Search

Vocalization in anurans is mainly studied in the context of male-specific advertisement calls, while release calls – characteristic of both sexes – usually attract less attention. Here we compare release calls of both sexes of hybrid Pelophylax esculentus (considering triploid hybrids) and its parental species P. ridibundus in Ukrainian population systems. The principal component analysis resulted in 83.3% of total variance explained by the first three components, while discriminant analysis correctly differentiated 69.6% of frogs only. Triploid male hybrids had intermediate positions between diploid hybrids and parental species. Triploid females had intermediate positions only in terms of temporal parameters because frequency parameters mainly depended on their body size. A significant correlation between peak frequency and body size was shown for females of both taxonomical groups and P. ridibundus males. Although we identified differences between the studied groups, these differences were not unambiguous, with overlapping frequency parameters in males. Including more triploids and the other parental species is important for further analysis. [ABSTRACT FROM AUTHOR]

Pelophylax esculentus (genotype LR), an interspecific hybrid of P. ridibundus (genotype RR) and P. lessonae (genotype LL), is one of the most studied examples of hemiclonal hybridogenic vertebrates. In most populations, hybrids produce clonal gametes of one parental species and backcross with the other parental species, forming a new generation of hybrids. In this study, we focused on the population system of water frogs in the Siverskyi Donets river basin (eastern Ukraine) with the aim to determine the genetic diversity of parental genomes and clarify how such a system is maintained in nature. Of the 55 frogs analyzed, only one individual was P. ridibundus, 48 belonged to diploid LR and five to triploid LRR hybrids. Using 16 microsatellite loci, we found significantly lower genetic diversity and significantly higher clonality in the L-genome of hybrids compared to the R-genome. This contrasting diversity might be attributed to the absence of P. lessonae in the studied region and the clonal inheritance of the L-genome. Our population-genetic results are partially inconsistent with previous studies focusing on hybrid gametogenesis in the Siverskyi Donets river basin, according to which hybrids form both clonal R and L gametes. We hypothesize that discrepancies between the type of clonally formed gametes and the genotypic composition of the studied population may be due to the selective mortality of some genotypes during larval development and metamorphosis. Selective mortality thus may play an important role in the dynamics of the hybridogenetic systems in eastern Ukraine. [ABSTRACT FROM AUTHOR]

We propose a modified and updated protocol to obtain mitotic chromosomes from the regenerated tissue of Pelophylax tadpole tail tips. Chromosomal preparations from regenerated tissue results in high-quality and clean slides suitable for further staining and study. Tadpoles remain alive, undergo minimum suffering, and can be grown to adulthood for further investigation. The method could be used for other groups of Anura and modified for other species with the ability to regenerate their tissues. [ABSTRACT FROM AUTHOR]

Semi-natural forests and dry grasslands are highly fragmented and influenced by human activity. Despite the small area, they serve as the refuge for habitat-specific species and enhance agrolandscape biodiversity. We studied spiders in Velykoburlutskyi Steppe Regional Landscape Park (northeastern Ukraine) for 10 years and found 224 species of 26 families; of these, 27 are rare and require protection. The araneofauna of small forests in gullies is poorer than that of the large oakeries and hosts fewer sylvatic species; the dry grassland fauna is rich, has typical steppe traits, and varies depending on topography and grazing history. The ungrazed gully hosted 125 spider species. The richest assemblages (97 species) were at the bottom, and they were similar to those of meadows and forest edges. The most typical steppe assemblages were formed on the ungrazed slope (77 species). The human-induced disturbance had a negative effect on spiders: we found only 63 species at the grazed bottom and 62 on the slope. After abrupt grazing cessation, four spider species appeared and occurred constantly at the bottom, while no species left this habitat. Grazing on the slopes declined gradually, and spider assemblages did not change significantly after the final cessation; moreover, they enriched on the abandoned slope (75 species). The presence of rare species and a variety of spider assemblages confirm the conservation value of the study site and the need to maintain its mosaic pattern. [ABSTRACT FROM AUTHOR]

• 15 Bufotes species dissected by genomics and multiple genetic/biometric datasets. • Widespread mitochondrial replacements and the super-cryptic species concept. • Diverse but asymmetric origins of allopolyploid hybrid species. • A discontinuous speciation continuum across 10 pairs of hybridizing lineages. • Major taxonomic revisions, including the descriptions of two new species. The radiation of Palearctic green toads (Bufotes) holds great potential to evaluate the role of hybridization in phylogeography at multiple stages along the speciation continuum. With fifteen species representing three ploidy levels, this model system is particularly attractive to examine the causes and consequences of allopolyploidization, a prevalent yet enigmatic pathway towards hybrid speciation. Despite substantial efforts, the evolutionary history of this species complex remains largely blurred by the lack of consistency among the corresponding literature. To get a fresh, comprehensive view on Bufotes phylogeography, here we combined genome-wide multilocus analyses (RAD-seq) with an extensive compilation of mitochondrial, genome size, niche modelling, distribution and phenotypic (bioacoustics, morphometrics, toxin composition) datasets, representing hundreds of populations throughout Eurasia. We provide a fully resolved nuclear phylogeny for Bufotes and highlight exceptional cyto-nuclear discordances characteristic of complete mtDNA replacement (in 20% of species), mitochondrial surfing during post-glacial expansions, and the formation of homoploid hybrid populations. Moreover, we traced the origin of several allopolyploids down to species level, showing that all were exclusively fathered by the West Himalayan B. latastii but mothered by several diploid forms inhabiting Central Asian lowlands, an asymmetry consistent with hypotheses on mate choice and Dobzhansky-Muller incompatibilities. Their intermediate call phenotypes potentially allowed for rapid reproductive isolation, while toxin compositions converged towards the ecologically-closest parent. Across the radiation, we pinpoint a stepwise progression of reproductive isolation through time, with a threshold below which hybridizability is irrespective of divergence (<6My), above which species barely admix and eventually evolve different mating calls (6–10My), or can successfully cross-breed through allopolyploidization (>15My). Finally, we clarified the taxonomy of Bufotes (including genetic analyses of type series) and formally described two new species, B. cypriensis sp. nov. (endemic to Cyprus) and B. perrini sp. nov. (endemic to Central Asia). Embracing the genomic age, our framework marks the advent of a new exciting era for evolutionary research in these iconic amphibians. [ABSTRACT FROM AUTHOR]