Search Results (31)

Pomacea canaliculata, a pervasive invasive gastropod, inflicts significant ecological and economic damage in Chinese rice ecosystems. With the limitations of chemical molluscicides, sustainable biological control solutions are urgently required. This study presents a comprehensive investigation into the biocontrol potential of larvae of the endemic aquatic firefly, Aquatica leii, against Pomacea canaliculata. Through controlled laboratory experiments, we evaluated the feeding preference of larvae when offered a choice between Pomacea canaliculata and a native snail (Cipangopaludina chinensis), and systematically quantified the predatory efficiency (lethal time and consumption amount) across the 3rd to 6th larval instars. Furthermore, the lethal activity of crude extracts from distinct anatomical regions of the larval digestive tract (mouthpart, foregut, midgut, and hindgut) was assayed via injection into Pomacea canaliculata. The larvae accepted Pomacea canaliculata as a viable prey source. Predatory performance varied markedly among instars; 4th-instar larvae exhibited optimal efficacy, characterized by the shortest mean lethal time (7.37 min) and the highest mean consumption (1.23 g). Midgut extract was identified as the principal causative agent of mortality, inducing a 96.7% mortality rate in Pomacea canaliculata, which was significantly superior to the minimal effects observed from other extract types. This points to the midgut secretion as a likely source of potent bioactive compounds responsible for rapid snail lethality, warranting further investigation. responsible for rapid snail lethality. Our results conclusively demonstrate, from both behavioral and physiological vantage points, the feasibility of Aquatica leii larvae as a highly effective native biocontrol agent. This work establishes a critical foundation for future research aimed at the isolation and characterization of the midgut-specific active substances, paving the way for the development of novel, target-selective biogenic molluscicides. Full article

This study assesses the diversity, distribution, and ecological interactions of freshwater gastropod communities across eight sites in southern Iraq, spanning marshes, rivers, and canal systems within the Tigris-Euphrates basin. Diversity indices (Shannon–Wiener H′ and Pielou’s evenness J) were calculated to evaluate community structure, and a revised stacked bar chart of relative abundances revealed widespread dominance by species such as Melanoides tuberculata and Physella acuta, which frequently exceeded 50% of local assemblages. While P. acuta is an established invasive species, M. tuberculata is now considered native or long-established in the region. Species interactions were examined using Pianka’s niche overlap index, and null model testing (999 permutations) revealed only a few statistically significant overlaps (p < 0.05), suggesting that species co-occurrence is shaped more by environmental filtering than direct competition. To directly examine the influence of environmental drivers on species composition, Multiple Factor Analysis (MFA) was performed. MFA revealed patterns of association between dissolved oxygen, salinity, and species assemblages, suggesting these abiotic factors may influence community structure. To our knowledge, this study is the first in Iraq to use null models, constrained ordination, and MFA to investigate community assembly of freshwater gastropods, ultimately producing novel insights regarding the interactions between environmental stressors and aquatic biodiversity patterns. The results of this study highlight the need for long-term ecological monitoring and conservation in marshland habitats important for the resiliency of native species. Full article

The Mangalia–Limanu coastal lake system, located in southeastern Romania along the Black Sea, represents a transitional aquatic environment shaped by the interplay between freshwater and marine influences. This study provides an integrated assessment of its physicochemical water parameters, sedimentological and geochemical properties, and benthic macroinvertebrate communities, aiming to evaluate its current ecological status and environmental dynamics. Field measurements using a multiparameter sonde revealed a predominantly freshwater to oligohaline system with moderate spatial heterogeneity. DO levels frequently reached supersaturation (>180%), coupled with high pH (~9.1), indicating intense daytime photosynthetic activity. Conductivity, TDS, and salinity increased longitudinally toward the port water area, while nitrate concentrations showed stronger signals upstream. Sediments were dominated by organic matter (18–88%), with lower carbonate (3–53%) and siliciclastic (8–49%) contents. Organic-rich deposits prevailed in the western-central sector, where reduced hydrodynamics and submerged vegetation favor autochthonous organic accumulation, whereas the eastern sector, exposed to marine action, showed more siliciclastic-rich substrates. Geochemical analyses revealed localized exceedances of Cr, Ni, Cu, Zn, and Pb regulatory thresholds (Order 161/2006), suggesting potential contamination hotspots. Benthic communities included 26 taxa, dominated by polychaetas, gammarids, and gastropods, with moderate diversity (H′ < 2). The results highlight a system under moderate anthropogenic pressure but retaining transitional lagoon characteristics, emphasizing the need for continued ecological monitoring and integrated management measures. Full article

