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Nowadays, pesticides are an environmental problem because they can act on non-target species. Therefore, the search for new pest control methods has focused on compounds with low or no toxic effects. Analogs of the juvenile hormone are one such group of pesticides since they work by interfering in the endocrine system of arthropods. However, the lack of effect on non-target species is frequently assumed, and it requires confirmation. This article analyzes the impact of Fenoxycarb, an analog of juvenile hormone, on Physella acuta, an aquatic gastropod. Animals exposed for one week to 0.01, 1, and 100 μg/L were used to obtain RNA and perform retrotranscription and real-time PCR. Forty genes related to the endocrine system, the DNA repair mechanisms, the different phases of detoxification, oxidative stress, the stress response, the nervous system, hypoxia, energy metabolism, the immune system, and apoptosis were analyzed. Three of the genes, AchE, Hsp17.9, and ApA, showed responses to the presence of Fenoxycarb at 1 μg/L, with no statistically significant responses in the rest of the genes and at the remaining concentrations. From the results it can be concluded that Fenoxycarb shows low toxicity in Physella acuta. However, the fact that a gene related to immunity was altered prevents any conclusions in relation to the putative long-term effects that this juvenile hormone analog could have. Therefore, additional research would be necessary to confirm the safety of Fenoxycarb in non-arthropod species.

The species composition and distribution of freshwater gastropods in the western part of the Kola Peninsula and northern Karelia has been studied. The explored region lies in the far north of Europe and covers several landscape zones: from the northern taiga to the tundra. In sum, seventeen species were found, for each of them the distribution maps and photographs of intraspecific forms of conchological variability are presented. The taxonomic remarks are also given when appropriate. Gyraulus acronicus (Planorbidae) and Ampullacena balthica (Lymnaeidae) are the most common species in the studied region. Two species ( Ampullacena balthica and Galba truncatula ) have been recorded in the Barents Sea islands off the Kola Peninsula. A single non-indigenous species, Physella acuta (Physidae) has been registered in the studied territory. Based on the results of a comparison of the faunas of gastropods from various areas within the whole territory studied and other regions of northern Europe and Western Siberia, it has been shown that the most dramatic reduction in the species composition occurs during the transition from taiga to tundra landscapes.

A new snail-eating leech, Batracobdelloides bangkhenensis sp. n., was discovered at Kasetsart University, Bangkhen Campus, Bangkok, Thailand. This species is found free living in the benthic zone of ponds; feeds on freshwater snails, including Bithynia siamensis siamensis, Indoplanorbis exustus, Radix rubiginosa, Physella acuta, and Pomacea canaliculata; and uses a shell as a shelter during the parental care period, with a colony of 7-15 juvenile individuals held on the venter inside the shell of host. Batracobdelloides bangkhenensis displays distinct morphological characters, including a rice-shaped body showing transparency, cephalization, two eye pairs merged on somite III, an anterior sucker twice as large as the cephalic region, a central mouth in the anterior sucker, seven light brown transverse rows in the neck region, absent dorsal papillae, rich green pigments on the dorsum, a male gonopore on XIIa2/XIIa3 (27-28), a female gonopore on XIIIa1/XIIIa2 (29-30), and diffuse aggregations of minute, spherical salivary glands in the neck region. Comparisons of the COI and COI-ND1 genes showed a monophyletic clade for Batracobdelloides, and the phylogenetic tree of the COI gene also indicated that B. bangkhenensis is distinct from other species in the genus, with strong support values.

International audience; Herbicides are well known for unintended effects on freshwater periphyton communities. Large knowledge gaps, however, exist regarding indirect herbicide impacts on primary consumers through changes in the quality of periphyton as a food source (i.e., diet-related effects). To address this gap, the grazer Physella acuta (Gastropoda) was fed for 21 days with periphyton that grew for 15 days in the presence or absence of the herbicide diuron (8 mu g/L) to quantify changes in the feeding rate, growth rate, and energy storage (neutral lipid fatty acids; NLFAs) of P. acuta. Periphyton biomass, cell viability, community structure, and FAs served as proxies for food quality that support a mechanistic interpretation of the grazers' responses. Diuron changed the algae periphyton community and fatty acid profiles, indicating alterations in the food quality, which could explain differences in the snails' feeding rate compared to the control. While the snails' growth rate was, despite an effect size of 55%, not statistically significantly changed, NLFA profiles of P. acuta were altered. These results indicate that herbicides can change the food quality of periphyton by shifts in the algae composition, which may affect the physiology of grazers.

