MALACOFAUNA OF CARPATHIAN LOESS-LIKE SEDIMENTS

Witold Paweł Alexandrowicz, Paulina Laskowska-Piekoszewska

AGH University of Science and Technology, Faculty of Geology, Geophysics and Environmental Protection, Al. A. Mickiewicza 30, 30-059 Kraków, Poland

Loess-like sediments are common in the Carpathians. These are mainly silt sediments with granulometric, textural and structural characteristics similar to those of classically developed loess. However, in contrast, the proportion of aeolian deposition is small. The formation of loess-like sediments is associated with cool climatic periods. Most profiles represent the last glacial period. Over the many years of study of the sediments in question, mollusc assemblages have been detected at 48 sites. This enabled the collection of research material comprising 200 samples, in which over 35,000 shells belonging to 17 species were found. Cold-loving taxa typical of loess, representing habitats ranging from dry to very humid, play the most important role. Aquatic molluscs were also present in some profiles. The age of the sediments was determined based on ¹⁴C dating (21 dates) and TL dating (10 dates). Despite the small number of species, the assemblages identified at individual sites differed. At sites within river valleys, taxa preferring wetter habitats dominated, while taxa from dry, open environments predominated on the plateaus. Hygrophilous taxa appeared more frequently during the warmer climatic period – MIS 3 (60–27 ka), while during the cooler period (MIS 2; 27–14 ka), assemblages with taxa from open environments predominated.

SYMBIO – MAINTENANCE-FREE EARLY WARNING SYSTEM FOR WATER POLLUTION

Hubert Białous

PROTE Technologies for our Environment LLC, 26 Franciszek Firlik St., 60-692 Poznań, Poland; e-mail: h.bialous@prote.pl

The SYMBIO Biomonitoring System is the only fully automated and maintenance-free system available on the market for monitoring intake water (online), increasing safety in terms of its overall toxicity. The SYMBIO biomonitoring system is used to continuously control the quality of water intake. In our system, we used freshwater mussels – the pointed mussel whose natural reaction to a sudden, significant change in the general toxicity of water is to close the mussel shells. This reaction is quick and unambiguous – the shells of a group of mussels are closed. An additional advantage in favour of their use for the purpose of constructing a maintenance-free intake security system is their practically sedentary lifestyle. Methods using living organisms to assess the state of the environment are called bioindication methods, and the organisms used are bioindicators (indicator organisms). The mussels used in the SYMBIO system (red mussel – a domestic species) meet all the conditions for indicator organisms: they react quickly and unequivocally to sudden changes in the environment, their reaction (closing the shell) is easy to observe and record, and the conditions and lifestyle allow for continuous monitoring of their behaviour in laboratory conditions. The reaction of mussels – the sudden closing of their shells – signals a change in environmental conditions – water parameters – recognised by them as harmful and dangerous.

WILL CORBICULA CLAMS COLONISE POLISH RIVERS?

Maciej Bonk¹, Joanna Kajzer-Bonk², Jacek Dołęga¹, Ainhoa Graciarena¹, Anna Maria Łabęcka³

¹ Institute of Nature Conservation, Polish Academy of Sciences, Al. Mickiewicza 33, 31-120 Kraków, Poland

² Department of Invertebrate Evolution, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Gronostajowa 9, 30-387 Kraków, Poland

³ Jagiellonian University, Faculty of Biology, Institute of Environmental Sciences, Life History Evolution Group, Gronostajowa 7, 30-387 Kraków, Poland

Asiatic Corbicula clams have been introduced to various regions of the world and are now among the most invasive freshwater organisms globally. In Poland they have been present for more than two decades in the Vistula and Odra rivers. However, information on their occurrence in other rivers has been lacking, except for single records from the Skawinka, the Nida, and the system of heated lakes near Konin. In particular, the upstream expansion of Corbicula populations has not been examined. The aim of this study was to assess whether Corbicula clams are colonising tributaries of the upper Vistula River. Field surveys were conducted in the Raba, Dunajec, Nida, Strumień Canal, Czarna Staszowska, and Wisłoka rivers, where selected sites were surveyed for the presence of clams. The presence of Corbicula was confirmed only in the lower reach of the Dunajec near its confluence with the Vistula and in the Nida River along a 70-km stretch. In the Nida, clams show a heterogenous distribution: they are abundant at the uppermost sites and near the river mouth, whereas between these locations they occur only sporadically. The size structure (smaller individuals dominating upstream) and the ratio of dead to live individuals (more empty shells downstream) may indicate recent colonization of the upstream sites. At the same time, this pattern suggests that colonization of the Nida likely results from independent introductions rather than gradual upstream spread.

ISOTOPIC RECORD IN THE SHELL OF LAND SNAILS – NEW DATA FROM THE SHELTER IN SMOLEŃ III

Izabela Cabała¹, Maciej Krajcarz², Marcin Szymanek³

¹ University of Warsaw, Doctoral School of Exact and Natural Sciences, Stefana Banacha 2c, 02-097 Warsaw, Poland

² Polish Academy of Science, Institute of Geological Sciences, Twarda 51/55, 00-818 Warsaw, Poland

³ University of Warsaw, Faculty of Geology, Żwirki i Wigury 93, 02-089 Warsaw, Poland

Stable oxygen and carbon isotope analysis is a well-established method widely applied in various disciplines of the natural sciences. Land snail shells record environmental conditions that prevail during the lifetime of the organism and can therefore serve as an additional source of information in paleoenvironmental and paleoclimatic studies. Although such analyses have been conducted in different regions of the world, they have not previously been applied in temperate climatic settings. The purpose of this study was to evaluate the potential for stable oxygen and carbon isotope analysis of land snail shells for paleoenvironmental reconstruction. Five species were selected and analysed for this purpose. Fossil material was obtained from the well-documented cave site Shelter in Smoleń III. The choice of a site with a well-established environmental history allowed verification of whether interpretations based on the new isotopic data are consistent with previous reconstructions. In addition, fossil shell analysis was complemented by measurements of modern specimens currently occurring in the study area. The results confirm previous findings indicating that δ¹⁸O values mainly reflect humidity conditions, whereas δ¹³C values are related to the character of the surrounding vegetation. However, in the analysed material, the δ¹³C signal is interpreted not as an indicator of C3/C4 plant proportion, but as a record of water stress in C3 plants related to climatic conditions.

WHY ARE SOME POPULATIONS OF CEPAEA NEMORALIS MORE POLYMORPHIC THAN OTHERS?

Robert Cameron

The Natural History Museum, Cromwell Road, London, SW7 5BD, UK; e-mail: robcam1943@gmail.com

The shell polymorphism of the land snail Cepaea nemoralis has resulted in hundreds of papers. Most concern variation in morph-frequencies among samples at many scales. Less attention has been paid to the level of polymorphism. A team is now looking at levels of polymorphism across the range. I will show preliminary results, using ca. 7,000 samples mostly from the Evolution MegaLab database. There are difficulties in analysing such data; and I use simple methods to draw conclusions. Among ca. 3,500 samples from Great Britain, there are clusters in small areas, and there is much variation among them. There are few regularities; lowlands, coastal sites and islands are highly polymorphic. Those from high limestone areas are less so, as at the limits of the range in Scotland. There are a few very weakly polymorphic cases, due to founder effects. This variation within a small part of the geographical range shows that interpreting large scale patterns will be difficult. Some recent, colonising populations are very polymorphic, while others are less so. High altitude populations within the natural range show the lowest levels of polymorphism. In the far south, we may be dealing with a different genetic background, an idea backed by DNA analysis of origins.

PRELIMINARY STUDIES ON THE INFECTION OF THE ALIEN SPECIES PHYSA ACUTA (DRAPARNAUD, 1805) WITH DIGENEANS (TREMATODA: DIGENEA)

Anna Cichy, Marta Dopieralska, Wiktoria Kiprijanovski, Anna Stanicka, Elżbieta Żbikowska

Department of Invertebrate Zoology and Parasitology, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; e-mail: annacichy@umk.pl

Physa acuta is an alien snail species native to North America. Studies on P. acuta infection with digeneans in Europe are scarce, and the interactions between this alien snail, the parasites, and the native malacofauna are unknown. The study aimed to assess the species diversity of Digenea in P. acuta and to check whether this snail can dilute parasite invasions in Radix sp. populations. The study was conducted in the summer of 2023–2024. Molluscs were collected from the thermally polluted Pątnowskie Lake and from the Włocławek Reservoir, which has a natural thermal regime. The trematode species Echinoparyphoum aconiatum Dietz, 1909, was used for experimental studies on the dilution effect. Four temperature variations (4 °C, 10 °C, 20 °C, and 30 °C) were applied to determine whether temperature affected the larvae’s ability to penetrate the molluscs. The results showed that P. acuta was infected exclusively with metacercariae, and that the mollusc served as a secondary intermediate host. Experimental studies of the P. acuta – E. aconiatum – Radix sp. system confirmed that E. aconiatum larvae penetrate the alien mollusc species, and thus the presence of P. acuta reduces infection in native snails. Future research should aim to determine whether the consumption of infected P. acuta individuals by waterfowl leads to the development of adult trematodes, and thus whether the alien snail may serve as an additional host of E. aconiatum, thereby increasing infection of definitive hosts.

SCHISTOSOME SNAIL RESOURCE (SSR) IN LONDON – CURRENT MALACOLOGICAL AND PARASITOLOGICAL RESEARCH

Adam Ciepliński¹, Fernanda Sales Coelho², Aidan Emery¹, Vanessa Yardley², Amaya Bustinduy², Bonnie Webster¹

¹ Natural History Museum, Cromwell Road, SW7 5BD, London, UK; e-mail: adam.cieplinski@nhm.ac.uk

² London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK

Schistosomiasis is a disease caused by flukes of the genus Schistosoma, commonly found in tropical countries and transmitted by freshwater snails, mainly of the genera Biomphalaria and Bulinus. Maintaining the life cycles of flukes requires specialised laboratory infrastructure and procedures limiting availability for many research groups worldwide. The Schistosome Snail Resource (SSR) is the largest centre for medical snail research in the UK and provides material for scientific research on schistosomiasis. The SSR plays a central role in global schistosomiasis research: it maintains the life cycles of the key species Schistosoma mansoni and Schistosoma haematobium and provides access to live and preserved research material. The SSR also coordinates and participates in interdisciplinary projects in various fields, such as diagnostics, ecology, snail and fluke behaviour, digitisation and education, and provides training opportunities for students and researchers, especially from countries endemic for schistosomiasis. This presentation discusses the biology of Schistosomes, provides insights into the SSR, and presents examples of recent projects conducted or supported by the SSR, including projects on the compatibility of flukes and snails, tracking the behaviour of Biomphalaria glabrata snails using machine learning, and an innovative project using 3D models as digital malacological educational aids.

