Melanoides Tuberculata Research Articles

Macrozoobenthos community structure as a bioindicator of water quality in the Banjaran River, Banyumas

The Banjaran River is one of the rivers in the Banyumas Regency. This research aims to produce information related to macrozoobenthic community structure as a bioindicator of water quality in the Banjaran River and to produce information related to water quality in the Banjaran River for macrozoobenthic life. The research was conducted in September 2022 – February 2023 on the Banjaran River, Banyumas. This research uses a survey method, sampling was carried out 3 times in September-November 2022. The sampling method was purposive random sampling, namely the river was divided into 3 stations based on certain criteria. The results of this research obtained 15 species and were divided into 11 families, namely Perlidae, Psychomyiidae, Thiaridae, Lumbricidae, Naididae, Gecarcinucidae, Palaemonidae, Elmidae, Hydropsychidae, Atyidae, and Chironomidae in the Banjaran River. The highest abundance of individuals was at station two, namely 3156 individuals/m2. The dominant species is Melanoides tuberculata with an abundance of 1852 individuals/m2 at station two. The dominance index values at the three stations ranged from 0.1864 to 0.2886, which is relatively low. The water quality in the Banjaran River for macrozoobenthic life is still quite good based on the results of measuring environmental parameters which consist of physical parameters, namely water temperature and current speed.Keywords: Banjaran River, Macrozoobenthos Community, Water Quality Indicators

Macrozoobentos Composition In The Babura River Sumatra Utara

To determine the composition of macrozoobenthos in the waters of the Babura river. The parameters measured are biological parameters, namely macrozoobenthos composition supported by physical and chemical parameters in the Babura river waters. The parameters measured in this research are biotic parameters, namely the type of macrozoobenthos and abiotic parameters, namely physical and chemical parameters. Physical parameters such as: temperature, turbidity, and chemical parameters such as: pH (degree of acidity), (DO), BOD, COD, and phosphate. Taking macrozoobenthos in shallow water using a quadrant and in deep water using an Eckman grab. Physical/chemical parameters are measured in situ and ex situ. Ex-situ is carried out in the BTKL laboratory. This type of research is ex-post de facto or only reveals existing data. Macrozoobenthos composition found in the Babura river: 1. There are six species of insects, namely Chironomus sp, Aeshna grandis, Dragonfiy nymph macronia, Agrion sp, Damsefly nymph, Dragonfly; 2. There are eight species of gastropods, namely: Thiara winteri, Thiara sp, Melanoides tuberculata, Melanoides rustica, Melanoides gramnifera, Brotia testudinaria, , Planorbis sp, Lymnaea rubiginosa; 3. There are two species of Hirudinea/Clitellata, namely Leeches and Glossiphoniidae; 4 There is one species of trematode, namely Pomatiopsis lapidaria Say; 5. There is one species of crustacean, namely Gammarus sp; 6. There is one species of nematode, namely the rolled worm; 7. There is one species of Oligochaeta, namely Tubifex sp; 8. There are three species of Turbilaria, namely Planaria sp, Dugesia sp, Mesostoma sp, so the macrozoobenthos composition consists of 8 classes with a total of 23 species. Physical/chemical parameters still support macrozoobenthos life in the waters of the Babura river.

Prediction of the potential Brazilian distribution for invasive mollusc Melanoides tuberculata (Müller, 1774), including a new record from Northern Coastal Region

The freshwater snail Melanoides tuberculata (Müller, 1774) native from Africa and Asia, recently spreads out over the world. Records of invasive species are extremely important, because it helps in future invasions mitigation. Here, we report for the first time the occurrence of M. tuberculata in a protected area of Northern Brazilian Coast and use predictive distribution modeling to know the potential Brazilian distribution for this species. The gastropod M. tuberculata were collected in the municipalities of Tutóia and Santo Amaro - Maranhão State. According to the results of the predictive map distribution for Brazil, the regions with the highest susceptibility are the northeast, southeast and midwest. Preciptation of month and Isothermalithy were de variables that most contribute to the species’ potential distribution. This species presented high to medium suitability of occurrence in 32 national protected areas. Futher studies are recommended to monitor the growth and dispersion, in order to determine its real impact.