This study is combined the data from two different studies that carried out different regions and time, presenting some information on the population structure (dominance, local distribution etc.) of Potamopyrgus antipodarum (Gray, 1843). According to our data, this species was found in the four different localities in the Delice River with various population densities. However, only of small population was found in the Kocabaş Stream. This species was the second dominant species in the Delice River with 31.43 % after Physella acuta (Draparnaud, 1805) (46.88%). On the other hand, the species was not reached noticeable aggregates in the Kocabaş Stream. In this paper, supporting factors that paving the way P. antipodarum invasion are discussed for the study area.

First records of invasive bivalve freshwater mollusc species Mytilopsis leucophaeata (Conrad, 1831) and Corbicula fluminalis (O. F. Müller, 1774) in Georgia are reported. No native or alien extant dreissenid species have ever been recorded form this region so far. A finding of C. fluminalis in Georgia is also a new record for the country though this species inhabits the rivers of adjacent Azerbaijan. Apart from two mentioned bivalve molluscs three non-indigenous gastropod species are registered from Georgia: freshwater Ferrisia californica (Rowell, 1863) and Physella acuta (Draparnaud, 1805) and land snail Eobania vermiculata (O. F. Müller, 1774).

48. Physella acuta (Draparnaud, 1805) Findings in Serbia. Phvsa acuta: Matoničkin et al. (1975); Jovanović (1990); Arambašić (1994); Karaman & Živić (2001); Marković et al. (2012, 2015); Martinović-Vitanović et al. (2013); Novaković (2014). Physa (Physella) acuta: Karaman (2001); Paunović et al. (2007 a). Haitia acuta: Karaman (2005). Physella (Costatella) acuta: Karaman & Karaman (2007). Physella acuta: Frank et al. (1990); Jovanović (1995 a); Reh et al. (1997); Novaković (2012, 2013, 2014); Marković et al. (2013); Raković et al. (2016). Common name. European Physa, tadpole snail, bladder snail and acute bladder snail. Morphology. Medium-sized snail (up to 16 mm /height). Sinistral, glossy, conical shell with acute apex. Mantle lacks finger-like extensions, and has gold spots, easily visible below the shell surface. Animal is black with violet hue. For more details see Welter-Schultes (2012: 56, figures in the middle and the top of the page). Distribution and ecology. Nearctic species, invasive in Europe (France as the first recipient region), present in Southern, Western and Central Europe. Standing and slowly flowing waters, tolerates drought and higher water temperatures. Prefers meso-to eutrophic waters with a muddy bottom (Glöer 2019). Widespread in Serbia: Danube, Sava, Tisza, Velika Morava, Zapadna Morava, Južna Morava, Karaš, Mlava, Nišava, Toplica, Brestovačka reka Rivers and DTD canals. Novaković (2014) has reported the highest abundances of this snail in medium-sized rivers with gravel-rocky bottom in central Serbia (Despotovica, Lepenica and Toplica Rievrs). Other remarks. Morphologically it resembles Physella gyrina (Say 1821), and can be misidentified. On the IUCN Red List it has been assessed as LC (Van Damme et al. 2017)., Published as part of Marković, Vanja, Gojšina, Vukašin, Novaković, Boris, Božanić, Milenka, Stojanović, Katarina, Karan-Žnidaršič, Tamara & Živić, Ivana, 2021, The freshwater molluscs of Serbia: Annotated checklist with remarks on distribution and protection status, pp. 1-64 in Zootaxa 5003 (1) on pages 26-27, DOI: 10.11646/zootaxa.5003.1.1, http://zenodo.org/record/5120059, {"references":["Draparnaud, J. P. R. (1805) Histoire naturelle des mollusques terrestres et fluviatiles de la France. Louis Colas, Paris, 140 pp.","Matonickin, I., Pavletic, Z., Habdija, I. & Stilinovic, B. (1975) Prilog valorizacije voda ekosistema rijeke Save. Sveucilisna