sub-Sahara: the Europe-Africa migration revisited

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    Migratory behaviour has repeatedly evolved across taxa as an adaptation to heterogeneity in space and time.However, insect migration is still poorly understood, partly because of the lack of field data. The painted ladybutterfly Vanessa cardui undertakes a long-distance annual migration between Europe and Africa. While springflights from the Maghreb to Europe are well characterized, it is not known how far the European autumnmigrants travel into Africa and whether they massively cross the Sahara Desert. We conducted fieldwork in fourAfrican countries (Chad, Benin, Senegal, and Ethiopia) in autumn and documented southward migrants incentral Chad and abundant breeding sites across the tropical savannah as far south as the Niger River in thewest and the Ethiopian highlands in the east. Given directionality and timing, these migrants probablyoriginated in Europe and crossed the Mediterranean, the Sahara and the Sahel, a hypothesis that implies thelongest (>4000 km) migratory flight recorded for a butterfly in a single generation. In the light of the newevidence, we revise the prevailing spatiotemporal model for the annual migration of V. cardui to incorporatetropical Africa, which could potentially be regarded as the missing geographic link between autumn (southwards)and spring (northwards) movements. © 2016 The Linnean Society of London, Biological Journal of the LinneanSociety, 2016.Funding was provided by the Committee for Research and Exploration of National Geographic (grant number 9528-14) and by the Spanish MINECO (project CGL2013-48277-P). G.T. is supported by the Marie Curie Actions FP7-PEOPLE-2013-IOF (project 622716) and by grant BP-A00275 (AGAUR-Generalitat de Catalunya).Peer Reviewe

    What is the phylogenetic signal limit from mitogenomes? The reconciliation between mitochondrial and nuclear data in the Insecta class phylogeny

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    Background: Efforts to solve higher-level evolutionary relationships within the class Insecta by using mitochondrial genomic data are hindered due to fast sequence evolution of several groups, most notably Hymenoptera, Strepsiptera, Phthiraptera, Hemiptera and Thysanoptera. Accelerated rates of substitution on their sequences have been shown to have negative consequences in phylogenetic inference. In this study, we tested several methodological approaches to recover phylogenetic signal from whole mitochondrial genomes. As a model, we used two classical problems in insect phylogenetics: The relationships within Paraneoptera and within Holometabola. Moreover, we assessed the mitochondrial phylogenetic signal limits in the deeper Eumetabola dataset, and we studied the contribution of individual genes. Results: Long-branch attraction (LBA) artefacts were detected in all the datasets. Methods using Bayesian inference outperformed maximum likelihood approaches, and LBA was avoided in Paraneoptera and Holometabola when using protein sequences and the site-heterogeneous mixture model CAT. The better performance of this method was evidenced by resulting topologies matching generally accepted hypotheses based on nuclear and/or morphological data, and was confirmed by cross-validation and simulation analyses. Using the CAT model, the order Strepsiptera was recovered as sister to Coleoptera for the first time using mitochondrial sequences, in agreement with recent results based on large nuclear and morphological datasets. Also the Hymenoptera-Mecopterida association was obtained, leaving Coleoptera and Strepsiptera as the basal groups of the holometabolan insects, which coincides with one of the two main competing hypotheses. For the Paraneroptera, the currently accepted non-monophyly of Homoptera was documented as a phylogenetic novelty for mitochondrial data. However, results were not satisfactory when exploring the entire Eumetabola, revealing the limits of the phylogenetic signal that can be extracted from Insecta mitogenomes. Based on the combined use of the five best topology-performing genes we obtained comparable results to whole mitogenomes, highlighting the important role of data quality. Conclusion: We show for the first time that mitogenomic data agrees with nuclear and morphological data for several of the most controversial insect evolutionary relationships, adding a new independent source of evidence to study relationships among insect orders. We propose that deeper divergences cannot be inferred with the current available methods due to sequence saturation and compositional bias inconsistencies. Our exploratory analysis indicates that the CAT model is the best dealing with LBA and it could be useful for other groups and datasets with similar phylogenetic difficulties