Lake Taihu, China’s third-largest freshwater lake, faces severe eutrophication challenges and therefore requires innovative ecological restoration strategies. This study systematically evaluates the ecological effects of aquatic vegetation restoration in Baimao Bay through comprehensive analysis of macrobenthic communities and environmental parameters, demonstrating significant water quality improvements including a 42.9% decrease in total phosphorus, a 69.4% decline in chl-a concentration, a 34.8% reduction in ammonium nitrogen, and a 81.2% increase in water transparency. Multivariate analysis revealed a fundamental ecological driver shift where post-restoration pH and transparency replaced nutrients as dominant factors, reducing total nitrogen/total phosphorus influence by 40–60%, while filter-feeding species (predominantly bivalves and gastropods) became the dominant macrobenthic biomass group (72.4%) with pollution-tolerant oligochaetes decreasing by 69.1% in abundance, alongside distinct spatial heterogeneity showing pH-regulated lakeshore communities (8.37 to 8.45), transparency-governed shallow-water communities (H′ = 1.35), and a residual nutrient-influenced deep-water area, with a shallow-water area (<2.5 m) unexpectedly exhibiting 3.2 times higher biomass (222.51 g/m²) than deep waters, highlighting vegetation-mediated habitat optimization. These findings advance restoration ecology theory by elucidating ecosystem transition mechanisms from nutrient-driven to light-regulated systems while providing a replicable technical framework for global shallow eutrophic lake restoration, establishing quantitative benchmarks including target transparency (>64 cm) and chlorophyll-a levels (<10 μg/L) for effective eutrophication reversal. Full article

Global awareness of introduced species as one of the primary drivers of biodiversity change—causing environmental impacts, and economic and social effects—emphasizes the need to enhance our understanding of these species. Developing a comprehensive database will enable policymakers to identify global bioinvasion patterns and strengthen their capacity to manage them effectively. Aquatic mollusks play a crucial role in the ecosystems they inhabit, influencing food webs and nutrient cycling, and habitat formation and modification. They are also the dominant group in aquaculture, contributing significantly to the economy while also causing economic losses through macrofouling and posing health risks. Despite their importance, information on the introduction, establishment, and dispersal of mollusk species in South America remains scarce and is often confined to the grey literature. With the aim of organizing, increasing, and strengthening the knowledge of non-native and transplanted mollusks in general and aquatic mollusks in particular, 29 specialists in the introduced mollusks of South America, from seven countries, have been working collaboratively since 2016. Each member contributes expertise, data, and bibliographic resources to build the status of the introduced mollusks in South America and provide critical information to prevent future introductions and transplants. In aquatic environments, 41 non-native mollusk species and 18 transplanted species have been identified. Among them, the bivalve Limnoperna fortunei stands out with the greatest economic effect, while the gastropods Lymnaeidae and Thiaridae represent significant health concerns. Although this research represents a major step forward, it also highlights challenges such as the scarcity of taxonomic studies and the limited investigation of vast areas in South America. The information compiled in this review serves as a resource for researchers, policymakers, and the general public when addressing mollusk bioinvasions in South America. Full article

While adult fireflies are terrestrial, their larvae inhabit various habitat types, and a lack of comprehensive research on the feeding habits of these larvae across different habitats has greatly impeded the development of artificial diets. Here, we tested 14 types of foods, primarily covering gastropods, vertebrates, and fruit, to survey feed for aquatic (Aquatica leii and Sclerotia substriata), semi-aquatic (Pygoluciola qingyu and Pygoluciola sp.), and terrestrial (Pyrocoelia analis) fireflies. The results show that A. leii, S. substriata, P. qingyu, Pygoluciola sp., and P. analis fed on 12, 6, 10, 10, and 7 different foods, respectively, showing an obvious difference in feeding range among various inhabit types of fireflies. Aquatic lineages preferred to consume freshwater snails, followed by pork meat and land slugs, while semi-aquatic fireflies favored freshwater snails, followed by fish and shrimp. Favorite foods were thus freshwater snails such as Cipangopaludina chinensis for both aquatic and semi-aquatic fireflies, but feeding preference differed for second favorite foods (e.g., pork vs. fish meat). Terrestrial Pyrocoelia analis showed different feeding preferences compared withthe other two habitat lineages, with terrestrial snails and slugs as their favorite foods, followed by freshwater snails, such as C. chinensis. These findings not only uncovered larval feeding habits of fireflies across various inhabit types but also indicated that readily available and affordable C. chinensis products can serve as wild snail alternatives in the artificial feeding of fireflies. This study is the first to explore the feeding habits of firefly species inhabiting water and land habitat types, adding to the understanding of the feeding characteristics of fireflies. Full article