naklada Liber, Zagreb, 95 pp.","Jovanovic, B. (1990) Prilog poznavanju faune Gastropoda (Mollusca) Deliblatske pescare. Glasnik Prirodnjackog muzeja, 45, 21 - 26. [in Serbian]","Arambasic, M. (1994) Composition and structure of mollusc fauna of the Yugoslav part of the Danube and saprobity estimation. In: Jankovic, D. & Jovicic, M. (Eds.), The Danube in Yugoslavia: Contamination, protection and exploitation. Institute for Biological Research Sinisa Stankovic, Beograd, pp. 124 - 130.","Karaman, B. & Zivic, I. (2001) Fauna Gastropoda (Mollusca) nekih fruskogorskih potoka (Vojvodina, Srbija). Zbornik radova Zasavica 2001, 1, 201 - 207. [in Serbian]","Markovic, V., Atanackovic, A., Tubic, B., Vasiljevic, B., Kracun, M., Tomovic, J., Nikolic, V. & Paunovic, M. (2012) Indicative status assessment of the Danube River (Iron Gate sector 849 - 1,077 rkm) based on the aquatic macroinvertebrates. Water Research and Management, 2 (2), 41 - 46.","Martinovic-Vitanovic, V. M., Rakovic, M. J., Popovic, N. Z. & Kalafatic, V. I. (2013) Qualitative study of Mollusca communities in the Serbian Danube stretch (river km 1260 - 863.4). Biologia, 68 (1), 112 - 130. https: // doi. org / 10.2478 / s 11756 - 012 - 0137 - 3","Novakovic, B. (2014) Distribution of the freshwater snail Physella acuta (Dreparnaud, 1805) in the 2009 - 2013 period. \" Zastita voda 2014 \", 2014, 77 - 81.","Paunovic, M., Csanyi, B., Knezevic, S., Simic, V., Nenadic, D., Jakovcev-Todorovic, D., Stojanovic, B. & Cakic, P. (2007 a) Distribution of Asian clams Corbicula fluminea (Muller, 1774) and C. fluminalis (Muller, 1774) in Serbia. Aquatic Invasions, 2 (2), 105 - 112. http: // doi. org / 10.3391 / ai. 2007.2.2.3","Karaman, B. (2005) Fauna Gastropoda (Mollusca) sliva Juzne Morave (Srbija i Crna Gora). Crnogorska Akademija nauka i umjetnosti, Glasnik odeljenja prirodnih nauka, 16, 41 - 49. [in Serbian]","Karaman, B. & Karaman, G. (2007) Catalogus of the freshwater snails (Mollusca, Gastropoda) of Serbia. Crnogorska Akademija Nauka i Umjetnosti Glasnik Odjeljenja prirodnih nauka, Podgorica, 17, 167 - 222.","Frank, C., Jungbluth, J. H. & Richnovszky, A. (1990) Die Mollusken der Donau vom Schwarzwald bis zum Schwarzen Meer: eine monographische Darstellung. Akaprint, Budapest, 142 pp.","Jovanovic, B. (1995 a) Vodeni puzevi (Gastropoda, Mollusca) podrucja Bora. Zbornik radova Nasa ekoloska istina, 3, 337 - 341. [in Serbian]","Reh, Z., Jovanovic, B. & Bobic, M. (1997) Preliminarna hidrobioloska istrazivanja Brestovacke reke. Zbornik radova Nasa ekoloska istina, 5, 126 - 131.","Novakovic, B. (2012) Indicative ecological status assessment of the Juzna Morava River based on aquatic macroinvertebrates. Water research and management, 2 (4), 45 - 50.","Markovic, V., Tomovic, J., Kracun, M., Ilic, M., Zoric, K., Vasiljevic, B., Atanackovic, A., Tubic, B. & Paunovic, M. (2013) Freshwater snails in the Belgrade region. \" EcoIst \" 13 \", Conference Proceedings, 21, 296 - 301.","Rakovic, J. M., Rakovic, B. M., Petrovic, A., Popovic, N., Duknic, J., Naunovic, Z. & Paunovic, M. (2016) Haplotype variation in the Physa acuta group (Basommatophora): genetic diversity and distribution in Serbia. Mediterranean Marine Science, 17 (1), 292 - 301. https: // doi. org / 10.12681 / mms. 1453","Welter-Schultes, F. W. (2012) European non-marine molluscs, a guide for species identification, planet poster editions. Planet Poster Editions, Gottingen, 674 pp. [in German]","Gloer, P. (2019) The freshwater gastropods of the West-Palaearctis. Biodiversity Research Laboratory, Hetlingen, 399 pp.","Van Damme, D., Ghamizi, M., Seddon, M. B., Budha, P. B., Dutta, J. & Cordeiro, J. (2017) Haitia acuta. The IUCN Red List of Threatened Species, 2017, e. T 155538 A 91354457. [downloaded 3 May 2021] https: // doi. org / 10.2305 / IUCN. UK. 2017 - 3. RLTS. T 155538 A 91354457. en"]}