BALTIC SCULPIN COTTUS MICROSTOMUS AS A HOST FOR LARVAE OF TWO SPECIES BELONGING TO UNIO CRASSUS COMPLEX: UNIO CRASSUS PHILIPSSON, 1788 AND UNIO NANUS LAMARCK, 1819

Jacek Dołęga¹, Adam M. Ćmiel¹, Dariusz Halabowski², Katarzyna Zając¹, Monika Mioduchowska³, Tadeusz Zając¹

¹ Institute of Nature Conservation of Polish Academy of Sciences, al. A. Mickiewicza 33, 31-120 Kraków, Poland

² University of Lodz, Faculty of Biology and Environmental Protection, Department of Ecology and Vertebrate Zoology, Narutowicza 68, 90-136 Łódź, Poland

³ Department of Genetics and Biosystematics, Faculty of Biology, University of Gdańsk, Wita Stwosza 59, 80-308 Gdańsk, Poland

Freshwater mussels of the family Unionidae require an obligatory parasitic larval stage on a specific fish host species to complete their ontogeny. This relationship can be highly specific to co-evolving species and geographically variable, although information regarding host suitability remains scarce. Recent advances in molecular and phylogenetic studies of fish have uncovered cryptic host species that have yet to be tested for their role in mussel development. The genus Cottus, particularly European bullhead Cottus gobio, is known to be a primary host for the threatened thick-shelled river mussel Unio crassus complex, a group of large freshwater mussels endemic to Europe. However, the recent revision of the geographical distribution of another Cottus species, Baltic sculpin Cottus microstomus, raises questions about its suitability as a host for species in U. crassus complex. We report here that the transformation of mussel larvae from population of mixed haplotypes of U. crassus sensu stricto and U. nanus into juvenile mussels is successful when C. microstomus serves as the host, with an effectiveness comparable to that of the well-established host Eurasian minnow Phoxinus phoxinus. The sympatric distribution of C. microstomus and U. crassus complex is confined to several river drainages in Central and Eastern Europe, areas that are affected by anthropogenic factors, which may pose challenges to their conservation.

EVIDENCE FOR DILUTION EFFECT BY GOBIO GOBIO, A DEAD-END HOST IN THE UNIO CRASSUS–CYPRINIDAE COEVOLUTIONARY SYSTEM

Jacek Dołęga, Tadeusz A. Zając, Adam M. Ćmiel, Anna M. Lipińska, Krzysztof Tatoj, Katarzyna Zając

Institute of Nature Conservation, Polish Academy of Sciences, Al. Adama Mickiewicza 33, 31-120 Kraków, Poland

Freshwater mussels (Unionidae) depend on specific fish hosts to complete their life cycle. Glochidia, their parasitic larvae, must attach to the gills or fins of suitable fish species to metamorphose. However, non-host fish may intercept glochidia, reducing larval availability for competent hosts – a phenomenon known as the dilution effect. We investigated this mechanism in a natural population of the endangered mussel Unio crassus, focusing on the interaction between the dominating host Phoxinus phoxinus and the non-host Gobio gobio. Both field surveys and a controlled infestation experiment demonstrated that G. gobio removes a substantial proportion of glochidia without supporting their metamorphosis. Co-occurrence analysis showed a negative relation between infestation levels of G. gobio vs P. phoxinus, with a significant interaction modulated by U. crassus density. At low mussel densities, the impact of G. gobio on parasitic success was strongest. Gobio gobio was recorded at 90% of the known U. crassus localities in Poland, and in all of these sites it formed a dominant component of the fish assemblage. Our findings provide direct evidence of a context-dependent dilution effect and highlight the importance of fish community composition and behaviour in conservation of unionid mussels. The presence of non-host fish in habitats with low mussel abundance may undermine recruitment and increase extinction risk in fragmented populations.

MOLLUSC FOSSILS IN THE GEOLOGICAL COLLECTIONS HOUSED AT THE JAGIELLONIAN UNIVERSITY NATURE EDUCATION CENTRE

Sławomir Florjan, Bartłomiej Kajdas

Nature Education Centre, Jagiellonian University, Gronostajowa 5, 30-387 Kraków, Poland; e-mails: slawomir.florjan@uj.edu.pl, bartlomiej.kajdas@uj.edu.pl

Mollusc fossils have been collected at the Jagiellonian University since the beginning of the nineteenth century through both fieldwork and acquisitions from renowned European dealers. Among the oldest specimens are those from the collection of Baltazar Hacquet (1739–1815). The scientifically and historically important collection of Alojzy Alth (1819–1886), containing Jurassic fossils from the Kraków region and Palaeozoic material from Podolia, also forms a valuable part of the holdings. Additional specimens were donated by private collectors. The fossil collection housed at the Jagiellonian University Nature Education Centre comprises more than 6,200 catalogued objects recorded in a database, as well as several thousand labelled specimens awaiting digitisation. A single catalogue entry may represent either one fossil or an entire assemblage. The collections include representatives of most major molluscan groups. Particularly well represented are Paleogene and Neogene gastropods, Jurassic, Cretaceous, Paleogene and Neogene bivalves, and Jurassic and Cretaceous ammonites and nautiloids. In 2023, the Centre acquired two outstanding collections assembled by Janusz Stanowski. One consists of Jurassic fossils from Łuków, dominated by cephalopods, bivalves and gastropods. The second, comprising thousands of specimens from the Middle Miocene deposits of Korytnica (Świętokrzyskie Mountains), is particularly rich in gastropods, including nearly 50 species representing 26 families. Many specimens preserve traces of bioerosion, and numerous representatives of the family Turritellidae have been prepared in longitudinal section. The collections require further taxonomic revision and species identification. We welcome collaboration with researchers interested in the scientific study of these valuable fossil assemblages.

GEOGRAPHIC MOSAIC OF RECIPROCAL PARASITISM DURING INVASION: RESPONSES OF RHODEUS AMARUS TO SINANODONTA WOODIANA

Dariusz Halabowski^{1, 2}, Kacper Pyrzanowski^{1, 2} , Grzegorz Zięba¹, Abhishek Nair Anil^{2, 3}, Joanna Grabowska¹, Carl Smith¹, Martin Reichard^{1, 2, 3}

¹ University of Łódź, Faculty of Biology and Environmental Protection, Department of Ecology and Vertebrate Zoology, Banacha 12/16, 90-237 Łódź, Poland

² Czech Academy of Sciences, Institute of Vertebrate Biology, Květná 8, 603 65 Brno, Czechia

³ Masaryk University, Faculty of Science, Department of Botany and Zoology, Kotlářská 2, 611 37 Brno, Czechia

Biological invasions create novel host–parasite systems whose dynamics depend on the duration of co-occurrence. In the bitterling–mussel relationship, we tested whether the response of Rhodeus amarus to the invasive Chinese pond mussel Sinanodonta woodiana forms a geographic mosaic shaped by sympatry history. We combined evidence on mussel host choice for spawning, natural glochidial infestation, infection costs, and behavioural responses across populations ranging from naive to those coexisting with S. woodiana for more than 40 years and representing different invasion stages. We found that R. amarus does not effectively use S. woodiana as a reproductive host, and all fish populations consistently avoided mussels from the most recent phase of invasion. In contrast, host choice for the native Anodonta anatina depended on individual mussel quality rather than population origin. Glochidia of S. woodiana were recorded on all studied fish species, with high infestation in R. amarus, especially in lentic habitats, on both gills and fins. Populations with the longest contact history showed the lowest parasite loads and post-infection mortality despite no behavioural avoidance of glochidia. These results indicate that invasion by S. woodiana asymmetrically restructures reciprocal parasitism. More than 40 years of sympatry did not produce a clear behavioural shift, but were sufficient for variation in host resistance and tolerance to emerge.

DOES A “BARCODE GAP” EXIST IN THE SUPERFAMILY TRUNCATELLOIDEA?

Sebastian Hofman¹, Artur Osikowski², Aleksandra Jaszczyńska³

¹ Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland

² Department of Animal Reproduction, Anatomy and Genomics, University of Agriculture in Kraków, Poland

³ Department of Invertebrate Evolution, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland

Correct species delimitation is currently one of the major challenges of modern integrative taxonomy, particularly in the context of recognising and protecting biodiversity. However, this task is far from trivial, as cryptic diversity and the different evolutionary and demographic histories of particular lineages may considerably complicate species delimitation. Molecular methods, may facilitate this process, although this approach is not free from limitations. The application of phylogenetic analyses and various species delimitation methods can, however, reduce the risk of interpretative errors. It may also be helpful to determine the level of genetic divergence characterising interspecific variation, i.e. the so-called barcode gap. However, defining this threshold is difficult, partly due to differences in evolutionary rates among particular phylogenetic lineages. The aim of our analyses was to compare levels of intra- and interspecific genetic divergence in different groups of snails belonging to the superfamily Truncatelloidea. Our results indicate that the barcode gap differs among particular groups of Truncatelloidea, but may nevertheless serve as a useful general guideline when assessing potential interspecific distinctness. When combined with species delimitation methods based on different analytical approaches, phylogenetic analyses, and morphological data, it may help to better recognise species diversity in natural populations.