Salt marshes support high biodiversity and provide essential ecosystem services, yet are increasingly threatened by climate change, reduced freshwater input, and human activities. This pilot study examined the physico-chemical characteristics and biodiversity of the Palud salt marsh in Istria, Croatia, during July 2021, focusing on phytoplankton, zooplankton, and macrozoobenthos communities across different habitats. The results show that while parameters like water temperature and pH remained stable, dissolved oxygen and nutrient levels fluctuated significantly. Water depth decreased due to drought and tidal oscillations, affecting salinity and nutrient concentrations. Phytoplankton communities were dominated by Bacillariophyta, with Cryptophyta, particularly Cryptomonas sp., having the highest abundance. Zooplankton communities were dominated by Rotifera, especially Brachionus plicatilis, while the macrozoobenthos communities were dominated by Ostracoda, with some variation in gastropod and chironomid abundance across sites. These findings indicate the dynamic nature of plankton and benthos communities in response to changing water levels in the Palud marsh. This study highlights the need for targeted conservation strategies to preserve the ecological integrity of Mediterranean salt marshes. Sustainable management practices must account for water level fluctuations, the role of aquatic vegetation, and the resilience of these ecosystems, emphasizing their importance in supporting biodiversity and ecosystem services in the face of environmental change. Full article

The research was carried out in calcareous fen habitats which share coverage with Natura 2000 sites designated under the EU Habitats and the Birds Directive. A total of 27 taxa of molluscs were recorded: 23 gastropod and 4 bivalve species. Anisus vorticulus, one of the species of Community interest whose conservation requires designation of special conservation areas within the Habitats Directive Natura 2000, was subrecedent and accedent in mollusc communities. Calcareous fen habitats offer the aquatic organisms harsh environmental conditions including a relatively high temperature of the water up to 33.29 °C (undrained fens), oxygen deficits in the water, high pH of up to 11.08 (fen pools) and conductivity above 3000 μS cm⁻¹ (fen ditches). Therefore molluscs have to face extreme environmental conditions. Temperature of the water, pH, dissolved oxygen and conductivity were the parameters most associated with the distribution of mollusc species in the calcareous fen habitats. The abundance of submerged and floating macrophytes, the degree of habitat persistence and the fish predation pressure on molluscs also exerted a significant effect on their distribution. The calcareous fen habitats that are listed in Annex I of the European Union Habitats Directive create a unique valuable ecosystem that contributes to the natural diversity of aquatic organisms. Full article

The artificially created Lake Pampulha, within the metropolitan area of Belo Horizonte, Minas Gerais State, lacks detailed information about its freshwater mollusks, representing a challenge for the assessment and conservation of this ecosystem. In this study, conducted during June and August 2021, we collected specimens on four different occasions and at five sampling points around the lake, using different sampling equipment, such as a shovel and a scoop. During these collections, we identified, enumerated and measured 1538 species of mollusks and additionally examined the presence of trematode larvae. We identified twelve species of fresh water bivalves and gastropods: Biomphalaria straminea, Biomphalaria kuhniana, Biomphalaria occidentalis, Drepanotrema cimex, Pomacea maculata, Stenophysa marmorata, Physa acuta, Gundlachia ticaga, Melanoides tuberculata, Pseudosuccinea columella, Omalonyx matheroni and Corbicula largillierti. Echinostome and strigeocercaria types of larval trematodes were detected in B. straminea. Notably, some species of mollusks have not previously been recorded at Lake Pampulha. The analyses revealed differences in the composition and abundance of species, highlighting the higher number of mollusk species in areas more impacted by human actions. This study expands our understanding of mollusk diversity at Lake Pampulha, and provides valuable data for longitudinal comparisons of water quality and considerations of the conservation of native species. Furthermore, it highlights the importance of choosing appropriate sampling equipment, depending on the research objectives. The presence of invasive species of medical and veterinary relevance as intermediate hosts of parasites reinforces the need for efficient environmental protection strategies to preserve this artificial, aquatic environment widely used by the local population and by tourists. Full article

