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As ecosystem disruptors and intermediate hosts for various parasites, freshwater snails have significant socioeconomic impacts on human health, livestock production, and aquaculture. Although traditional molluscicides have been widely used to mitigate these effects, their environmental impact has encouraged research into alternative, biologically based strategies to create safer, more effective molluscicides and diminish the susceptibility of snails to parasites. This review focuses on alterations in glucose metabolism in snails under the multifaceted stressors of parasitic infections, drug exposure, and environmental changes and proposes a novel approach for snail management. Key enzymes within the glycolytic pathway, such as hexokinase and pyruvate kinase; tricarboxylic acid (TCA) cycle; and electron transport chains, such as succinate dehydrogenase and cytochrome c oxidase, are innovative targets for molluscicide development. These targets can affect both snails and parasites and provide an important direction for parasitic disease prevention research. For the first time, this review summarises the reverse TCA cycle and alternative oxidase pathway, which are unique metabolic bypasses in invertebrates that have emerged as suitable targets for the formulation of low-toxicity molluscicides. Additionally, it highlights the importance of other metabolic pathways, including lactate, alanine, glycogenolysis, and pentose phosphate pathways, in snail energy supply, antioxidant stress responses, and drug evasion mechanisms. By analysing the alterations in key metabolic enzymes and their products in stressed snails, this review deepens our understanding of glucose metabolic alterations in snails and provides valuable insights for identifying new pharmacological targets. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing interest in exploring novel natural sources for antioxidant and anti-inflammatory agents, driven by the need for alternative therapeutic strategies with fewer side effects. This study investigates the potential of the Biomphalaria alexandrina snail as a valuable model organism to evaluate the antioxidant and anti-inflammatory properties of Sarcophaga argyrostoma larval hemolymph. The choice of B. alexandrina snails as a model is based on its ecological relevance and physiological similarities to other organisms, supporting well-established use in ecological and physiological research, as well as it provides a valuable platform for such investigations. Ultimately, this study may open avenues for the development of innovative and sustainable therapeutic interventions rooted in the rich biodiversity of the natural world. The experimental design involves the extraction of hemolymph from S. argyrostoma larvae, followed by a comprehensive analysis of its antioxidant capacity and anti-inflammatory effects using adult snails. Various biochemical assays, including total antioxidant capacity, immunomodulatory markers and histological investigation, will be employed to assess the bioactive potential of the hemolymph. The outcomes of this research can be attributed to the identification of the anti-oxidant and anti-inflammatory effects of hemolymph. This effect was observed through the reduction of oxidative stress and proinflammatory mediators, impacting the biological activities of the snails. The study is the first to shed light on the potential benefits of S. argyrostoma larval hemolymph using an animal model, showcasing its ability to mitigate oxidative and inflammatory responses within the biological context of the snails. [ABSTRACT FROM AUTHOR]

Nanotechnology has been used to apply nanoparticle essential elements to enhance the ability of animals to absorb these elements and consequently improve their reproductive performance. High concentrations of nanoparticles (NPs) can directly harm a range of aquatic life forms, ultimately contributing to a decline in biodiversity. Helisoma duryi snails are a good model for studying the toxicological effects of bulk zinc oxide (ZnO‐BPs) and nano zinc oxide (ZnO‐NPs) on freshwater gastropods. This study aimed to compare the toxic effects of ZnO‐BPs and ZnO‐NPs on H. duryi snails and explore how waterborne and dietary exposure influenced the reproductive performance of this snail. ZnO‐BPs and ZnO‐NPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X‐ray powder (XRD). This study revealed that the size of ZnO‐BPs and ZnO‐NPs were 154 nm and 11–31 nm, respectively. The results showed that exposure of adult snails to sub‐lethal concentrations of both ZnO forms (bulk and nano) for 24 h/week for 4 weeks markedly changed their reproductive performance in a concentration‐dependent manner, where fecundity was negatively affected by high concentrations. It was concluded that dietary exposure to the lowest tested concentration of ZnO‐NPs (1 ppm) has a positive effect as the number of eggs and egg masses/snails increased and the incubation period decreased. Also, poly‐vitelline eggs (The formation of twins) were observed. ZnO‐NPs at low concentrations positively affect the reproductive performance of snails, especially after dietary exposure. The results revealed that 1 ppm ZnO‐NPs could be supplementary provided to snails to improve their fertility, reduce the developmental time course, increase hatchability percentage, and produce poly‐vitelline eggs. Research Highlights: ZnO‐NPs at low concentrations have positive effects on the reproductive performance of H. duryi snails, especially after dietary exposure.One ppm ZnO‐NPs could be supplementary provided to snails for improving their fertility, reducing the developmental time course, increasing hatchability percentage, and producing poly‐vitelline eggs. [ABSTRACT FROM AUTHOR]

Monachoides is a genus of medium‐sized European land snails in the family Hygromiidae. Systematics of this family was until recently based on traits of the genital system that were shown to be uninformative, resulting in revisions of classifications at the genus and family levels. Up to six species were recognized in Monachoides lately, but the inclusion of three of these species was questionable. Our phylogenetic analysis and morphological examinations show that the genus includes species previously classified in two different Hygromiidae subfamilies. After transferring three Balkan species to the unrelated genus Xerocampylaea, Monachoides emerged as a group that diversified relatively northerly, at the boundary between the Balkans and Central Europe. One species, Monachoides bacescui, is synonymized here and a previously overlooked one is redescribed, leaving only three valid species in Monachoides as currently understood: M. incarnatus, M. vicinus and M. welebitanus. These can be distinguished from other hygromiid species by their distinctive microsculpture of the shell surface, which also allows for identification of juveniles or fragmented fossil material. However, the clade comprising the three above species was found to also include the two species currently classified in Perforatella. As a result, the two genera are synonymized, with Perforatella having priority. [ABSTRACT FROM AUTHOR]

Background: Along the southern shoreline of Lake Malawi, the incidence of schistosomiasis is increasing with snails of the genera Bulinus and Biomphalaria transmitting urogenital and intestinal schistosomiasis, respectively. Since the underlying distribution of snails is partially known, often being focal, developing pragmatic spatial models that interpolate snail information across under-sampled regions is required to understand and assess current and future risk of schistosomiasis. Methods: A secondary geospatial analysis of recently collected malacological and environmental survey data was undertaken. Using a Bayesian Poisson latent Gaussian process model, abundance data were fitted for Bulinus and Biomphalaria. Interpolating the abundance of snails along the shoreline (given their relative distance along the shoreline) was achieved by smoothing, using extracted environmental rainfall, land surface temperature (LST), evapotranspiration, normalised difference vegetation index (NDVI) and soil type covariate data for all predicted locations. Our adopted model used a combination of two-dimensional (2D) and one dimensional (1D) mapping. Results: A significant association between normalised difference vegetation index (NDVI) and abundance of Bulinus spp. was detected (log risk ratio − 0.83, 95% CrI − 1.57, − 0.09). A qualitatively similar association was found between NDVI and Biomphalaria sp. but was not statistically significant (log risk ratio − 1.42, 95% CrI − 3.09, 0.10). Analyses of all other environmental data were considered non-significant. Conclusions: The spatial range in which interpolation of snail distributions is possible appears < 10km owing to fine-scale biotic and abiotic heterogeneities. The forthcoming challenge is to refine geospatial sampling frameworks with future opportunities to map schistosomiasis within actual or predicted snail distributions. In so doing, this would better reveal local environmental transmission possibilities. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) is the third most common malignancy cause of cancer-related mortality worldwide. Epithelial-mesenchymal transition (EMT) promotes cancer metastasis and a tumour-based Glasgow EMT score was associated with adverse clinical features and poor prognosis. In this study, the impact of using the established five tumour-based EMT markers consisting of E-cadherin (E-cad), β-catenin (β-cat), Snail, Zeb-1, and Fascin in combination with the stromal periostin (PN) on the prediction of CRC patients' prognosis were invesigated. Formalin-fixed paraffin-embedded tissues of 202 CRC patients were studies the expressions of E-cad, β-cat, Snail, Zeb-1, Fascin, and PN by immunohistochemistry. Individually, cytoplasmic Fascin (Fc), cytoplasmic Snail (Sc), nuclear Snail (Sn), stromal Snail (Ss), and stromal PN (Ps) were significantly associated with reduced survival. A combination of Ps with Fc, Fs, and Sn was observed in 2 patterns including combined Fc, Fs, and Ps (FcFsPs) and Fc, Sn, and Ps (FcSnPs). These combinations enhanced the prognostic power compared to individual EMT markers and were independent prognostic markers. As the previously established scoring method required five markers and stringent criteria, its clinical use might be limited. Therefore, using these novel combined prognostic markers, either FcFsPs or FcSnPs, may be useful in predicting CRC patient outcomes. [ABSTRACT FROM AUTHOR]

