Adult Snails Research Articles

Sensitivity assessment of Biomphalaria glabrata (SAY, 1818) using reference substance sodium dodecyl sulfate for ecotoxicological analyzes.

Sodium dodecyl sulfate (SDS) is a surfactant used and recommended by regulatory agencies as a reference substance in ecotoxicological analyzes. In this work, acute toxicity assays were performed with adults and embryos of the freshwater snail Biomphalaria glabrata, an endemic organism with environmental and public health importance, to evaluate the effects of the surfactant and establish a sensitivity control chart. The organisms were exposed to SDS for 24 h to a range of concentrations, as well as a control group. Six assays were performed to establish the control chart for adults (with a median LC50 of 36.87 mg L-1) and differential sensitivity was observed at each embryonic stage (EC50 = blastulae 33.03, gastrulae 35.03, trochophore 39.71 and veliger 72.55 mg L-1). The following behavioral responses were observed in exposed adult snails: release of hemolymph and mucus, body outside the shell, and penile overexposure. Embryos at the blastulae and gastrulae stages were more sensitive, and teratogenic effects were accentuated in the trochophore stage. The difference in results obtained between adults and embryos underscore the importance of carrying out analyzes at different developmental stages. The serial assays established with SDS for B. glabrata demonstrated efficiency and constancy conditions in the assays with good laboratory practice standards. The wide distribution of Biomphalaria species in several countries, their easy maintenance and cultivation in the laboratory, in addition to ecological importance, make them economical alternatives for ecotoxicological assays.

Evaluation of the Effects of Papain on Schistosoma mansoni: Miracidial Infection Capacity, Infection Prevalence, Cercarial Shedding and Molecular Changes in Biomphalaria alexandrina.

The aim of the present study is to assess the molluscicidal, larvicidal and genotoxicological activities of papain and how it can affect the host-parasite interactions. Toxicity of papain on snails by making series of concentrations to calculate LC50, and then study its larvicide effect on the free larval stages of S. mansoni and infection rate of snails. Papain has a molluscicidal activity on adult snails of Biomphalaria alexandrina with a lethal concentration LC50 equals to 43.1mg/L. In addition, it has activity on miracidia with half Lethal time (LT50) of 16.11min., and on cercariae with 12.1min. compared to control ones. The sub lethal concentration LC10 and LC25 (6.9 or 24.1mg/L, respectively) decreased the survival rate of snails at the first cercarial shedding, the rate of infection, the average total number of cercariae per snail, the shedding period and the life span of snails, while the prepatent period was significantly increased than the control ones. The morphological alterations in cercariae after exposure to papain were occurred where the cercariae lacked motility and some had a dark tail with complete detachment of head and tail. Compared to the control group, the levels of cytochrome oxidase subunit I (COI) and (ND1) genes significantly decreased in snails after exposure to papain. Papain could be used as a potential molluscicide for elimination of schistosomiasis and decrease its transmission and deterioration of host-parasite interaction.

Ultrasonography Analysis and Incidence of Urinary Schistosomiasis among some Selected Junior Secondary School Students in Rigachikun, Igabi Local Government Area, Kaduna State, Nigeria

Study’s Excerpt/Novelty This study assesses urinary schistosomiasis prevalence and associated ultrasonographic abnormalities among school-aged children in Rigachikun, Igabi Local Government Area of Kaduna State. By combining urine sample analysis and ultrasound examination, the research identifies a significant infection rate (5.00%) and highlights the presence of urinary tract abnormalities in 70% of infected subjects. The findings underscore the ongoing disease burden of schistosomiasis in the region and advocate for expanded research on adult populations and snail intermediate hosts to inform targeted intervention strategies. Full Abstract This study evaluated urinary schistosomiasis and ultrasonography incidence among school-aged children in Rigachikun, Igabi Local Government Area of Kaduna State. Three hundred urine samples were collected from students within 5-16 years from 3 selected schools. The samples were tested for urinary schistosomiasis, and information was gathered using a standardized questionnaire. The weight and height of the samples were measured using an electronic scale (9201 SV3R) and a portable stadiometer (ADE MZ10042). 5.29% of males and 3.70% of females tested positive for urinary schistosomiasis. Ultrasound examination was performed on ten positive and one negative subjects for confirmation. The mean age was 11.00±5.72 years. Seven out of ten (70%) subjects showed urinary tract abnormalities. The ultrasound findings revealed two out of ten (20%) had bladder wall thickening, four out of ten (40%) had an irregular shape of the bladder wall, and ureteric dilatation was observed in one out of ten (10%) among the subjects. Ultrasound is a useful tool for identifying the morbidity of S. haematobium. Schistosomiasis infection amongst schools in Rigachikun was established at 5.00%. This has confirmed that schistosomiasis is still a disease burden amongst school-aged students in Rigachikun and, by extension, all the study area's inhabitants. It can be recommended that further studies need to be carried out on adults and snail intermediate hosts.

