Freshwater mussels (Anodonta anatina) reduce transmission of a common fish trematode (eye fluke, Diplostomum pseudospathaceum)

SUMMARYRecent results suggest that bivalves can play an important role in restraining the spread of various aquatic infections. However, the ability of mussels to remove free-living stages of macroparasites and reduce their transmission is still understudied, especially for freshwater ecosystems. We investigated the influence of the common freshwater mussel (Anodonta anatina) on the transmission of a trematode (eye fluke, Diplostomum pseudospathaceum), which frequently infects fish in farms and natural habitats. In our experiments, mussels caused a significant decrease (P < 0·001) in the abundance of trematode free-living stages, from 6520 to 1770 cercariae L−1 on average (about 4-fold in 2 h). Individual clearance rates of mussels were 0·6‒3·7 L per hour (mean 1·9). These tests were followed by experimental infections of rainbow trout (Oncorhynchus mykiss) with different doses of D. pseudospathaceum cercariae in the presence or absence of mussels. Exposure of fish to cercariae in the presence of mussels significantly (P < 0·05) reduced the infection intensities in fish (by 30–40%) at all exposure doses. Our results indicate that freshwater bivalves can markedly reduce local cercariae densities and could be useful in mitigation of trematodoses harmful to fish farming.

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Innate antipredator behavior can promote infection in fish even in the absence of predators

Behavioral Ecology ◽

10.1093/beheco/arz188 ◽

2019 ◽

Vol 31 (1) ◽

pp. 267-276 ◽

Cited By ~ 2

Author(s):

Victor N Mikheev ◽

Anna F Pasternak ◽

Andrew Yu Morozov ◽

Jouni Taskinen

Keyword(s):

Antipredator Behavior ◽

Parasite Burden ◽

Fish Farming ◽

Ventilation Rate ◽

Diplostomum Pseudospathaceum ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Microhabitat Choice ◽

Commercial Species ◽

Eye Fluke

Abstract Natural enemies—predators and parasites—largely shape the dynamics of ecosystems. It is known that antipredator and antiparasite defense can be mutually conflicting, however consequences of this trade-off for the regulation of infection burden in animals are still poorly understood. We hypothesize that even in the absence of cues from predators, innate antipredator behavior (“ghost of predation past”) interferes with defense against parasites and can enhance the infection risk. As a case study, we explore interactions between a commercial species, the rainbow trout Oncorhynchus mykiss, and its parasite, the trematode eye-fluke Diplostomum pseudospathaceum. Fish–parasite interactions were tested in compartmentalized tanks where shelters and parasites were presented in different combinations providing various conditions for microhabitat choice and territorial behavior. Shelters were attractive and contestable despite the absence of predators and presence of parasites. The individuals fighting for shelters acquired more than twice the number of cercariae as compared to those in infected shelter-free compartments. Most infected were subordinate fish with a higher ventilation rate. Fish possessing shelters were less vulnerable to parasites than fighting fish. Grouping reduced the infection load, although less efficiently than sheltering. Our data demonstrate that the innate antipredator behavior can undermine antiparasite tactics of the fish and result in higher infection rates. Using our empirical results, we construct a mathematical model which predicts that enriching the environment in fish farming will be beneficial only when a large number of shelters is provided. Using insufficient number of shelters will increase the parasite burden in the fish.

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The Patterns and Puzzles of Genetic Diversity of Endangered Freshwater Mussel Unio crassus Philipsson, 1788 Populations from Vistula and Neman Drainages (Eastern Central Europe)

Life ◽

10.3390/life10070119 ◽

2020 ◽

Vol 10 (7) ◽

pp. 119

Author(s):

Adrianna Kilikowska ◽

Monika Mioduchowska ◽

Anna Wysocka ◽

Agnieszka Kaczmarczyk-Ziemba ◽

Joanna Rychlińska ◽

...