Plastic pollution is one of the leading environmental problems. Phthalates are widely used plastic additives released into the environment. Although the effects of phthalates on vertebrates have been extensively studied, there is a knowledge gap regarding their effects on invertebrates. This work analyzes the impact of three phthalates, diethyl phthalate (DEP), benzyl butyl phthalate (BBP), and bis-(2-ethylhexyl) phthalate (DEHP), on the gastropod Physella acuta at the molecular level to establish the putative pathways involved in its response to them. By real-time PCR, we obtained the expression profile of 30 genes in animals exposed for 1 week to 0.1, 10, and 1000 μg/L of each phthalate. The genes cover DNA repair, detoxification, apoptosis, oxidative and stress responses, immunity, energy reserves, and lipid transport. The results show that while DEP and DEHP did not alter the mRNA levels, BBP modulated almost all the analyzed genes. It can be concluded that the impact of BBP is extensive at the molecular level. However, it cannot be dismissed that the increase in transcriptional activity is a general response due to this compound’s well-known role as an endocrine disruptor. Additional research is needed to elucidate the differences observed in the impact of these compounds on the gastropod P. acuta.

Several species of avian schistosomes are known to cause dermatitis in humans worldwide. In Europe, this applies above all to species of the genus Trichobilharzia. For Austria, a lot of data are available on cercarial dermatitis and on the occurrence of Trichobilharzia, yet species identification of trematodes in most cases is doubtful due to the challenging morphological determination of cercariae. During a survey of trematodes in freshwater snails, we were able to detect a species in the snail Physella acuta (Draparnaud, 1805) hitherto unknown for Austria, Trichobilharzia physellae; this is also the first time this species has been reported in Europe. Species identification was performed by integrative taxonomy combining morphological investigations with molecular genetic analyses. The results show a very close relationship between the parasite found in Austria and North American specimens (similarity found in CO1 ≥99.57%). Therefore, a recent introduction of T. physellae into Europe can be assumed.

We investigated the prevalence, morphological characters and molecular classifications of trematode cercariae in freshwater snails randomly collected from 59 sampling localities in Bangkok from May 2018 to March 2019. We used a crushing technique to observe the cercarial stage inside each snail body and amplified the internal transcribed spacer 2 regions of cercarial DNA using polymerase chain reaction methodology. The associated phylogenetic tree was reconstructed using Bayesian inference analyses. A total of 517 of 15 621 examined snails were infected with trematode cercariae, and the infected snails were classified into 11 species of seven families with a 3.31% overall prevalence of the infection. The Bithynia siamensis siamensis snail displayed the highest prevalence of infection (16.16%), whereas the Physella acuta snail exhibited the lowest prevalence (0.08%) of infection. Eight morphological types of cercariae were observed. The highest prevalence of infection was observed in mutabile cercaria (1.86%). Based on molecular investigations, the phylogram revealed eight cercaria types assigned to at least nine digenean trematode families, of which five belong to groups of human intestinal flukes. Although, with the exception of schistosome cercaria, trematode cercariae are not known to directly damage humans, understanding the general biology of trematode cercariae (including diversity, distribution, infection rates and host range) is important and necessary for the prevention and control of parasitic transmission that impacts aquatic cultivations, livestock farming and human health.

Los moluscos son un grupo altamente diverso en apariencia, anatomía, fisiología y ecología y representa el segundo mayor grupo de invertebrados. El objetivo del presente trabajo consistió en confeccionar un modelo matemático en función de variables meteorológicas, que permita predecir la distribución y abundancia de los gasterópodos fluviales y terrestres en el municipio Santa Clara, Cuba. Para ello se analizaron las cinco áreas de salud del municipio, en el período comprendido entre marzo y julio del 2019. Se colectaron especímenes en los ecosistemas con uso humano de estas áreas de salud, así como datos meteorológicos de la estación que mantiene vigilancia sobre ellas. En el desarrollo del modelo predictivo se empleó la Modelación Objetiva Regresiva (ROR). El área de salud con una mayor abundancia y diversidad de gasterópodos fue Capitán Roberto Fleites, la especie fluvial con una mayor distribución resultó ser Physella acuta (Draparnaud, 1805) y la más abundante, Tarebia granifera (Lamarck, 1816). En el caso de las especies terrestres ambos valores correspondieron a Praticolella griseola (Pfeiffer, 1841). Las variables meteorológicas con mayor influencia sobre los gasterópodos fueron las temperaturas y las precipitaciones; a medida que estas aumentan, disminuyen las cantidades de gasterópodos. El modelo de predicción introdujo a la temperatura mínima y la humedad relativa mínima como variables directamente proporcionales a la cantidad de gasterópodos; por otra parte, introdujo a la precipitación y la presión atmosférica como variables inversamente proporcionales. La influencia predicha del anticiclón del Atlántico resultó ser inversamente proporcional a la cantidad de gasterópodos esperada.