The endocannabinoid system (ECS) plays an important role in neuroprotection, neuroplasticity, energy balance, modulation of stress, and inflammatory responses, acting as a critical link between the brain and the body's peripheral regions, while also offering promising potential for novel therapeutic strategies. Unfortunately, in humans, pharmacological inhibitors of different ECS enzymes have led to mixed results in both preclinical and clinical studies. As the ECS has been highly conserved throughout the eukaryotic lineage, the use of invertebrate model organisms like the pond snail Lymnaea stagnalis may provide a flexible tool to unravel unexplored functions of the ECS at the cellular, synaptic, and behavioral levels. In this study, starting from the available genome and transcriptome of L. stagnalis, we first identified putative transcripts of all ECS enzymes containing an open reading frame. Each predicted protein possessed a high degree of sequence conservation to known orthologues of other invertebrate and vertebrate organisms. Sequences were confirmed by qualitative PCR and sequencing. Then, we investigated the transcriptional effects induced by different stress conditions (i.e., bacterial LPS injection, predator scent, food deprivation, and acute heat shock) on the expression levels of the enzymes of the ECS in Lymnaea's central ring ganglia. Our results suggest that in Lymnaea as in rodents, the ECS is involved in mediating inflammatory and anxiety‐like responses, promoting energy balance, and responding to acute stressors. To our knowledge, this study offers the most comprehensive analysis so far of the ECS in an invertebrate model organism. [ABSTRACT FROM AUTHOR]

Background: Gastropods of the genus Biomphalaria (Family Planorbidae) are exploited as vectors by Schistosoma mansoni, the most common causative agent of human intestinal schistosomiasis. Using improved genomic resources, overviews of how Biomphalaria responds to S. mansoni and other metazoan parasites can provide unique insights into the reproductive, immune, and other systems of invertebrate hosts, and their responses to parasite challenges. Results: Using Illumina-based RNA-Seq, we compared the responses of iM line B. glabrata at 2, 8, and 40 days post-infection (dpi) to single infections with S. mansoni, Echinostoma paraensei (both digenetic trematodes) or Daubaylia potomaca (a nematode parasite of planorbid snails). Responses were compared to unexposed time-matched control snails. We observed: (1) each parasite provoked a distinctive response with a predominance of down-regulated snail genes at all time points following exposure to either trematode, and of up-regulated genes at 8 and especially 40dpi following nematode exposure; (2) At 2 and 8dpi with either trematode, several snail genes associated with gametogenesis (particularly spermatogenesis) were down-regulated. Regarding the phenomenon of trematode-mediated parasitic castration in molluscs, we define for the first time a complement of host genes that are targeted, as early as 2dpi when trematode larvae are still small; (3) Differential gene expression of snails with trematode infection at 40dpi, when snails were shedding cercariae, was unexpectedly modest and revealed down-regulation of genes involved in the production of egg mass proteins and peptide processing; and (4) surprisingly, D. potomaca provoked up-regulation at 40dpi of many of the reproduction-related snail genes noted to be down-regulated at 2 and 8dpi following trematode infection. Happening at a time when B. glabrata began to succumb to D. potomaca, we hypothesize this response represents an unexpected form of fecundity compensation. We also document expression patterns for other Biomphalaria gene families, including fibrinogen domain-containing proteins (FReDs), C-type lectins, G-protein coupled receptors, biomphalysins, and protease and protease inhibitors. Conclusions: Our study is relevant in identifying several genes involved in reproduction that are targeted by parasites in the vector snail B. glabrata and that might be amenable to manipulation to minimize their ability to serve as vectors of schistosomes. [ABSTRACT FROM AUTHOR]

Physella acuta is a freshwater snail native to North America. Understanding the phylogeography and genetic structure of P. acuta will help elucidate its evolution. In this study, we used mitochondrial (COI and 16S rDNA) and nuclear (ITS1) markers to identify the species and examine its genetic diversity, population structure, and demographic history of P. acuta in Thailand. Phylogenetic and network analyses of P. acuta in Thailand pertained to clade A, which exhibits a global distribution. Analysis of the genetic structure of the population revealed that the majority of pairwise comparisons showed no genetic dissimilarity. An isolation-by-distance test indicates no significant correlation between genetic and geographical distances among P. acuta populations, suggesting that gene flow is not restricted by distance. Demographic history and haplotype network analyses suggest a population expansion of P. acuta, as evidenced by the star-like structure detected in the median-joining network. Based on these results, we concluded that P. acuta in Thailand showed gene flow and recent population expansion. Our findings provide fundamental insights into the genetic variation of P. acuta in Thailand. [ABSTRACT FROM AUTHOR]

Aim: The rat lungworm, Angiostrongylus cantonensis, has recently been found in the city of Valencia, parasitizing rats, Rattus norvegicus and Rattus rattus, its natural definitive hosts. This is the first finding of this zoonotic nematode in continental Europe. After informing local and national health authorities, the collection of local terrestrial snails took place with the aim of elucidating their potential role as intermediate hosts of A. cantonensis. Methods and Results: A total of 145 terrestrial snails, belonging to the species Cernuella virgata, Cornu aspersum, Eobania vermiculata, Otala punctata, Pseudotachea splendida, Rumina decollata and Theba pisana, were randomly collected between May and December 2022 in public gardens, parks and orchards in six districts of Valencia, in five of which A. cantonensis had been reported previously in rats. Once collected and identified, the snails were frozen at −20°C. Subsequently, the DNA was isolated and screened by PCR using specific primers targeting the A. cantonensis COI gene. Seven individual snails, belonging to the species C. virgata, C. aspersum and T. pisana, were positive, for an overall prevalence of 4.8%. The PCR product from one of them was sequenced by Sanger sequencing. Conclusions: The three positive terrestrial snail species are among the edible species that are frequently included in various dishes in Spain. C. virgata is reported as a previously unrecorded intermediate host and should be added to the list of more than 200 species of terrestrial snails that have been reported worldwide as intermediate hosts of the rat lungworm. Considering that these terrestrial snails may release infective larvae of A. cantonensis on leafy green vegetables on which they feed and during their handling and preparation for consumption, prophylactic measures to prevent human neuroangiostrongyliasis in Valencia and other regions to which this zoonotic parasite may spread are recommended. [ABSTRACT FROM AUTHOR]

The intricate relationships between parasites and hosts encompass a wide range of levels, from molecular interactions to population dynamics. Parasites influence not only the physiological processes in the host organism, but also the entire ecosystem, affecting mortality of individuals, the number of offspring through parasitic castration, and matter and energy cycles. Understanding the molecular mechanisms that govern host-parasite relationships and their impact on host physiology and environment remains challenging. In this study, we analyzed how infection with Microphallus trematodes affects the metabolome of two Littorina snail species inhabiting different intertidal zone shore levels. We applied non-targeted GC–MS-based metabolomics to analyze biochemical shifts induced by trematode infection in a host organism. We have identified changes in energy, amino acid, sugar, and lipid metabolism. In particular, we observed intensified amino acid catabolism and nitrogenous catabolites (glutamine, urea) production. These changes primarily correlated with infection and interspecies differences of the hosts rather than shore level. The changes detected in the host metabolism indicate that other aspects of life may have been affected, both within the host organism and at a supra-organismal level. Therefore, we explored changes in microbiota composition, deviations in the host molluscs behavior, and acetylcholinesterase activity (ACE, an enzyme involved in neuromuscular transmission) in relation to infection. Infected snails displayed changes in their microbiome composition. Decreased ACE activity in snails was associated with reduced mobility, but whether it is associated with trematode infection remains unclear. The authors suggest a connection between the identified biochemical changes and the deformation of the shell of molluscs, changes in their behavior, and the associated microbiome. The role of parasitic systems formed by microphallid trematodes and Littorina snails in the nitrogen cycle at the ecosystem level is also assumed. [ABSTRACT FROM AUTHOR]

We investigated the evolutionary patterns of two forest-dwelling endemic terrestrial snails (Gittenedouardia spadicea and Maizania wahlbergi) in the Maputaland–Pondoland–Albany biodiversity hotspot in South Africa to examine the degree of phylogeographical congruence between the two species. Phylogenetic relationships and divergence time estimations within each species were inferred using the combined mitochondrial DNA (mtDNA) sequence dataset for the cytochrome c oxidase subunit I (COI) and large subunit ribosomal RNA (16S rRNA). In addition, the rapidly evolving COI datasets were used to infer intraspecific genetic structure and population differentiation within both species. Phylogeographical concordance factor (PCF) analysis was used to statistically estimate the degree of congruence between the two species at localities where both species were sampled. Phylogenetically, G. spadicea exhibited two clades that diverged during the Plio/Pleistocene, while M. wahlbergi formed a single shallow clade that showed Pleistocene divergence. The haplotype networks for the COI locus demonstrated evidence of geographical and genetic isolation within both species. PCF analysis demonstrated partial phylogeographical concordance, suggesting that the two species may have been affected by similar ancient climatic events. Traits other than poor dispersal capabilities and limited gene flow may also influence how a species responds to fluctuating climate change. [ABSTRACT FROM AUTHOR]