Keyword(s):

Genetic Diversity ◽

Genetic Structure ◽

Spatial Scales ◽

Freshwater Mussel ◽

Its Region ◽

Strong Relationship ◽

Mantel Test ◽

Freshwater Ecosystems ◽

Hierarchical Organization ◽

Anthropogenic Factors

Mussels of the family Unionidae are important components of freshwater ecosystems. Alarmingly, the International Union for Conservation of Nature and Natural Resources Red List of Threatened Species identifies almost 200 unionid species as extinct, endangered, or threatened. Their decline is the result of human impact on freshwater habitats, and the decrease of host fish populations. The Thick Shelled River Mussel Unio crassus Philipsson, 1788 is one of the examples that has been reported to show a dramatic decline of populations. Hierarchical organization of riverine systems is supposed to reflect the genetic structure of populations inhabiting them. The main goal of this study was an assessment of the U. crassus genetic diversity in river ecosystems using hierarchical analysis. Different molecular markers, the nuclear ribosomal internal transcribed spacer ITS region, and mitochondrial DNA genes (cox1 and ndh1), were used to examine the distribution of U. crassus among-population genetic variation at multiple spatial scales (within rivers, among rivers within drainages, and between drainages of the Neman and Vistula rivers). We found high genetic structure between both drainages suggesting that in the case of the analyzed U. crassus populations we were dealing with at least two different genetic units. Only about 4% of the mtDNA variation was due to differences among populations within drainages. However, comparison of population differentiation within drainages for mtDNA also showed some genetic structure among populations within the Vistula drainage. Only one haplotype was shared among all Polish populations whereas the remainder were unique for each population despite the hydrological connection. Interestingly, some haplotypes were present in both drainages. In the case of U. crassus populations under study, the Mantel test revealed a relatively strong relationship between genetic and geographical distances. However, in detail, the pattern of genetic diversity seems to be much more complicated. Therefore, we suggest that the observed pattern of U. crassus genetic diversity distribution is shaped by both historical and current factors i.e. different routes of post glacial colonization and history of drainage systems, historical gene flow, and more recent habitat fragmentation due to anthropogenic factors.

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Elemental composition of mantle tissue granules in Hyridella depressa (Unionida) from the Hawkesbury-Nepean River system, Australia: inferences from catchment chemistry

Marine and Freshwater Research ◽

10.1071/mf98083 ◽

2000 ◽

Vol 51 (2) ◽

pp. 183 ◽

Cited By ~ 14

Author(s):

Maria Byrne ◽

Peter A. Vesk

Keyword(s):

Freshwater Mussel ◽

River System ◽

Direct Analysis ◽

Common Elements ◽

Mantle Tissue ◽

South Wales ◽

The Common ◽

Australian Freshwater ◽

River Site

The Australian freshwater mussel Hyridella depressa sequesters elements in calcium phosphate (CaP) granules that form extensive aggregations in its tissues. Elements contained in these granules were determined by X-ray microanalysis of river and lake mussels from the Hawkesbury–Nepean River system, New South Wales. Granules in freeze-substituted mantle tissue were analysed to determine the variation in element profiles in granules among mussels and among sites. For the common elements Ca, P, Fe, Mg and Mn, granule composition reflected catchment lithology and site trophic status and indicated exogenous input. These were most important for differentiation among lake sites and also indicated differences between lake and river mussels. Site differences seen with some common elements in granules from lake mussels correlated with differences in water chemistry. Trace elements, particularly Al, Cu, Zn and Pb, were also important in lake and river site differentiation. The granules play a major role in element dynamics in freshwater mussel tissues and provide a focal structure for direct analysis of element accumulation by these bivalves. The results indicate that characterization of element content of granules in mussel populations would provide valuable insights into animal–element interactions in freshwater systems for ecological and ecotoxicological investigations.

