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Light pollution is a modern environmental problem. The scale of light pollution is increasing yearly and is negatively affecting the functioning of terrestrial and aquatic ecosystems. Of the aquatic ecosystems, marine ecosystems are the most studied, while there is very little information on the effect of artificial lighting on freshwater ecosystems. Among freshwater aquatic organisms, there are relatively little data on the effect of artificial light on crustaceans and fish, while we could find no meaningful data on the effect of artificial light on molluscs are practically absent. Here we test whether different types of artificial lighting, differing in their spectra, affect the activity of the Holarctic mollusc Radix auricularia. For this, we used two light sources (with warm and cold light) and a 1-m long aquarium. We found that both light sources affect individuals of this species, but the effects of this exposure are different. Artificial lighting (depending on the spectral characteristics) can increase the activity of molluscs of this species or reduce it. In the long term, the impact on the ecosystem will depend on the type of water body where light pollution is present, where individuals of this species live, and the type of light sources., The study was supported by the Project of Russian Ministry of Science and Education No. FZZE-2020-0026. The author declare that they have no conflict of interest. All authors gave their consent to participate in this manuscript. All authors approve its publication.The datasets generated and analysed during the current study are available from the corresponding author on reasonable request

Radix auricularia (Lymnaea auricularia) snails are the main intermediate host of Fasciola gigantica in the middle and South of Iraq. Recently, some studies suggest these snails are not present in Iraq, in particular Basrah province. Thus, the current study was aimed to use the bioinformatics analysis in the determination of Radix sp. in Basrah and also aimed to identify morphological characteristics of this species in the AL-Sewaib river, Basrah. Four hundred R. auricularia snails were collected from the AL-Sewaib river during May 2018 to March 2019. The results of the bioinformatics analysis showed according to the mitochondrial cytochrome c oxidase subunit I, the presence of R. auricularia snails in Basrah province and these snails are more closely related to Iranian R. auricularia snails than those for European counties and Russia. This study also displayed the existence of the polymorphism phenomenon in R. auricularia snails collected from the AL-Sewaib river which there were six different forms (A, B, C, D, E and F). These forms had variations in the colour and form of shells along with a variation in the number of eggs (30-56) per an egg mass. In addition to this, these R. auricularia forms had variations in their distributions. Form E had the highest spread percentage (33%) followed by 17, 15, 14, 11 and 10% for forms B, D, C, A and F, respectively. These forms had also variations in their morphological characteristics. The largest form was the form D whereas the smallest form was the form B but other forms A, C, E and F were similar and had moderate sizes.Thus, the current study concludes the existence of R. auricularaia snails in Basrah as a representative city for the southern part of Iraq and also confirmed the presence of the polymorphism phenomenon in the members of R. auricularaia obtained from the AL-Sewaib river.

Palaeohydrochemical and palaeohydrological changes of lakes have seldom been reconstructed from the fossil shells of the gasropod Radix auricularia, which is a new, and potentially high-resolution environnmental archive. We conducted a geochemical and stable isotope study of the shells of Radix from the exposed fluvio-lacustrine sediments near Lake Yamdrok Yumtso in the southern Tibetan Plateau. Our aims were to determine the sedimentary environment, palaeo-lake hydrochemistry and hydrological status. AMS 14C and OSL dating indicates that a lake-level stage of Yamdrok Yumtso higher than that of today occurred during ~4.7–1.2 cal. kyr BP. Results of Sr/Ca, δ13C and δ18O analysis of the fossil shells of Radix auricularia indicate that the lake-level fluctuations were mainly controlled by changes of the Indian Summer Monsoon; decreasing evaporation during the mid- to late-Holocene was also responsible. In addition, based on the geochemical relationship between Radix sp. shells and the ambient water in lakes, the values of δ18OPalaeo-water and Sr/CaPalaeo-water reconstructed using the fossil shells of Radix auricularia are −8.2‰ to −5.1‰ and 0.0012 to 0.0057, respectively. Further, based on the values of δ18Oshell, together with geomorphological evidence, we infer that Yamdrok Yumtso was a closed lake system, and we estimate its possible extent during the interval of high lake-level. In addition, we speculate that the water level of Yamdrok Yumtso at this time exceeded 4448.9 m a.s.l., but was less than 4451 m a.s.l., and that the major separation of various components of the Yamdrok Yumtso system occurred after 1.2 kyr BP.