A NEW SUBFAMILY OF STYGOBIONT SNAILS (CAENOGASTROPODA: TRUNCATELLOIDEA: HYDROBIIDAE) AND THEIR RADIATION IN THE WESTERN BALKANS

Aleksandra Jaszczyńska¹, Andrzej Falniowski², Jozef Grego³, Sebastian Hofman⁴

¹ Jagiellonian University, Institute of Zoology and Biomedical Research, Department of Invertebrate Evolution, Gronostajowa 9, Kraków, Poland; e-mail: a.jaszczynska@uj.edu.pl

² Jagiellonian University, Institute of Zoology and Biological Research, Department of Malacology, Gronostajowa 9, Kraków, Poland

³ University of Ljubljana, Biotechnical Faculty, Department of Biology, SubBioLab, Jamnikarjeva 101, 1000 Ljubljana, Slovenia

⁴ Jagiellonian University, Institute of Zoology and Biomedical Research, Department of Comparative Anatomy, Gronostajowa 9, Kraków, Poland

The Balkans, particularly the Dinaric Karst region, inhabited by approximately 30% of the currently known species of stygobiont snails, represent one of the most important global centres of biodiversity for this group of animals. Despite nearly two centuries of research, the state of knowledge of this fauna remains insufficient. This results, among other factors, from numerous imprecise species descriptions (based solely on empty shells), fragmentary morphological and anatomical data, and the still limited number of molecular studies. Moreover, information on species localities is often unclear, and many type localities have disappeared or been destroyed. However, ongoing molecular studies combined with the exploration of hard to access subterranean habitats are bringing new discoveries. One example is an obligate stygobiont clade described by us, comprising six genera new to science represented by nine new species. The material was collected from 18 localities, including 15 in Croatia and three in Slovenia. Phylogenetic analyses based on sequences of the mitochondrial cytochrome c oxidase subunit I gene (COI) and the nuclear markers 18S rRNA and histone H3 allowed the reconstruction of a relatively well supported phylogeny of this new group. Additionally, the shell morphology of the new species was characterised, and the morphological variability of their reproductive organs and radulae was analysed.

ANALYSIS OF ENVIRONMENTAL CHANGES IN THE VICINITY OF KRAKÓW BASED ON SUBFOSSIL MALACOFAUNA FOUND IN THE LOESS SEDIMENTS OF MASZKÓW

Paulina Laskowska-Piekoszewska, Witold Paweł Alexandrowicz

AGH University of Science and Technology, Faculty of Geology, Geophysics and Environmental Protection, Al. A. Mickiewicza 30, 30-059 Kraków, Poland; e-mail: laskowska@agh.edu.pl

The aim of the study was to reconstruct environmental changes based on mollusc assemblages identified in loess deposits found near Kraków, in the town of Maszków, in the southern part of the Kraków-Częstochowa Upland. Loess deposits in this area are attractive for malacological studies, primarily due to their high CaCO₃ content, which positively affects the condition of preserved shells. The outcrops selected for study vary in thickness, ranging from several to as much as 10 meters. Detailed malacological examinations were conducted on samples from sites in the Dłubnia Valley, 15 km north of Kraków. The beginning of loess sedimentation in Maszków is dated to approximately 24,000 years B.P. Based on the mollusc assemblages identified in the samples, the shells most likely date from the Late Vistulian period. The analysis was based on material obtained from 25 samples. The presence of malacofauna typical of loess was identified. The identified material contained nine species of land snails, represented by over 1,500 specimens – a rich fauna in the case of loess – enabling a reconstruction of changes in the natural environment of the area in question. The research allowed for an analysis of the development of loess in Maszków, confirming the occurrence of an erosion phase preceding sedimentation. Habitat diversity depends on local conditions (substrate type, humidity, exposure), but this did not hinder interpretation.

OCCURRENCE OF MOLLUSCS IN VARIOUS ZONES OF THE LAKE

Krzysztof Lewandowski, Beata Jakubik

University of Siedlce, Faculty of Science, Institute of Biological Sciences, Bolesława Prusa 14, 08-110 Siedlce, Poland; e-mail: krzysztof.lewandowski@uws.edu.pl

A lake is a very complex ecosystem, which creates different environmental conditions for molluscs in different places. Hydrobiologists distinguish in the lake eulittoral, littoral, sublittoral, profundal and pelagic. Molluscs can be found practically everywhere in the lake. In the eulittoral we find shell accumulations. The littoral is the richest zone, where more than 30 species of mollusc are usually recorded. The sublittoral zone is a place where empty shells accumulate. The composition, species abundance, and shell sizes in the sublittoral zone are different from those in the littoral zone. This is related to the appearance and disappearance of different species, different decomposition times for shells of different species and different size classes. Environmental conditions for molluscs are not particularly favourable in the profundal zone, but even here small mussels of the genus Pisidium are sometimes found. The only mollusc species recorded in the pelagic zone is the zebra mussel, which occurs here in the form of planktonic larvae. Different species of molluscs in the lake form different communities. First of all, it is benthos, macrofauna living on plants, on stones, but also periphyton, plankton and neuston. Molluscs can occur on other animals, e.g. zebra mussels on crayfish, on Unionidae. Some molluscs can be found in the digestive tracts of water birds and fish. Empty shells of small molluscs are often incorporated into the cases of Trichoptera larvae.

HOW NOT TO FREEZE? SURVIVAL STRATEGIES OF FRESHWATER MUSSELS ACROSS EUROPEAN CLIMATIC ZONES

Anna M. Lipińska¹, Paweł Adamski¹, Adam M. Ćmiel¹, Maria J. Golab¹, Paulina A. Idczak-Figiel², Manuel Lopes-Lima^{3, 4}, Jon H. Mageroy⁵, Anna Nowakowska⁶, Martin Österling⁷, Szymon Sniegula¹, Amílcar Teixeira⁸, Silvana Costa⁹, Simone Varandas¹⁰, Dariusz Halabowski^{11, 12}

¹ Institute of Nature Conservation, Polish Academy of Sciences, Kraków, Poland

² Academia Copernicana, Department of Animal Physiology and Neurobiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland

³ CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório; Associado, Universidade do Porto, Vairão, Portugal

⁴ BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal

⁵ Norwegian Institute for Nature Research, Sognsveien 68, 0855 Oslo, Norway

⁶ Department of Animal Physiology and Neurobiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Toruń, Poland

⁷ River Ecology and Management, Research Group RivEM, Department of Environmental and Life Sciences, Karlstad University, 65188, Karlstad, Sweden

⁸ CIMO, LA SusTEC, Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal

⁹ MORE-Laboratório Colaborativo Montanhas de Investigação-Associação, Portugal

¹⁰ CITAB-Center for Research and Technology of Agro-Environment and Biological Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal

¹¹ University of Łódź, Faculty of Biology and Environmental Protection, Department of Ecology and Vertebrate Zoology, Łódź, Poland

¹² Czech Academy of Sciences, Institute of Vertebrate Biology, Brno, Czechia

Freshwater mussels have evolved numerous adaptations that enable them to survive harsh winter conditions. In the context of ongoing climate change and the increasing frequency of extreme weather events, the survival strategies of these organisms may be subject to strong selective pressures. In this study, we analysed variation in glycogen levels, supercooling point (SCP), and shell size in individuals of Anodonta anatina along a broad climatic gradient from southern to northern Europe. We tested three hypotheses: (1) northern populations exhibit higher glycogen levels as a physiological adaptation to prolonged winter stress; (2) individuals from northern regions more frequently display the ability to supercool as a strategy to avoid freezing; and (3) they attain larger shell sizes in accordance with the temperature-size rule. The results revealed significant geographic variation in physiological traits but did not confirm differences in shell size. The highest glycogen levels were recorded in northern populations, supporting the hypothesis of increased energy storage as an adaptation to low temperatures. The ability to supercool was rare (2.5%) and observed almost exclusively in northern individuals. These findings suggest that A. anatina copes with low temperatures mainly through a combination of strategies such as metabolic depression and burrowing into sediments.

DO UNIONID FRESHWATER MUSSELS INCUR REPRODUCTIVE COSTS DURING THE INCUBATION OF THE BITTERLING FISH?

Anna Maria Łabęcka¹, Martin Reichard^{2, 3, 4}

¹ Jagiellonian University, Faculty of Biology, Institute of Environmental Sciences, Life History Evolution Group, Gronostajowa 7, 30-387 Kraków, Poland; e-mail: anna.labecka@uj.edu.pl

² Institute of Vertebrate Biology, Czech Academy of Sciences, Květná 8, 603 65 Brno, Czechia

³ University of Łódź, Faculty of Biology and Environmental Protection, Department of Ecology and Vertebrate Zoology, Banacha 12/16, 90-237 Łódź, Poland

⁴ Masaryk University, Faculty of Science, Department of Botany and Zoology, Kotlářská 2, 611 37 Brno, Czechia

Unionid mussels belong to one of the most threatened groups of animals. Their decline is primarily driven by anthropogenic pressures, including habitat transformation and loss, as well as climate change. The role of interspecific interactions in shaping mussel condition and reproductive success remains poorly understood. Therefore, the aim of our study was to assess the reproductive costs incurred by unionids as a result of parasitism by ostracophilous fishes.

In an in situ experiment conducted in a Morava River oxbow lake, we tested the effect of the bitterling Rhodeus amarus on the reproduction of its surrogate host, the swollen river mussel Unio tumidus. Bitterling broods were incubated by male, female, and hermaphroditic mussels, although males hosted higher numbers of fish offspring. Bitterling eggs and embryos deformed the gill brood chambers of mussels. Females parasitised by bitterling exhibited reduced fecundity, expressed as fewer ovulated oocytes and a higher number of degenerated germ cells. At the same time, mussel ovaries contained follicles with developing oocytes that may represent a source of subsequent cohorts of germ cells within the same reproductive season. Our results indicate that the incubation of bitterling embryos imposes a substantial reproductive cost on unionid mussels. The prolonged gonadal activity of U. tumidus, allowing multiple spawning events within a single reproductive season, may partially compensate for the effects of fish parasitism.

“AN AMATEUR IS ALSO A HUMAN BEING, ONLY MORE NORMAL THAN A SCIENTIST” (PROF. ANDRZEJ WIKTOR). THE INATURALIST SOCIAL-SCIENCE NETWORK AS A TOOL FOR MALACOLOGISTS

Jarosław Maćkiewicz

Poland; e-mail: jarekmackiewicz@o2.pl

The internet network iNaturalist, founded in California in 2008, is an online social network, where people share information on biodiversity, to help each other in discovering and recording nature. The organization’s mission is to give people the ability to connect with nature and promote biodiversity science and its conservation through modern technology. Currently, as of March 2026, the network connects over 4 million users worldwide, who have recorded data on the occurrence of 556,000 species of organisms from all kingdoms, creating a database of nearly 300,000,000 verifiable records, i.e., records enabling the identification of an organism. Nearly five million observations refer to molluscs, of which approximately 21,000 species have been recorded in the database to date. For Europe, these data are as follows: 1,166,000 observations of 2,837 species of molluscs. From Poland, 35,440 observations of 221 species have been recorded so far, with the most frequently recorded being Cepaea nemoralis (4,768), Helix pomatia (3,394), Arion vulgaris (1,575), and from bivalves: Macoma balthica (1,032), Cerastoderma glaucum (890), and Mytilus trossulus (485). Thirty-six species are represented by only one observation from Poland. The presentation discusses the possibilities of the iNaturalist app in the context of malacologist work.