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Free-living freshwater nematodes from Brazil: checklist of genera and regional patterns of diversity

Nematology ◽

10.1163/15685411-bja10100 ◽

2021 ◽

pp. 1-14

Author(s):

Taciana Kramer de Oliveira Pinto ◽

Sérgio A. Netto ◽

André Morgado Esteves ◽

Francisco José Victor de Castro ◽

Patricia Fernandes Neres ◽

...

Keyword(s):

Benthic Communities ◽

Extreme Environments ◽

Freshwater Ecosystems ◽

Freshwater Biodiversity ◽

High Turnover ◽

Free Living ◽

Regional Patterns ◽

Freshwater Nematodes ◽

Spatial Coverage ◽

Freshwater Habitats

Summary Brazil has one of the largest varieties of aquatic ecosystems and rich freshwater biodiversity, but these components have constantly been damaged by the expansion of unsustainable activities. Free-living nematodes are an abundant and ubiquitous component of continental benthic communities, occurring in all freshwater habitats, including extreme environments. Despite this, hardly any studies have examined the generic composition of nematodes in different latitudes and the geographic overlap of assemblages. We provide data on nematode genera from six regions in Brazil, over a north-south gradient spanning about 4000 km, encompassing rivers, coastal lakes, and reservoirs with different levels of human impact. Interpolation/extrapolation curves were generated and the zeta diversity was used to assess the overlap of nematode assemblages. Freshwater nematode assemblages comprised 54 families and 132 genera. Mononchidae, Monhysteridae, Chromadoridae, Tobrilidae and Dorylaimidae were the most diverse families. Differences in diversity and high turnover of genera were found among regions, probably related to stochastic processes. Mononchus was the only widely distributed genus. Our results revealed a high biodiversity of free-living freshwater nematodes among the regions. The limited spatial coverage of the data reveals an enormous knowledge gap in a country with 12% of the world’s freshwater resources. The lack of spatial patterns, e.g., latitudinal variation, suggests that freshwater nematode assemblages are primarily structured by the intrinsic properties of habitats. This reinforces the uniqueness of freshwater ecosystems and suggests that the nematode assemblages may be sensitive to environmental disturbances, since the limited distributions of taxa may lead to lower resilience.

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First record of Stenostomum sphagnetorum (Platyhelminthes, Catenulida) from India

Zootaxa ◽

10.11646/zootaxa.4816.3.11 ◽

2020 ◽

Vol 4816 (3) ◽

pp. 392-396

Author(s):

DAIZY BHARTI ◽

FRANCISCO BRUSA ◽

SANTOSH KUMAR ◽

KAILASH CHANDRA

Keyword(s):

North America ◽

South America ◽

Marine Species ◽

First Record ◽

Freshwater Ecosystems ◽

Ganga River ◽

Knowledge Gap ◽

Free Living ◽

First Report ◽

The World

Catenulida are mostly inhabitants of freshwater ecosystems, like ponds, streams, though the marine species are few (Larsson and Willems, 2010). About 110 species of catenulids are known worldwide, with most of the studies conducted in South America (Marcus, 1945a, 1945b; Noreña et al., 2005), North America (Kepner and Carter 1931; Nuttycombe and Waters, 1938) and Scandinavian Peninsula (Luther, 1960, Larsson and Willems, 2010; Larsson et al., 2008). The diversity of catenulids from India has not been studied intensively; however some reports on other turbellaria exists for the country (Annandale, 1912; Whitehouse, 1913; Kapadia, 1947; Basil and Fernando, 1975; Apte and Pitale, 2011; Kalita and Goswami, 2012; Venkataraman et al., 2015). The genus Stenostomum, however, has been studied extensively around the world with identification of over 60 species (Tyler et al., 2006-2016). This is first report of the genus from India. The present study was part of the project to catalogue the diversity of free living protozoan ciliates from the Hooghly stretch of the Ganga River during which the flatworms were found. The worms were studied based on the live observations, with recognition of characters which led to its identification. This study serves to fill knowledge gap in the freshwater flatworms from India.