Background: Snails of the Lymnaeidae family are the intermediate hosts of Fasciola species, the causative agents of fascioliasis. The purpose of this study was to determine the prevalence of Fasciola species in lymnaeid snails and to investigate the association of geoclimatic factors and Fasciola species distribution in northwestern provinces of Iran using geographical information system (GIS) data. Methods: A total of 2000 lymnaeid snails were collected from 33 permanent and seasonal habitats in northwestern Iran during the period from June to November 2021. After identification by standard morphological keys, they were subjected to shedding and crushing methods. Different stages of Fasciola obtained from these snails were subjected to the ITS1 polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method for species identification. The associations of weather temperature, rainfall, humidity, evaporation, air pressure, wind speed, elevation, and land cover with the distribution of Fasciola species were investigated. Geographical and statistical analysis was performed using ArcMap and SPSS software, respectively, to determine factors related to Fasciola species distribution. Results: Of the 2000 snails collected, 19 were infected with Fasciola hepatica (0.09%), six with F. gigantica (0.03%), and 13 with other trematodes. Among geoclimatic and environmental factors, mean humidity, maximum humidity, and wind speed were significantly higher in areas where F. hepatica was more common than F. gigantica. The altitude of F. hepatica-prevalent areas was generally lower than F. gigantica areas. No significant relationship was observed between other investigated geoclimatic factors and the distribution of infected snails. Conclusions: The present study showed the relationship of humidity and wind speed with the distribution of snails infected with F. hepatica or F. gigantica in the northwestern regions of Iran. In contrast to F. gigantica, F. hepatica was more prevalent in low-altitude areas. Further research is recommended to elucidate the relationship between geoclimatic factors and the presence of intermediate hosts of the two Fasciola species. [ABSTRACT FROM AUTHOR]

Background: Snail-borne trematodes afflict humans, livestock, and wildlife. Recognizing their zoonotic potential and possible hybridization, a One Health approach is essential for effective control. Given the dearth of knowledge on African trematodes, this study aimed to map snail and trematode diversity, focusing on (i) characterizing gastropod snail species and their trematode parasites, (ii) determining infection rates of snail species as intermediate hosts for medically, veterinary, and ecologically significant trematodes, and (iii) comparing their diversity across endemic regions. Methods: A cross-sectional study conducted in 2021 in Chiredzi and Wedza districts in Zimbabwe, known for high human schistosomiasis prevalence, involved malacological surveys at 56 sites. Trematode infections in snails were detected through shedding experiments and multiplex rapid diagnostic polymerase chain reactions (RD-PCRs). Morphological and molecular analyses were employed to identify snail and trematode species. Results: Among 3209 collected snail specimens, 11 species were identified, including schistosome and fasciolid competent snail species. We report for the first time the invasive exotic snail Tarebia granifera in Zimbabwe, which was highly abundant, mainly in Chiredzi, occurring at 29 out of 35 sites. Shedding experiments on 1303 snails revealed a 2.24% infection rate, with 15 trematode species identified through molecular genotyping. Five species were exclusive to Chiredzi: Bolbophorus sp., Schistosoma mansoni, Schistosoma mattheei, Calicophoron sp., and Uvulifer sp. Eight were exclusive to Wedza, including Trichobilharzia sp., Stephanoprora amurensis, Spirorchid sp., and Echinostoma sp. as well as an unidentified species of the Plagiorchioidea superfamily. One species, Tylodelphys mashonensis, was common to both regions. The RD-PCR screening of 976 non-shedding snails indicated a 35.7% trematode infection rate, including the presence of schistosomes (1.1%) Fasciola nyanzae (0.6%). In Chiredzi, Radix natalensis had the highest trematode infection prevalence (33.3%), while in Wedza, R. natalensis (55.4%) and Bulinus tropicus (53.2%) had the highest infection prevalence. Conclusions: Our xenomonitoring approach unveiled 15 trematode species, including nine new records in Zimbabwe. Schistosoma mansoni persists in the study region despite six mass deworming rounds. The high snail and parasite diversity, including the presence of exotic snail species that can impact endemic species and biomedically important trematodes, underscores the need for increased monitoring. [ABSTRACT FROM AUTHOR]

The genus Pseudamnicola Paulucci, 1878, is commonly found throughout the Mediterranean region. The genus displays considerable levels of endemism, accompanied by notable systematic and taxonomic ambiguity. However, the application of molecular data has proven highly effective in clarifying taxonomy and unveiling the diversity of cryptic species within the genus. Therefore, we employed all cytochrome c oxidase subunit I sequence data available and generated new ones from Greece to infer the phylogeny of the genus throughout its Mediterranean range and estimate the divergence times as well as the ancestral area of diversification. Our phylogenetic and time‐estimate analyses demonstrate that with 36 to 38 extant Pseudamnicola species and genetic divergences across species ranging from 0.5% to 11.9% on average, the genus underwent relatively recent diversification during late Miocene (6.53 Ma), and the primary speciation events occurred during Plio‐Pleistocene. The Italian Peninsula and Islands and the Ionian Drainages as defined by the Freshwater Ecoregions of the World are the ancestral regions of the genus following two different dispersal routes. Our study contributes to deepening our understanding of Pseudamnicola phylogeny by using data from throughout its range for the first time. This phylogeny provides evidence and confirms previous studies that relatively recent habitat isolation, followed by founder and dispersal events, has been one of the primary reasons for the evolution of the genus Pseudamnicola in the Mediterranean basin. [ABSTRACT FROM AUTHOR]

Four invasive Mediterranean snails, i.e., Theba pisana (Müller, 1774), Cernuella virgata (da Costa, 1778), Cochlicella acuta (Müller, 1774) and Cochlicella barbara (Linnaeus, 1758) cost $170 million yearly to the grain industry in Australia. Their impact is mainly due to their estivation behavior: snails climb on cereal and legume stalks to rest during summer, which coincides with harvest, causing grain contamination issues in crops such as wheat, barley and canola. Diverse management methods have been developed to regulate snail populations, with limited success. Our study investigates the potential for a push–pull strategy to divert invasive snails from cultivated fields. A “push” part (i.e. using a repellent stimuli) was based on the use of a chemical deterrent repelling snails from the cultivated field, and a “pull” part (i.e. using an attractive stimuli) was based on offering attractive estivation supports for snails to aggregate outside the cultivated field. First, artificial estivation supports of different colors were tested under laboratory and field conditions and showed that red supports were the most attractive for these snails. Second, different substances were tested as potential snail deterrents (garlic, coffee, coffee grounds, copper). Garlic extracts were the most powerful snail deterrent and were shown to effectively protect an estivation support and food source from snails under laboratory conditions. These results, which were highly consistent for the four species, illustrate the potential of a push–pull strategy against invasive snails in Australia. It is the first attempt to develop a push–pull strategy relying on both visual and chemical stimuli to achieve results, as well as manipulating the estivation behavior of a pest. [ABSTRACT FROM AUTHOR]

The occurrence of trematodes among ruminants and their snail vectors is a major concern across various agro-ecological regions of Ethiopia. Trematodes pose significant threats to animals, causing considerable economic losses and impacting public health. In this study, we have investigated 784 ruminant fecal samples, and 520 abattoir samples, alongside the collection and identification of snail vectors from various agro-ecological regions. Fecal examinations revealed Fasciola, Paramphistomum and Schistosoma species infected 20.5% (95% CI: 17.6, 23.8), 11.7% (95% CI: 9.6, 14.2), and 6.3% (95% CI: 4.1, 9.1) of the animals, respectively. The overall prevalence of trematodes among ruminants was 28.8% (95% CI: 25.7, 32.1%), with 6.0% (95% CI: 4.3, 7.7) showing mixed infections. Fasciola was more prevalent in Asela (26%) compared to Batu (19%) and Hawassa (11.5%), while a higher proportion of animals in Batu were infected with Paramphistomum. Schistosoma eggs were detected only in Batu (12.5%), but not in other areas. Sheep and cattle exhibited higher infection rates with Fasciola, Paramphistoma, and Schistosoma compared to goats. Significant associations were observed between trematode infections and risk factors including agro-ecology, animal species, body condition score, and deworming practices. About 20.8% and 22.7% of the slaughtered animals harbored Fasciola and Paramphistomum flukes, respectively, with a higher prevalence in Asela and Hawassa abattoirs compared to Batu abattoir. Additionally, a total of 278 snails were collected from the study areas and identified as lymnae natalensis, lymnae trancatula, Biomphalaria pffiferi, Biomphlaria sudanica, and Bulinus globosus. In conclusion, the study highlights the widespread occurrence of trematode infections, emphasizing the need for feasible control measures to mitigate their economic and public health impacts. [ABSTRACT FROM AUTHOR]

