Drohvalenko M. Composition diversity of Pelophylax esculentus complex hemiclonal population systems in Ukraine and the factors maintaining their stability

Dissertation is dedicated to the study of intra-population processes in hemiclonal population systems of water frogs Pelophylax esculentus complex in Ukraine, namely their composition, ontogenetic features of different genetic forms and the features of selection among progeny, as one of the mechanisms maintaining the stable existing of such systems, and its relation to the genomes’ genetic diversity. The work is composed of the description of the new and dynamic analysis of already known HPS of Ukraine (Dunai, Western Buh, Dnipro basins sensu lato) and Siverskyi Donets basin in particular; the investigation of water frogs’ development in natural conditions and in conditions of experimental crossings, along with registration of different anomalies (developmental, phenological); molecular and cytological study of different population systems and experimental progeny from some of their members. The work was conducted using material from the collection and database of Amphibian population ecology laboratory (KhNU, Zoology and Animal Ecology department) and KhNU Natural Museum, from the personally conducted expeditions, from the experimental laboratory crossings of water frogs collected in natural HPS. The study on HPS diversity in Ukraine found the distribution of L-E, R-E, and L-E-R HPS types in Ukraine without signs of systems of E-type. For the first time, the composition of population systems in Chornobyl Zone and “Seimskyi” RLP was described, composition of HPS in Siverskyi Donets (with tributaries), Merla, Udai (with tributaries), Psel (with tributaries), Prut and Western Buh was specified. The dynamics of five model population systems in Siverskyi Donets diversity center, analyzed based on long-term monitoring data, demonstrated the internal differences, intrinsic to HPS even of the same R-E-Ep type, which concern their composition (described in terms of three forms: P. ridibundus, 2n та 3n P. esculentus). It was established that the distribution of triploid-containing HPS may be wider than previously expected. The new potential sites of triploid P. esculentus distribution include HPS of Chornobyl Zone, lower stretches of Dnipro (Hola Prystan) and some northern tributaries of Ukrainian flow of Siverskyi Donets (where triploids had not been registered). The R-E HPS was registered in the basin of Oskol river (NP “Dvorichanskyi” and Dvorichna city), where hybrids had not been not found before. Based on the existing assisted reproductive technologies for anurans, there was developed and successfully implemented an original method for intravital artificial crossing of water frogs. It was shown that the tadpole morphology of different genetic forms of P. esculentus complex allows under certain conditions (analysis of tadpoles in certain age) to distinguish all these forms. The analysis may involve as qualitative (coloration features), as quantitative (multidimensional analysis of body measurements) features. The link between genome diversity, gametogenesis features and selection among progeny was shown for Iskiv pond HPS. The high clonality of L-genomes is matched here with high diversity of R-genomes, that shows the significant role of recombination occurring here probably in few P. ridibundus and, hypothetically, LRR-P. esculentus. Significant (or full) elimination of progeny of both parental genotypes and the part of diploid and triploid hybrids is suggested. The scientific novelty of the work consists of studying of HPS composition in new localities in Ukraine, not having covered by special research on hemiclonal population systems before, including the protected areas. The wider than expected distribution of triploid P. esculentus in Ukraine was shown. For the first time, the composition, genetic diversity and dynamics of the unique R-Epf HPS in lower Siverskyi Donets stretches was studied. For the first time, the long-term dynamics of composition and morphological and cytological estimators of a few HPS from Siverskyi Donets diversity center of water frogs diversity was summarized. The reproduction, selection and genomes diversity was studied for the set of model HPS. The morphological differences of early development were found for different P. esculentus forms; also, their morphological and phenological anomalies of reproduction and development was found. A new intravital technique for artificial crossing of frogs was developed and tested. The practical value of the work’s results consists of widening the data on the diversity of the European water frog complex in Ukraine, particularly of unique and exclusively complicated systems. The data, obtained on the comparatively rich Ukrainian material, allow to deepen our knowledge about the evolution of hybridogenetic species complexes on the molecular and population levels.