Theodoxus fluviatilis (Linnaeus, 1758) (Gastropoda: Neritidae) is an oligohaline aquatic gastropod that inhabits most of Europe and adjacent areas of Asia. Two different ecotypes can be distinguished: One in freshwater (FW) and another along the Baltic Sea coast in brackish water habitats (BW). Individuals of either ecotype use free amino acids and urea as organic osmolytes to adjust body fluid osmolality to the external medium; however, the BW ecotype is able to accumulate them in larger quantities. The use of urea as an organic osmolyte in aquatic gastropods such as T. fluviatilis has only recently been initially described and raised the question of how urea transport between body fluids and the environment is balanced. Upon examining transcriptome and preliminary genome sequence data of T. fluviatilis, we identified putative homologues of DUR3 genes, which code for urea transporters (UTs) in other organisms. In this study, we provide evidence for the presence of four different subtypes of DUR3-like UTs that belong to two distinct families. Two of the UT subtypes were subject to qRT-PCR analyses to investigate differences in mRNA expression during the acclimation of individuals of both ecotypes to different salinities. Our results indicate that only BW animals regulate DUR3 gene expression in the context of osmoregulation. Full article

Gut microbes play a critical role in helping hosts adapt to external environmental changes and are becoming an important phenotype for evaluating the response of aquatic animals to environmental stresses. However, few studies have reported the role that gut microbes play after the exposure of gastropods to bloom-forming cyanobacteria and toxins. In this study, we investigated the response pattern and potential role of intestinal flora in freshwater gastropod Bellamya aeruginosa when exposed to toxic and non-toxic strains of Microcystis aeruginosa, respectively. Results showed that the composition of the intestinal flora of the toxin-producing cyanobacteria group (T group) changed significantly over time. The concentration of microcystins (MCs) in hepatopancreas tissue decreased from 2.41 ± 0.12 on day 7 to 1.43 ± 0.10 μg·g⁻¹ dry weight on day 14 in the T group. The abundance of cellulase-producing bacteria (Acinetobacter) was significantly higher in the non-toxic cyanobacteria group (NT group) than that in the T group on day 14, whereas the relative abundance of MC-degrading bacteria (Pseudomonas and Ralstonia) was significantly higher in the T group than that in the NT group on day 14. In addition, the co-occurrence networks in the T group were more complex than that in the NT group at day 7 and day 14. Some genera identified as key nodes, such as Acinetobacter, Pseudomonas, and Ralstonia, showed different patterns of variation in the co-occurrence network. Network nodes clustered to Acinetobacter increased in the NT group from day 7 to day 14, whereas the interactions between Pseudomonas and Ralstonia and other bacteria almost changed from positive correlations in the D7T group to negative correlations in the D14T group. These results suggested that these bacteria not only have the ability to improve host resistance to toxic cyanobacterial stress by themselves, but they can also further assist host adaptation to environmental stress by regulating the interaction patterns within the community. This study provides useful information for understanding the role of freshwater gastropod gut flora in response to toxic cyanobacteria and reveals the underlying tolerance mechanisms of B. aeruginosa to toxic cyanobacteria. Full article

Frequent outbreaks of harmful cyanobacterial blooms and the cyanotoxins they produce not only seriously jeopardize the health of freshwater ecosystems but also directly affect the survival of aquatic organisms. In this study, the dynamic characteristics and response patterns of transcriptomes and gut microbiomes in gastropod Bellamya aeruginosa were investigated to explore the underlying response mechanisms to toxic cyanobacterial exposure. The results showed that toxic cyanobacteria exposure induced overall hepatopancreatic transcriptome changes. A total of 2128 differentially expressed genes were identified at different exposure stages, which were mainly related to antioxidation, immunity, and metabolism of energy substances. In the early phase (the first 7 days of exposure), the immune system may notably be the primary means of resistance to toxin stress, and it performs apoptosis to kill damaged cells. In the later phase (the last 7 days of exposure), oxidative stress and the degradation activities of exogenous substances play a dominant role, and nutrient substance metabolism provides energy to the body throughout the process. Microbiomic analysis showed that toxic cyanobacteria increased the diversity of gut microbiota, enhanced interactions between gut microbiota, and altered microbiota function. In addition, the changes in gut microbiota were correlated with the expression levels of antioxidant-, immune-, metabolic-related differentially expressed genes. These results provide a comprehensive understanding of gastropods and intestinal microbiota response to toxic cyanobacterial stress. Full article