Comparative reproduction performance of Giant African Land Snail (Archachatina marginata) fed with the leguminous plant Leucaena leucocephala

The study was carried out between July and October 2022 at the sub–station of the Faculty of Agriculture Research and Teaching farm to assess the reproductive performance of Archachatina marginata fed the leguminous Leucaena leucocephala leaf meal as feed additive. 208 adult snails were randomly partitioned into 4 treatments and 4 repetitions of 13 comparable snails (weight and size). The treatment T0 (control) received only the experimental diet as described while three other treatments received not only diet but, L. leucocephala leaf meal at 0.25%, 0.5% and 0.75% for a period of 12 weeks. In each treatment, every morning, the substrate of each breeding bucket was stirred entirely and minutely to collect the eggs to determine the laying and morphometric characteristics of the eggs. The eggs were then placed 10 cm deep in loose soil substrates until hatching to evaluate the characteristics of the fecundity. The unhatched eggs were opened, and the state of embryonic development observed to determine early embryonic mortality rate and late embryonic mortality. At the end of the experiment, animals of each replicate were sacrificed; the hemolymph was collected determine the total cholesterol and protein. The results showed that the characteristics of reproduction were affected with graded level of L. leucocephala. The highest number of eggs laid (17.29 ± 13.44) and the number of clutches (268.91) was recorded in animals receiving 0.5% and 0.75% L. leucocephala in the diet respectively while the highest value of fecundation rate (95.50 ± 8.80), hatch rate (94.55 ± 9.36), and hatchability (98.99 ± 3.15) was registered in the treatment that received 0.75%. The highest value of total protein and cholesterol was recorded in the same treatment. In conclusion 0.75% of L. leucocephala can be added in the diet of adult snail to increase its reproductive performance.

Perilaku Harian Keong Mas Pomacea canaliculata (Gastropoda: Ampullariidae)

P. canaliculata (Gastropoda: Ampullariidae) is a water snail that can be found in Indonesia. P. canaliculata is of concern to the community since it can become a pest in the agricultural sector and harm the community. This study aimed to determine the daily behaviour of P. canaliculata, which is located in Lake SDGs IPB University. The observations used the scan sampling method on 10 adult snails for 24 hours with three times repetitions. The results of this study indicate that P. canaliculata has four dominant behaviours: exploration, social interaction, immobile (fixed), and immobile (loose). In addition, P. canaliculata exhibits other behaviours such as siphoning out, feeding, mating, spawning, burying, exploration, and floating. Water temperature changes also influenced active and inactive behaviours. The observed activity of P. canaliculata snails was mostly carried out in water. P. canaliculata was more active in the dark phase (18.00-06.00) with water temperatures ranging from 29 to 32°C and more inactive in the light phase with water temperatures ranging from 28 to 29°C.

Effect of Metaldehyde on Survival, Enzyme Activities, and Histopathology of the Apple Snail Pomacea canaliculata (Lamarck 1822).

