Chromosome-Level Assembly and Annotation of the Pearly Heath Coenonympha arcania Butterfly Genome.

We present the first chromosome-level genome assembly and annotation of the pearly heath Coenonympha arcania, generated with a PacBio HiFi sequencing approach and complemented with Hi-C data. We additionally compare synteny, gene, and repeat content between C. arcania and other Lepidopteran genomes. This reference genome will enable future population genomics studies with Coenonympha butterflies, a species-rich genus that encompasses some of the most highly endangered butterfly taxa in Europe.

Cytogenetics of the Hybridogenetic Frog Pelophylax grafi and Its Parental Species Pelophylax perezi.

Hybrid taxa from the genus Pelophylax can propagate themselves in a modified way of sexual reproduction called hybridogenesis ensuring the formation of clonal gametes containing the genome of only one parental (host) species. Pelophylax grafi from South-Western Europe is a hybrid composed of P. ridibundus and P. perezi genomes and it lives with a host species P. perezi (P-G system). Yet it is unknown, whether non-Mendelian inheritance is fully maintained in such populations. In this study, we characterize P. perezi and P. grafi somatic karyotypes by using comparative genomic hybridization, genomic in situ hybridization, fluorescent in situ hybridization, and actinomycin D-DAPI. Here, we show the homeology of P. perezi and P. grafi somatic karyotypes to other Pelophylax taxa with 2n = 26 and equal contribution of ridibundus and perezi chromosomes in P. grafi which supports F1 hybrid genome constitution as well as a hemiclonal genome inheritance. We show that ridibundus chromosomes have larger regions of interstitial (TTAGGG)n repeats flanking the nucleolus organizing region on chromosome no. 10 and a high quantity of AT pairs in the centromeric regions. In P. perezi, we found species-specific sequences in metaphase chromosomes and marker structures in lampbrush chromosomes. Pericentromeric RrS1 repeat sequence was present in perezi and ridibundus chromosomes, but the blocks were stronger in ridibundus. Various cytogenetic techniques applied to the P-G system provide genome discrimination between ridibundus and perezi chromosomal sets. They could be used in studies of germ-line cells to explain patterns of clonal gametogenesis in P. grafi and broaden the knowledge about reproductive strategies in hybrid animals.

Molecular and acoustic evidence support the species status of Anthus rubescens rubescens and Anthus [rubescens] japonicus (Passeriformes: Motacillidae).

The Buff-bellied Pipit Anthus rubescens comprises two allopatric subspecies groups: A. r. rubescens and A. r. alticola in North America and A. [r.] japonicus in north-east Asia. Despite their great morphological resemblance in breeding plumage, most individuals can be assigned to one or the other subspecies group in non-breeding plumage. Allopatric distributions, morphological differentiation and previously reported molecular divergence suggested the need for additional taxonomic study to assess the rank of these two populations. To resolve the taxonomy of the Buff-bellied Pipit species complex we analysed i) two mitochondrial DNA (mtDNA) loci and ii) nine bioacoustic parameters across 69 sound recordings (338 flight calls) recovered from public databases using principal component analysis and Euclidean distance measures. By comparing our mtDNA and call divergence measures with similar values measured between long-recognised species pairs of the genus, we show that the level of mitochondrial and acoustic divergence between the two Buff-bellied Pipit subspecies groups is typical of species-level divergence in the genus Anthus. Therefore, we recommend splitting the Buff-bellied Pipit species complex into two species: Anthus rubescens (American Pipit) and Anthus japonicus (Siberian Pipit). Our results also suggest that the Water Pipit A. spinoletta deserves taxonomic reassessment as its lineages are highly divergent in acoustics and mtDNA, while mtDNA relationships suggest paraphyly relative to the Rock Pipit A. petrosus. Our work highlights the crucial importance of integrative approaches in taxonomy and the usefulness of bioacoustics in studying cryptic diversity.

A new westward migration route in an Asian passerine bird.

The evolution of migration routes in birds remains poorly understood as changes in migration strategies are rarely observed on contemporary timescales.1-3 The Richard's Pipit Anthus richardi, a migratory songbird breeding in Siberian grasslands and wintering in Southeast Asia, has only recently become a regular autumn and winter visitor to western Europe. Here, we examine whether this change in occurrence merely reflects an increase in the number of vagrants, that is, "lost" individuals that likely do not manage to return to their breeding grounds, or represents a new migratory strategy.4-6 We show that Richard's Pipits in southwestern Europe are true migrants: the same marked individuals return to southern France in subsequent winters and geo-localization tracking revealed that they originate from the western edge of the known breeding range. They make an astonishing 6,000 km journey from Central Asia across Eurasia, a very unusual longitudinal westward route among Siberian migratory birds.7,8 Climatic niche modeling using citizen-science bird data suggests that the winter niche suitability has increased in southwestern Europe, which may have led to increased winter survival and eventual successful return journey and reproduction of individuals that initially reached Europe as autumn vagrants. This illustrates that vagrancy may have an underestimated role in the emergence of new migratory routes and adaptation to global change in migratory birds.9,10 Whatever the underlying drivers and mechanisms, it constitutes one of the few documented contemporary changes in migration route, and the first longitudinal shift, in a long-distance migratory bird.