    Discovered just before extinction? The first endemic ant from the Balearic Islands (Lasius balearicus sp. nov.) is endangered by climate change

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    ABSTRACT Aim We analyse the taxonomic status, phylogenetic relationships, distribution and age of a newly discovered ant taxon found in the mountaintops of the island of Mallorca (Spain). We also consider the potential impact of short-term climate change on the survival of this ant and make proposals on its conservation status, risks and management. Location Balearic Islands (Spain). Methods We used morphological, molecular and ecological evidence to assess the specific status of the potential new species. We gathered distribution data to conduct climate-based distribution modelling of present and future occupancy under several SRES emission scenarios. Results The existence of a new non-cryptic species of ant (Lasius balearicus Talavera, Espadaler & Vila, sp. nov.) is described from the island of Mallorca. Its distribution was found to be extremely restricted (Serra de Tramuntana) and elevationally constrained to island summits (between 800 and 1400 m a.s.l.). Molecular dating indicated that this species diverged about 1.51 million years ago from its nearest relatives, from which it can be distinguished based on several morphological traits. Ecological niche modelling shows a dramatic reduction of areas with suitable climatic conditions under the different scenarios studied. Main conclusions Lasius balearicus represents the first endemic ant to be described in the Balearic Islands, as well as the first endemic Lasius species in the Mediterranean islands. Distribution modelling predictions, the low intraspecific genetic diversity observed, and the geographical and elevational isolation of the populations indicated a low probability for the survival of the species in the short term, thus making it a potential model to study real-time climate-based biodiversity loss. As a consequence, we strongly recommend including L. balearicus in the IUCN Red List of Threatened Species under the category 'Endangered'. This case illustrates that a fraction of biodiversity remains unexplored even within Europe, arguably the best-studied region of the planet, and that the available time-window for us to study and protect it may be in some instances notably narrow

    One-note samba: the biogeographical history of the relict Brazilian butterfly Elkalyce cogina

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    [Aim] Biogeographically puzzling taxa represent an opportunity to understand the processes that have shaped current species distributions. The systematic placement and biogeographical history of Elkalyce cogina, a small lycaenid butterfly endemic to Brazil and neighbouring Argentina, are long-standing puzzles. We use molecular tools and novel biogeographical and life history data to clarify the taxonomy and distribution of this butterfly.[Location] South America, with emphasis on the Atlantic Rain Forest and Cerrado biomes (Brazil and Argentina).[Methods] We gathered a data set of 71 Polyommatini (Lycaenidae) samples, including representatives of all described subtribes and/or sections. Among these, we contributed new sequences for E. cogina and four additional relevant taxa in the target subtribes Everina, Lycaenopsina and Polyommatina. We inferred a molecular phylogeny based on three mitochondrial genes and four nuclear markers to assess the systematic position and time of divergence of E. cogina. Ancestral geographical ranges were estimated with the R package BioGeoBEARS. To investigate heterogeneity in clade diversification rates, we used Bayesian analysis of macroevolutionary mixtures (bamm).[Results] Our results confirm the hypothesis that E. cogina belongs to the subtribe Everina and not Lycaenopsina, but unexpectedly recovered it as the sister group to the rest of Everina, with an estimated divergence time of approximately 10 Ma. Ancestral geographical range reconstruction points to an old colonization from Asia, the centre of diversity for the Everina, to the New World. The Neotropical Polyommatina lineage diversified to produce almost 100 species in multiple genera, whereas the E. cogina lineage did not diversify at all. Such lack of diversification is unique among the seven Everina/Polyommatina lineages that colonized the New World. We also show that the larvae of E. cogina feed on Fabaceae, supporting the identification of this host-plant family as the ancestral state for the whole group.[Main conclusions] The age and biogeographical reconstruction of the Elkalyce lineage are similar to those of the Neotropical lineage of Polyommatina and suggest that both travelled via the route proposed by Vladimir Nabokov (Asia-Beringia-North America-South America). This coincidence suggests that the climatic conditions at c. 10 Ma favoured dispersal from Asia to the Neotropics and that later events may have erased traces of these butterfly lineages in North America.Funding was provided by the Spanish Ministerio de Economía y Competitividad (project CGL2013-48277-P). G.T. is supported by the grant BP-A00275 (AGAUR-Generalitat de Catalunya), Marie Curie Actions FP7-PEOPLE-2013-IOF (project 622716) and the grant 1.50.1617.2013 at Saint Petersburg State University; L.A.K. was supported by CAPES (3200-14-0); A.V.L.F. thanks ICMBio for research permits (SISBIO no. 10802-5), CNPq (fellowship 302585/2011-7 and grant 564954/2010-1), RedeLep-SISBIOTA-Brasil/CNPq (563332/2010-7), the National Science Foundation (DEB-1256742), BR-BoL (MCT/CNPq/FNDCT 50/2010) and FAPESP (grant 2012/50260-6 and BIOTA-FAPESP Programs 2011/50225-3 and 2013/50297-0).Peer Reviewe