ENDANGERED AND THREATENED SPECIES OF CLAUSILIIDAE (GASTROPODA: STYLOMMATOPHORA) IN POLAND – DISTRIBUTION, ECOLOGY AND REPRODUCTIVE BIOLOGY

Tomasz K. Maltz¹, Anna Sulikowska-Drozd²

¹ Museum of Natural History, University of Wrocław, Poland

² Department of Invertebrate Zoology and Hydrobiology, University of Łódź, Poland

Among the 24 species of door snails (Clausiliidae) recorded in Poland, 13 have been regarded as threatened or endangered. Five species are strictly protected and classified as Critically Endangered (CR), one species is Vulnerable (VU), while the remaining taxa are listed as Near Threatened (NT) according to Red List criteria. Door snails are generally considered typical forest dwellers; however, some species prefer more open or rocky habitats (e.g. Charpentieria ornata, Clausilia rugosa parvula, Balea perversa). Most taxa are mesophilous, whereas Macrogastra tumida, Balea stabilis and Vestia gulo are hygrophilous. Calciphilous species include Cochlodina costata, Ch. ornata, C. rugosa parvula and B. perversa. With the exception of Ch. ornata and B. perversa, which in Poland are associated with anthropogenically transformed habitats (e.g. abandoned limestone quarries or the walls of medieval castle ruins), all other species occupy natural deciduous and mixed forests which are characterised by diverse microhabitats. We propose that the remaining seven species be granted at least partial legal protection and assigned the Vulnerable (VU) category. In many of their preferred habitats – especially outside national parks or nature reserve – potential threats persist, including intensive forestry practices (tree felling, removal of dead wood and stumps, drainage) and conservation works involving renovation of historic stone walls, which may adversely affect local populations.

NGS SEQUENCING IN SNAIL MICROBIOME ANALYSIS – COMPARISON OF AVAILABLE SEQUENCING APPROACHES USING THE EXAMPLE OF V3–V4 16S RDNA METABARCODING SERVICE AT GENOMED S.A.

Piotr Małysa

Genomed S.A., Ponczowa 12, 02-971 Warsaw, Poland; e-mail: piotr.malysa@genomed.pl

Next-generation sequencing (NGS) currently represents one of the key tools used for the analysis of microbial diversity. These methods are widely applied in studies of the microbiome of various animal organisms, including snails. An important step in experiment planning is the appropriate selection of a sequencing strategy, depending on the type of tested samples. Genomed S.A. provides NGS services based on technologies developed by Element Biosciences (AVITI platform), Illumina (NovaSeq and MiSeq platforms), as well as long-read sequencing technologies – Oxford Nanopore Technologies and Pacific Biosciences. Each of these approaches has different technical parameters, costs and limitations. One of the most commonly used, cost-effective, and sensitive approaches for microbiome studies in various snail species is metabarcoding based on sequencing of the V3–V4 hypervariable regions of the 16S rDNA gene. At Genomed S.A., this service is performed on the AVITI platform in PE300 mode. Compared with analogous analyses performed on Illumina platforms, the AVITI system enables the generation of higher-quality sequencing data at a lower service cost while maintaining the standard output format (.fastq files). The application of long-read sequencing technologies may further improve taxonomic resolution in microbiome analyses. However, these approaches are associated with higher costs and specific requirements regarding the quantity and quality of DNA extracted from the analysed samples.

EXTINCT AND ENDANGERED SNAILS OF THE GENUS ACHATINELLA (GASTROPODA: ACHATINELLIDAE) FROM THE ISLAND OF O’AHU (HAWAII, USA)

Dominika Mierzwa-Szymkowiak¹, Maksymilian Zieliński², Jaroslav Hlaváč³

¹ Museum and Institute of Zoology PAS, Twarda 51/55, 00-818 Warszawa, Poland; e-mail: dmierzwa@miiz.waw.pl

² L. Rydygiera 15/4, 01-793 Warszawa, Poland

³ Sušice Museum of Šumava, nám. Svobody 40, 342 01 Sušice, Czechia

Achatinellidae is a family of tropical land snails occurring on Pacific islands. Species of the genus Achatinella are endemic to Hawaii, primarily the island of O’ahu. According to the IUCN Red List, 10 species of this genus are critically endangered, while the remaining 30 are extinct. Due to their endangered status, the CITES Convention protects both live snails and shells held in museum collections. The oldest shell collection in Poland from O’ahu, including species such as Achatinella decora, A. casta and A. curta, is housed at the Museum and Institute of Zoology PAS. The shells were largely acquired by W. Lubomirski between 1867 and 1882, approximately 70–80 years before the mass snail die-off on O’ahu. Drastic declines in snail populations were recorded in the 1950s and 1960s. The primary cause was the introduction of the predatory snail Euglandina rosea as a biological control agent for the invasive snail Lissachatina fulica. The dietary preferences of E. rosea proved contrary to expectations. Its diet consisted primarily of small (rather than large) snails, including Achatinella species, which contributed to their extinction. The introduction of non-native plant species to O’ahu also had a negative impact, eventually displacing native plants. This resulted in a decline in the population density of snails, which feed on fungi growing on Hawaiian trees. This project aims to develop museum material including endemics of the Hawaiian archipelago, a biodiversity hotspot.

MALACOLOGICAL INVENTORY OF REMBEZY ISLAND IN THE MIDDLE VISTULA VALLEY – PRELIMINARY RESULTS

Franciszek Mika¹, Artur Szpalek², Krzysztof Godlewski³, Pola Emma Brettschneider⁴, Jan Rapczyński⁵

¹ Student Scientific Association “Atlas”, Warsaw University of Life Sciences (SGGW), Faculty of Animal Breeding, Bioengineering and Conservation, Jana Ciszewskiego 8, 02-786 Warsaw, Poland

² Zoological Section of the Student Zoological Society, Warsaw University of Life Sciences (SGGW), Faculty of Animal Breeding, Bioengineering and Conservation, Jana Ciszewskiego 8, 02-786 Warsaw, Poland

³ University of Warmia and Mazury in Olsztyn, Faculty of Biology and Biotechnology, Michała Oczapowskiego 1A, 10-719 Olsztyn, Poland

⁴ Warsaw University of Life Sciences (SGGW), Faculty of Biology and Biotechnology, Building 37, Nowoursynowska 159, 02-776 Warsaw, Poland

⁵ Nature Conservation Foundation “Na Skrzydłach”, Woronicza 78/172, 02-640 Warsaw, Poland

Rembezy Island (approx. 320 ha), located on the Vistula River in the Middle Vistula Valley in the Mazowieckie Voivodeship (near Czersk, Góra Kalwaria municipality), constitutes a mosaic habitat complex including willow–poplar riparian forest Salici-Populetum, tall-herb communities dominated by Solidago gigantea, as well as open areas with meadow vegetation and sandy surfaces with sparse vegetation characteristic of primary succession. The aim of the study was to conduct a qualitative and quantitative inventory of terrestrial and freshwater molluscs occurring on the island. In May 2025, a preliminary survey of the area was carried out and four microhabitats (two terrestrial and two aquatic) were selected. The material was collected on 29 August 2025 and 23 September 2025 using timed hand searching (“visual search”; two persons for one hour per microhabitat), sieving of collected and dried leaf litter, and sampling with a hydrobiological dip net. In total, 1,449 individuals representing 19 species were collected. Additionally, based on observations made in May and records from the mobile application iNaturalist, a further nine taxa were recorded, giving a total of 28 species forming the malacofauna of the island. The research will be continued in 2026, with a planned expansion of the number of analysed microhabitats.

(UN)EXPECTED DIVERSITY OF XEROCAMPYLAEA LAND SNAILS ENDEMIC TO THE BALKANS (STYLOMMATOPHORA: HYGROMIIDAE)

Małgorzata Proćków¹, Tereza Adamcová², Lucie Juřičková², Tomasz Strzała³, Ondřej Korábek²

¹ University of Wrocław, Museum of Natural History, H. Sienkiewicza 21, 50-335 Wrocław, Poland; e-mail: malgorzata.prockow@uwr.edu.pl

² Charles University, Department of Zoology, Praha, Czechia

³ Wrocław University of Environmental and Life Sciences, Department of Genetics, Wrocław, Poland

We focused on a little-known and taxonomically complex group of land snails, historically classified within Xerocampylaea, Trochulus, Monachoides and Semifruticicola. Integrated analyses of morphological and genetic data were reconciled with available nominal taxa. All populations represent Xerocampylaea that encompassed 13 mitochondrial lineages, each corresponding to a morphotype with a well-defined distribution and a valid name: X. zelebori, X. erjaveci, X. hirci, X. osoria, X. blaui, X. floerickei, X. costulata, X. waldemari, X. leptolasia, X. serbica, X. fallax, X. taraensis and X. kosovoensis. The objective definition of taxonomic species boundaries was possible based on comprehensive approach with an identification of a source of phenotypic variation. Several lineages may represent undescribed species, and some historical names cannot be assigned to biological entities. We suggest introgression as one of the solutions explaining discrepancies between our data, highlighting a cautious interpretation of mtDNA phylogeny. This is the first and important step towards elucidating the complex diversity of this group, but future work using genomic methods will be essential. The association between Xerocampylaea diversity and high-altitude mountain ranges indicates the importance of these areas for biodiversity conservation. Studies should focus on species with specific requirements and limited range, especially in the face of habitat changes caused by climate and human pressure.

HIDDEN MANIPULATORS: THE INFLUENCE OF PARASITES ON THE BEHAVIOUR OF FRESHWATER MUSSELS

Daria Skibińska¹, Maria Urbańska¹, Nicoletta Riccardi², Sandra Kaźmierczak¹

¹ Department of Zoology, Faculty of Veterinary Medicine and Animal Sciences, Poznan University of Life Sciences, Poland

² CNR Water Research Institute, Verbania, Italy

Trematodes of the genus Rhipidocotyle are one of the groups of organisms parasitizing freshwater mussels. Numerous studies show that infections negatively affect mussels. At the early stage of infection, the parasites penetrate the reproductive system causing castration. In later stages, they migrate to the hepatopancreas and finally to the gills, thereby significantly reducing the mussels’ chances of survival in their natural environment. Many publications analyse the relationships between freshwater mussels and trematodes of the genus Rhipidocotyle, focusing on aspects such as reduced reproductive capacity or preferences in host selection. However, only a few studies address issues related to the influence of parasites on the behaviour of freshwater mussels. To determine whether parasites of the genus Rhipidocotyle affect the behaviour of Unio elongatulus, experiments were conducted on more than 100 individuals. Mussels were subjected to a series of experiments using Hall sensors (valvometry), which measured the gaping behaviour. Additionally, a modified open-field test was conducted with and without the presence of fish, using video recording. To identify individuals infected with parasites, gonadal biopsies were performed, and the results were confirmed by dissection. The behaviour of parasitised individuals differed from that of healthy mussels in the presence of a potential subsequent intermediate host.