Pomacea canaliculata, as an invasive exotic species in Asia, can adversely affect crop yields, eco-environment, and human health. Application of molluscicides containing metaldehyde is one effective method for controlling P. canaliculata. In order to investigate the effects of metaldehyde on adult snails, we conducted acute toxicological experiments to investigate the changes in enzyme activities and histopathology after 24 h and 48 h of metaldehyde action. The results showed that the median lethal concentrations (LC) of metaldehyde on P. canaliculata were 3.792, 2.195, 1.833, and 1.706 mg/L at exposure times of 24, 48, 72, and 96 h, respectively. Treatment and time significantly affected acetylcholinesterase (AChE), glutathione S-transferase (GST), and total antioxidant capacity (TAC) activity, with sex significantly affecting AChE, GST, and TAC activity and time significantly affecting carboxylesterase (CarE). In addition, the interaction of treatment and time significantly affected the activity of GST, CarE and TAC. In addition, histopathological changes occurred in the digestive glands, gills and gastropods of apple snail exposed to metaldehyde. Histological examination of the digestive glands included atrophy of the digestive cells, widening of the hemolymph gap, and an increase in basophils. In treated snails, the hemolymph gap in the gills was widely dilated, the columnar cells were disorganized or even necrotic, and the columnar muscle cells in the ventral foot were loosely arranged and the muscle fibers reduced. The findings of this study can provide some references for controlling the toxicity mechanism of invasive species.

Molluscicidal Activity and Inhibition of Acetylcholinesterase Activity of Azadirachta Indica Extract on Pomacea Canaliculata

The Golden Apple Snail, Pomacea canaliculata, is a notorious pest in Malaysia, leading to substantial agricultural and economic losses, while, the neem tree, Azadirachta indica has been identified as alternative source for bio-pesticides. There is currently limited information on A. indica as natural molluscicide against P. canaliculata. This study aims to evaluate the effects of A. indica on P. canaliculata at various life stages (eggs, juvenile and adult). The bioactive compound, azadirachtin in A. indica extracts was quantified using high-performance liquid chromatography (HPLC). Egg hatchability was determined using spot spraying on egg clusters while the molluscicidal activity of A. indica on juvenile and adult specimens was evaluated using the immersion bioassay approach. The snail's acetylcholinesterase (AChE) inhibition was assessed using Ellman assay. The azadirachtin content in the ethanolic extract of A. indica leaves at a concentration of 1 µg/mL was found to be 45.42%. Increasing the concentration of A. indica extracts resulted in lower egg hatchability and increased mortality of juvenile and adult snails. Azadirachta indica extracts showed the highest effectiveness against adult P. canaliculata with an LC50 value of 0.52 mg/mL, compared to 0.92 mg/mL for juveniles and 0.74 mg/mL for eggs. Additionally, A. indica extract exhibited greater inhibition of AChE in adult specimens compared to juvenile specimens and eggs. The IC50 for adult is 0.60 μg/mL, which is the lowest while the IC50 for juvenile is 0.68 μg/mL, the highest. Taken together, A. indica shows immerse potential as natural pesticide for managing the population of P. canaliculata.

Development of an artificial propagation and breeding method for the beehorn snail (Clithon diadema)

Beehorn snail (Clithon diadema), known for its vibrant colors, is threatened with extinction due to excessive field collection. Therefore, this study investigated the effects of different diets and salinity (0‰–35‰) on the gonadal development, capsule productivity, embryonic development, and larval survival and growth of C. diadema. Adult snails (shell length: 9.09 ± 0.87 mm) were fed diatoms, including pennate marine diatom (Nitzschia grossestriata), boat-shaped diatom algae (Navicula sp.) and Cylindrotheca sp., along with giant tiger prawn (Penaeus monodon) commercial feed, sea lettuce (Ulva lactuca), or Cladophora fascicularis, while snail larvae (shell length: 154.85 ± 6.03 μm) were fed Isochrysis galbana or Chaetoceros muelleri. The diatom group outperformed commercial feed and U. lactuca groups. The highest capsule productivity, yielding 79–82 capsules in 4 weeks, occurred at 15‰-20‰ salinity for diatom-fed adults. Embryos thrived at 0‰ but didn't hatch; hatching required salinities above 0‰, highlighting saline necessity. In addition, acute salinity changes (0‰ to 30‰) can deform embryo. Embryonic development at 15‰–20‰ salinity lasted 13.56–14.33 days with 100% larval hatching. However, larvae hatched at >20‰ salinity exhibit improved the percentage of survival without feeding (longer median lethal times). I. galbana-fed larvae survived 68 days with a 75% rate, outlasting C. muelleri-fed larvae which perished within 28 days. I. galbana-fed larvae, raised for 68 days at 25‰ salinity, showed 100% survival, 44.44% metamorphosis, and a 3.1 times growth increase. Metamorphosis rates were highest at 25‰ salinity with I. galbana, exceeding the 20‰ group by 3.2 times. Mucus of C. diadema boosts larval metamorphosis to 50.00%, 9 times higher than without inducers. Based on previous results, we developed an artificial propagation and breeding method for C. diadema. Artificially propagating C. diadema in large quantities could reduce the need for wild harvesting, thereby mitigating negative ecological impacts from excessive collection.