To analyze the response of the snail Physella acuta to Echinostoma paraensei, a compatible digenetic trematode, Illumina RNA-seq data were collected from snails with early infection (5 snails at 2 days post-exposure [DPE]) and established infection (4 snails, 8 DPE), and 7 control (unexposed) snails. A reference transcriptome (325,563 transcripts, including 98% of eukaryotic universal single-copy orthologs; BUSCO) and a draft P. acuta genome (employing available genomic Illumina reads; 799,945 scaffolds, includes 88% BUSCO genes) were assembled to guide RNA-seq analyses. Parasite exposure of P. acuta led to 10,195 differentially expressed (DE) genes at 2 DPE and 8,876 DE genes at 8 DPE with only 18% of up-regulated and 22% of down-regulated sequences shared between these time points. Gene ontology (GO) analysis yielded functional annotation of only 1.2% of DE genes but did not indicate major changes in biological activities of P. acuta between 2 and 8 DPE. Increased insights were achieved by analysis of expression profiles of 460 immune-relevant DE transcripts, identified by BLAST and InterProScan. Physella acuta has expanded gene families that encode immune-relevant domains, including CD109/TEP, GTPase IMAP, Limulus agglutination factor (dermatopontin), FReD (≥82 sequences with fibrinogen-related domains), and transcripts that combine C-type lectin (C-LECT) and C1q domains, novel among metazoa. Notably, P. acuta expressed sequences from these immune gene families at all time points, but the assemblages of unique transcripts from particular immune gene families differed between 2 and 8 DPE. The shift in profiles of DE immune genes, from early exposure to parasite establishment, suggests that compatible P. acuta initially respond to infection but switch to express immune genes that likely are less effective against E. paraensei but counter other types of (opportunistic) pathogens and parasites. We propose that the latter expression profile is part of an extended phenotype of E. paraensei, imposed upon P. acuta through parasite manipulation of the host, following successful parasite establishment in the snail after 2 DPE.

Endosulfan is a persistent pesticide that has been in use for more than five decades. During this time, it has contaminated soil, air, and water reservoirs worldwide. It is extremely toxic and harmful to beneficial non-target invertebrates, aquatic life, and even humans upon consumption, which is one of the many dangers of this pesticide since it biomagnifies in the food chain. The effects of three endosulfan concentrations (1, 10, and 100 µg/L) on the freshwater snail Physella acuta, an invasive cosmopolitan species, were examined over a week-long exposure period. Alterations in the expression of ten genes related to stress and xenobiotic detoxification were measured against the endogenous controls rpL10 and GAPDH by Real-Time polymerase chain reaction. Four genes are described here for the first time in this species, namely Hsp60, Grp78, GSTk1, and GSTm1. The rest of genes were Hsp90, sHsp16.6, cyp2u1, cyp3a7, cyp4f22, and MRP1. cyp2u1, sHsp16.6, and Grp78 expression were all altered by endosulfan. These results suggest a low pesticide concentration activates the acute response in P. acuta by affecting detoxification and stress responses and alter endoplasmic reticulum function and lipid metabolism. Furthermore, the newly identified genes extend the number of processes and cellular locations that can be analyzed in this organism.

The acute bladder snail Physella acuta (Draparnaud, 1805) was observed for the first time in the wild waters of Lithuania at one site in the lower reaches of the Nevėžis River in 2015. The restricted distribution and low density suggest recent introduction. Although P. acuta in the first half of the 20th century was reported in ponds of the Kaunas Botanical Garden, they appear to have vanished as of 2012. Thus we conclude that recent invasion into the wild most probably has resulted from disposal of aquarium organisms.

The freshwater snail Physella acuta was selected to expand the perspective of comparative snail immunology. Analysis of Physella acuta, belonging to the Physidae, taxonomic sister family to Planorbidae, affords family-level comparison of immune features characterized from Biomphalaria glabrata, the model snail often used to interpret general gastropod immunity. To capture constitutive and induced immune sequences, transcriptomes of an individual Physella acuta snail, 12 h post injection with bacteria (Gram -/+) and one sham-exposed snail were recorded with 454 pyrosequencing. Assembly yielded a combined reference transcriptome containing 24,288 transcripts. Additionally, genomic Illumina reads were obtained (∼15-fold coverage). Recovery of transcripts for two macin-like antimicrobial peptides (AMPs), 12 aplysianins, four LBP/BPIs and three physalysins indicated that Physella acuta shares a similar organization of antimicrobial defenses with Biomphalaria glabrata, contrasting a modest AMP arsenal with a diverse set of antimicrobial proteins. The lack of predicted transmembrane domains in all seven Physella acuta PGRP transcripts supports the notion that gastropods do not employ cell-bound PGRP receptors, different from ecdysozoan invertebrates yet similar to mammals (vertebrate deuterostomes). The well-documented sequence diversification by Biomphalaria glabrata FREPs (immune lectins comprising immunoglobulin superfamily domains and fibrinogen domains), resulting from somatic mutations of a large FREP gene family is hypothesized to be unique to Planorbidae; Physella acuta revealed just two bonafide FREP genes and these were not diversified. Furthermore, the flatworm parasite Echinostoma paraensei, confirmed here to infect both snail species, did not evoke from Physella acuta the abundant expression of FREP proteins at 2, 4 and 8 days post exposure that was previously observed from Biomphalaria glabrata. The Physella acuta reference transcriptome also revealed 24 unique transcripts encoding proteins consisting of a single fibrinogen-related domain (FReDs), with a short N-terminal sequence encoding either a signal peptide, transmembrane domain or no predicted features. The Physella acuta FReDs are candidate immune genes based on implication of similar sequences in immunity of bivalve molluscs. Overall, comparative analysis of snails of sister families elucidated the potential for taxon-specific immune features and investigation of strategically selected species will provide a more comprehensive view of gastropod immunity.