EVOLUTION OF THE GLICZARÓW LANDSLIDE IN PODHALE IN THE LIGHT OF MALACOLOGICAL STUDIES

Sylwia Skoczylas-Śniaz¹_,Witold Paweł Alexandrowicz²

¹ Władysław Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Kraków, Poland

² AGH University of Science and Technology, Faculty of Geology, Geophysics, and Environmental Protection, al. Mickiewicza 30, 30-059 Kraków, Poland

A shallow landslide has developed on the slope of the Gliczarów Stream valley (a tributary of the Biały Dunajec River). Within the colluvium, depressions filled with calcareous tufa and peat were found. Mollusc shells were found within the tufa. The analysis was based on 13 profiles, from which 71 samples were collected. 30,000 specimens and 72 species were identified. The age of the sediments was determined using radiocarbon dating.

The malacofauna and ¹⁴C dating results enabled characterization of environmental changes and the chronology of the landslide formation. The oldest sediments represent the Younger Dryas and contain a relatively poor fauna with cold-loving species. The formation of the landslide is associated with this period. The tufas overlying the older colluvium contain fauna with species typical of continental coniferous forests and correspond to the early Holocene. At the end of this phase, the landslide zone was activated. Mollusc assemblages representing the middle Holocene are characterised by a dominance of shade-loving taxa typical of mixed forests and a milder climate with greater oceanic influences. There is no malacological record in the earlier part of the Upper Holocene. A high proportion of open-environment snails characterises mollusc assemblages representing the younger part of the Upper Holocene. Nowadays, in the spring zones, tufas are precipitated containing numerous, though little differentiated faunas.

GENETIC STRUCTURE OF ROMAN SNAIL (HELIX POMATIA L.) POPULATIONS FROM THE FORMER CISTERCIAN REGIONS OF WESTERN POLAND

Marianna Soroka¹, Wiktoria Abramska¹, Maksymilianna Bieda¹, Barbara Wąsowicz^{1, 2}

¹ University of Szczecin, Department of Genetics and Genomics, Institute of Biology, Felczaka 3c, 71-413 Szczecin, Poland

² Adam Mickiewicz University, Geohazards Research Unit, Institute of Geology, Bogumiła Krygowskiego 12, 61-680 Poznań, Poland

The Roman snail (Helix pomatia) is one of the largest terrestrial snails in Europe. This species is primarily associated with moist, calcium-rich habitats. It occurs in the natural environment and in the cultural landscape, including gardens, parks, forest edges, and mosaics of semi-natural habitats. As part of the interdisciplinary project “Natural Heritage of the Post-Cistercian Lands in Western Poland,” carried out by the University of Szczecin, the level of genetic diversity and the population structure of H. pomatia were studied. Six populations located on the grounds of former Cistercian monasteries in western Poland were analysed, as the Cistercians brought this species to Poland in the 12th century and bred snails in their monastery gardens as a fasting food. Due to its limited mobility, its preference for specific habitat conditions, and the possibility of human-mediated dispersal, H. pomatia is an interesting subject for research on population variability and historical dispersal patterns. The analyses were based on sequences of the mitochondrial cox1 gene and STR markers, commonly used in phylogeographic and population studies. The obtained results enabled assessment of haplotype diversity and STR loci within the studied populations, as well as the degree of genetic similarity between them.

THE PIENINY MOUNTAINS AS A HOTSPOT OF TERRESTRIAL SNAIL DIVERSITY – A SUMMARY OF MONITORING STUDIES

Anna Sulikowska-Drozd

Department of Invertebrate Zoology and Hydrobiology, Faculty of Biology and Environmental Protection, University of Łódź, Poland

The geology of the the Pieniny Mts. creates favourable conditions for terrestrial snails, making this region one of the main hotspots of their diversity in Poland. The most comprehensive studies of the Pieniny malacofauna were conducted in the 1930s by J. Urbański and later continued in the second half of the 20th century by A. Riedel, A. Wiktor and A. Dzięczkowski. Most investigations focused on the Pieniny National Park. More than 100 terrestrial snail species have been recorded in the region so far, representing about 60% of the Polish malacofauna. At the initiative of Anna Dyduch-Falniowska, terrestrial snails were included in the nature monitoring programme of the Pieniny National Park. Monitoring covers selected species characteristic of local habitats, including Acicula parcelineata, Aegopinella minor, Daudebardia rufa, Macrogastra ventricosa and Pupilla sterii, as well as spring snails of the genus Bithynella. Surveys include analyses of species composition and dominance structure at reference sites and targeted searches in suitable habitats. Six monitoring surveys conducted between 2006 and 2025 indicate a stable malacofauna, with about 70 terrestrial snail species recorded regularly, including most monitored taxa. Some species reported in the past from single localities, however, have not been confirmed again, which may indicate their local extinction or extremely rare occurrence in inaccessible sites.

MUSSELS IN A TOXIC ENVIRONMENT – A CASE STUDY. STRUCTURAL ANALYSIS OF MUSSEL SHELLS FROM LAKE ORTA

Kamil Szpotkowski¹, Maria Urbańska², Nicoletta Riccardi³

¹ Division of Surface Science, Faculty of Chemical Technology and Engineering, Bydgoszcz University of Science and Technology, Poland; e-mail: szpotkowskik@gmail.com

² Department of Zoology, Faculty of Veterinary Medicine & Animal Science, Poznań University of Life Sciences, Poland

³ CNR Water Research Institute, Verbania, Italy

Lake Orta in northern Italy was heavily contaminated with copper and acidified by long-term wastewater discharges from a viscose factory and galvanising plants operating since the 1920s. At the peak of degradation, mean copper concentrations in the water column reached several tens of µg Cu l⁻¹, and pH dropped to about 4, leading to severe impoverishment of plankton and benthic communities. After large-scale liming, alkalinity increased, and copper and aluminium concentrations in the water fell to nearly zero, initiating an ongoing biological recovery of the lake. We analysed shells of Unio elongatulus from Lake Orta, reference specimens from Lake Maggiore, and individuals transplanted from Lake Maggiore to Lake Orta. Shells were examined using microcomputed tomography, powder Xray diffraction, electron and confocal microscopy, infrared and emission spectroscopy, and protein composition was assessed by SDSPAGE. Our results show that shells are not major sinks for excess heavy metals but exhibit clear microstructural alterations in mussels from Lake Orta, which we interpret as effects of metabolic changes induced by environmental stress and persistent sediment toxicity.

MOLLUSCS OF ARCHAEOLOGICAL SITES IN CHATKAL RANGE (WESTERN TIAN SHAN, UZBEKISTAN)

Marcin Szymanek

Faculty of Geology, University of Warsaw, Poland

The investigation was conducted in archaeological sites located in mountain valleys Katta Sai and Ertash Sai of Chatkal Range in the western Tian Shan piedmont, Uzbekistan. The open-air loess sites comprised rich upper Middle Palaeolithic and initial Upper Paleolithic artifacts (about 38-26 ka BP) accompanied by molluscan remains. In Katta Sai five taxa of land snails, represented by 313 individuals and 447 shell fragments, were identified. The assemblage from Ertash Sai consisted of 9 taxa represented by 831 individuals and 958 fragments. The assemblages are mostly composed of open-country and shrubland species often occurring in screes in Central Asia. The most numerous are Pseudonapaeus sogdianus and Fruticicola lantzi. Additionally, quite numerous shells of Leucozonella mesoleuca and Vallonia ladacensis occurred. Further studies and precise correlation of faunal and archaeological results is required, but the malacological record offers a perspective for the palaeoenvironmental reconstruction during human occupation in the sites. Presumably studied areas were dominated by open and grassy habitats with the possible occurrence of screes.

NOTES ON THE MORTALITY OF RIVER MUSSELS (UNIONIDAE) CAUSED BY MAINTENANCE WORKS ON SMALL STREAMS

Cezary J. Tajer

Lower Silesian Landscape Park Association, Poland

Maintenance work is carried out annually by the State Water Management Authority Wody Polskie on hundreds of sections of rivers and canals of various sizes. This involves excavators removing sediments and seaweed from the bottom. An unintended consequence of direct technical intervention in the streambed is the death of many aquatic organisms. Those with poor locomotion are particularly vulnerable. These include mussels, which, if left on the bank, react by closing their shells and have no chance of surviving for more than a few hours or days (depending on conditions). The smaller the watercourse undergoing maintenance, the greater the risk to local mussel populations. To more precisely assess the impact of maintenance work on the mortality of Unionidae mussels, observations were conducted on two small rivers: the Prądnia River (2023) and the Sąsiecznica River (2024). In both streams, the following mussel species were found: Anodonta cygnea, Anodonta anatina, Unio tumidus and Unio pictorum. Based on the comparative analysis, it can be concluded that maintenance work significantly negatively impacts the mussel population. However, it does not completely eliminate them, allowing some populations to survive and perhaps rebuild in the long term. Massive declines in the number of mussels as a result of maintenance work can be significantly reduced by organising campaigns to collect them and put them back in the stream.