Immunomodulatory and antioxidant properties of Sarcophaga argyrostoma larval hemolymph: utilizing the Biomphalaria alexandrina snail as a model

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.

Reproductive performance of freshwater snail, Helisoma duryi under the effect of bulk and nano zinc oxide.

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.

Molluscicidal activity of Nigella sativa seed, Azadirachta indica leaf and Khaya senegalensis bark ethanolic extracts against Bulinus truncatus snails

In order to control schistosomiasis, a strategy involves eliminating the intermediate host responsible for its transmission. Plant-derived molluscicides have been extensively researched as a cost-effective approach to combat this disease, seeking alternative solutions to synthetic molluscicides. The study aimed to analyze the phytoconstituents and assess the molluscicidal impact of ethanolic extracts on adult Bulinus truncatus snails. Dried plant materials were ground into powder, and then extracted using ethanol 96%. Preliminary phytochemical screening was carried out using standard procedures. In vitro Molluscicidal activity was evaluated for the three plants extracts in different concentrations (125, 250, 500 and 1000 ppm). Every 5 adult snails were placed in a plastic cup containing a specific amount of dechlorinated water with plant sample. Control negative was prepared by placing the snails in dechlorinated water only, the numbers of survived and dead snails were recorded after 24 and 48 hours. The Lethal dose and Standard deviation were calculated. The phytochemical screening revealed the presence of different chemical constituents in the three plants samples. The result showed that all the plants extracts possessed molluscicidal activity against B. truncatus snails. The A. indica leaf extract was the most effective with LD50 of 74.32544 ppm. From the findings of this study, Molluscicide of plant origin could be useful against the common snail species in Sudan; therefore, the selected plants can play a big role in community based Schistosomiasis control.

Perfil químico da tinta de Octopus vulgaris e validação de seu potencial como antioxidante, antimicrobiano, anticancerígeno e antiesquistossomótico in vitro

ABSTRACT Among marine creatures including squids, cephalopods and Octopus, one of the most unique features is production of ink which is an extremely valuable source of pharmaceuticals. The current study investigates the ink produced from Octopus vulgaris chemically as well as its potential antioxidant, anticancer, antimicrobial, and anti-schistosomal activities in vitro. Twenty-one different compounds were identified by GC-MS analysis of Octopus vulgaris ink. Results revealed that O. vulgaris ink had antioxidant capability to cover DPPH free radical when compared to ascorbic acid. Moreover, Octopus vulgaris ink exhibited antibacterial activity against Bacillus subtilis followed by Escherichia coli and Pseudomonas aeuroginosa and exhibited a molluscicidal activity against adult Biomphalaria alexandrina snails and had a distinguished mortal effect on free larval phases of Schistosoma mansoni. Furthermore, its anticancer activity was confirmed, where IC50 value of breast cancer cell line MCF-7, human hepatocellular carcinoma (HCT) and human liver cancer cell line (HepG2) were 29.8, 38.29 and 30.38μg/mL, respectively. In conclusion, ink extracted from O. vulgaris may be considered as source of valuable compounds that can be used as molluscicidal, antioxidant, antimicrobial, anticancer and anti-schistosomal agents.