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Draft Genome Sequence of Rhizobium tropici SARCC-755, a Free-Living Rhizobium That Nodulated and Promoted Growth in Pigeonpea [Cajanus cajan (L.) Millsp.]

Microbiology Resource Announcements ◽

10.1128/mra.01122-19 ◽

2020 ◽

Vol 9 (2) ◽

Author(s):

Francina Lebogang Bopape ◽

Ahmed Idris Hassen ◽

Zacharias H. Swanevelder ◽

Eastonce T. Gwata

Keyword(s):

Genome Sequence ◽

Cajanus Cajan ◽

Draft Genome ◽

Soil Bacterium ◽

Draft Genome Sequence ◽

Rhizobium Tropici ◽

Free Living ◽

Content Type ◽

Legume Plant ◽

The Common

Rhizobium tropici SARCC-755 is a free-living soil bacterium that formed nodules on pigeonpea roots in the present study. However, the draft genome sequence reveals that this Rhizobium species contains the nolR gene but lacks the common nodulation (nodABC) genes and probably uses other pathways to induce nodules on the legume plant.

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Nanomaterials and Annelid Immunity: A Comparative Survey to Reveal the Common Stress and Defense Responses of Two Sentinel Species to Nanomaterials in the Environment

Biology ◽

10.3390/biology9100307 ◽

2020 ◽

Vol 9 (10) ◽

pp. 307 ◽

Cited By ~ 1

Author(s):

Kornélia Bodó ◽

Nicoló Baranzini ◽

Rossana Girardello ◽

Bohdana Kokhanyuk ◽

Péter Németh ◽

...

Keyword(s):

Protein Corona ◽

Defense Responses ◽

Freshwater Ecosystems ◽

Special Focus ◽

Early Stress ◽

Corona Formation ◽

Evolutionarily Conserved ◽

Stress Signal ◽

The Common

Earthworms and leeches are sentinel animals that represent the annelid phylum within terrestrial and freshwater ecosystems, respectively. One early stress signal in these organisms is related to innate immunity, but how nanomaterials affect it is poorly characterized. In this survey, we compare the latest literature on earthworm and leeches with examples of their molecular/cellular responses to inorganic (silver nanoparticles) and organic (carbon nanotubes) nanomaterials. A special focus is placed on the role of annelid immunocytes in the evolutionarily conserved antioxidant and immune mechanisms and protein corona formation and probable endocytosis pathways involved in nanomaterial uptake. Our summary helps to realize why these environmental sentinels are beneficial to study the potential detrimental effects of nanomaterials.

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Occurrence of microplastics in pellets from the common kingfisher (Alcedo atthis) along the Ticino River, North Italy

Environmental Science and Pollution Research ◽

10.1007/s11356-020-10163-x ◽

2020 ◽

Vol 27 (33) ◽

pp. 41731-41739

Author(s):

Anna Winkler ◽

Alessandro Nessi ◽

Diego Antonioli ◽

Michele Laus ◽

Nadia Santo ◽

...

Keyword(s):

Food Webs ◽

Visual Inspection ◽

Bird Species ◽

Freshwater Ecosystems ◽

Spectroscopic Techniques ◽

Plastic Pollution ◽

Research Attention ◽

Marine Bird ◽

First Report ◽

The Common

Abstract Previous research has reported avian plastic ingestion in marine bird species. Yet, while research attention on plastic pollution is shifting from marine to freshwater ecosystems, very few information on plastic ingestion is available for freshwater birds. Here, we examined the presence of microplastic in regurgitated pellets of the common kingfisher (Alcedo atthis) collected along the Ticino River (North Italy). In total, 133 kingfisher’s pellets were examined between March and October 2019 from 54 transects along the river. Plastic elements were detected and identified by visual inspection followed by μ-FTIR and SEM-EDS. Overall, we found 12 (micro)plastics from at least three different polymers in 7.5% of the pellets. This study provides the first report of plastic uptake of this bird species. It highlights the importance of spectroscopic techniques in plastic monitoring studies in order to avoid misidentification of items found. Documenting the presence of plastic ingestion by top carnivores such as fish-eating birds is necessary to understand the pervasiveness and impact of (micro)plastic pollution in food webs of freshwater ecosystems.