PARAERGASILUS RYLOVI IN FRESHWATER MUSSELS: NEW HOST ASSOCIATIONS AND RANGE EXTENSION INTO THE SOUTHERN BALTIC CATCHMENT

Maria Urbańska¹, Sandra Kaźmierczak¹, Daria Skibińska¹, Janusz Golski¹, Joanna Szpotkowska^{2, 3}, Kamil Szpotkowski⁴

¹ Department of Zoology, Faculty of Veterinary Medicine & Animal Science, Poznań University of Life Sciences, Poland

² Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland

³ Department of Animal Biotechnology and Genetics, Faculty of Animal Breeding and Biology, Bydgoszcz University of Science and Technology, Poland

⁴ Division of Surface Science, Faculty of Chemical Technology and Engineering, Bydgoszcz University of Science and Technology, Poland

Parasitic copepods of the family Ergasilidae are common in freshwater fish, but records from freshwater bivalves are scarce. We report the ergasilid copepod Paraergasilus rylovi from freshwater mussels in a glacial lake of the lower Vistula drainage (Lake Sudomie, northern Poland), thereby extending its known northern European range from northwestern Russia and southern Finland into the southern Baltic catchment. P. rylovi was found on Anodonta anatina, A. cygnea and Unio tumidus, with the highest mean intensity in A. cygnea; infections in A. cygnea and U. tumidus represent previously undocumented host associations. Single individuals were also detected on the invasive zebra mussel Dreissena polymorpha, suggesting accidental, probably non-reproductive use of this phylogenetically distant host. Combined with earlier records, our data support a macroecological pattern in which P. rylovi functions mainly as a host-specialised parasite of Anodonta spp., with other unionids serving as marginal hosts and dreissenids as dead-end hosts. Confirmed records remain restricted to a few Baltic draining regions, and recent surveys in other European countries have not detected this species, indicating that P. rylovi is neither widespread nor abundant in unionid parasite faunas and may be underrecorded due to low prevalence and imperfect detection.

THE LAND SNAIL CORNU ASPERSUM IN POLAND – DISTRIBUTION AND GENETIC STUDIES

Kamil Walczak¹, Barbara Wąsowicz², Marianna Soroka²

¹ West Pomeranian University of Technology in Szczecin, Faculty of Biotechnology and Animal Sciences, Janickiego 32, 71-270 Szczecin, Poland

² University of Szczecin, Department of Genetics and Genomics, Institute of Biology, Felczaka 3C, 71-413 Szczecin, Poland

Climate change, globalisation, and the intensification of tourism and transport promote the spread of many alien species into new areas. The land snail Cornu aspersum, native to the Mediterranean region, has been introduced to numerous locations across Europe, including Poland. This species is characterised by high ecological plasticity and a strong reproductive potential. In Poland, individual specimens of C. aspersum are mainly recorded in synanthropic habitats, although stable, natural populations have also been observed. The subspecies C. aspersum aspersum and C. aspersum maxima are farmed in Poland for human consumption, which increases the risk of their expansion into natural habitats. The first farms of these snails in Poland were established in the south-eastern and south-western parts of the country in the 1990s. The presented results document the current distribution of C. aspersum in Poland, including the presence of individual specimens, populations, and commercial farms. Genetic analyses based on the sequence of the mitochondrial cox1 gene involve wild individuals, natural populations of C. aspersum, and farmed specimens (C. a. aspersum and C. a. maxima). These studies will allow estimation of the level of genetic diversity among individuals and populations of Cornu in Poland.

CO-OCCURRENCE AND NEW LOCALITIES OF MONACHA CARTUSIANA (O. F. MÜLLER, 1774) AND MONACHA CLAUSTRALIS (ROSSMÄSSLER, 1834) IN POLAND

Jakub Zaguła, Zuzanna Kossowska, Aleksandra Jaszczyńska

Jagiellonian University, Faculty of Biology, Institute of Zoology and Biomedical Research, Department of Invertebrate Evolution, Gronostajowa 9, 30-387 Kraków, Poland

Monacha cartusiana (O. F. Müller, 1774) and Monacha claustralis (Rossmässler, 1834) are two species of land snails from the Hygromiidae which have expanded their range in Poland in recent decades. Due to their very high morphological similarity, distinguishing them in the field, particularly based solely on diagnostic shell characteristics, is significantly difficult. This especially concerns M. claustralis, which for a long time could have been misidentified as M. cartusiana or overlooked in faunistic analyses. Studies conducted in recent years, combining classical field methods with molecular analyses (DNA barcoding using the COI gene), have allowed for the precise identification of both species. Through the use of integrative methods, new localities of M. claustralis in southern Poland (including Kraków) were confirmed, a tendency for M. cartusiana to further expand its range in the country was demonstrated, and the co-occurrence of both species in Kraków was confirmed. These results indicate dynamic changes in the distribution of both taxa, likely caused by human activity and climate change. The obtained data show that both species inhabit the same niche and indicate the necessity of widespread implementation of molecular analyses in malacofaunistic research, as well as the need for a critical revision of earlier findings based solely on shell characteristics.

SNAILS OF THE GENUS FAUSTINA KOBELT, 1904 IN THE TATRA MOUNTAINS – CURRENT STATUS AND PERSPECTIVES

Kamila S. Zając-Garlacz¹, Rafał Garlacz²

¹ Nature Education Centre, Jagiellonian University, Gronostajowa 5, 30-387 Kraków, Poland; e-mail: kamila.zajac12@gmail.com

² Nature Education Centre, Jagiellonian University, Gronostajowa 5, 30-387 Kraków, Poland

The malacofauna of the Tatra Mountains includes three species of the genus Faustina: F. cingulella, F. rossmaessleri and F. faustina, showing a mosaic distribution related to local habitat conditions. The most frequently recorded species was F. faustina, occurring both as the typical banded form and as an unornamented form. This study focused on the two species with a more restricted distribution: F. cingulella and F. rossmaessleri. F. cingulella was recorded only in selected areas of the Western Tatras (including Czerwone Wierchy, the vicinity of Giewont, Kobylarzowy Żleb, the Tomanowa and Kościeliska valleys and the Kraków Gorge), always on limestone substrate. F. rossmaessleri was found in the Kościeliska Valley and on Gęsia Szyja. Collected material was analysed using molecular and morphometric methods. Sanger sequencing revealed very low genetic variability in both species, indicating a lack of clear population structure despite their isolated distribution. Shell morphometrics of F. cingulella showed a relationship between shell size and elevation, with the largest individuals occurring at the highest sites. These results suggest that high-mountain populations of Faustina in the Tatras may remain genetically homogeneous despite spatial isolation, while phenotypic variation may be shaped by microhabitat conditions. This provides a starting point for further research on the colonization history and adaptation of these snails.

SPECIFIC IMMUNITY OF SNAILS – AN INTERESTING RELATIONSHIP IN THE SNAIL-DIGENEA SYSTEM

Elżbieta Żbikowska

Department of Invertebrate Zoology and Parasitology, Nicolaus Copernicus University, Toruń, Poland

Studies of snail immunity are primarily conducted on snail-fluke systems. The specificity within these associations is noteworthy, meaning that a limited group of snail taxa transmits a specific parasite species. The nature of this specificity, including its immunological basis, arises. Biomphalaria glabrata is a model snail species due to its importance in schistosomes transmission. Historical work, combined with modern molecular techniques, provides a valuable source of knowledge about snails’ ability to mount specific immune responses. Interactions between fibrinogen-related proteins (FREPs) and diverse parasite antigens equipped with specific carbohydrates determine host-parasite recognition and trigger specific immunity. Complex glycan structures play an important role in the host specificity of snails towards flukes. These observations indicate an interesting bilateral relationship: Digenea influence the dynamic development of snail-specific immunity, and specific defence responses in snails are a factor in Digenea speciation.

REPRODUCTIVE POTENTIAL OF PHYSA ACUTA (DRAPARNAUD, 1805) AS A CAUSE OF COLONISATION SUCCESS – A CASE STUDY IN AN ANTHROPOGENIC RESERVOIR

Anna Cieplok, Julia Kiraga, Oskar Palmąka, Aneta Spyra

University of Silesia, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, Bankowa 9, 40-007 Katowice, Poland; e-mail: anna.cieplok@us.edu.pl

Physa acuta is a freshwater snail originating from the Mediterranean region, recognised as an invasive and expanding species. The aim of the research was to assess the reproductive potential of P. acuta, measured by the hatching success. The snails were collected from an anthropogenic water body and placed in aquaria under the same conditions until egg masses laying occurred. Masses were monitored, measured, and counted daily. The hatching moment was considered to be the emergence of young individuals. The egg masses collected from the field were transparent and surrounded by a thick, stiff, and relatively strong external casing. After collection, it was observed that each mass contained between 29 and 77 eggs. When transferred to the laboratory, hatching began after five days. Analysis of the incubation and hatching of P. acuta eggs showed that 65% of the juvenile snails emerged after five days, and 100% after 14 days. The laboratory-laid masses were delicate, transparent, and weak. The average number of eggs was similar in both types of masses, but laboratory-laid masses contained a higher number of empty eggs. In the case of laboratory masses, hatching started only after seven days, with a success rate of 94.8%. A characteristic feature of P. acuta is its very high dispersal ability, enabling a wide distribution across different continents. This is also reflected in the high hatching success of this species and a high population density.

HITCHHIKERS ON DEAD SHELLS: AN UNANTICIPATED PATHWAY OF ALIEN SPECIES INVASION ASSOCIATED WITH DISCARDED SEAFOOD REMAINS AT OYSTER TASTING SITES

Halyna Gabrielczak^1,2, Yuriy Kvach^1,3, Mikhail O. Son¹

¹ Institute of Marine Biology, National Academy of Science of Ukraine, Italiyska St. 37, 65048, Odesa, Ukraine

² Department of Ecology and Vertebrate Zoology, University of Łódź, Banacha 12/16, 90-237 Łódź, Poland

³ Institute of Vertebrate Biology of the Czech Academy of Sciences, Květná 170/8, 603 00 Brno, Czechia

This study investigates the diversity of invertebrate species colonizing live and discarded oyster shells originating from a farm and oyster bar in the Tylihul Estuary, northwestern Black Sea. Molecular techniques identified several invasive species associated with discarded shells, including Semibalanus balanoides, Austrominius modestus and Monocorophium insidiosum, not previously documented in the region. Macrofaunal composition differed between live and discarded shells, with invasive species richness higher than expected. Discarded shells act as colonization substrate and potential invasion vectors. We performed a Species-related Risk Assessment identifying potential ecological impacts on local biodiversity. The study proposes management strategies to mitigate risks associated with shells discarded by oyster bars, including informing recreational travellers and retailers about implications of discarding shells into water and controlling risks related to shell use as construction material.