The present study has been achieved to estimate the acute toxicity effect of pesticide (endosulfan) (organochlorine) and its sublethal concentrations effect on the oxygen consuming rate of three various snails species (Melanoides tuberculata, Radix auricularia and Theodoxus jordani) collected from Shatt Al-Arab river along the region extended from Abu-Al-Khasib to Garmat-Ali during 2018. The 24 hr LC50 indicated that the M. tuberculata was more resistant, while R. auricularia and T. jordani were more effective to endosulfan and showed no difference. The study indicated that the employ of various species of snails, with their differing degree of sensitivity to the same toxicant, might be a useful tool in aquatic environmental toxicological investigations. The sublethal concentrations exposure (24 hr LC50) of pesticide had no considerable influence on the rates of oxygen consumption for each snail species. However, a decrease in the capability of snails to preserve respiratory independence through hypoxia was observed 24 hr after exposure to this dose.

Introduction Radix auricularia (Linnaeus, 1758) is a freshwater gastropod belongs to the Lymnaeidae (pond snails) family which act as intermediate hosts or vectors of various parasitic flukes. No study has yet been undertaken on the prevalence of Petasiger spp. infection in R. auricularia . Species of Petasiger (Dietz, 1909) are a cosmopolitan parasite that utilize snails as the first intermediate host, with vertebrates like amphibians larvae and fish as the second intermediate host, followed by fish-eating birds. The current paper is considered to be the first report of Petasiger exaeretus parasitized R. auricularia in Iraq, which is supported with molecular and phylogenetic analysis. Material and methods Freshwater snails R. auricularia were collected during October 2016 – September 2017 from different locations of Sufaia village on the Greater Zab river, Erbil province, Iraq. Results A total of 307 freshwater snails R. auricularia were collected, only five of them were infected with a prevalence of Petasiger exaeretus (1.62%). Conclusions The current study agrees with the opinion of Selbach, Soldánová (26), which suggested the possibility of a much higher morphological diversity within Petasiger species, based on the number of described cercariae, compared with adult forms.It is clear that P. phalacrocoracis specimens have often been erroneously designated as P. exaeretus by many authors (Našincová et al., 1994). Certain morphological similarities and dissimilarities between P. exaeretus and P. phalacrocoracis can be detected: the pear-shaped body resembles P. exaeretus , whereas, P. phalacrocoracis have an elongated body.

Fascioliasis is caused by Fasciola species transmitted by freshwater Lymnaeidae snails and infecting herbivorous mammals and humans worldwide. In southern Asia, fascioliasis is a problem in livestock from the Near East to Bangladesh, where recent human infection reports are worrying. In this region, Fasciola gigantica is transmitted by species of the Radix auricularia superspecies group. In the densely populated northern Indian state of Uttar Pradesh, livestock appears infected throughout. The economic importance of buffaloes highlights the need to control their very high infection rates. In the Gorakhpur area, a molecular method based on the two specific primer sets of genomic DNA was applied to fasciolids from buffaloes slaughtered in local abattoirs and cercariae from R. acuminata snails from freshwater collections. PCR products and sequences demonstrated that the cercariae belonged to F. gigantica and that R. acuminata acts as vector for its transmission to buffaloes. The 72.0% rate found in one transmission focus appears to be the highest worldwide record of fasciolid infection in a lymnaeid population. Lymnaeid prevalences and burdens found close to human communities indicate a very high infection risk. This method is simple, fast and cheap because there is no need for sequencing, it differentiates between fasciolid species and between fasciolids and other trematodes infecting R. acuminata, facilitates epidemiological surveys, and is useful for surveillance to evaluate the efficiency of control measures. Within climate change predictions, future increases of rain events and floods suggest the need for control and surveillance efforts in this endemic area.

The cryptic diversity of trematodes was evaluated in the Nagayama-Shinkawa River, an artificial canal of the Ishikari River System of Hokkaido, Japan. Numerous migratory waterfowls use the canal as a stopover point in every spring season. The lymnaeid snail, Radix auricularia, and the semisulcospirid snail, Semisulcospira libertina, colonize the static and flowing water areas, respectively. The trematode fauna of the two snails was assessed by molecular phylogenetic and population genetic analyses. Each of distinctive clades in mitochondrial DNA trees was arbitrarily set as a species. In total, 14 species of the families Diplostomidae, Echinostomatidae, Notocotylidae, Plagiorchiidae, and Strigeidae occurred in R. auricularia, wherease S. libertina harbored 10 species of the families Echinochasmidae, Heterophyidae, Notocotylidae, and Lecithodendridae and Cercaria creta, an unclassified species whose adult stage is still unknown. The species diversity of the larval trematodes could be recognized as a “hot spot”, suggesting that the seasonal visit of waterfowls is very important to spread trematodes and to keep their diversity. A high intraspecific genetic diversity was observed in the echinostomatid, notocotylid, echinochasmid, and heterophyid species, whose definitive hosts include birds. It seems likely that each of the parasite populations is always disturbed by repeated visits of waterfowls.