Improvement of the reproduction and gonado-somatic index of Archachatina marginata with a medicinal plant (Thymus vulgaris) in the Equatorial Zone of Cameroon

A study was carried out to assess the reproduction and gonado-somatic index of Archachatina marginata with a medicinal plant (Thymus vulgaris). Three hundred adult snails were randomly partitioned into four treatments and six replicates of 15 comparable snails. The Treatment T0 (control) received only the experimental diet. The other treatments (T0.25, T0.5, and T0.75) received, in addition to the experimental diet, Thymus vulgaris powder at 0.25%, 0.5% and 0.75% respectively. The results showed that the lowest value of egg weight (1.33 0.66) was registered in animals receiving 0.5% of Thymus vulgaris in the diet compared to other treatments. In contrast, the lowest value of egg length (14.68 1.14) was recorded in the control group. The lowest (16.25 0.00) number of clutches per treatment was registered in animals that received 0.5% of thymus vulgaris in the diet compared to the control group and other treatments. The hatching and fertilization rate values increase with increasing Thymus vulgaris in the diet, while the reverse was observed for the mortality rate. The highest value of gonadosomatic index (0.020.00) is recorded in animals receiving the highest level of thymus vulgaris (T0.75) in the diet, followed by animal in the control group (T0). The total protein and triglyceride increase significantly (p<0.05) with increasing Thymus vulgaris in the treatment that is receiving Thymus vulgaris in the diet. Contrarily, the total cholesterol decreases significantly (p<0.05) with increasing level of Thymus vulgaris in the diet. In conclusion, Thymus vulgaris at 0.75% can be used in the diet of breeding snails.

Hemocytes from neonates of Biomphalaria glabrata are functionally less mature than those from adult snails

AbstractGastropod molluscs, which serve as obligatory intermediate hosts for digenetic trematodes, possess an internal defense system (IDS) consisting of phagocytic hemocytes and plasma factors. This IDS is responsible for resistance to infection with larval trematodes, which are encapsulated and killed by hemocytes in incompatible snails. Like other physiological systems, the IDS probably undergoes maturation during early stages of life, and the relatively undeveloped state of the IDS in young snails has been hypothesized to be a factor in their increased susceptibility to infection with larval trematodes. In this study, hemocytes were examined in the BS‐90 laboratory strain of Biomphalaria glabrata that is resistant to infection with Schistosoma mansoni as adults but susceptible to infection as neonates. Compared with hemocytes from adults, hemocytes from neonates had a smaller perimeter and lower intrinsic directional motility on glass microscope slides. Additionally, in vitro assays showed a lower association with fucoidan‐linked polystyrene beads and less ability to produce superoxide anion in hemocytes from neonates compared to hemocytes from adults. These results support the hypothesis that the gastropod IDS undergoes maturation during growth. However, whether the observed differences between hemocytes of neonatal and adult BS‐90 snails play a role in the susceptibility of the former and resistance of the latter to infection with S. mansoni is not known.