    Long-distance autumn migration across the Sahara by painted lady butterflies: exploiting resource pulses in the tropical savannah

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    The painted lady, Vanessa cardui, is a migratory butterfly that performs an annual multi-generational migration between Europe and North Africa. Its seasonal appearance south of the Sahara in autumn is well known and has led to the suggestion that it results from extremely long migratory flights by European butterflies to seasonally exploit the Sahel and the tropical savannah. However, this possibility has remained unproven. Here, we analyse the isotopic composition of butterflies from seven European and seven African countries to provide new support for this hypothesis. Each individual was assigned a geographical natal origin, based on its wing stable hydrogen isotope (¿2Hw) value and a predicted ¿2Hw basemap for Europe and northern Africa. Natal assignments of autumn migrants collected south of the Sahara confirmed long-distance movements (of 4000 km or more) starting in Europe. Samples from Maghreb revealed a mixed origin of migrants, with most individuals with a European origin, but others having originated in the Sahel. Therefore, autumn movements are not only directed to northwestern Africa, but also include southward and northward flights across the Sahara. Through this remarkable behaviour, the productive but highly seasonal region south of the Sahara is incorporated into the migratory circuit of V. cardui.K.A.H. was funded by an operating grant and D.X.S. by an NSERC visiting fellowship from Environment Canada. Funding to R.V. and G.T. was provided by the Committee for Research and Exploration of National Geographic (grant no. 9528-14) and by the Spanish Ministerio de Economía y Competitividad (CGL2013-48277-P). G.T. is supported by the Marie Curie Actions FP7-PEOPLE-2013-IOF (project 622716) and the grant BP-A00275 (AGAUR-Generalitat de Catalunya). Expeditions in Morocco were funded by Antoni Jonch Cooperació.Peer Reviewe