An unknown species of the genus Notocotylus (Digenea: Notocotylidae) was found as the larval stage from the lymnaeid snail, Radix auricularia, in a static water area of the Chubetsu River, Hokkaido, the northernmost island of Japan. A DNA barcoding identification system was applied to detect the adult stage. Through the inspection of anatid game birds in Hokkaido, Anas crecca, Anas platyrhynchos, Anas zonorhyncha, and Mareca penelope were demonstrated to serve as the definitive hosts. The detailed morphological features of the species were characterized using adults raised experimentally in immunosuppressed mice and naturally developed larvae in R. auricularia. Although the species is morphologically similar to Notocotylus attenuatus and Notocotylus magniovatus in both adult and larval stages, its taxonomic independence was confirmed by a comprehensive study based on molecular phylogeny, morphology, and ecology. Here we propose Notocotylus ikutai n. sp. for this species. The migratory behavior of the anatid hosts and the North-Eurasian distribution of R. auricularia suggest that the new species is widely distributed in the northern Far East.

The taxonomy of freshwater pulmonates (Hygrophila) has been in a fluid state warranting the search for new morphological criteria that may show congruence with molecular phylogenetic data. We examined the muscle arrangement in the penial complex (penis and penis sheath) of most major groups of freshwater pulmonates to explore to which extent the copulatory musculature can serve as a source of phylogenetic information for Hygrophila. The penises of Acroloxus lacustris (Acroloxidae), Radix auricularia (Lymnaeidae), and Physella acuta (Physidae) posses inner and outer layers of circular muscles and an intermediate layer of longitudinal muscles. The inner and outer muscle layers in the penis of Biomphalaria glabrata consist of circular muscles, but this species has two intermediate longitudinal layers separated by a lacunar space, which is crossed by radial and transverse fibers. The muscular wall of the penis of Planorbella duryi is composed of transverse and longitudinal fibers, with circular muscles as the outer layer. In Planorbidae, the penial musculature consists of inner and outer layers of longitudinal muscles and an intermediate layer of radial muscles. The penis sheath shows more variation in muscle patterns: its muscular wall has two layers in A. lacustris, P. acuta, and P. duryi, three layers in R. auricularia and Planorbinae and four layers in B. glabrata. To trace the evolution of the penial musculature, we mapped the muscle characters on a molecular phylogeny constructed from the concatenated 18S and mtCOI data set. The most convincing synapomorphies were found for Planorbinae (inner and outer penis layers of longitudinal muscles, three-layered wall of the penis sheath). A larger clade coinciding with Planorbidae is defined by the presence of radial muscles and two longitudinal layers in the penis. The comparative analysis of the penial musculature appears to be a promising tool in unraveling the phylogeny of Hygrophila.

Human cercarial dermatitis is a parasitic disease that causes an allergic reaction in the skin (swimmer's itch) as a consequence of contact with cercariae of bird schistosomes present in water, mainly of the genus Trichobilharzia Skrjabin et Zakarow, 1920. The main objective of the study was to confirm the presence of the zoonotic disease agent following reports of human infections in recreational water in Slovakia. We identified two species of freshwater snails at Kosice Lake, Radix auricularia (Linnaeus, 1758) and Physa acuta (Draparnaud, 1805). Trematode infections were observed only in R. auricularia. Of the 62 snails collected, 11 (17.7%) were infected with 5 different species of larval stages of trematodes. The blood fluke Trichobilharzia franki was found in 2 (3.2%) of the examined snails. The present record provides the first evidence that T. franki from the pulmonate snail R. auricularia represents a source of human cercarial dermatitis in recreational water in Slovakia. Our finding complements the easternmost records of both swimmer's itch and the confirmed occurrence of a bird schistosome in a waterbody in Europe. The present work suggests that the health risks associated with trichobilharziasis need to be further studied by detailed monitoring of the occurrence of the major causative agent of human cercarial dermatitis, T. franki.