Melanoides tuberculata and Zootecus insularis gastropod shells provide a snapshot into past hydroclimatic conditions of arid environments: New perspectives from Oman

Shells of the aquatic gastropod Melanoides tuberculata and the terrestrial gastropod Zootecus insularis were analysed using high-resolution isotope sampling (up to 274 samples per shell) to assess their potential use as a proxy for hydroclimatic and palaeoenvironmental reconstruction in drylands. A total of 169 snails (fossil and modern) were collected from 37 sites in Northern Oman and Dhofar, with each site selected for its specific geomorphological, archaeological or ecological context. This included fluvial terraces, playa environments, modern oasis gardens, irrigation channels and archaeological sites from the Neolithic (6,000–3,200 BCE) and Early Bronze Age (3,200–2,000 BCE) periods. The δ18O data obtained from these gastropods could be classified into eight different patterns, three for the aquatic snails (Type 1 A–C) and five for the terrestrial snails (Type 2 A–E), which were linked to the environmental context of their habitat. Furthermore, the use of the aquatic snails enabled us to distinguish between groundwater and surface water signals, whereas the terrestrial snails were employed to reconstruct changes in rainfall origin, humidity, evaporation, regular wet-dry cycles, and meteorological events. According to the results, gastropods can be used to elucidate the long-term, local evolution of rain-fed floodplain ecosystems in drylands and to identify the hydrological resources present in the vicinity of archaeological sites, particularly with regard to type 1 A-C (e.g., surface water vs groundwater).

Ecosystem links: Anthropogenic activities, environmental variables, and macrophytes structure snail preferences in man-made waterbodies

Freshwater snails act as obligate intermediate hosts for trematode parasites that cause trematodiases threatening public and veterinary health, and biodiversity conservation. While interest in snail control for trematodiases has re-emerged, their ecology remains poorly understood. We examined the relationship between ecosystem indicators – such as environmental variables, macroinvertebrates, macrophytes, and land use – and their correlation with snail abundance, diversity, and infection prevalence in 19 man-made ponds in eastern Zimbabwe. In total, 926 freshwater snails from 10 species were collected, with 547 individuals belonging to five schistosome-competent species: Bulinus tropicus, Bulinus truncatus, Bulinus globosus, Bulinus forskalii, and Biomphalaria pfeifferi. The remaining 379 snails comprised Radix natalensis, Gyraulus sp., and the exotic invasive species Melanoides tuberculata, Pseudosuccinea columella, and Physella acuta. Six cercarial types – mammalian schistosomes, avian schistosomes, longifurcate pharyngeates, echinostomes, amphistomes, and xiphidiocercariae – were isolated from 104 out of 926 snails (11.2 %). PCR revealed a significantly higher infection rate, with 70.2 % of snails testing positive for trematodes. Snail taxon diversity and infection rate significantly varied across land use types, with the lowest values observed in the commercial tobacco farm section, highlighting the potential adverse effects of agriculture on biodiversity. Ponds with extensive Lagarosiphon major (oxygen weed) coverage appeared to facilitate the presence and abundance of P. acuta and P. columella. Schistosome-competent snails such as B. truncatus and B. tropicus seemed to favor shallow water depths and more eutrophic sites characterized by high levels of nitrates, phytoplankton biomass, turbidity, and phycocyanin. These ponds were predominantly associated with the emergent macrophyte Cladium mariscus, revealing a potential association with important intermediate snail hosts. In conclusion, our study emphasizes the complex interplay among environmental factors, macrophyte composition, land use, and the abundance, diversity, and infection prevalence of freshwater snails, offering insights into potential strategies for targeted snail control and disease management in man-made waterbodies.

Invasion stage of the exotic snail Melanoides tuberculata related to environmental and biological factors in a subtropical river drainage