POST-SIEGE GENOTOXIC HAZARDS IN LAKE LANAO, PHILIPPINES BY MICRONUCLEUS ASSAY

Massive war pollutants brought by Marawi Siege in the Philippines have contaminated the city environs and the surrounding ancient Lake Lanao. Munition residues including heavy metals are reportedly genotoxic hence this study was conducted to determine the post-siege genotoxic hazards posed by the munition pollutants through micronucleus (MN) assay on the slow-moving edible gastropod snails Vivipara angularis Muller (locally known as “suso”) thriving in the lake. MN, a biomarker of genotoxicity was examined and counted in the hemocytes of exposed juvenile and adult snails. Results revealed that MN frequencies (no. of MN/1000 hemocytes) were significantly higher in snails sampled in Lake Lanao lakeshores than in the reference site Lake Dapao. Among adult samples, there was a decreasing trend of MN frequencies with increasing distance from lakeshore fronting warzone ‘ground zero’ where the battle was heaviest (site A) to sampling sites away from it: sites B, C, and D (Lake Dapao) which are 8.15 km, 24.41 km, and 34.45 km, respectively. Moreover, varied patterns of micronucleation were observed between age groups and sites, i.e., in all sites except C, adults had greater MN counts than juveniles which were significant in site A only. Unexpectedly juveniles displayed significantly high MN counts than adults in site C. The elevated MN frequencies in the snail hemocytes exposed to war pollution could be attributed to genotoxic munition residues eroded and washed into the lake water. Moreover, heavy metals which are common components of weaponries were also detected in the snail muscles, although at concentrations within safe levels but continued consumption may be cautioned to avoid biomagnification. Other genotoxins must be present in site C other than munition residues predisposing the juvenile snails. The results are baseline data on the MN frequencies in V. angularis exposed to war pollutants in Lake Lanao which need further investigation. Post-siege genotoxic hazards in the lake by MN assay cannot be ignored, thus local leaders must be informed of the results for possible intervention to protect the health and well-being of the community. 
 

Effects of Commercial Sunscreens on Survival, Reproduction and Embryonic Development of the Aquatic Snail Biomphalaria glabrata (SAY, 1818).

Over the past few years, there has been a significant increase in the use of sunscreens. Consequently, the occurrence in aquatic environments of ultraviolet filters has also increased. The present study aims to evaluate the toxicity of two commercial sunscreens to the aquatic snail Biomphalaria glabrata. Acute assays were performed with adult snails exposed to solutions of the two products in synthetic soft water. Reproduction and development assays were carried out, involving individual adult and egg masses exposure to assess fertility and embryonic development. Sunscreen A showed a LC50-96h of 6.8g/L and reduction in number of eggs and egg masses per individual in the concentration of 0.3g/L. Sunscreen B presented higher malformation rates in 0.4g/L with 63% of malformed embryos. Results indicate that the formulation used in sunscreens is an important factor in aquatic toxicity and needs to be evaluated before the final product is commercialized.

Effects of sediment and water column acidification on growth, survival, burrowing behaviour, and GABAA receptor function of benthic invertebrates

In coastal regions, sediment-dwelling animals are exposed to a high degree of variability in seawater and sediment pH and pH is expected to decline due to anthropogenic effects. The impacts of 6-week exposure to reduced-pH seawater on length, weight, and survival of two species of molluscs that inhabit mudflats, juvenile soft-shell clams (Mya arenaria) and adult mud snails (Tritia obsoleta), were examined in two laboratory trials (2017 and 2018). The interactive effects of this prior exposure to water column acidification and subsequent sediment acidification on burrowing behaviour were then investigated for these mollusc species and adults of the amphipod Corophium volutator. In a separate experiment, the potential involvement of GABAA receptors in changes in burrowing behaviour in reduced-pH conditions was tested by exposing three species: C. volutator, T. obsoleta, and the Baltic clam Limecola balthica to sediment acidification and the neuroinhibitor gabazine. Reduced-pH water conditions only decreased the shell length of T. obsoleta in 2017 while all other morphometric metrics were not significantly impacted for this species in either year or for M. arenaria. The burrowing of T. obsoleta was reduced by 13% in acidified sediments in one of the two years but not by prior exposure to water column acidification. The burrowing of M. arenaria was not affected by either factor. The burrowing of C. volutator was impacted by the interaction of water column exposure and sediment acidification in 2017 with the acidified water, control sediment treatment having 14% higher burrowing then the remaining treatment combinations. In 2018, C. volutator burrowing was reduced in acidified sediment by 30%. The presence of gabazine only had an interactive effect on the burrowing of one species, C. volutator. The presence of gabazine increased the proportion of C. volutator individuals burrowed in the acidified water treatment by almost 30%, suggesting that GABAA neuroreceptors are involved in the mechanism for the impact of sediment acidification on burrowing in this species. The results of our experiments indicate that there is taxonomic variation in species' responses of benthic invertebrates to ocean and sediment acidification with respect to growth, survival, and burrowing behaviour.