Using landform evolution and lake sediment records to reconstruct Quaternary environmental changes requires reliable chronology. However, there is an ongoing debate regarding the fossil shells of aquatic gastropods in carbonate rock area to be used for radiocarbon dating. The focus of this debate is whether living gastropods incorporate the dead carbon, which would affect the accuracy of the dating results. Living aquatic gastropods were selected from habitats on carbonate terrain in arid region. In this study, 64 shell samples from living gastropods, including Cipangopaludina chinensis, Gyraulus convexiusculus, and Radix auricularia, collected from the Alashan Plateau of northwestern China, were dated by accelerator mass spectrometry (AMS) 14C dating. The results revealed that only five samples (~8%) from the same site contained no dead carbon. The other 59 samples (~92%) contained dead carbon in various amounts: ~59% samples contained 0–10% dead carbon, and ~33% samples contained more than 10% dead carbon. Of the samples, 56 were Radix auricularia and their 14C ages varied from present to 3253 cal yr BP. Two of the samples were Gyraulus convexiusculus samples dated at 379 and 290 cal yr BP which are highly consistent with 14C ages of Radix auricularia samples from the same site. The other six Cipangopaludina chinensis samples were dated at 407–863 cal yr BP. Thus, most of living aquatic gastropods from habitats on carbonate terrain contained dead carbon. The amount of dead carbon in the gastropod shells was nonselective among the three species. Radiocarbon dating of aquatic gastropod shells may not be useful for studying processes that occurred over multi-millennial timescales at different localities in areas of carbonate rock. It is difficult to establish high-resolution chronologies using 14C ages of gastropod shells in arid regions with carbonate rocks unless the limestone effect has been corrected.

Freshwater gastropods comprise a diverse and highly imperiled taxonomic group that is threatened by anthropogenic factors including the introduction of nonnative species. We surveyed 10 wetland ponds in Turnbull National Wildlife Refuge to assess the possible expansion of the nonnative European ear snail (Radix auricularia) and to determine the genus richness and relative abundance of native gastropods. D-frame dip nets were used to sample gastropods at 4 locations in each pond. Six genera of gastropods were found, including R. auricularia in 6 ponds where it was not previously known. Radix auricularia is now the dominant genus in Middle Pine and Lower Pine Lakes, with relative abundances of 84.13% and 92.31%, respectively. Due to the high abundance and spread of R. auricularia in Turnbull National Wildlife Refuge, resource managers need to investigate the snail's impacts and implement strategies to reduce possible negative effects of this nonnative snail on native gastropods and other wildlife.

Mashkova IV, Krupnova TG, Kostryukova AM, Harutyunova LJ, Varuzhan HS, Egorov NO. 2018. Short Communication: Mollusks biodiversity of Lake Sevan, Armenia. Biodiversitas 19: 1509-1513. The paper considers mollusks biodiversity in the freshwater lakes of Lake Sevan, Armenia. Lake Sevan is the largest water body in Armenia and one of the largest freshwater lakes in Eurasia. Since 1930 it has been actively used for irrigating Ararat plain and in hydropower. So, its water level fell by 20 m, and its volume became 40% less. Since mid-2000 when two tunnels had been built water level started to grow. For the last 6 years, water level was reported to grow. As a result of our study, 11 aquatic mollusks species (10 gastropod and 1 bivalve taxa) were currently found living in the Sevan lake. We found Lymnaea stagnalis (Linnaeus, 1758), Radix auricularia (Linnaeus, 1758), R. tumida (Held, 1836), R. balthica (Linnaeus, 1758), R. lagotis (Schrank, 1803), Galba truncatula (O. F. Müller, 1774), Planorbis planorbis (Linnaeus, 1758), Bathyomphalus contortus (Linnaeus,1758), Gyraulus acronicus (Férussac, 1807), Valvata piscinalis (O. F. Müller, 1774), Euglesa casertana (Poli, 1791). Lymnaeidae represented the largest number of species. The most abundant species was Lymnaea stagnalis (Linnaeus, 1758).