The three most important genera of snails for the transmission of schistosomes are Bulinus, Biomphalaria and Oncomelania. Each of these genera, found in two distantly related families, includes species that act as the intermediate host for one of the three most widespread schistosome species infecting humans, Schistosoma haematobium, S. mansoni and S. japonicum, respectively. An important step in the fight against schistosomiasis in Asia has been taken with the publication of the article "Chromosome-level genome assembly of Oncomelania hupensis: the intermediate snail host of Schistosoma japonicum", which means that genomes for all three major genera, including species across three continents, are now available in the public domain. This includes the first genomes of African snail vectors, namely Biomphalaria sudanica, Bi. pfeifferi and Bulinus truncatus, as well as high-quality chromosome level assemblies for South American Bi. glabrata. Most importantly, the wealth of new genomic and transcriptomic data is helping to establish the specific molecular mechanisms that underly compatibility between snails and their schistosomes, which although diverse and complex, may help to identify potential targets dictating host parasite interactions that can be utilised in future transmission control strategies. This new work on Oncomelania hupensis and indeed studies on other snail vectors, which provide deep insights into the genome, will stimulate research that may well lead to new and much needed control interventions. [ABSTRACT FROM AUTHOR]

Simple Summary: The importance of sleep in memory formation has been demonstrated primarily in mammals. Some invertebrates exhibit a sleep-like state. We investigated the relationship between sleep and memory consolidation in the pond snail Lymnaea stagnalis, using learning to suppress escape behavior. Learning to suppress escape was observed in snails that were allowed a sleep-like period between training and memory-test sessions; however, escape suppression was not observed in snails that were prevented from entering the sleep-like state between training and test sessions. The latency of the first escape was significantly shorter in the memory-test session in snails prevented from entering the sleep-like state between the training and memory-test sessions. Thus, the sleep-like state enhanced memory consolidation after escape behavior suppression learning in the snails. These data are consistent with the hypothesis that a sleep-like state plays an important role in memory formation in an invertebrate model system. To test the hypothesis that a sleep-like quiescent state enhances memory consolidation in the pond snail Lymnaea stagnalis, we interposed a period in which snails experienced either a quiescent, sleeping state or an active, non-sleeping state following escape behavior suppression learning (EBSL). During EBSL training, the number of escapes made by a snail from a container was significantly suppressed using an external aversive stimulus (punishment). After training, the snails were divided into two groups. One group of snails was allowed to move freely and to experience a sleep-like quiescent state for 3 h in distilled water. The other group was stimulated with a sucrose solution every 10 min to keep them active (i.e., non-sleeping). In the memory test, escape behavior was suppressed in the group that experienced the quiescent state, whereas the suppression was not observed in snails that were kept active. Additionally, the latency of the first escape in the memory test was shorter in the snails kept active than in those that experienced the quiescent state. Together, these data are consistent with the hypothesis that a sleep-like quiescent state enhances EBSL memory consolidation in L. stagnalis. [ABSTRACT FROM AUTHOR]

Predicting climate change‐mediated environmental effects on organisms is difficult because their direction and strength may depend on multiple ecological factors that vary in nature. This is because the effects of environmental factors often interact. One potentially important factor modifying organisms' thermal performance is their resource level.We experimentally examined the dependence of phenotypic responses to heatwaves on resource/food availability in the freshwater snail, Lymnaea stagnalis. We maintained snails at different food levels (unlimited, reduced [50% of expected consumption], no food), and exposed them to either a heatwave temperature (27°C) or a benign temperature (17°C) for 1 week, followed by a post‐heatwave week (17°C). To estimate snail performance, we quantified their metabolic activity (respiration rate), growth rate, fecundity, and immune activity.All examined traits responded to temperature, and changes in fitness‐related traits (growth rate, fecundity) depended on snail resource level. During the heatwave phase, the benefits of the elevated temperature (enhanced growth rate and fecundity) were higher with unlimited than with limited resources. Additionally, during the post‐heatwave phase, the performance of previously heat‐challenged snails reduced most strongly in resource‐limited snails. The high‐temperature treatment negatively affected snail immune activity even under the high food supply, but immune traits recovered after the heatwave. Interestingly, the phenotypic effects of the high temperature were mainly direct rather than driven by increased metabolic activity.Our results indicate that heatwave responses of L. stagnalis snails are sensitive to their resource level. Such condition dependence may have important ecological and evolutionary implications by: (1) making natural populations in low‐quality habitats the most susceptible to heatwaves; and (2) altering climate change‐mediated evolution by modifying the expression of phenotypic variation in thermal performance. By demonstrating condition‐dependent heatwave responses, our study highlights the importance of examining the interactive effects of climate change‐mediated environmental alterations and ecological factors that vary in nature. [ABSTRACT FROM AUTHOR]

Schistosoma mansoni worms cause a waterborne parasitic disease called schistosomiasis. It commonly affects individuals in lack of sanitation structure. In Brazil, Pará state has Belém as one of the worst sanitation-ranking places in 2023, where schistosomiasis transmission was already documented. This study reports the occurrence of schistosomiasis in residents of Ilha das Onças, an island next to Belém. Stool samples were obtained from participants over 2 years old, all residents from Furo do Rio Grande, one of the rivers on the island. The Kato-Katz technique was performed for parasite investigation in the stool samples. Each participant responded to a sociodemographic and clinical questionnaire. The residences were georeferenced for map designing. Three out of 263 participants were S. mansoni positive, all men, ages ranging from 19 to 41 years old, with low parasitic load. Malacological surveys were carried out, but no Biomphalaria snails were found. Risk factors for schistosomiasis establishment are present on the island, and the lack of sanitation makes it a potential risk area. Malacological surveys are highly encouraged as preventive measures, as well as health surveillance for riverside populations, generating data that will help health authorities in the management and planning of preventive control actions. [ABSTRACT FROM AUTHOR]

Several species of birds deliberately drop hard food items, such as walnuts and molluscs, from high places to break the shell and eat the content. Although the carrion crow Corvus corone preys on the introduced apple snail Pomacea canaliculata by directly breaking the shells with their beaks in paddy fields in Japan, snails living in ponds are too large and hard for crows to directly break the shells. We found that carrion crows dropped apple snails in and around dried ponds in winter in Marugame, Kagawa, Japan, and conducted detailed observations on their predation behaviour. The crows dropped the snails onto various substrates in and around Hachijo Pond, and the release point was higher when the substrate was wet mud than when it was concrete, rock, or grass. As carrion crows rarely prey on other freshwater snails in Japan, this foraging behaviour has likely developed since the introduction of apple snails in the 1980s. The intense predation by the crows likely reduced the snail density in this reservoir pond. [ABSTRACT FROM AUTHOR]

Despite seawalls becoming ubiquitous coastal features, and having some physical similarities to natural rocky shores, it remains unclear how these urban habitats influence predator–prey interactions. Predators can affect intertidal mobile prey densities through two pathways: (1) successful predation directly influences prey mortality rates, and (2) direct and indirect effects of predation can scare and induce motile prey to seek safer areas. In this study, we investigated whether intertidal predators affect the density of the marine gastropod, Nerita undata, at four seawall sites in Singapore. Using a tethering method that we developed, we monitored the mortality and other evidence of predation (shell state) of tethered N. undata. Field experiments revealed high (22.5%–82.5%) predation potential of N. undata across the four sites, with significantly higher predation risk at lower shore heights and for snails with mixed shell coloration. Observations and analysis of the shell state after 3 days showed that predation on seawalls was primarily by crushing predators such as fish. Other predators of N. undata include predatory snails, with various feeding methods that left behind different predator signatures. Our results add substantially to the limited knowledge on predator–prey interactions on seawalls, particularly for Nerita undata, and suggest that seawall systems are more dynamic than previously thought. This further highlights the role of these artificial structures as important habitats and feeding grounds in urban coastal ecosystems. [ABSTRACT FROM AUTHOR]

Understanding how and why some species or lineages become invasive is critically important for effectively predicting and mitigating biological invasions. Here, we address an important unanswered question in invasion biology: do key life‐history traits of invasive versus native lineages within a species differ in response to key environmental stressors? We focus on the environmental factor of population density, which is a fundamental characteristic of all populations, and investigate how changes in density affect native versus invasive Potamopyrgus antipodarum (New Zealand mudsnail). P. antipodarum has invaded 39 countries and detrimentally affects invaded environments. Previous studies of native and invasive populations and from laboratory experiments have demonstrated that growth and reproduction of P. antipodarum is sensitive to population density, though whether and how this sensitivity varies across native versus invasive lineages remains uncharacterized. We quantified individual growth rate and reproduction in P. antipodarum from multiple distinct native and invasive lineages across three different population density treatments. The growth of native but not invasive lineages decreased as density increased. There was no differential effect of density treatment on embryo production of invasive versus native snails, but a significantly higher proportion of snails were reproductive in high density compared to intermediate density for invasive lineages. In native lineages, there were no significant differences in the relative frequency of reproductive snails across density treatments. While the extent to which these results from our laboratory study can be extrapolated to the more complex natural world remain unclear, our findings are consistent with a scenario where differential sensitivity to population density could help explain why some lineages become successful invaders. Our findings also align with previous studies that show that invasive P. antipodarum lineages exhibit a relatively wide range of tolerance to environmental stressors. [ABSTRACT FROM AUTHOR]