The mollusks represent the main invasive taxon of the freshwater ecosystem in North America. Environmental degradation may increase the susceptibility of the ecosystem to invasion and favor the abundance and density increment in some benthic mollusks. Melanoides tuberculata is a snail native from Africa and Asia that was introduced in Mexico in the sixties through aquarium activities. Its reproduction by parthenogenesis, fast growth, longevity, omnivore habits, and wide tolerance to pollution and environmental stressors, confers to this snail great capability like invasive species. However, the information concerning the relationships between the invasion stage of this exotic snail and environmental and biological variables is still unknown. This study aimed to document the establishment of several new registered populations of M. tuberculata in subtropical river drainage in central Mexico, since at least 10 years ago, and its relationship with indicator variables of environmental degradation. We visited 15 localities during the dry season in 2016 and 2022. At each study site, the macroinvertebrate assemblages were collected, and physical variables of habitat and physicochemical water characteristics were measured. In addition, the biological condition was assessed using aquatic macroinvertebrate assemblages. Each individual of M. tuberculata was counted and measured. The abundance and density of the snail with physical, chemical, and biological variables were correlated, and further multivariate analyses were performed to confirm these relationships. We demonstrated a positive relationship between the presence, abundance, and density of M. tuberculata with environmental variables that are indicators of degradation of physical attributes such as water flow alterations and loss of habitat heterogeneity in 2016 and 2022. We supported the hypothesis that anthropic habitat degradation can favor the invasion of M. tuberculata.

Assessment of the ecological status of an ancient reservoir using macroinvertebrate assemblage and water quality parameters

BackgroundAtori Reservoir, located in the heart of southwestern Nigeria, is a tribute to the region's historical significance and natural splendor. Its establishment as a reservoir in 1935 marked a water resource management watershed in the region, transforming Atori into one of Nigeria’s oldest and most important waterbodies. Despite its ancient age and indisputable importance, the exact ecological state of Atori Reservoir has been shrouded in mystery for decades. This study was necessitated by a paucity of information on the ecological status of Atori Reservoir.ResultsThe study identified 953 macroinvertebrates belonging to four classes, distributed across nine orders and nineteen families within Atori Reservoir. Among these, the class Insecta exhibited the highest diversity, while Melanoides tuberculata, a member of the Mollusca class, emerged as the dominant species. Despite the diverse macroinvertebrate community, the physicochemical parameters of the water raised concerns. Elevated values of total dissolved solids and conductivity indicated poor water quality, which was further reflected in the predominance of pollution-tolerant species and the absence of pollution-sensitive ones. Canonical correspondence analysis highlighted potential correlations between macroinvertebrates and water quality variables, yet statistical significance was lacking, as demonstrated by the Monte Carlo permutation test.ConclusionThis study sheds light on the ecological state of Atori Reservoir, revealing a diverse macroinvertebrate community but highlighting concerns regarding water quality. The study also emphasizes the pressing need for improved management practices to safeguard the ecological health of Atori Reservoir, given the critical role it plays in the region's ecosystem and local communities.

The physical soldier caste of an invasive, human-infecting flatworm is morphologically extreme and obligately sterile

We show that the globally invasive, human-infectious flatworm, Haplorchis pumilio, possesses the most physically specialized soldier caste yet documented in trematodes. Soldiers occur in colonies infecting the first intermediate host, the freshwater snail Melanoides tuberculata, and are readily distinguishable from immature and mature reproductive worms. Soldiers possess a pharynx five times absolutely larger than those of immature and mature reproductives, lack a germinal mass, and have a different developmental trajectory than reproductives, indicating that H. pumilio soldiers constitute a reproductively sterile physical caste. Neither immature nor mature reproductives showed aggression in in vitro trials, but soldiers readily attacked heterospecific trematodes that coinfect their host. Ecologically, we calculate that H. pumilio caused ~94% of the competitive deaths in the guild of trematodes infecting its host snail in its invasive range in southern California. Despite being a dominant competitor, H. pumilio soldiers did not attack conspecifics from other colonies. All prior reports documenting division of labor and a trematode soldier caste have involved soldiers that may be able to metamorphose to the reproductive stage and have been from nonhuman-infectious marine species; this study provides clear evidence for an obligately sterile trematode soldier, while extending the phenomenon of a trematode soldier caste to freshwater and to an invasive species of global public health concern.