The present study preliminarily examined the differences in maximum handling size, prey size and species selectivity of growth hormone transgenic and non-transgenic common carp Cyprinus carpio when foraging on four gastropods species (Bellamya aeruginosa, Radix auricularia, Parafossarulus sinensis and Alocinma longicornis) under laboratory conditions. In the maximum handling size trial, five fish from each age group (1-year-old and 2-year-old) and each genotype (transgenic and non-transgenic) of common carp were individually allowed to feed on B. aeruginosa with wide shell height range. The results showed that maximum handling size increased linearly with fish length, and there was no significant difference in maximum handling size between the two genotypes. In the size selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on three size groups of B. aeruginosa. The results show that the two genotypes of C. carpio favored the small-sized group over the large-sized group. In the species selection trial, three pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on thin-shelled B. aeruginosa and thick-shelled R. auricularia, and five pairs of 2-year-old transgenic and non-transgenic carp were individually allowed to feed on two gastropods species (P. sinensis and A. longicornis) with similar size and shell strength. The results showed that both genotypes preferred thin-shelled Radix auricularia rather than thick-shelled B. aeruginosa, but there were no significant difference in selectivity between the two genotypes when fed on P. sinensis and A. longicornis. The present study indicates that transgenic and non-transgenic C. carpio show similar selectivity of predation on the size- and species-limited gastropods. While this information may be useful for assessing the environmental risk of transgenic carp, it does not necessarily demonstrate that transgenic common carp might have lesser environmental impacts than non-transgenic carp.

One of the major evolutionarily conserved pathways in innate immunity of invertebrates is the toll-like receptor (TLR) pathway. However, little is known of the TLR protein family in gastropod molluscs despite their role in the transmission of human diseases, especially the common lymnaeid freshwater snail species Radix auricularia and Lymnaea stagnalis, key intermediate hosts of zoonotic trematodes. Using comparative genomics and gene prediction approaches utilising the freshwater snail Biomphalaria glabrata genome as a reference ten putative TLR proteins were identified in both R. auricularia and L. stagnalis. Phylogenetic analyses revealed that unlike other molluscs the lymnaeid species also possessed class 1 TLRs, previously thought to be unique to B. glabrata. Gene duplication events were also seen across the TLR classes in the lymnaeids with several of the genes appearing to exist as potential tandem elements in R. auricularia. Each predicted TLR was shown to possess the typical the leucine-rich repeat extracellular and TIR intracellular domains and both single cysteine clusters and multiple cysteine clusters TLRs were identified in both lymnaeid species. Principle component analyses of 3D models of the predicted TLRs showed that class 1 and 5 proteins did not cluster based on similarity of structure, suggested to be potential adaptation to a range of pathogens. This study provides the first detailed account of TLRs in lymnaeids and affords a platform for further research into the role of these proteins into susceptibility and compatibility of these snails with trematodes and their role in transmission.

This study focuses on the inter- and intra-specific variability in δ13C and δ18O values of shells and opercula of gastropods sampled live from the littoral zone of Lake Lednica, western Poland. The δ13C and δ18O values were measured in individual opercula of Bithynia tentaculata and in shells of Bithynia tentaculata, Gyraulus albus, Gyraulus crista, Lymnaea sp., Physa fontinalis, Radix auricularia, Theodoxus fluviatilis and Valvata cristata. The gastropods selected for the study are among the species most commonly found in European Quaternary lacustrine sediments. The carbon isotope composition of the gastropod shells was species-specific and the same order of species from the most to the least13C-depleted was observed at all sites sampled. Differences in shell δ13C values between species were similar at all sampling sites, thus the factors influencing shell isotopic composition were interpreted as species-specific. The δ18O values of shells were similar in all the species investigated. Significant intra-specific variability in shell δ13C and δ18O values was observed not only within the populations of Lake Lednica, which can be explained by heterogeneity of δ13C DIC, δ18O water and water temperature between the sites where macrophytes with snails attached were sampled, but also between individuals sampled from restricted areas of the lake’s bottom. The latter points to the importance of factors related to the ontogeny of individual gastropods.

Avian schistosomes are of medical and veterinary importance as they are responsible for the annually occurring cercarial dermatitis outbreaks. For Austria, so far, only Trichobilharzia szidati Neuhaus 1952 was confirmed on species level as causative agent of cercarial dermatitis. Here we present the first record of Trichobilharzia franki Müller & Kimmig 1994 in Austria. The species was detected during a survey of digenean trematodes in Upper Austrian water bodies. Furthermore, we provide DNA barcodes of T. franki as well as measurements of several parasite individuals to indicate the intraspecific diversity. We also recommend the usage of an alternative primer pair, since the “standard COI primer pair” previously used for Schistosomatidae amplified an aberrant fragment in the sequence of T. franki. Overall, our study shows how limited our knowledge about occurrence and distribution of avian schistosomes in Austria is and how important it is to acquire such a knowledge to estimate ecological and epidemiological risks in the future.