Background: The land snail Monacha obstructa, commonly known as the glassy clover snail, poses a significant threat to crops, causing substantial damage in agriculture and horticulture. It particularly thrives in regions of Egypt, where it can reproduce rapidly, leading to substantial population increases and consequent damage. This study aimed to perform laboratory experiments and field trials to assess the effectiveness of bacterial (Bacillus thuringiensis) and fungal (Metarhizium anisopliae and Trichoderma harzianum) isolates, as well as methomyl, a carbamate compound approved by the Ministry of Agriculture in Egypt against the terrestrial snails. Various methods including contact and leaf dipping as well as baiting techniques were applied under both laboratory and field conditions, using spray and baiting techniques. Results: Bacillus thuringiensis (Bt) and M. anisopliae isolates showed the most effective results outcomes in comparison with methomyl against M. obstructa. Out of all the application approaches tested, the residual film (contact) technique of these microorganisms proved to be the most potent, with LC50 values of 6.49 × 106 cells/ml Bt (after 14 days), 1.24 × 108 and 1.49 × 108 spores/ml (M. anisopliae, T. harzianum, respectively), after 21 days and 620 ppm, for methomyl after 7 days of treatments. Besides, the findings demonstrated that Bt exhibited the highest success rate in decreasing the number of snails in the field. It was also observed that pathological symptoms increased as the duration of exposure increased, and the snails ceased to feed and showed a noticeable decline in their activity. A slimy, almost tan-like substance coated the exterior of their shells for Bt, and part of the soft body came out of the shell for M. anisopliae. In the case of T. harzianum, fungus hypha growth took on a white color formed inside the shell, and in addition, a black substance formed on the mouth of the shell. Conclusions: The gathered data revealed that Bt and M. anisopliae effectively combatted the terrestrial snail, making them viable options in integrated pest control as substitutes for pesticides. [ABSTRACT FROM AUTHOR]

Furcocercariae, of the trematodes from the family Diplostomidae, were found in freshwater snails—Radix auricularia, which were collected in a reservoir located on Popov Island (Peter the Great Bay, Sea of Japan). The life cycle was experimentally reproduced for the first time, while morphometric data for the development stages were studied and described for the newly discovered trematode. Moreover, molecular data for nuclear and mitochondrial markers were also obtained. It was determined that the morphometric characteristics of the trematode coincided with the species Diplostomum cf. vanelli, the molecular data analysis validates the species independence. Furthermore, the study highlights the issue of species identification in the Diplostomum genus. [ABSTRACT FROM AUTHOR]

Land snails, including some economically important species, are commonly found in forests and mountainous regions of Türkiye. Türkiye's large geomorphological region and four surrounding seas, which offer a variety of malacofauna, help Türkiye achieve an endemism grade of over 65%. Despite extensive research over the past few decades, we still lack a sufficient understanding of the species identification of land snails in Türkiye, particularly in areas like forested mountain regions, and it is assumed that there are more than 1000 taxa in total. This review emphasizes the existence of invasive non-native snail species in Türkiye, such as Arion ater (Linnaeus, 1758) and Arion vulgaris Moquin-Tandon, 1855, which have a negative impact on agricultural and horticultural output. In addition to these species, Theba pisana, Cornu aspersum, Xeropicta derbentina, Xeropicta krynickii, Cernuella virgata and Eobania vermiculata are also found in Türkiye as non- native land snail species. Moreover, it also places a strong emphasis on the necessity of managing invasive species to reduce their detrimental effects on natural ecosystems by giving examples from the world and covers the predictions about the possible threats that the presence of non-native invasive land snail species in Türkiye may pose in the future. [ABSTRACT FROM AUTHOR]

Predators affect their prey through consumptive and non-consumptive effects (NCEs). Regarding marine NCEs, predator chemical cues (e.g., exudates) can trigger various anti-predator responses in prey that can vary in magnitude according to the intensity of the perceived cues. Specimens of the mussel Perumytilus purpuratus were exposed to seawater that held different densities of the predatory snail Acanthina monodon as a proxy for predator cue intensity. The response of mussels was quantified in terms of valve gape size (VGS), clearance rate (CR), and oxygen consumption rate (OCR). The results showed that mussels reduced VGS, CR, and OCR as a function of the intensity of the predator exudates to which they were exposed. These results suggest that mussels are not only able to detect predators through their chemical exudates but can also detect the intensity of the predatory signal and thus respond physiologically (CR, OCR) and behaviorally (VGS) in accordance to the potential predation risk. These responses may have cascading effects at the community level, given that mussels are foundation species. [ABSTRACT FROM AUTHOR]

[Display omitted] • Wider distribution of invasive snails compared with native snails in the Limpopo River system. • cox 1 genetic data shows multiple lineages of invasive snails outside their native ranges. • More digenean species occurred in Pseudosuccinea columella than in the other snails. • The present xiphidiocercaria represents an unknown species of Orientocreadium. Invasive snails are associated with ecological problems in freshwater bodies worldwide. However, their impact on the transmission of digenean infections remain underreported. In the present study, 1708 specimens representing four snail species were sampled from four impoundments in the Limpopo River system in South Africa. Gyraulus chinensis (Planorbidae), Physella acuta (Physidae) and Pseudosuccinea columella (Lymnaeidae), which are invasive, were found in all the sampling sites. In contrast, the native lymnaeid Radix natalensis occurred at only one study site. Digeneans were observed only from R. natalensis (prevalence = 49%) and Ps. columella (prevalence = 23%). Morphological and genetic analyses revealed four digeneans: Fasciola nyanzae , Orientocreadium sp., Petasiger sp. and Patagifer vioscai. Pseudosuccinea columella was infected by the four digeneans while R. natalensis harboured only Orientocreadium sp. and Petasiger sp. Partial sequences of Orientocreadium sp. from the current study differed from congeners whose DNA data are available on GenBank, by p-distances of at least 1.84 and 2.2% for 28S and the internal transcribed spacer (ITS) rDNA, respectively. Phylogenetic analyses demonstrated that the present species is sister to Orientocreadium batrachoides. Genetic and phylogenetic data based on 28S and ITS rDNA suggested that Petasiger sp. from the present study and isolates of three unidentified Petasiger spp. from Kenya, Hungary and Australia, were representatives of the same species. This is the first known report of Orientocreadium , Petasiger and Patagifer from Ps. columella. The occurrence of F. nyanzae in Ps. columella indicates spillback from R. natalensis. These findings echo the concerns raised in previous studies about the potential role of Ps. columella in the amplification of digenean diseases in its introduced range. Phylogenetic analyses of partial sequences of the cytochrome c oxidase subunit 1 mitochondrial gene (cox 1) showed multiple lineages of Ps. columella in North and South America. Pseudosuccinea columella specimens from the present study belong to an invasive genotype that has spread globally and has been reported from Zimbabwe, Egypt, Portugal, Australia, Argentina, Colombia and New Mexico (USA). Physella acuta from the current study had a stronger genetic relationship with isolates from Canada and Iceland, than with isolates from other parts of Africa, suggesting several invasion routes into Africa. This is the first known DNA characterisation of G. chinensis from Africa. Phylogenetic reconstruction indicated multiple exit events of G. chinensis from Asia into Europe and Africa. South African isolates clustered in a recent branch containing isolates from the Czech Republic and Hong Kong, China. Considering the presence of invasive snails in all the sampling sites in the present study, it is necessary to investigate the factors that enhance their establishment and to monitor their effects on the native snail populations. [ABSTRACT FROM AUTHOR]

Aim: We aimed to understand how biogeographical processes and moisture niche ecology contributed to the spatio‐temporal diversification dynamics in the land snail genus Vertigo. Location: Global (North America, Europe, Asia, Africa). Time Period: Cenozoic era. Major Taxa Studied: Minute terrestrial snails of the genus Vertigo. Methods: We reconstructed a time‐calibrated phylogeny of 94 Vertigo taxa (~85% of all known extant species) based on mitochondrial and nuclear DNA data. Leveraging this phylogeny with distributional and ecological data from >7000 populations, we performed biogeographic and ecological modelling to investigate evolutionary mechanisms of global Vertigo diversification. Results: Vertigo has diversified since the Early Eocene, ca. 47.6 Ma (95% HPD = 46.0–52.7), with its six subgenera originating from the Late Eocene (30.2–48.7 Ma) to the Early Miocene (13.3–23.0 Ma). Species diversity accumulated linearly, with a slight increase 35–30 and 25–20 Ma, coinciding with the emergence of most subgenera and northern hemisphere cooling, respectively. Biogeographic modelling indicated that most diversification events occurred in sympatry (no range modification), but that rare founder events drove global diversification. Soil moisture conditions, a major variable defining Vertigo niches, displayed significant phylogenetic signal, but varied less among subgenera relative to within. Shifts in biogeographical ranges and moisture niches (or the absence thereof) were significantly associated at macroevolutionary scales, with most niche shifts upon sympatric cladogenesis and hardly any upon founder‐event speciation. Main Conclusions: Our results indicate that ecological shifts in soil moisture niches occasionally drove cladogenesis in sympatry and anagenetic range extensions, but that long‐distance dispersal was mainly successful in the absence of such shifts. A combination of neutral (founder events and drift) and selective mechanisms (adaptive habitat shifts) has determined the macroevolutionary success of Vertigo. Our results imply that species with high niche fidelity or fewer opportunities for long‐distance dispersal will be more vulnerable to future anthropogenic stressors. [ABSTRACT FROM AUTHOR]