In the context of biological invasions, freshwater aquatic invertebrates represent one of the most successful groups of organisms. At the same time, the secondary hydrographic system of a river catchment acts as a preferential pathway for the dispersion of Non-Indigenous Species (NIS) to nearby ecosystems. The present study investigates the macrozoobenthos assemblage inhabiting 13 representative semi-natural streams of the secondary hydrographic system of the southern course of the River Ticino (Lombardy, Northern Italy). The level of biocontamination of the habitats under study was assessed by the Site-specific BioContamination Index (SBCI), which was paired with a preliminary screening of the NIS that may cause ecological and economic impacts at the sites under study using the recently-developed Aquatic Species Invasiveness Screening Kit (AS-ISK) tool. The SBCI classified one stream as ‘high class’, one as ‘good class’, two as ‘moderate class’, seven as ‘poor class’, and the remaining two as ‘bad class’. Six macrozoobenthic NIS were identified, namely the amphipod Gammarus roeselii, the gastropods Physella acuta, Potamopyrgus antipodarum and Pseudosuccinea columella, the bivalve Corbicula fluminea and the limpet Ferrissia fragilis. Based on the AS-ISK outcomes, the most potentially invasive species were C. fluminea followed by P. columella, both of which were categorised as ‘high risk’. Also, the potential invasiveness of the above species increased after accounting for climate change predictions, as did that for all other species assessed, hence regardless of their corresponding risk level. By combining the results of the SBCI index with those from AS-ISK, a first step is provided towards the identification and refinement of potential management strategies aimed to reduce the impacts of NIS in the RAA, whilst accounting for predicted effects of climate change.

The biocidal potential of Brevibacillus laterosporus against mosquitoes of major medical importance has been widely documented, but its effects on non-target invertebrates are still poorly known. In this study, we determined the lethal and sub-lethal effects of B. laterosporus strain UNISS 18, an entomopathogenic bacterium known for its effectiveness against synanthropic Diptera, on the larvae of the Asian tiger mosquito Aedes albopictus, a vector of several pathogens to humans. Moreover, we compared the larvicidal activity with the lethal action on the invasive snail Physella acuta and on two non-target water-dwelling species: the mayfly Cloeon dipterum, and the harlequin fly Chironomus riparius. B. laterosporus exhibited significant lethal effects on all the tested species with a concentration-dependent activity. However, the susceptibility varied among species, with a higher susceptibility of Ae. albopictus (LC50 = 0.16 × 107 spores mL−1) than the other species (LC50 = 0.31, 0.33, and 0.30 × 107 spores mL−1 for C. dipterum, C. riparius, and P. acuta, respectively). While 1st instar mosquito larvae were very susceptible to the bacterial infection, no effects on preimaginal development stages and adult emergence were observed at sub-lethal spores’ concentrations. Even if the efficacy of B. laterosporus against Ae. albopictus and the invasive freshwater snail P. acuta is promising for their control, the susceptibility of non-target beneficial aquatic insects, highlights the need of accurate evaluations before applying B. laterosporus for pest management in water environments.