Radix (Radix) auricularia (Linnaeus, 1758) Distribution. We recorded the species in 4 localities: 2, 10, 17 and 33 (fig. 1, table 1); shell image is given in Anistratenko et al. (2018: fig. 3, I). It was reported in the region earlier by other authors (Zdun, 1960; Stadnichenko, Gyrin, 2011 a). In Ukraine this snail is known from all regions (Anistratenko, Сhernogorenko, 1989; Stadnichenko, 2004). General distribution — Palaearctic, introduced into North America (Vinarski, Kantor, 2016). Remarks. In the Transcarpathia R. auricularia inhabits shoreline zone of lowland (from 110 up to 170 m a. s. l.) rivers, reservoirs in their floodplain area and ponds associating mostly with macrophytes at depths up to 0.5 m (table 2)., Published as part of Anistratenko, V. V., Furyk, Yu. I., Anistratenko, O. Yu. & Degtyarenko, E. V., 2019, A Review Of Species Diversity, Distribution And Ecology Of Freshwater Gastropod Molluscs Inhabiting The Ukrainian Transcarpathian, pp. 349-374 in Vestnik Zoologii 53 (5) on pages 364-365, DOI: 10.2478/vzoo-2019-0033, http://zenodo.org/record/6949164, {"references":["Anistratenko, V. V., Vinarski, M. V., Anistratenko, O. Yu., Furyk, Yu. I., Degtyarenko, E. V. 2018. New data on pond snails (Mollusca: Gastropoda: Lymnaeidae) inhabiting the Ukrainian Transcarpathian: diversity, distribution and ecology. Ecologica Montenegrina, 18, 1 - 14.","Zdun, V. I. 1960. On the fauna of Transcarpathian Mollusca, Naukovi Zapyski Lvivskogo naukovo-pryrodnychogo museyu AN URSR, 8, 83 - 95 [In Ukrainian].","Stadnichenko, A. P., Gyrin, V. K. 2011 a. On fauna and ecology of fresh-water molluscs of the Transcarpathian (families Lymnaeidae, Bulinidae, Physidae). Communication 1. Wyksztalcenie i nauka bez granic - 2011. Materialy VII Miedzynarodowej naukowi-praktycznej konferencji 07 - 15 grudnia 2011 roku, Vol. 25. Biologiczne nauki. Nauka i studia, Przemysl, 19 - 21 [In Russian].","Stadnichenko, A. P. 2004. Pond snails and limpet snails (Lymnaeidae and Acroloxidae) of Ukraine. Tsentr uchebnoy literatury, Kiev, 1 - 327 [In Russian].","Vinarski, M. V., Kantor, Yu. I. 2016. Analytical catalogue of fresh and brackish water molluscs of Russia and adjacent countries. A. N. Severtsov Institute of Ecology and Evolution of RAS, Moscow, 1 - 544."]}

The reality of ecological and local races was investigated in two widespread Palearctic species of lymnaeid snails (Lymnaea stagnalis and Radix auricularia). Several methods of statistical analysis were used, including two-way ANOVA, cluster analysis, and discriminant analysis for six plastic shell characters. It was shown that none of the methods used could convincingly demonstrate that ecological and local races were present in the studied species. Even in cases when statistically significant differences among the populations in the morphology of shells were revealed, these differences were very small and did not correspond to the meaning that was put into the concept of “race” by malacologists in the past. Perhaps, the formation of such races in pond snails is possible only in case of populations being formed in suboptimal conditions, for example, in thermal springs or at large depths. This being the case, the distinguishing of races requires using other shell characters, both quantitative and qualitative ones.