Simple Summary: The apple snail is one of the most dangerous invasive species in freshwater environments. Using molecular and morphological tools, we re-describe an echinostomatid digenean parasitizing snails from two sites in the Buenos Aires Province, Argentina. The two stages found (i.e., rediae and metacercariae) demonstrate that the apple snail acts as the first and second intermediate host in its life cycle. The prevalence of the parasite was higher at one of the sampling sites, probably because the birds bearing the adult stage are more abundant in that area. A histological study showed that this parasite quickly invades multiple organs of the snail, which is different from most digenean infections, which only infect the gonad and digestive glands. Heavy deterioration of female and male reproductive structures associated with the presence of the parasite was also observed, which indicates castration. Pomacea canaliculata is one of the most dangerous invasive species. Morphological and molecular analyses have revealed that a digenean species belonging to the family Echinostomatidae parasitizes this snail at two sites in Buenos Aires Province, Argentina, South America. Molecular results confirmed that the species belongs to a genus closely related to Patagifer. Analysis of the 28S rDNA showed that the sequences of the rediae and metacercariae are identical, indicating that the apple snail acts as the first and second intermediate host. The cercariae may encyst as metacercaria inside the redia and also emerge and re-infect the same snail or another snail. The prevalence of digeneans was higher in one of the sampling locations (15.1% vs. 0.72%), probably because the bird species that acts as the definitive host is more abundant in that area. Histopathological examination showed that the parasite quickly invades multiple host organs (gills, intestines, albumen gland, lung, kidney, and mantle border) besides the gonad and digestive gland, as is usual in digeneans. In addition, the partial or total castration of snails was observed in cases of moderate and high infection intensity. In males, there was loss of integrity in testicular tubules, while in females, the replacement of ovarian tissue by rediae was found. [ABSTRACT FROM AUTHOR]

The cryptic invasion of golden apple snails (Pomacea canaliculata and P. maculata) in Taiwan has caused significant ecological and economical damage over the last few decades, however, their management remains difficult due to inadequate taxonomic identification, complex phylogeny, and limited population genetic information. We aim to understand the current distribution, putative population of origin, genetic diversity, and potential path of cryptic invasion of Pomacea canaliculata and P. maculata across Taiwan to aid in improved mitigation approaches. The present investigation conducted a nationwide survey with 254 samples collected from 41 locations in 14 counties or cities across Taiwan. We identified P. canaliculata and P. maculata based on mitochondrial COI and compared their genetic diversity across Taiwan, as well as other introduced and native countries (based on publicly available COI data) to understand the possible paths of invasion to Taiwan. Based on mitochondrial COI barcoding, sympatric and heterogeneous distributions of invasive P. canaliculata and P. maculata were noted. Our haplotype analysis and mismatch distribution results suggested multiple introductions of P. canaliculata in Taiwan was likely originated directly from Argentina, whereas P. maculata was probably introduced from a single, or a few, introduction event(s) from Argentina and Brazil. Our population genetic data further demonstrated a higher haplotype and genetic diversity for P. canaliculata and P. maculata in Taiwan compared to other introduced regions. Based on our current understanding, the establishment of P. canaliculata and P. maculata is alarming and widespread beyond geopolitical borders, requiring a concerted and expedited national and international invasive species mitigation program. [ABSTRACT FROM AUTHOR]

The pace of biological invasions has increased in recent decades, leading to multiple invasions and the potential dominance of invasive species, destabilizing local ecological networks. This provides opportunities to study new ecological species interactions, including predation. Tropical freshwaters have been particularly concerned by aquatic invasions and we focused here on the Martinique island (Lesser Antilles). We examined the predator–prey relationships involving invasive Thiarid snails (Tarebia granifera and Melanoides tuberculata) and the native Neritina punctulata, both confronted with a newcomer predator, the redclaw crayfish (Cherax quadricarinatus). We conducted several mesocosm experiments to assess the impact of crayfish predation on snail survival and the passive and active antipredator responses of snails. A first experiment indicated snail survival rates between 50% and 80%, depending on crayfish size and sex. Notably, there was a negative correlation between snail survival and male crayfish size and the predation method (shell crushing vs. "body sucking") varied with crayfish size. The second experiment suggested no refuge size for snails, with both very small (<5 mm) and very large (>5 mm) unable to escape predation, regardless of crayfish size (from 77 to 138 mm) or sex. Finally, we investigated the escape behavior of Thiarids regarding three crayfish cues. Melanoides tuberculata tend to bury in the substrate and T. granifera to climb up aquarium walls, what was expected from their shell morphologies, and both responding to crayfish cues within minutes. Overall, C. quadricarinatus proves to be an efficient snail predator with limited escape options for snails, potentially contributing to the decline of certain snail populations in Martinique. This omnivorous predator might impact other native species across different groups, including shrimps and fish. Our study underscores the urgent need for monitoring efforts, solidifying the redclaw crayfish reputation as a dangerous invasive species for freshwater macrobenthic faunas worldwide. [ABSTRACT FROM AUTHOR]

The almost complete absence of regulations to protect invertebrates is a common condition in legal systems, including the European one, especially when it comes to invertebrates intended for human consumption. Thus, in the vast majority of cases, edible invertebrates do not receive even the most basic protection at slaughter. Despite recent research indicating that invertebrates are capable of feeling pain and stress, the humane step of stunning is not used on them. This is also the case for land snails, which are gastropod invertebrates whose consumption has now reached significant levels, already involving tonnes and that is expected to increase significantly as edible snail farming becomes more popular as a relatively low-cost, easy-to-perform, and sustainable alternative animal husbandry, thereby making land snails an increasingly economically important species. This paper presents and investigates a proposed stunning method based on the immersion of mollusks in CO2-supplemented and refrigerated water that could be used in the snail meat production chain to reduce the slaughter suffering of millions of these invertebrates. To this end, body condition descriptors (hemolymph parameters) in snails were determined before and after CO2 treatment in cold water, while generating useful data for defining a preliminary set of reference intervals for basal values. [ABSTRACT FROM AUTHOR]

Marine snails (genus Littorina) have recently emerged as a model for speciation research, with repeated formation of different types of barriers to gene flow in contact zones between ecotypes and taxa. Inversion polymorphisms are found in an increasing number of species, including Littorina snails, and have been suggested to promote both local adaptation, ecotype formation and speciation, but their roles can vary. In Littorina , their role in later stages of speciation remains particularly unclear. A one-dimensional speciation continuum is frequently used to frame our understanding of the speciation process. However, a number of recent studies have argued that no single measure adequately summarises reproductive isolation and, therefore, the speciation process is best viewed in multiple dimensions. The many Littorina contact zones provide empirical data to illustrate how this principle can be applied. Speciation is a key evolutionary process that is not yet fully understood. Combining population genomic and ecological data from multiple diverging pairs of marine snails (Littorina) supports the search for speciation mechanisms. Placing pairs on a one-dimensional speciation continuum, from undifferentiated populations to species, obscured the complexity of speciation. Adding multiple axes helped to describe either speciation routes or reproductive isolation in the snails. Divergent ecological selection repeatedly generated barriers between ecotypes, but appeared less important in completing speciation while genetic incompatibilities played a key role. Chromosomal inversions contributed to genomic barriers, but with variable impact. A multidimensional (hypercube) approach supported framing of questions and identification of knowledge gaps and can be useful to understand speciation in many other systems. [ABSTRACT FROM AUTHOR]

Archaeological evidence for local environmental change is obscured by the tendency for humans to remove natural resources from places of procurement and deposit them elsewhere, sometimes at great distance. This is especially problematic for changes in relative sea level, which clearly affected the inhabitability of low-elevation coastal landforms but not necessarily the regional availability of resources of cultural or economic value. Needed are proxies for relative sea level from non-dietary taxa. One genus of terrestrial snails, Truncatella, offers good potential in this respect because of its specific niche at the interface between seawater and land. However, like food resources displaced by people, Truncatella shells are displaced by storms and redistributed landward of the coastline. Distinguishing between autochthonous and allochthonous deposits is essential to inferring relative sea level from the occurrence of this taxon alone. To this end, assemblages of Truncatella shell from stratified sites along the north Gulf Coast of Florida, USA are compared to associated archaeological snails of other taxa and to snail shells from the wrack of proximate foreshores to infer changes in relative sea level over the past four millennia. Variation in the morphology of shorelines and in the accumulation rates of archaeological midden mitigates any direct relationship between terrestrial snail frequencies and sea level, but the results of this study suggest that our approach can be applied to other non-dietary taxa occupying marginally terrestrial niches to refine estimates for sea level derived from the sedimentary records of geological cores. [ABSTRACT FROM AUTHOR]