We carried out field studies and laboratory experiments to assess the impact of fluoride (F−) and turbidity on the freshwater snail Physella acuta in a polluted river receiving an industrial effluent (the middle Duraton River, Central Spain). Fluoride concentrations and turbidity levels significantly increased downstream from the industrial effluent (with the highest values being 0.6 mg F−/L and 55.2 nephelometric turbidity unit). In addition, higher deposition of fine inorganic matter was evident at polluted sampling sites. Conversely, the abundance of P. acuta significantly declined (until its virtual disappearance) downstream from the industrial effluent. Toxicity bioassays showed that P. acuta is a relatively tolerant invertebrate species to fluoride toxicity, with estimated safe concentrations (expressed as LC0.10 values for infinite hours of exposure) for juvenile and adult snails being 2.4 and 3.7 mg F−/L, respectively. Furthermore, juvenile snails (more sensitive than adult snails) did not show significant alterations in their behavior through 15 days of exposure to 2.6 mg F−/L: mean values of the proportion of test snails located on the water surface habitat, as well as mean values of the sliding movement rate (velocity) of test snails, never showed significant differences when comparing control and treatment glass vessels. It is concluded that instream habitat degradation, derived from increased turbidity levels, might be a major cause for significant reductions in the abundance of P. acuta downstream from the industrial effluent. The presence of the competing gastropod Ancylus fluviatilis could also affect negatively the recovery of P. acuta abundance.

Physella acuta (Draparnaud, 1805) is an aquatic pulmonate snail notorious for its high invasive potential. Of New World origin, this species now occurs on all continents. The aim of this study was to trace P. acuta dispersal through the Western Palearctic starting from its first arrival in the Old World and to determine possible drivers of this process. A range of literary sources as well as some rich European malacological collections have been consulted to ascertain the dates of the first finding of P. acuta in the countries of Europe, Transcaucasia, and Central Asia and to map the most significant localities. The shell characteristics of this species are so distinctive that they almost preclude misidentification and confusion with any native species. This allows one to rely on historical records, including older sources (18th to the first half of the 19th centuries). The earliest reliable records of P. acuta in the Old World can be dated to 1742, which implies an earlier date for the first arrival of the species in Europe, possibly in the 17th century. Its introduction may be explained either by accidental dispersal mediated by humans (for example, during transport of exotic plants to European botanical gardens) or by natural causes (long-distance dispersal from the Americas to Europe). Three successive phases leading to the current invasive range of P. acuta in the Western Palearctic can be identified. The species’ current Old World range can be viewed as a result of the interaction of natural and anthropogenic factors. The human-mediated drivers of dispersal include canal building, the aquarium trade and, more recently, alteration of natural freshwater habitats.

Recently, a highly invasive alien species, the zebra mussel Dreissena polymorpha, has colonized Italian aquatic ecosystems that had been previously colonized by another highly invasive alien species—the North American crayfish Procambarus clarkii. This was the first time and world region where these two species met. To evaluate the relative importance of their interactions, we studied prey selection according to its length, as well as prey choice by P. clarkii preying on D. polymorpha in the presence and absence of alternative prey—the freshwater snail Physella acuta. We followed an optimability-based approach, by first estimating the most profitable length of each mollusc and then by conducting a prey choice experiment, on which both species were provided simultaneously to a crayfish with different size combinations. Prey selection was dependent on prey length, handling time and crayfish length for both molluscs. According to our profitability estimates, snails should be more profitable than mussels in the length range 7–10 mm, while for lengths over 11.0 mm, mussels should be more profitable. The results of the prey choice experiment indicated that D. polymorpha length, P. acuta length, and the difference in profitability between the offered individuals were all relevant for the choice of one species over the other by P. clarkii. However, the overall tendency was the choice of the smallest prey, regardless of species, and the estimates of prey profitability were not useful to predict prey choice. Our study shows that D. polymorpha represents a novel prey resource for P. clarkii, even in the presence of an alternative prey, and that zebra mussels may be a preferred prey, especially small-sized individuals (5–10 mm).

The majority of pharmaceuticals and personal health-care products are ionisable molecules at environmentally relevant pHs. The ionization state of these molecules in freshwater ecosystems may influence their toxicity potential to aquatic organisms. In this study we evaluated to what extent varying pH conditions may influence the toxicity of the antibiotic enrofloxacin (ENR) and the personal care product ingredient triclosan (TCS) to three freshwater invertebrates: the ephemeropteran Cloeon dipterum, the amphipod Gammarus pulex and the snail Physella acuta. Acute toxicity tests were performed by adjusting the water pH to four nominal levels: 6.5, 7.0, 7.5 and 8.0. Furthermore, we tested the efficiency of three toxicity models with different assumptions regarding the uptake and toxicity potential of ionisable chemicals with the experimental data produced in this study. The results of the toxicity tests indicate that pH fluctuations of only 1.5 units can influence EC50-48 h and EC50-96 h values by a factor of 1.4–2.7. Overall, the model that only focuses on the fraction of neutral chemical and the model that takes into account ion-trapping of the test molecules showed the best performance, although present limitations to perform risk assessments across a wide pH range (i.e., well above or below the substance pKa). Under such conditions, the model that takes into account the toxicity of the neutral and the ionized chemical form is preferred. The results of this study show that pH fluctuations can have a considerable influence on toxicity thresholds, and should therefore be taken into account for the risk assessment of ionisable pharmaceuticals and personal health-care products. Based on our results, an assessment factor of at least three should be used to account for toxicity differences between standard laboratory and field pH conditions. The models evaluated here can be used to perform refined risk assessments by taking into account the influence of temporal and spatial pH fluctuations on aquatic toxicity.