The present study addressed the effects of growth hormone-transgenic and non-transgenic common carp (Cyprinus carpio L.) predation on the community and populations of four gastropod species cultured in artificial environments. After a 110-day population-based predation experiment (three replicate pools [16m(2)] for each genotype with one fish [total length 45.0 similar to 51.4cm] and 150 Bellamya aeruginosa (Reeve 1863) per pool), there were no significant effects of predation by either transgenic or non-transgenic carp on the biomass, number, or size selectivity of the population. Following a 10-day community-based predation experiment (three replicate pools [16m(2)] for each genotype with one fish [total length 45.0 similar to 50.5cm] and 150 Alocinma longicornis (Benson 1842), 100 Parafossarulus sinensis (Neunayr 1883), 55 B.aeruginosa, and 33 Radix auricularia L. per pool), the consumption rate and the number of gastropods predated by transgenic carp were 2.60 times and 2.85 times higher, respectively, than those of non-transgenic carp. Furthermore, the biomass of A.longicornis, P.sinensis and B.aeruginosa consumed by transgenic carp was significantly (p

After numerous reports the local press about the “stinging water” in created on the Dzierzecinka River—Water Valley reservoir and recognizing in bathers the symptoms of swimmers’ itch, environmental study on the presence of bird schistosome larvae in snail hosts was conducted. Snails belonging to Lymnaeidae and Planorbidae were collected at two sites: (i) part of anthropogenic reservoir (192 individuals) and (ii) the river part (37 individuals). Higher prevalence of Digenea was observed in snail populations living in Water Valley (29.8 %) compared to Dzierzecinka River (21.3 %). The larvae of bird schistosomes were recorded in both localities in 1.8 % of collected snails. The prevalence of bird schistosomes reached 2.9 % in Planorbarius corneus, 2.8 % in Radix auricularia, and 5.9 % in Radix balthica/labiata. Laboratory tests have shown that at 19 °C the number of bird schistosome cercariae released from snail hosts significantly exceeded the number of cercariae of other identified Digenea species. It is worth underlining that despite the low prevalence of bird schistosomes, the high number of released cercariae was sufficient to create a real threat of swimmers’ itch in bathers. As indicated by the example presented, anthropogenic reservoirs create excellent conditions for Digenea species including bird schistosomes. In view of the real risk of people using the waters, tests on presence of the parasites in snail hosts should be included to the standard procedure of security control in bathing places.

Swimmer's itch is caused by the penetration of free-swimming larvae of trematodes of the family Schistosomatidae in human skin. It is usually reported in people engaged in recreational water activities in freshwater bodies and in most of cases, it is provoked by bird schistosomes of the genus Trichobilharzia. In the summer 2017, many cases of dermatitis were recorded in people bathing in the waters of the Albano Lake (Rome, Italy) and a parasitological investigation was carried out in order to ascertain the causative agent of these cases. Snails of the family Lymnaeidae, natural intermediate hosts of bird schistosomes, were collected from lake shallow waters to detect the presence of trematodes of the genus Trichobilharzia. Pools of maximum 10 snails were placed in Petri dishes, and cercarial emergence was stimulated exposing snails to strong artificial light intensity at 25°C. Three hundred and thirty-seven snails were collected and screened for the shedding of cercariae. Furcocercariae of the family Schistosomatidae, with a morphology overlapping that of the genus Trichobilharzia, were detected in seven Petri dishes. Assuming that in each positive Petri dish just one snail was shedding furcocercariae, the minimum infectious rate was 2.1%. Molecular analysis of furcocercariae allowed ascribing them to the species Trichobilharzia franki. Snails of the species Radix auricularia were identified as intermediate hosts of the parasite. This is the second record of T. franki causing cercarial dermatitis in Central Italy, the third in Italy. The 2017 was in Italy exceptionally warm and dry. Trematodes are sensitive to changes in temperature, being cercarial production and emission rates temperature dependent. Small increases in water temperature would speed up parasite development and transmission, leading to a manifold increase in cercarial emergence. Moreover, high temperatures raise chances to acquire the infection, due to increased time spent in water by people.

Freshwater snails, as the first intermediate hosts of trematodes, can cause health hazards in animals and humans. Recently, the World Health Organization has included Iran in a list of 6 countries known to have serious problems with fascioliasis. In addition, cercarial dermatitis is a job-related disease that is seen often in paddy workers, agricultural labourers, and fishermen in Iran, particularly in Mazandaran Province. Many studies have been conducted in Iran to survey larval trematodes in freshwater snails. However, to the best of our knowledge, no comprehensive data exist regarding infections in gastropods. Therefore, the aim of the present study was to estimate the types and prevalence of cercarial infections in snails in Iran. Electronic English-language and Persian-language databases were searched to identify 24 published articles reporting the prevalence of trematode infections in snails (9 species from 6 families) in various provinces of Iran. In total, 4.4% of gastropods were infected with the larval stages of trematodes. According to the studies reviewed in this meta-analysis‚ the highest infection prevalence was found in Radix auricularia (9.9%). Twelve larval species of trematodes were identified, and the highest prevalence of cercariae was found for Echinostomatidae cercariae (4.3%). Among the provinces explored, West Azerbaijan had the highest prevalence of infected snails (16.9%). The presence of trematodes in snails could pose a serious health problem in Iran. Thus, further studies are necessary to characterize these infections in other provinces.