Forecasting the potential distribution and niche of two similar gastropod species in South America: the intermediate host of schistosomiasis Biomphalaria glabrata and the invasive Melanoides tuberculata

Forecasting the potential distribution and niche of two similar gastropod species in South America: the intermediate host of schistosomiasis Biomphalaria glabrata and the invasive Melanoides tuberculata

Toxicity of CuSO4.5H2O on Some Snails in Al-Shamiyah River, Al-Diwaniyah City

The toxicity of copper sulfate was tested as part of the current research (CuSO4.5H2O) as it impacts freshwater snails of three species. Species Melanoides tuberculata, Melanopsis praemorsa, and Viviparus bengalensis are chosen for conducting the current research. Stock solution of copper sulphate was prepared previously and series of concentrations were conducted and were 0, 0.3, 0.5, 0.7, 0.9, and 1 ppm. Then, the mortality of tested species were recorded at each intermittent periods and were 24, 48, 72, 96 hours, respectively of which death has been noticed and recorded. LC50 values were ranged between 0.21 to 0.41, as recommended for application in the farms. To conclude, copper sulphate is highly toxic to laboratory test organisms. More research in this regard should be taken into account in agricultural and environmental work and avoid excessive use of toxic substance as they are common pollutants to freshwaters such as rivers.

Epidemiological aspects and malacofauna of the São Francisco River, northeastern Brazil

Limnic mollusks could negatively affect the ecosystem in which they are found, the economy, human and animals´ health. This study reports on a survey of freshwater sources mollusks and their spatial distribution, as well as investigating them for the presence of trematodes in the municipality of Nossa Senhora de Lourdes, Sergipe, Brazil. This study was performed through March 2016 and November 2017. The mollusks were collected in different water bodies in the georeferenced studied area, identified and analyzed for the presence of trematodes. Thirty-four water bodies were sampled, and mollusks were found in 18 (53%) of them. From the 5,196 found, 4,747 (91%) were gastropods and 449 (9%) bivalves - distributed in seven families and eleven species. Among the species found, two are of medical-veterinary importance (Biomphalaria straminea and Melanoides tuberculata) and four are exotic invasive species (Corbicula fluminea, C. largillierti, Limnoperna fortunei and M. tuberculate). Of the 1,473 mollusks analyzed for trematodes, five (0.33%) gastropods were infected, one specimen contained Vivax, two Pleurolophocercous, and two Virgulate. For the first time these six taxa have been described in the State of Sergipe: Drepanotrema depressissimum, D. cimex, D. lucidum, Ancylidae, Physa acuta and C. largillierti. This survey contributes to the knowledge of the biodiversity and spatial distribution of limnic mollusks and the presence of trematodes, in addition to serving to support the monitoring and prevention of exotic bio invasive species, and intermediate hosts, since the studied area presented potential for helminth transmission. KEY WORDS: Snails; trematodes freshwater sources; spatial distribution; exotic and invasive mollusks; Sergipe State.

Benthic Macroinvertebrates Composition, Diversity and Distribution of Daberam Reservoir, Katsina State, Nigeria

Study’s Novelty/Excerpt This study offers insight into the diversity and distribution of benthic macroinvertebrates in the Daberam Reservoir, Katsina State, highlighting their role as bioindicators for assessing aquatic health. By identifying and analyzing 1,483 individuals across various taxa, with Melanoides tuberculata being the most prevalent species, the research underscores the correlation between low diversity in certain sampling stations and high pollutant levels. These findings contribute valuable data to the understanding of aquatic ecosystem dynamics in the region and emphasize the need for stringent environmental protection measures to mitigate human impact. Full Abstract Macrobenthic invertebrates are significantly considered to be bioindicators by providing a key concept in understanding the dynamics in aquatic conditions rather than chemical and microbiological data, which at least give short-term fluctuations. Recent trends in hydrobiological research show a drastic decline in the aquatic fauna. However, this research aimed to identify the benthic macroinvertebrates’ diversity and distribution in the Daberam reservoir of Katsina State. The reservoir serves multiple purposes for different individuals, ranging from domestic to economic activities such as fishing and irrigation farming around the reservoir. The water samples were collected from four (4) different sampling stations (A, B, C and D). Collection of the Bethic Macro invertebrates was conducted around 8:00 am monthly for 10 months from each sampling station using a circular framed sieve (250µm mesh size). The samples collected were fixed in the field with 10% formalin and subsequently preserved in 70% ethyl alcohol for further analysis. A standard identification chart (Identification guide to freshwater macroinvertebrates) was used to classify the Benthic Macro invertebrates into various taxa and species. The abundance and distribution of macro benthic invertebrates were compared using One Way ANOVA) and significant differences between the sampling stations were tested using chi-square at 5% level of significance. The present study has identified 1483 individuals of benthic macro invertebrates in the Daberam Reservoir of Katsina state. Mollusca (29.63%) is the most dominant group, followed by Diptera (22.22%), Coleoptera (14.81%), Oligochaetae (14.81%); Hemiptera (11.11%), Ephemeroptera (3.70%): and Odonata (3.70%) are the least prevalent with only one specie each. Melanoides tuberculata was found to have the highest number of occurrences, with a total number of 332 individuals across all the sampling sites representing (22.25%). The highest number of benthic macro invertebrates recorded was in Site D, with a cumulative total number of 603 (40.42%) organisms. Site B recorded the least total number of benthic macro invertebrates with a cumulative total number of 250 (16.76%) organisms. The low diversity of macrobenthic invertebrates in some sample stations in the study area was an indication of the presence of high levels of pollutants in the water bodies. Strict environmental protective measures are required to reduce human stressors within the study area.