OCCURRENCE AND CHARACTERISTICS OF PEARLS IN FRESHWATER MUSSELS SPECIES CURRENTLY LIVING IN POLAND

Dariusz Halabowski^{1, 2}, Maja Jurek³ , Paulina Gajzler³

¹ University of Łódź, Faculty of Biology and Environmental Protection, Department of Ecology and Vertebrate Zoology, Banacha 12/16, 90-237 Łódź, Poland

² Czech Academy of Sciences, Institute of Vertebrate Biology, Květná 8, 603 65 Brno, Czechia

³ University of Łódź, Faculty of Biology and Environmental Protection, Students’ Scientific Association of Animal Ecology, Banacha 12/16, 90-237 Łódź, Poland

Pearls are a well-known product of freshwater mussels, but their occurrence in natural populations of species currently living in Poland remains poorly recognised. This study aimed to determine which freshwater mussel species produce pearls and to characterise their number, distribution, and basic morphometric traits. We examined 1075 individuals representing seven species from 12 sites located in standing and flowing waters. Pearls were found in 9 individuals (0.84% of all mussels), exclusively in Sinanodonta woodiana (7 individuals; 4.61%) and Anodonta anatina (2 individuals; 0.80%), while no pearls were recorded in the remaining five species. Pearl-bearing mussels originated from four sites, and pearls were more frequent in standing than in flowing waters, although this difference was not statistically significant. In total, 24 pearls were recorded. Most positive individuals contained a single pearl, whereas one S. woodiana individual contained as many as 14. Pearl length ranged from 657.72 to 2157.45 µm, width from 517.71 to 1990.61 µm, and measured mass from 0.0003 to 0.0105 g. Pearls were significantly more frequent in S. woodiana than in native mussels taken together. No significant differences in shell length or body mass were found between mussels with and without pearls. These results indicate that pearl occurrence is rare but unevenly distributed and, in the studied material, was associated mainly with the invasive S. woodiana.

FIVE NEW SPECIES OF RADOMANIOLA (TRUNCATELLOIDEA: HYDROBIIDAE) FROM BALKANS

Aleksandra Jaszczyńska¹, Jozef Grego², Luboš Beran³, Sebastian Hofman⁴, Andrzej Falniowski⁵, Artur Osikowski⁶

¹ Department of Invertebrate Evolution, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland

² Department of Biology, SubBioLab, Biotechnical Faculty, University of Ljubljana, Slovenia

³ Regional Office Kokořínsko – Máchův kraj Protected Landscape Area Administration, Nature Conservation Agency of the Czech Republic, Czechia

⁴ Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland

⁵ Department of Malacology, Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland

⁶ Department of Animal Reproduction, Anatomy and Genomics, University of Agriculture in Kraków, Poland

The genus Radomaniola Szarowska, 2006 encompasses minute gastropods that predominantly inhabit springs, although they also occur in streams, rivers, and subterranean aquatic systems. The 36 species described to date represent only a fraction of the true diversity within the genus. Considerable morphological variability necessitates the use of molecular characters for reliable taxonomic delineation. Among these, cytochrome c oxidase subunit I (COI) remains the most commonly employed marker in DNA barcoding, suitable for identification at the species and genus level, but insufficient for resolving deeper phylogenetic relationships.

The material analysed in this study was collected over more than two decades (2001–2022) from 101 localities in Croatia, Bosnia and Herzegovina, Montenegro, Albania, and Greece. Based on well-supported molecular evidence, supplemented by morphological and anatomical examination, we describe five species new to science, recorded from 21 localities in Croatia, Bosnia and Herzegovina, and Greece. Extensive intraspecific variation, combined with subtle morphological and anatomical differences between the taxa, suggest morphostatic evolution within the genus Radomaniola. The study was supported by the grant N18/DBS/000012, from the Institute of Zoology and Biomedical Research, Jagiellonian University.

MORPHOMETRIC ANALYSES AND THEIR USAGE IN INTEGRATIVE TAXONOMY OF SNAILS FROM THE GEOMITRIDAE FAMILY

Zuzanna Kossowska, Jakub Zaguła, Aleksandra Jaszczyńska

Jagiellonian University, Faculty of Biology, Institute of Zoology and Biomedical Research, Department of Invertebrate Evolution, Gronostajowa 9, 30-387 Kraków, Poland

Accurate species differentiation is one of the most challenging aspects of modern taxonomy. Molecular tools have clearly demonstrated that distinguishing species solely based on morphological characteristics leads to numerous errors related to both overestimation and underestimation of biodiversity, particularly in the case of cryptic species. One of the solutions to this problem is an integrative taxonomy approach, which, in the case of gastropods, takes into account, among other things, detailed morphometric analyses of shells for various taxonomic units, distinguished based on molecular studies. The aim of this study was to determine whether such analyses can demonstrate the differentiation of shells belonging to distinct genera of gastropods in the family Geomitridae. The studied genera are relatively distant, both genetically and morphologically, allowing for the determination of whether there are significant differences in shell shape – both between and within these genera. Analyses of this type can both allow to better understand the diversity of the studied genera, and also provide important information on the usefulness of this method in integrative taxonomic studies, particularly in the context of analysing cryptic and pseudocryptic variation. Furthermore, they demonstrate the importance of shell morphology in research on gastropod taxonomy and biodiversity.

GROWTH DYNAMICS OF PERFORATELLA INCARNATA AND P. VICINA (GASTROPODA: HYGROMIIDAE) UNDER NATURAL AND LABORATORY CONDITIONS

Elżbieta Kuźnik-Kowalska¹, Małgorzata Proćków², Magdalena Marzec³

¹ Wrocław University of Environmental and Life Sciences, Institute of Biology, Department of Animal Biology and Ecology, Wrocław, Kożuchowska 5b, 51-631 Wrocław, Poland

² University of Wrocław, Museum of Natural History, H. Sienkiewicza 21, 50-335 Wrocław, Wrocław, Poland

³ Poland; e-mail: magdamarzec@poczta.onet.pl

Studies on the population biology of snails of the genus Perforatella allow for a better understanding of the adaptive strategies of taxa with diverse habitat preferences. The project covered two species: P. incarnata and P. vicina. Although both inhabit moist forests, the former has a wider habitat spectrum, enabling it to colonise anthropogenic landscapes. Data from field observations and laboratory breeding were used. The mark-recapture method allowed for the tracking of monthly whorl increments with an accuracy of 0.05. Snails in the laboratory reached a significantly higher number of whorls than in the wild (U-test, p<0.0001). The median size for P. incarnata increased from 5.75 to 6.2, and for P. vicina from 6.1 to 6.6. The mean growth period (until lip formation) was 18.9 and 20.1 months, respectively. In the field, the average growth rate for P. incarnata was 0.18 whorls/month; for P. vicina, it was 0.28. The highest growth rate was observed in spring, after which it gradually declined. In both taxa, the growth rate was negatively correlated with the current shell size. In P. incarnata, seasonality dominated (r = −0.7), while in P. vicina, the influence of individual size and season was equivalent (r = −0.5). Mathematical models indicate that in nature, both species typically complete their growth in the third year of life (after two hibernations). Depending on environmental conditions and individual traits, the growth period may be extended by further seasons.

DOES THE SPANISH SLUG ARION VULGARIS THREATEN POPULATIONS OF THE GROVE SNAIL CEPAEA NEMORALIS? THE TROPHIC IDENTITY OF A. VULGARIS UNDER SCRUTINY

Elżbieta Kuźnik-Kowalska¹, Małgorzata Proćków², Małgorzata Ożgo³

¹ Wrocław University of Environmental and Life Sciences, Institute of Biology, Department of Animal Biology and Ecology, Wrocław, Kożuchowska 5b, 51-631 Wrocław, Poland; e-mail: elzbieta.kowalska@upwr.edu.pl

² University of Wrocław, Museum of Natural History, H. Sienkiewicza 21, 50-335 Wrocław, Wrocław, Poland

³ Kazimierz Wielki University, Department of Evolutionary Biology, Ossolińskich 12, 85-093 Bydgoszcz, Poland

Arion vulgaris is among the most invasive invertebrates in Europe. Reports of necrophagy and attacks on bird nestlings suggest that this species may exhibit a tendency toward facultative predation, potentially including other molluscs. We aimed to verify whether A. vulgaris can limit the abundance of native species, such as C. nemoralis, through the consumption of eggs, juveniles and adults. The experiment was conducted under controlled laboratory conditions. In a series of choice and no-choice (starvation) tests, 30 individuals of A. vulgaris were offered eggs (both intact and damaged), as well as juvenile and adult C. nemoralis. Responses to the eggs of Helix pomatia and Perforatella vicina were also tested. Vertebrate muscle tissue (Gallus gallus) served as a positive control. Over 50 observation series were performed. In none of the variants was predation by A. vulgaris observed on any developmental stage of C. nemoralis. Even under starvation conditions, the slugs did not consume the offered prey, instead feeding on cellulose or dying despite the availability of biological material. However, an immediate necrophagic response (100% of trials) was recorded toward the vertebrate tissue, as well as intensive covering of the eggs with mucus, which may interfere with their incubation. These results do not support the hypothesis of predation by A. vulgaris on C. nemoralis. The decline in grove snail populations is likely due to resource competition or habitat modification.

A SURPRISING ADAPTATION OF THE SNAIL-FLUKE SYSTEM IN THE HEATED KONIN LAKES

Kinga Lesiak¹, Przemysław Ciapka¹, Anna Cichy¹, Anna Stanicka¹, Julita Templin¹, Janusz Żbikowski², Mateusz Augustyniak², Elżbieta Żbikowska¹

¹ Department of Invertebrate Zoology and Parasitology, Nicolaus Copernicus University, Toruń, Poland

² Department of Ecology and Biogeography, Nicolaus Copernicus University, Toruń, Poland

Heated lakes receiving cooling water from power plants provide a natural model for studying the impact of climate warming on communities, including host-parasite systems. The hypothesis is that climate warming will limit the spread and transmission of psychrophilic parasites with complex life cycles. The aim of this study was to determine whether transmission of the parasite Diplostomum pseudospathaceum in the snail L. stagnalis would persist under conditions of long-term water heating. A total of 3,350 L. stagnalis specimens were examined during the 2015–2017 and 2023–2024 (May–October) seasons: 1,511 from heated lakes and 1,839 from lakes with a natural thermal regime. The presence of Digenea was assessed intravitally and post-mortem. The affiliation of D. pseudospathaceum was confirmed using molecular methods and phylogenetic analyses. The seasonal dynamics of the parasite’s prevalence, the snails’ thermal preferences, and their survival at constant temperatures were assessed. The high parasite prevalence in snails from heated lakes and the presence of patent infections during the warmest period of the study were surprising. In culture conditions snails from these lakes exhibited better survival than individuals from cold lakes. Under experimental conditions, uninfected L. stagnalis from heated lakes chose significantly higher temperatures than snails from cold lakes. These results suggest that the L. stagnalis–D. pseudospathaceum system will remain stable under global warming.