The hyperparasitism of tetracotyle metacercariae (Cotylurus sp.; Strigeidae) in trematode asexually multiplicating larval stages (sporocysts and/or rediae) within snail intermediate hosts have been perceived for years as a highly evolved mode of life strategy within trematodes, enhancing their development and transmission success. Here, we verified these data and the potential implications for the co-evolution of life strategies within the host–parasite–hyperparasite system. During complex research on the taxonomy and life cycles of trematodes of the family Strigeidae, the results showed that the phenomenon of metacercariae hyperparasitism on sporocysts/rediae within snail hosts is not uncommon in natural conditions in central Europe. However, the relatively low rate of cases of hyperparasitism within the population of snails and the lack of visible trends favouring such a life strategy suggest the accidental nature of this phenomenon. Simultaneously, we found a significantly higher prevalence and mean intensity of tetracotyles in snails without sporocysts/rediae than in snails co-infected by these larval stages and tetracotyles. These distinctions suggest negative relationships between tetracotyles and trematode asexually multiplicating larval stages within snails, with a potential impact on the structure and functioning of trematode larval infracommunities in snail intermediate hosts. [ABSTRACT FROM AUTHOR]

The change in the distribution of organisms in freshwater ecosystems due to natural or manmade processes raises the question of the impact of alien species on local communities. Although most studies indicate a negative effect, the positive one is more difficult to discern, especially in multispecies systems, including hosts and parasites. The purpose of the study was to check whether the presence of an alien host, Potamopyrgus antipodarum , reduces the intensity of Echinoparyphium aconiatum metacercariae in a native host, Radix spp. We additionally tested the impact of water temperature and the biomass of the alien host on the dilution effect. We experimentally studied (1) the lifespan of echinostome cercariae in different temperatures, (2) the infectivity of cercariae toward the alien host and native host, and (3) the impact of different biomass of the alien host on the intensity of metacercariae in the native host. We found that cercarial survival and infectivity were temperature dependent. However, cercarial survival decreased with increasing temperature, contrary to cercarial infectivity. Echinostome cercariae entered the renal cavity of both the native host and alien host, and successfully transformed into metacercariae. The number of metacercariae in the native host decreased with the increasing biomass of the alien host. Our results indicate that lymnaeids may benefit from the co-occurrence with P. antipodarum , as the presence of additional hosts of different origins may reduce the prevalence of parasites in native communities. However, the scale of the dilution effect depends not only on the increased spectrum of susceptible hosts but also on the other variables of the environment, including water temperature and host density. [ABSTRACT FROM AUTHOR]

The Psychedelic Rock Gecko (Cnemaspis psychedelica), is a species endemic to southernmost Vietnam. It was recently assessed as Endangered in the IUCN Red List and also included in the CITES Appendix I, due to anthropogenic threats such as habitat degradation and over-collection for the pet trade. To protect wild populations and the natural habitat of this species, knowledge of its demography and ecology is essential to implement fitting conservation measures. In this study, we conducted field surveys on Hon Khoai Island, Ca Mau Province, southern Vietnam in both dry and wet seasons, and obtained food contents of 114 individuals of C. psychedelica by water-flushing the stomach without sacrificing them. Consequently, 685 invertebrate items were identified, belonging to 24 different prey types of 20 invertebrate orders, as well as flatworms, snails and plant parts. Araneae, Blattodea, Hymenoptera and Isoptera were identified as the most important prey of C. psychedelica , among which Araneae accounted for the highest percentage, and thus the highest importance index, during the dry season and Hymenoptera during the wet season. There was a large overlap in the trophic niche between the two seasons, and between males and females of C. psychedelica. This study shows that not only suitable habitat but also a particular food spectrum is a requirement for the species and this, in addition, is important to optimize conservation breeding programs. [ABSTRACT FROM AUTHOR]

This is the first report on microbial communities associated with the freshwater snail Kamtschaticana kamtschatica inhabiting diverse types of water bodies in Eastern Siberia and the Russian Far East. Using metabarcoding data based on 16S rRNA gene fragments, taxonomic profiling of bacterial communities associated with snails from three water bodies of the Magadan Oblast was carried out. Predominant phyla in the studied bacterial communities were Pseudomonadota, Bacillota, Cyanobacteriota, Actinomycetota, Verrucomicrobiota, Planctomycetota, and Bacteroidota. The highest alpha-diversity, according to the Chao1 index, was revealed in the mollusks from the Orotukan Reservoir. The relative abundance of bacteria of the genera Snowella, Leptolyngbya, Nodosilinea, Arenimonas, and Polaromonas significantly distinguished the mollusks of this habitat from mollusks of the other two water bodies. The greatest similarities in the composition of the microbiota in K. kamtschatica were found for the genus Pseudomonas, which was present in the majority of samples in the amount of more than 1% and was not found in the sediment samples. Obtained data on the diversity and composition of bacterial communities associated with lymnaeid snails are of fundamental importance for the ecology of freshwater mollusks. [ABSTRACT FROM AUTHOR]

The cryptic invasion of golden apple snails (Pomacea canaliculata and P. maculata) in Taiwan has caused significant ecological and economical damage over the last few decades, however, their management remains difficult due to inadequate taxonomic identification, complex phylogeny, and limited population genetic information. We aim to understand the current distribution, putative population of origin, genetic diversity, and potential path of cryptic invasion of Pomacea canaliculata and P. maculata across Taiwan to aid in improved mitigation approaches. The present investigation conducted a nationwide survey with 254 samples collected from 41 locations in 14 counties or cities across Taiwan. We identified P. canaliculata and P. maculata based on mitochondrial COI and compared their genetic diversity across Taiwan, as well as other introduced and native countries (based on publicly available COI data) to understand the possible paths of invasion to Taiwan. Based on mitochondrial COI barcoding, sympatric and heterogeneous distributions of invasive P. canaliculata and P. maculata were noted. Our haplotype analysis and mismatch distribution results suggested multiple introductions of P. canaliculata in Taiwan was likely originated directly from Argentina, whereas P. maculata was probably introduced from a single, or a few, introduction event(s) from Argentina and Brazil. Our population genetic data further demonstrated a higher haplotype and genetic diversity for P. canaliculata and P. maculata in Taiwan compared to other introduced regions. Based on our current understanding, the establishment of P. canaliculata and P. maculata is alarming and widespread beyond geopolitical borders, requiring a concerted and expedited national and international invasive species mitigation program. [ABSTRACT FROM AUTHOR]

The pace of biological invasions has increased in recent decades, leading to multiple invasions and the potential dominance of invasive species, destabilizing local ecological networks. This provides opportunities to study new ecological species interactions, including predation. Tropical freshwaters have been particularly concerned by aquatic invasions and we focused here on the Martinique island (Lesser Antilles). We examined the predator–prey relationships involving invasive Thiarid snails (Tarebia granifera and Melanoides tuberculata) and the native Neritina punctulata, both confronted with a newcomer predator, the redclaw crayfish (Cherax quadricarinatus). We conducted several mesocosm experiments to assess the impact of crayfish predation on snail survival and the passive and active antipredator responses of snails. A first experiment indicated snail survival rates between 50% and 80%, depending on crayfish size and sex. Notably, there was a negative correlation between snail survival and male crayfish size and the predation method (shell crushing vs. "body sucking") varied with crayfish size. The second experiment suggested no refuge size for snails, with both very small (<5 mm) and very large (>5 mm) unable to escape predation, regardless of crayfish size (from 77 to 138 mm) or sex. Finally, we investigated the escape behavior of Thiarids regarding three crayfish cues. Melanoides tuberculata tend to bury in the substrate and T. granifera to climb up aquarium walls, what was expected from their shell morphologies, and both responding to crayfish cues within minutes. Overall, C. quadricarinatus proves to be an efficient snail predator with limited escape options for snails, potentially contributing to the decline of certain snail populations in Martinique. This omnivorous predator might impact other native species across different groups, including shrimps and fish. Our study underscores the urgent need for monitoring efforts, solidifying the redclaw crayfish reputation as a dangerous invasive species for freshwater macrobenthic faunas worldwide. [ABSTRACT FROM AUTHOR]