Malacological news from the Czech and Slovak Republics in 2023

This paper presents important faunistic records conducted in the Czech and Slovak Republics during 2023. We also include records generated before 2023, which have yet to be published, mainly because their correct identification was unavailable earlier. In a separate section we present records of unintentionally introduced species, reported for the first time for the countries from greenhouses (Dryachloa dauca and Guppya gundlachii). The first outdoor colony of Melanoides tuberculata was found in a stream artificially heated by wastewater from the Dukovany nuclear power plant and Planorbella duryi found in a brook with thermal water flowing from the Sliač spa. Records of native species include findings of protected and rare species (e.g., Aplexa hypnorum, Ladislavella occulta, Daudebardia brevipes, and Theodoxus danubialis), but also still poorly known species (Ampullaceana lagotis and Pyramidula saxatilis). During 2023, many new records were made for non-native and currently spreading species as for example Clathrocaspia knipowitschii, Corbicula fluminea, Hygromia cinctella, Krynickillus melanocephalus, Sinanodonta woodiana, and Tandonia kusceri.

First occurrence of Melanoides tuberculata (O. F. Müller, 1774) in an open environment in the Czech Republic

The invasive species Melanoides tuberculata (O. F. Müller, 1774) is reported from the open environment from the Czech Republic for the first time. An abundant population was found in the artificially heated Skryjský potok, a stream which flows from the cooling reservoir below the Dukovany nuclear power plant. The species is unlikely to occur outside the heated water due to its affinity for warm water.

Monitoring Environmental Changes in the Shatt al-Arab River Using the Organic Pollution Index (OPI) and Two Species of Benthic Invertebrates Melanoides tuberculata and Neritina violacea

Monitoring Environmental Changes in the Shatt al-Arab River Using the Organic Pollution Index (OPI) and Two Species of Benthic Invertebrates Melanoides tuberculata and Neritina violacea

Salt tolerance and survival of the freshwater bioinvasive gastropod Melanoides tuberculata (Thiariidae): when different methodologies tell us different stories

ABSTRACT The study of the ecophysiology of invasive species is one of the main steps in understanding the dynamics of territorial expansion of these species and establishing prevention, control, and combat measures and protocols. For freshwater molluscs, one of the main limiting factors is salinity. Laboratory tests closer to reality are needed to make more efficient models. Melanoides tuberculata is an invasive freshwater snail monitored worldwide, and it also has implications for human health. Recent studies supported that its rapid expansion has been enabled through its adaptation to both estuarine conditions and saline waters. The present study aims to determine the real tolerance range of M. tuberculata through a stepwise acclimation test as a more realistic model of a transitional gradient from a lentic to an estuarine environment and so determine the real potential for salinity adaptation. It also aims to check differences in the tolerance responses between age groups and life history, using two distinct populations subject to distinct ambient conditions. The stepwise acclimation test was effective in proving that M. tuberculata may be highly adaptable to salinity variation, contrasting with all previous tests. Thus, the results support the hypothesis of dispersion via estuaries by salinity-tolerant M. tuberculata juveniles.