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Limited impacts of chronic eye fluke infection on the reproductive success of a fish host

Biological Journal of the Linnean Society ◽

10.1093/biolinnean/blz189 ◽

2019 ◽

Vol 129 (2) ◽

pp. 334-346

Author(s):

Veronika Nezhybová ◽

Martin Reichard ◽

Caroline Methling ◽

Markéta Ondračková

Keyword(s):

Reproductive Success ◽

Fish Host ◽

Control Fish ◽

Parasitic Infections ◽

Control Group ◽

Juvenile Mortality ◽

Diplostomum Pseudospathaceum ◽

Fluke Infection ◽

The Impact ◽

Eye Fluke

Abstract Parasitic infections may affect the reproductive success of the host either directly, through behavioural modification, or indirectly, by altering their reproductive investment in response to infection. We determined the effects of infection with the eye fluke Diplostomum pseudospathaceum (Trematoda) on the reproductive traits of European bitterling (Rhodeus amarus, Cyprinidae), an intermediate fish host with a resource-based mating system. Male bitterling infected by Diplostomum exhibited a larger but less pronounced red eye spot (sexually selected signal) than control males, suggesting that infected males were less preferred by females. The frequency of female ovulation and number of offspring were comparable between the infected and the control group, although there was a 1–2 week delay in the peak of ovulation and offspring production in infected fish, which is known to coincide with higher juvenile mortality. Chronic eye fluke infection had minimal metabolic costs (measured as oxygen consumption) and, consistent with these results, reproductive activity did not differ between infected and control fish in an experimental test of intersexual selection. Overall, the impact of eye fluke infection on the reproduction of European bitterling was limited. We consider the potential effect of favourable conditions during experiments (abundant food, access to spawning substrate and lack of predators and co-infections) on experimental outcomes and recognize that the effects of chronic eye fluke infection in natural conditions might be more pronounced.

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Local differences in immunocompetence reflect resistance of sticklebacks against the eye fluke Diplostomum pseudospathaceum

Parasitology ◽

10.1017/s0031182005008681 ◽

2005 ◽

Vol 132 (1) ◽

pp. 105-116 ◽

Cited By ~ 80

Author(s):

M. KALBE ◽

J. KURTZ

Keyword(s):

Gasterosteus Aculeatus ◽

Hepatosomatic Index ◽

Energy Status ◽

Habitat Types ◽

Parasite Abundance ◽

Diplostomum Pseudospathaceum ◽

Hybrid Fish ◽

Eye Fluke ◽

Lake Fish ◽

River Fish

We investigated population differences in immunological adaptation of three-spined sticklebacks (Gasterosteus aculeatus) to one of their most abundant macroparasites, the eye fluke Diplostomum pseudospathaceum. We compared infection success in lab-bred fish of 2 populations in northern Germany, from a lake, where eye flukes are prevalent, and a river, where these parasites do not occur. In order to discriminate between protection through innate and acquired immunity, we exposed fish either only once or repeatedly. Lake fish were significantly less susceptible than river sticklebacks already after a single exposure, indicating that in sympatric hosts innate immunity plays the major role in the defence against this helminth infection. In both habitat types, previous exposures only marginally decreased infection rates within 12 weeks. Lake fish showed higher immunocompentence by means of respiratory burst activity and spleen size, regardless of the infection status. Furthermore, they were in a better energy status than river fish, as indicated by a higher hepatosomatic index and haematocrit value. Interestingly, F1 hybrid fish of both populations ranged between the pure habitat types in parasite susceptibility as well as in immunological and condition parameters. Our results suggest that sticklebacks from lakes are better adapted to cope with higher parasite abundance in this habitat.

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