    The atlas of mitochondrial genetic diversity for Western Palaearctic butterflies

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    Motivation Butterflies represent a model in biology and a flagship group for invertebrate conservation. We provide four new resources for the Western Palaearctic butterflies: (1) an updated checklist comprising 552 species; (2) a curated dataset of 32,126 mitochondrial cytochrome c oxidase subunit I (COI) sequences for 532 species, including a de novo reference library for the Maghreb (Morocco, northern Algeria and Tunisia) and Macaronesia (Azores, Madeira and Canary Islands); (3) seven indexes of intraspecific genetic variation (IGV): observed and expected number of haplotypes, haplotype and nucleotide diversity, two fixation indexes and maximum p-distance; and (4) species-level maps illustrating the distribution of COI variability and haplotype networks. The updated checklist will be fundamental for any application dealing with butterfly diversity in the Western Palaearctic. The IGV indexes provide measures for genetic polymorphism and spatial structure and represent proxies for dispersal capacity. These resources will facilitate comparative studies of macrogenetics, foster integrative taxonomy and aid conservation strategies. Main types of variables contained A complete species checklist in table format, 32,126 mitochondrial DNA barcodes provided with metadata (species membership, WGS84 coordinates and sequence length) and a book in PDF format, including the IGV atlas and indexes, are provided. Spatial location and grain The checklist encompasses Europe up to the Urals in the east, north Macaronesia (the Azores, Madeira and the Canary Islands) and the Maghreb (Morocco, northern Algeria and Tunisia). COI sequences have been retained in the geographical interval of -31.3 to 67.5° of longitude and 27.5 - 71.2° of latitude. Time period and grain COI sequences originate from studies published between 1998 and 2022 and from de novo sequencing of 2541 specimens done between 2007 and 2022. Major taxa and level of measurement Butterflies (Lepidoptera: Papilionoidea), analysed from individual to species level. Software format Data and functions to manage the dataset are provided in the iodatabase R package (https://github.com/leondap/iodatabase) and in Dryad (https://doi.org/10.5061/dryad.9w0vt4bjj).Support for this research was provided by the Academy of Finland (Academy Research Fellow, decision no. 328895) and by a Marie Curie International Outgoing Fellowship within the 7th European Community Framework Programme (project no. 625997) to V.D., by “la Caixa” Foundation (ID 100010434) to M.M. (grant LCF/BQ/DR20/11790020), and by projects CGL2010-21226/BOS and CGL2013-48277-P (Spanish Ministerio de Economía y Competitividad), CGL2016-76322 (AEI/FEDER, UE), PID2019-107078GB-I00 (MCIN/AEI/10.13039/501100011033) and 2017-SGR-991 (Generalitat de Catalunya) to R.Vi., the grant BES-2017-080641 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future” to J.C.H., the project PID2020-117739GA-I00 (MCIN/AEI/10.13039/501100011033) to G.T., and by the Direttiva Biodiversità 2019 and 2020 projects (Ministero della Transizione Ecologica) to L.D.1 INTRODUCTION 2 METHODS 2.1 Checklists and geographical ranges 2.2 Data acquisition, curation and quality control 2.3 Indexes of genetic variation 2.4 Maps of genetic variation 2.5 Haplotype networks 2.6 Script availability 3 RESULTS AND DISCUSSION ACKNOWLEDGMENTS FUNDING INFORMATION CONFLICT OF INTEREST BIOSKETC

    Integrating three comprehensive datasets shows that mitochondrial DNA variation is linked to species traits and paleogeographic events in European butterflies

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    Understanding the dynamics of biodiversity, including the spatial distribution of genetic diversity, is critical for predicting responses to environmental changes, as well as for effective conservation measures. This task requires tracking changes in biodiversity at large spatial scales and correlating with species functional traits. We provide three comprehensive resources to understand the determinants for mitochondrial DNA differentiation represented by i) 15,609 COI sequences and ii) 14 traits belonging to 307 butterfly species occurring in Western‐Central Europe and iii) the first multi‐locus phylogenetic tree of all European butterfly species. By applying phylogenetic regressions we show that mitochondrial DNA spatial differentiation (as measured with Gst, G'st, D and Dst) is negatively correlated with species traits determining dispersal capability and colonization ability. Thanks to the high spatial resolution of the COI data, we also provide the first zoogeographic regionalization maps based on intraspecific genetic variation. The overall pattern obtained by averaging the spatial differentiation of all Western‐Central European butterflies shows that the paradigm of long‐term glacial isolation followed by rapid pulses of post‐glacial expansion has been a pervasive phenomenon in European butterflies. The results and the extensive datasets we provide here constitute the basis for genetically‐informed conservation plans for a charismatic group in a continent where flying insects are under alarming decline
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