Three introduced Monacha species (Gastropoda: Hygromiidae) in and near Lviv with remarks on M. cartusiana spreading in Ukraine and its Western part

The distribution of three introduced Monacha species in Lviv and its immediate environs was analysed. For this, adult snails collected at 33 sites from 2011 to 2022 were studied anatomically. We found Monacha fruticola in two sites (Lviv, Briukhovychi), two cryptic species M. cartusiana and M. claustralis in 4 sites (Lviv, Yampil), only M. claustralis in one site in Lviv, and only M. cartusiana (single individuals or populations) in the remaining 26 cases. The distal genitalia of M. claustralis from new discoveries in and near Lviv, the variability of the vagina shape in M. cartusiana and M. claustralis from the studied area are shown. The possible role of private cars in the rapid spread of M. cartusiana in the study area is discussed. The chronology of registration of M. cartusiana in Western Ukraine is shown in a tabular format. A significant expansion of the range of M. cartusiana in Ukraine was noted, although almost until the very end of the 20th century this species was mentioned only for the southern part of the country, including Crimea.

The Roman snail (Gastropoda: Helicidae) is not a generalist herbivore, but shows food preferences for Urtica dioica and plant litter

ABSTRACT The food preferences and palatability of different plant species for snail and slug species in arable fields has been a major area of research in the past. The assumed diet of Helix pomatia (Linnaeus, 1758), however, provides an example of the limited knowledge of snail diets in nonagricultural habitats. This species has been described as a generalist herbivore, although it showed preferences for individual plant species in another study. Helix pomatia is considered a pest species, while also being listed as endangered in several Red Lists. In this study, the feeding activity of eight subpopulations of H. pomatia were recorded in a nature reserve in Cottbus, Germany, from April to October 2021 to understand food preferences and feeding behaviour. Along with the plant species on which feeding was observed, the height of feeding in the vegetation, shell width and height, number of whorls, and exposure to direct sunlight at observation sites were recorded. Results indicate that H. pomatia prefers Urtica dioica, and plant litter, which accounted for 35% and 44% of all observed feeding interactions respectively, as food resources, while generally only feeding on 27 of 143 available plant species. The importance of U. dioica as a food resource for 19 other terrestrial snail species is confirmed by 18 previous studies. In H. pomatia, analysis of the width and height of shells indicated that smaller, juvenile snails consumed plant material significantly higher up in vegetation as compared to adult snails, which fed closer to the ground. Awareness of the preference in H. pomatia for U. dioica as a food resource may be beneficial for land managers regarding the impact of this snail as an agriculture pest to crops. Urtica dioica is a very important food plant for terrestrial snails, and could play an important role in future species conservation strategies.

Molluscicidal and Larvicidal Potency of N-Heterocylic Analogs against Biomophalaria alexandrina Snails and Schistosoma mansoni Larval Stages.

This work describes the synthesis of quinoline-based N--heterocyclic arenes and their biological evaluation as molluscicides against adult Biomophalaria alexandrina snails as well as larvicides against Schistosoma mansoni larvae (miracidia and cercariae). Molecular docking studies were demonstrated to investigate their affinity for cysteine protease protein as an interesting target for antiparasitics. Compound AEAN showed the best docking results followed by APAN in comparison to the co-crystallized ligand D1R reflected by their binding affinities and RMSD values. The egg production, hatchability of B. alexandrina snails and ultrastructural topography of S. mansoni cercariae using SEM were assessed. Biological evaluations (hatchability and egg-laying capacity) revealed that the quinoline hydrochloride salt CAAQ was the most effective compound against adult B. alexandrina snails, whereas the indolo-quinoline derivative APAN had the most efficiency against miracidia, and the acridinyl derivative AEAA was the most effective against cercariae and caused 100% mortality. CAAQ and AEAA were found to modulate the biological responses of B. alexandrina snails with/without S. mansoni infection and larval stages that will affect S. mansoni infection. AEAA caused deleterious morphological effects on cercariae. CAAQ caused inhibition in the number of eggs/snail/week and reduced reproductive rate to 43.8% in all the experimental groups. CAAQ and AEAA can be recommended as an effective molluscicide of plant origin for the control program of schistosomiasis.