In this study we focused on Physella acuta, an alien snail species in order to determine their ability of bioaccumulation of heavy metals in their shells, bodies, the difference in accumulation in relation to age classes, and the influence of ecological variables on the community composition and density. On the basis of the results of ecological, toxicological, and experimental analyses we aimed to study the potential invasive features of P. acuta in comparision with the native species Stagnicola palustris. The content of Cu and Zn in the substratum and ammonia in the water was strongly related to the patterns of distribution of P. acuta. The content of Cd, Pb, and Cu in the shell fraction was always significantly lower than in the body fraction. A comparison of accumulation with respect to the size classes of P. acuta indicated that the lowest metal concentration in the body was typical for the largest individuals, except for Zn. Metal content in the bodies of the native species did not differ from the content measured in their analogous group of the largest individuals of P. acuta. The lowest value of bioaccumulation factor (BAF) was found for the large class of specimens of this species for each metal. A distinct decrease in the value of BAF in relation to the size of snails was found for cadmium. A 100% hatching success found in masses collected from pond confirmed the high reproductive potential of P. acuta which can be a factor that promotes its invasive features following its ability to occur in very high densities, but not necessarily the ability of metal accumulation in the body. Physella acuta can be used as a model organism in the studies on the accumulation of heavy metals however, the extend of accumulation can differ among the age classes. Because of the high tolerance of P. acuta to heavy metal pollution, in the future this species can be found in significantly polluted habitats, inhabiting free ecological niches, and occurring in high densities in snail communities.

Summary 1.Sediments accumulate chemicals that can be toxic to biota and often contribute to aquatic ecosystem decline. Measuring mortality in laboratory-bred organisms is a common way to assess sediment toxicity. However, mortality-based responses of resilient laboratory organisms may not reflect indigenous macroinvertebrate responses, which can be relatively more sensitive to sediment toxicants. A possible solution is to also measure responses at the sub-individual level. 2.Several organism responses to sediment copper toxicity were assessed in a field-based microcosm. Responses of laboratory-bred chironomids and snails deployed in microcosms were compared at sub-individual (metabolomic and gene expression), individual (survival and dry weight) and population (reproduction) levels, and contrasted to the abundance of colonizing macroinvertebrates in the microcosms. 3.Colonizing macroinvertebrate abundance showed a range of sensitivities based on EC50 (effect dose 50% change). Chironomidae made up 94.5% of the microcosm macroinvertebrates, with Paratanytarsus the most sensitive genus (EC50: 89 mg/kg copper) and Procladius the least sensitive (EC50: 681 mg/kg). 4.Survival of laboratory-bred organisms was the least sensitive response, comparable to decreased abundance of the least sensitive macroinvertebrate. Juvenile production in the snail, Potamopyrgus antipodarum, was the most sensitive population level response (EC50: 121 mg/kg), in contrast the snail Physella acuta was relatively more tolerant (EC50: 298 mg/kg). 5.Changes in sub-individual responses (gene expression and metabolite abundance) in laboratory-bred chironomid, Chironomus tepperi, were evident at 60 mg/kg. These changes likely reflect the direct effects of copper exposure and represent metal-specific responses. 6.Synthesis and applications. We showed that copper toxicity in sediments could be readily detected through changes in gene expression and metabolites in laboratory-bred chironomids exposed in field-based microcosms. These responses were more sensitive than mortality, and detected copper levels that caused microcosm chironomid populations to decline. These novel approaches will provide managers with new tools to better assess sediment toxicity. This article is protected by copyright. All rights reserved.

Freshwater mollusk Physella (Costatella) acuta (Draparnaud, 1805) was previously known in Eastern Europe from the Black Sea coasts to the southern part of the Baltic Sea basin. In 2015, population of Physella acuta was discovered in Lake Imandra (Kola Peninsula, 67°28′ N, 32°26′ E) in the spillway channel of the Kol’skaya Nuclear Power Plant affected by elevated water temperature. The finding of Physella acuta in the White Sea basin is the northernmost record of this species in Eurasia and the first finding of warm-water snail in the inland waters of Fennoscandia.