Transversotrema hafniensis n. sp. infection in Poecilia reticulata by cercariae released from Melanoides tuberculata in Denmark

BackgroundExotic and ornamental fish are highly popular companion animals resulting in a significant transcontinental trade of fish, invertebrates and aquatic plants. A major issue is the diseases associated with these organisms, as they have a major impact on health of the fish in both public and private household aquaria. A secondary issue is the trade with these products, which potentially may expand the distribution area and spread a range of diseases to new habitats.ResultsWe here describe how Poecilia reticulata (guppy), produced in a private household aquarium, were invaded by cercariae of an exotic trematode released by imported Melanoides tuberculata snails. The fish presented with severe clinical signs (tremor, flashing, scraping of body against objects). A standard parasitological examination and morphometric identification showed scale pocket infections with a digenean trematode species within the genus Transversotrema. Molecular identification by PCR, sequencing and phylogenetic analyses of a 2646 bp sequence encoding ribosomal RNA (partial 18 S, ITS1, 5.8 S, ITS2, partial 28 S) was performed. The 1107 bp sequence of mitochondrial DNA (cox1) showed that the parasite differed from previously described Transversotrema species in M. tuberculata. Morphometrics of adult and larval specimens of this isolate also differed from previously described freshwater species within the genus. The new species was described and is named after Copenhagen, for its geographic origin.ConclusionsThe genus Transversotrema comprises a range of species, adapted to a microhabitat in scalepockets of teleosts. A combination of morphological and molecular characterization techniques has been shown to provide a good differentiation between species. The fish were not purchased from a pet shop but produced in the home aquarium. This indicated that an infection pressure existed in the aquarium, where the source of infection was found to be exotic intermediate host snails M. tuberculata, which originally were imported and purchased from a pet shop. The potential spread of fish diseases associated with trade of fish and snails to new geographic regions, where climate conditions are favourable, is discussed.

DULCITRANSVERSOTREMA N. GEN. (DIGENEA: TRANSVERSOTREMATIDAE) AND FIRST MORPHOLOGICAL AND NUCLEOTIDE-BASED CONFIRMATION OF THE LIFE CYCLE OF A TRANSVERSOTREMATID IN NORTH AMERICA.

We propose Dulcitransversotrema n. gen. for the freshwater transversotrematids Dulcitransversotrema patialense (Soparkar, 1924) n. comb. and Dulcitransversotrema chauhani (Agrawal and Singh, 1960) n. comb. Dulcitransversotrema is unique by the combination of lacking an oral sucker and an extensively coiled uterus as well as having testes that are not deeply lobed and that abut or nearly abut the inner posterolateral margins of the digestive tract (vs. deeply lobed testes that abut the cyclocoel region of the digestive tract only or that do not abut the ceca), a pre-oral genital pore (vs. post-oral genital pore), an ovary that is anterior to and abuts or nearly abuts the sinistral testis (vs. an ovary that is separated from the sinistral testis by some distance or having an ovary that is median and immediately pre-testicular), non-embryonated eggs (vs. embryonated eggs), typically having none or sparse vitelline follicles between the testes and ceca (vs. having a wholly inter-cecal vitellarium comprising a pair of highly compacted clusters of vitelline follicles anterolateral to the testes or having numerous vitelline follicles between the testes and ceca), an oblong, median, and primarily inter-testicular vitelline reservoir (vs. an extensively elongate, pre-testicular vitelline reservoir that arches anteriorly around the sinistral testis), and a subterminal excretory pore opening on the dorsal body surface between the level of the cyclocoel and posterior body end (vs. a terminal excretory pore). We describe the redia and cercaria of Dulcitransversotrema cf. patialense from the red-rimmed melania snail, Melanoides tuberculata (Müller, 1774) (Cerithioidea: Thiaridae), and their corresponding adult from beneath the scales of the zebrafish, Danio rerio (Hamilton, 1822) (Cypriniformes: Danionidae). All hosts were sampled from a spring-fed earthen pond at a private aquaculture facility near Ruskin, Florida. No transversotrematid life cycle was known from North America previously. The large subunit ribosomal DNA and ribosomal internal transcribed spacer 2 sequences of D. cf. patialense from Florida were most similar to those from D. patialense infecting red-rimmed melania from Mayagüez, Puerto Rico and differed by 134 and 69 nucleotides, respectively. Both phylogenetic analyses recovered Dulcitransversotrema as monophyletic and sister to a clade comprising Transversotrema spp. plus Crusziella formosa Cribb, Bray, and Barker, 1992.

Multiple invasions and predation: The impact of the crayfish Cherax quadricarinatus on invasive and native snails.

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.

Diversity of Freshwater Mollusks from Lake Pampulha, Municipality of Belo Horizonte, Minas Gerais, Brazil

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.