IN THE SHADOW OF FROST: EFFECTS OF LOW TEMPERATURE ON THE WINTER ACTIVITY OF VERTIGO SNAILS

Anna M. Lipińska¹, Zofia Książkiewicz², Adam M. Ćmiel¹, Oksana Hnatyna³, Paulina Laskowska-Piekoszewska⁴, Dariusz Halabowski⁵

¹ Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, 31-120 Kraków, Poland; e-mail: lipinska@iop.krakow.pl

² Department of General Zoology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland

³ Ivan Franko National University of Lviv, Hrushevskoho Str. 4, 79005 Lviv, Ukraine

⁴ AGH University of Kraków, Faculty of Geology, Geophysics and Environmental Protection, Department of General Geology and Geotourism, Kraków, Poland

⁵ University of Łódź, Faculty of Biology and Environmental Protection, Department of Ecology and Vertebrate Zoology, Łódź, Poland

Although Vertigo antivertigo and Vertigo moulinsiana are terrestrial snails, their life cycles are closely associated with wetland ecosystems such as fens, marshes, and riparian zones. Their occurrence depends on the presence of standing water and specific vegetation structure, particularly communities dominated by sedges (Carex) and reed sweet-grass (Glyceria maxima). However, these habitats are becoming increasingly rare in Europe due to wetland drainage and degradation. The aim of this study was to determine the effects of low temperatures on the functioning of both species: whether they remain active at temperatures close to zero or enter hibernation. Winter survival strategies were assessed by measuring activity at low temperatures (0 °C, 2 °C and 5 °C), determining the supercooling point (SCP) as an indicator of cold tolerance, and analysing shell morphology in populations from different regions of Poland. Both species exhibited a freeze-avoidance strategy. However, V. moulinsiana showed slightly higher SCP values, consistent with its preference for warmer microclimatic conditions. The activity of this species clearly decreased with declining temperature and ceased at 0 °C. Morphological differences among populations suggest possible local adaptation to environmental conditions. The results indicate that climate change and the ongoing loss of wetland habitats may pose a serious threat to the long-term survival of these species.

MICROSCOPIC CONQUERORS: A BEETLE AS A POTENTIAL DISPERSAL VECTOR OF VERTIGO SNAILS

Anna M. Lipińska¹, Miłosz A. Mazur², Oksana Hnatyna³, Dariusz Halabowski⁴

¹ Institute of Nature Conservation, Polish Academy of Sciences, Kraków, Poland; e-mail: lipinska@iop.krakow.pl

² Institute of Biology, University of Opole, Oleska 22, 45-052 Opole, Poland

³ Ivan Franko National University of Lviv, Hrushevskoho Str. 4, Lviv, 79005, Ukraine

⁴ University of Łódź, Faculty of Biology and Environmental Protection, Department of Ecology and Vertebrate Zoology, Łódź, Poland

Dispersal of minute terrestrial snails remains one of the least understood aspects of their ecology, particularly in taxa with extremely limited active mobility. Despite their small body size and often narrow habitat requirements, species of the genus Vertigo exhibit relatively wide distributions, suggesting an important role of passive dispersal mechanisms. During fieldwork conducted in southern Poland, a juvenile snail of the genus Vertigo was observed attached to the body of the weevil Sitona lineatus (Coleoptera: Curculionidae). This observation documents a previously unreported case of a terrestrial snail potentially being dispersed by a phytophagous beetle. Although the event appears incidental, it provides direct evidence that insects may occasionally act as unintentional vectors transporting minute snails. For organisms with such limited mobility, even short-distance transport may enable the crossing of environmental barriers, the colonization of new microhabitats, and the maintenance of population connectivity. This finding suggests that incidental interactions between insects and microsnails may represent a previously overlooked mechanism of dispersal in terrestrial landscapes.

ESTIMATION OF THE PRESSURE EXERTED ON THE SURFACE BY THE INVASIVE SNAIL POTAMOPYRGUS ANTIPODARUM

Katarzyna Łapkiewicz

Department of Ecology and Biogeography, Nicolaus Copernicus University, Toruń, Poland; e-mail: 50379@doktorant.umk.pl

Our research results presented here constitute part of a broader project aimed at identifying key factors that may limit the occurrence of the New Zealand mud snail (Potamopyrgus antipodarum) (Gray, 1883) and other snails in the deeper zones of lakes. One of these factors may be the decreasing consolidation of bottom sediments with increasing depth. The aim of this study was to estimate the pressure exerted by the snail on the substrate using the mass of the snail together with its shell and the surface area of its foot. Compared to its small size, the New Zealand mud snail possesses a relatively thick and heavy shell. For each of the 30 examined individuals, the surface area of the foot was calculated based on three photographs using the ImageJ software, and the snails were then weighed on an analytical balance. In addition, the pressure exerted by the foot of P. antipodarum on an area of 1 mm² was calculated. This unit was chosen because it will allow, in the next stage of the research, a comparison of P. antipodarum with other snail species. As essential part of these studies will be the future determination of the degree of sediment consolidation.

DIVERSITY OF MALACOFAUNA SPECIES AND ITS SIGNIFICANCE FOR THE RECONSTRUCTION OF THE PALAEOENVIRONMENT AT THE ZAHAJKI SITE (WESTERN POLESIE)

Sylwia Skoczylas-Śniaz¹, Marcin Szymanek², Anna Hrynowiecka³, Marcin Żarski⁴

¹ W. Szafer Institute of Botany Polish Academy of Sciences in Kraków, Lubicz 46, 31-512, Kraków, Poland; e-mail: s.skoczylas@botany.pl

² Faculty of Geology, University of Warsaw, Al. Żwirki i Wigury 93, PL-02-089 Warszawa, Poland

³ Polish Geological Institute-National Research Institute, Marine Geology Branch, Kościerska 5, 80-328 Gdańsk, Poland

⁴ Polish Geological Institute-National Research Institute, Rakowiecka 4, 00-975 Warszawa, Poland

Studies conducted in Western Polesie have revealed numerous sites with sediment sequences corresponding to the Mazovian Interglacial (MIS 11c). These sites provide valuable information on environmental changes and landscape development in this region during the Middle Pleistocene. One such site is Zahajki, where palaeoenvironmental analyses documented a record of environmental transformations from the Mazovian Interglacial (MIS 11c) to the Holocene. In the early phase of the Mazovian Interglacial, communities of lake molluscs occurred, including Gyraulus albus, Acroloxus lacustris, Valvata cristata. In the following phase, the malacofauna was dominated by Lithoglyphus jahni, with only sporadic occurrences of other taxa. With climatic warming and during the interglacial optimum, Bithynia tentaculata became dominant and aquatic mollusc communities showed clear species diversification. In the final phase of the interglacial, water ferns persisting on the surface of the reservoir probably led to the decline of most taxa inhabiting the water column. Climate cooling during the Early Liviecian Glaciation caused the complete disappearance of mollusc communities, which did not re-establish during the Vistulian or in the Holocene. The research was funded by NCN MINIATURA 9 (No. 2025/09/X/ST10/00181) and subsidies from the W. Szafer Institute of Botany, Polish Academy of Sciences.

MOLLUSCA SPECIES IDENTIFICATION: METHODS, CHALLENGES AND INTEGRATIVE SOLUTIONS

Antonina Tarnas, Joanna R. Pieńkowska

Department of Cell Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland

Methods of species identification have come a long way, from morphological taxonomy to contemporary integrative approaches using genetic, anatomical, and ecological data. Our goal is to synthetise and critically evaluate methods for species identification in Mollusca, assessing accuracy, scalability, and limitations, and proposing an integrative framework. Identification is challenged by morphological plasticity, phenotypic convergence, and cryptic speciation. Traditional morphology remains fundamental, especially with preserved voucher specimens, though shell shape and anatomical traits can be environmentally influenced. Non-destructive 3D imaging (e.g. micro-CT) enhances resolution and allows virtual examination of rare or type material. Molecular approaches are central. Mitochondrial DNA sequences (COI, 16S rRNA) provide species-level resolution but can be affected by introgression, incomplete lineage sorting, and database gaps. Nuclear markers (ITS, 18S rRNA) and multilocus or genome-wide SNP datasets improve delimitation confidence. Proteomic approaches (e.g. MALDI-TOF) allow rapid diagnostics but need validated reference libraries. Environmental DNA metabarcoding and machine-learning image classification increase throughput but are sensitive to primer bias and training data imbalance. To sum up, no single method suffices; integrative workflows combining morphology, multilocus genetics, and proteomics offer the most reliable framework for molluscan species identification.

MICROBIOME OF MOUNTAIN SNAILS OF THE GENUS FAUSTINA (KOBELT, 1904)

Kamila S. Zając-Garlacz¹, Rafał Garlacz², Hanna Kaczmarczyk³, Michał Kolasa⁴

¹ Nature Education Centre, Jagiellonian University, Gronostajowa 5, 30-387 Kraków, Poland; e-mail: kamila.zajac12@gmail.com

² Nature Education Centre, Jagiellonian University, Gronostajowa 5, 30-387 Kraków, Poland

³ Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland

⁴ Department of Farm Animal Biodiversity Conservation and Horse Breeding, National Research Institute of Animal Production, Krakowska 1, Balice, Poland

Mountain refugia provide an excellent system for studying the effects of isolation and environmental specialization, particularly in endemic and relict species. This study compared the microbiome composition of three snail species of the genus Faustina representing different geographic ranges: the Tatra endemic F. cingulella, the relict species F. rossmaessleri, and the widespread mountain species F. faustina. F. cingulella was collected in limestone habitats of the Western Tatras along an elevational gradient (ca. 950–2,000 m a.s.l.), whereas F. rossmaessleri was sampled from rocky sites in the Kościeliska Valley and the Gęsia Szyja. Comparative material of F. faustina originated from several locations across the Carpathians. Endemic and relict species were collected exclusively from rock substrates, while F. faustina also occurred on vegetation, allowing assessment of microhabitat effects on microbiome composition. Microbiome composition was determined using amplicon sequencing of the V4 region of the 16S rRNA gene. The microbiome was dominated by taxa previously associated with terrestrial snails, including Buttiauxella gaviniae, Lactococcus lactis, Aeromonas veronii and Mycoplasma sp. Differences in bacterial richness among species were small, whereas variation in symbiont abundance was mainly related to sampling location, suggesting an important role of microhabitat and diet in shaping the microbiome of Faustina snails.