Lymnaeidae snail species are known to be intermediate hosts of human and livestock helminths parasites, especially Fasciola species. Identification of these species and their geographical distribution is important to better understand the epidemiology of the disease. Significant diversity has been observed in the shell morphology of snails from the Lymnaeidae family and the systematics within this family is still unclear, especially when the anatomical traits among various species have been found to be homogeneous. Although there are records of lymnaeid species of southern Africa based on shell morphology and controversial anatomical traits, there is paucity of information on the molecular identification and phylogenetic relationships of the different taxa. Therefore, this study aimed at identifying populations of Lymnaeidae snails from selected sites of the Okavango Delta (OKD) in Botswana, and sites located in the KwaZulu-Natal (KZN) and Mpumalanga (MP) provinces of South Africa using molecular techniques. Lymnaeidae snails were collected from 8 locations from the Okavango delta in Botswana, 9 from KZN and one from MP provinces and were identified based on phylogenetic analysis of the internal transcribed spacer (ITS-2). Analyses based on the ITS-2 marker identified the presence of a well-supported Radix clade containing Radix auricularia, R. natalensis and R. rubiginosa, which were not well resolved. Experimental samples from the OKD and KZN present in this clade were referable to these species. An unidentified experimental taxon from the OKD formed a well-supported sister clade to the Radix clade, although it was not possible to identify it. Galba truncatula was well supported in a sister relationship to a well-supported Pseudosuccinea columella clade which included samples from MP and KZN provinces of South Africa. We observed that P. columella shared the same habitats with R. natalensis and R. auricularia in KZN. Our study contributes new knowledge on the Lymnaeidae species present in Southern Africa and their phylogenetic relationships. The study further identifies the species which are likely to co-exist in the same environment and this information will be of use to those designing control programs for fasciolosis. This is the first study reporting the presence of R. auricularia in the OKD of Botswana and KZN province of South Africa.

Due to its wide distribution across the world, the snail Radix auricularia plays a central role in the transferal of energy and biomass by consuming plant biomass in freshwater systems. The gut microbiota are involved in the nutrition, digestion, immunity, and development of snails, particularly for cellulolytic bacteria, which greatly contribute to the digestion of plant fiber. For the first time, this study characterized the gut bacterial communities of R. auricularia, as well as predicted functions, using the Illumina Miseq platform to sequence 16S rRNA amplicons. Both juvenile snails (JS) and adult snails (AS) were sampled. The obtained 251,072 sequences were rarefied to 214,584 sequences and clustered into 1,196 operational taxonomic units (OTUs) with 97% sequence identity. The predominant phyla were Proteobacteria (JS: 36.0%, AS: 31.6%) and Cyanobacteria (JS: 16.3%, AS: 19.5%), followed by Chloroflexi (JS: 9.7%, AS: 13.1%), Firmicutes (JS: 14.4%, AS: 6.7%), Actinobacteria (JS: 8.2%, AS: 12.6%), and Tenericutes (JS: 7.3%, AS: 6.2%). The phylum Cyanobacteria may have originated from the plant diet instead of the gut microbiome. A total of 52 bacterial families and 55 genera were found with >1% abundance in at least one sample. A large number of species could not be successfully identified, which could indicate the detection of novel ribotypes or result from insufficient availability of snail microbiome data. The core microbiome consisted of 469 OTUs, representing 88.4% of all sequences. Furthermore, the predicted function of bacterial community of R. auricularia performed by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States suggests that functions related to metabolism and environmental information processing were enriched. The abundance of carbohydrate suggests a strong capability of the gut microbiome to digest lignin. Our results indicate an abundance of bacteria in both JS and AS, and thus the bacteria in R. auricularia gut form a promising source for novel enzymes, such as cellulolytic enzymes, that may be useful for biofuel production. Furthermore, searching for xenobiotic biodegradation bacteria may be a further important application of these snails.