Environmental temperature affects ectotherm performance and fitness because physiological performance increases up to a sublethal optimum temperature; this is not fixed, but depends on the species and individual history. We explored the influence of species identity, size and thermal history on thermal tolerance in four species of littorinid snails in South Africa. As expected, heat coma temperature (HCT) was lower than the lethal temperatures (LT50), and was greater for juveniles, while LT50 was greater for adults. The ranking by both metrics was Echinolittorina natalensis > Littoraria glabrata > Afrolittorina africana > A. knysnaensis, reflecting their biogeographical distributions. No species showed an effect of laboratory acclimation for 14 days at temperatures from 20 to 35 °C, though HCT was lower for field fresh individuals than for all other treatments. Nor was there acclimatisation of LT50 between seasons. Bioregion is a proxy for lifetime acclimatisation yet the Afrolittorina species showed nonsignificant differences between conspecifics from different regions. The effect of size differed between the two metrics, and field fresh individuals showed lower HCT values than laboratory-treated individuals—which taken together indicates the need for care when interpreting the results of lab work. The thermal tolerances of these species reflect their biogeography and appear fixed with little or no plasticity, rendering these littorinids vulnerable to future climate warming. [ABSTRACT FROM AUTHOR]

[Display omitted] • Recombinase Polymerase Amplification (RPA) is a simple and accurate tool for fast detection of Schistosoma mansoni DNA. • RPA targeting the S. mansoni mitochondrial minisatellite region (Sm MIT-RPA) can be used to detect infected snails. • Sm MIT-RPA detects S. mansoni early pre-patent infections in laboratory snails. • Sm MIT-RPA is a sensitive and specific tool for S. mansoni snail xenomonitoring. Improvements in diagnostics for schistosomiasis in both humans and snail hosts are priorities to be able to reach the World Health Organization (WHO) goal of eliminating the disease as a public health problem by 2030. In this context, molecular isothermal amplification tests, such as Recombinase Polymerase Amplification (RPA), are promising for use in endemic areas at the point-of-need for their accuracy, robustness, simplicity, and time-effectiveness. The developed recombinase polymerase amplification assay targeting the Schistosoma mansoni mitochondrial minisatellite region (Sm MIT-RPA) was used to detect S. mansoni DNA from both laboratory and field Biomphalaria snails. Laboratory snails were experimentally infected and used at one, seven, and 28 days post-exposure (dpe) to 10 S. mansoni miracidia to provide samples in the early pre-patent infection stage. Field samples of Biomphalaria spp. were collected from the Mucuri Valley and Jequitinhonha Valley regions in the state of Minas Gerais, Brazil, which are endemic for S. mansoni. The sensitivity and specificity of the Sm MIT-RPA assay were analysed and compared with existing loop-mediated isothermal amplification (LAMP), PCR-based methods, parasitological examination of the snails, and nucleotide sequencing. The Sm MIT-RPA assay was able to detect S. mansoni DNA in the experimentally infected Biomphalaria glabrata as early as one dpe to 10 miracidia. It also detected S. mansoni infections (55.5% prevalence) in the field samples with the highest accuracy (100% sensitivity and specificity) compared with the other molecular tests used as the reference. Results from this study indicate that the Sm MIT-RPA assay is a good alternative test to be used for snail xenomonitoring of S. mansoni due to its high sensitivity, accuracy, and the possibility of detecting early pre-patent infection. Its simplicity and portability also make it a suitable methodology in low-resource settings. [ABSTRACT FROM AUTHOR]

Pomacea canaliculata is widely distributed in the Chinese provinces south of the Yangtze River, causing serious damage to aquatic ecosystems, rice cultivation, and human health. Predicting the potential geographic distributions (PGDs) of P. canaliculata under current and future climate conditions in China is crucial for developing effective early warning measures and facilitating long-term monitoring. In this study, we screened various species distribution models (SDMs), including CTA, GBM, GAM, RF, and XGBOOST, to construct an ensemble model (EM) and then predict suitable habitats for P. canaliculata under current and future climate scenarios (SSP1-26, SSP2-45, SSP3-70, SSP5-85). The EM (AUC = 0.99, TSS = 0.96) yielded predictions that were more precise than those from the individual models. The Annual Mean Temperature (Bio1) and Precipitation of the Warmest Quarter (Bio18) are the most significant environmental variables affecting the PGDs of P. canaliculata. Under current climate conditions, the highly suitable habitats for P. canaliculata are primarily located south of the Yangtze River, collectively accounting for 17.66% of the nation's total area. Unsuitable habitats predominate in higher-latitude regions, collectively covering 66.79% of China's total land area. In future climate scenarios, the total number of suitable habitats for P. canaliculata is projected to expand into higher latitude regions, especially under SSP3-70 and SSP5-85 climate conditions. The 4.1 °C contour of Bio1 and the 366 mm contour of Bio18 determine the northernmost geographical distribution of P. canaliculata. Climate change is likely to increase the risk of P. canaliculata expanding into higher latitudes. [ABSTRACT FROM AUTHOR]

Intrashell oxygen isotope (δ18Os) analyses of terrestrial snails have been carried out over two decades. However, the intraspecies/interspecies differences are not yet well understood. Here, we conducted a high‐resolution intrashell δ18Os study on 43 shells from Cathaica fasciola and Bradybaena ravida, and 1449 δ18Os data were obtained. These large amounts of data demonstrate the reproducibility of intrashell δ18Os. Our results suggest that C. fasciola and B. ravida have similar growing seasons mainly from March to October in the studied region. The ecological habits of the two species could explain the distinctive variations in their δ18Os sequences. Therefore, our study may interpret the discrepancy between the studies of land snail species and the stable/clumped isotopes of their shells. Moreover, the calculated average growth rate is ∼290 μm/day (from 250 to 330 μm/day) for nonadult C. fasciola. Thus, the use of snail shells for reconstructing high‐resolution terrestrial climate changes is promising. Plain Language Summary: Land snails are sensitive to climatic and environmental changes. Therefore, the oxygen isotopic composition of snail shells (δ18Os) has often been used to study environmental changes. Researchers started to collect multiple samples from a single shell for δ18Os analyses about two decades ago. However, it is still unclear whether high‐resolution intrashell δ18Os results are repeatable and whether the influences of different individuals/species may exist. To address these issues, we collected 43 snail shells from Cathaica fasciola and Bradybaena ravida. In total, 1449 δ18Os data were obtained. The large amount of data showing similar variations in the intrashell δ18Os from different shells demonstrates the repeatability. Accordingly, our data suggest that the two species have similar growing seasons, mainly from March to October, although their ecological habits are different. In addition, the ecological habits of these two species could explain the subtle differences in their δ18Os. Taken together, our study could resolve the discrepancy between previous work on land snail species and stable/clumped isotopes. Furthermore, the estimated average growth rate is ∼290 μm/day (from 250 to 330 μm/day) for nonadult C. fasciola. Overall, snail shells are promising records for exploring high‐resolution terrestrial climate changes in the future. Key Points: The intrashell δ18Os of land snails is reproducible, which mainly records the δ18O of precipitationCathaica fasciola and Bradybaena ravida have different ecological habits but similar growing seasonEcological habits could explain the discrepancy between studies of land snail species and stable/clumped isotopes [ABSTRACT FROM AUTHOR]

We report a new land snail species representing a new genus from the mountainous area of Zhejiang, China. The snail has a depressed shell with granules all over the surface. The soft part of the new taxon is characterized by the presence of a mantle lobe whose form is reviewed herein across a wide range of helicoid snails, the presence of a developed epiphallic papilla, and the absence of a penial sheath, a dart sac apparatus and a flagellum. As indicated by a molecular-based phylogeny (16S + ITS2), the new taxon is deeply nested in the eastern Asian camaenid genera and shows a close relationship with the camaenids distributed in Central China. [ABSTRACT FROM AUTHOR]

Inundative biological control (biocontrol) efforts in pest management lead to the mass distribution of commercialized biocontrol agents. Many 'biocontrol gone awry' incidents have resulted in disastrous biodiversity impacts, leading to increased scrutiny of biocontrol efforts. The nematode Phasmarhabditis hermaphrodita is sold as a biocontrol agent on three continents and targets pest gastropods such as Deroceras reticulatum, the Grey Field Slug; P. hermaphrodita is not presently approved for use in the United States. Investigations into the potential for P. hermaphrodita to infect non-target gastropod species of conservation relevance, however, are limited. We examined the effects of three strains of P. hermaphrodita on mortality in Monadenia fidelis, the Pacific Sideband, a snail species endemic to the Pacific Northwest of North America, in laboratory conditions. Across a 71-day laboratory infectivity assay, snails exposed to each of the three nematode strains, each analyzed at two doses, experienced a mean 50% mortality by days 20–42. All nematode-treated snails were dead by the end of the study. By contrast, 30/30 water-control snails experienced no mortality. Nematodes killed smaller, juvenile-stage snails significantly faster than those in larger and more developmentally advanced hosts. Our results provide direct evidence that the biocontrol nematode P. hermaphrodita infects and kills M. fidelis, a non-target gastropod species endemic to the Pacific Northwest, in laboratory conditions. This study suggests that introduction of P. hermaphrodita to new ecosystems might negatively impact endemic gastropod biodiversity and advocates for further investigation of non-target effects, including in conditions closer to the natural environments of non-target species. [ABSTRACT FROM AUTHOR]