Surface collecting is the first and sometimes the only type of sampling carried out in many fossiliferous localities, including vertebrate microfossil assemblages. Nevertheless, it is rare to test how representative these surface-collected samples are of the palaeobiocoenosis. A first approach to the palaeontological analysis of Los Menires, a Barremian vertebrate microfossil assemblage, is here performed while testing the usefulness of the surface collection method. New fossil material obtained by surface collection is described, and the resulting data are compared with those obtained by screen-washing. The fossil assemblage of Los Menires is dominated by parautochthonous remains of freshwater aquatic and semiaquatic organisms—i.e., charophytes, ostracods, bivalves, gastropods, testudinatans, crocodylomorphs, lissamphibians, and osteichthyans—although parautochthonous remains of terrestrial vertebrates—i.e., dinosaurs, lacertilians, and mammaliforms—are also present. The accumulation of vertebrate hard parts in Los Menires took place in a low-energy, shallow-water, depositional environment within the alluvial-lacustrine system represented by the Mirambel Formation. Sampling test results indicate that surface collection is effective in recognizing the main fossil groups present in an assemblage. Yet, it is not suitable for capturing delicate and tiny fossils nor for recognizing the abundance of eggshells. In contrast, it can generate an overrepresentation of other hard components such as coprolites or ornithopod teeth. Full article

Freshwater gastropods play key roles in shallow aquatic ecosystems, with a central position in the periphyton–gastropod–fish trophic pathway, as they feed on periphyton and are preyed on by animals of higher trophic levels. Thus, it is of great interest to explore how climate change impacts the gastropod community and the trophic cascading effects on periphyton. Here, we constructed a simplified, shallow lake food web in 24 large mesocosm tanks to simulate warming (+4.5 °C) on the population responses of two common snails (Bellamya aeruginosa and Radix swinhoei) in two different systems (without/with common carp Cyprinus carpio) over 200 days. We found that warming lowered the biomass and density of R. swinhoei by 16.8% and 41.6%, respectively, and accelerated the average time of density peak of R. swinhoei by 21.5 days in the common carp-absent system. The density of B. aeruginosa in the warming with common carp group was lowered by 79.8% more than in the warming group without common carp. The averaged biomass and density of R. swinhoei in the fish-present system significantly lowered by 64.4% and 92.5%, respectively, compared to the fish-absent system. Cascading effects were also observed, as the snail communities declined under warming, that is, the grazing pressure on periphyton was less, resulting in its higher biomass. In conclusion, in the fish-absent system, warming decreased the biomass and density of the R. swinhoei, and in both snail populations, the biomass and density were much higher than those in the fish-present system. Due to the different phenology of snail species and species-specific predation, future stronger predation in a continuous warming condition might undermine the diversity of the gastropods, thereby changing food web structures in shallow freshwater ecosystems. Full article

Invertebrates have long been an important tool for assessing water pollution due to their characteristics as intermediate consumers in aquatic ecosystem food chains. Most of the time, the effects of contaminants are measured by their effect on oxidative status or by mortality, although there already exists an easier tool—hemocytes. Hemocytes are circulating cells with a very important role in the immune system of invertebrates, which can be found within the hemolymph, analogous to the blood in vertebrates. The collection of hemolymph samples is easy, fast, minimally invasive, and poses no danger to the life of invertebrates. The purpose of this review was to highlight the advantages of using hemolymph for toxicity assays of various substances, including heavy metals, micro- and nano-plastics, pesticides, hydrocarbons, and oil spills. A literature search was conducted for this purpose using the most common and most often used databases, with a focus on the most recent and relevant studies. Bivalve mollusks, crustaceans, and gastropods were chosen for this investigation. This review found a growing number of studies choosing to use hemolymph as the standard methodology for toxicology assays, confirming their qualities as reliable tools. Full article