Larval trematode communities in Radix auricularia and Lymnaea stagnalis in a reservoir system of the Ruhr River

Abstract

BackgroundAnalysis of the data available from traditional faunistic approaches to mollusc-trematode systems covering large spatial and/or temporal scales in Europe convinced us that a parasite community approach in well-defined aquatic ecosystems is essential for the substantial advancement of our understanding of the parasite response to anthropogenic pressures in urbanised areas which are typical on a European scale. Here we describe communities of larval trematodes in two lymnaeid species, Radix auricularia and Lymnaea stagnalis in four man-made interconnected reservoirs of the Ruhr River (Germany) focusing on among- and within-reservoir variations in parasite prevalence and component community composition and structure.ResultsThe mature reservoir system on the Ruhr River provides an excellent environment for the development of species-rich and abundant trematode communities in Radix auricularia (12 species) and Lymnaea stagnalis (6 species). The lake-adapted R. auricularia dominated numerically over L. stagnalis and played a major role in the trematode transmission in the reservoir system. Both host-parasite systems were dominated by bird parasites (13 out of 15 species) characteristic for eutrophic water bodies. In addition to snail size, two environmental variables, the oxygen content and pH of the water, were identified as important determinants of the probability of infection. Between-reservoir comparisons indicated an advanced eutrophication at Baldeneysee and Hengsteysee and the small-scale within-reservoir variations of component communities provided evidence that larval trematodes may have reflected spatial bird aggregations (infection 'hot spots'). Two life history groupings of dominant species, the 'cyprinid' and 'anatid' parasites, that depict two aspects of progressive eutrophication in this mature reservoir system, were identified.ConclusionsWe conclude that trematode communities in the lake-adapted R. auricularia are better suited for monitoring the effect of environmental change on host-parasite associations in the reservoir system on the Ruhr River and other similar systems due to the important role of this host in trematode transmission in lakes. Whereas variations in trematode community diversity and abundance may indicate the degree of eutrophication on a larger scale (among reservoirs), the infection rates of the two life history groups of dominant species, the 'cyprinid' and 'anatid' assemblages, may be particularly useful in depicting environmental variability, eutrophication effects and infection 'hot spots' on smaller spatial scales.

New cryptic species of the ‘revolutum’ group of Echinostoma (Digenea: Echinostomatidae) revealed by molecular and morphological data

“…; Faltýnková et al [24] also provided this number for E. revolutum ex L. stagnalis . It is worth noting that recent field studies indicate that E. revolutum most commonly occurs in L. stagnalis in Europe [23,24], infections with this species have occasionally been reported in the past from R. auricularia , R. peregra and R. ovata (Draparnaud, 1805) [22,37-45]. Further molecular study would reveal whether Echinostoma spp.…”

“…In a study of the digeneans parasitising molluscs in central and northern Europe we found that Radix auricularia (Linnaeus, 1758), Radix peregra (Müller, 1774) and Stagnicola palustris (Müller, 1774) were infected with larval stages of two species of the Echinostoma ‘ revolutum ’ complex of cryptic species, one resembling E. revolutum sensu stricto (s.s.) and one undescribed species (see also [23]). Here we describe the cercariae of these two species and provide morphological and molecular evidence for their delimitation.…”

Diverse Applications of Environmental DNA Methods in Parasitology

“…Very recently the use of transcriptomics to integrate eco-toxicogenomics into marine health evaluation has been assessed [107] via contamination-associated gene expression markers. Parasites themselves have been shown to be useful markers of ecosystem status and its response to change [108,109], including response to climate change [110]. The employment of eDNA methods for such studies can be very effective if appropriate sampling and molecular strategies are chosen (Boxes 1 and 2), both reducing sampling effort and maximizing sampling coverage.…”

Small-scale to large-scale and back: larval trematodes in Lymnaea stagnalis and Planorbarius corneus in Central Europe

“…Snail-trematode systems can be used to assess anthropogenic change (e.g. Morley 2007;Soldánová et al 2010), the effect of wetland restoration projects (e.g. Huspeni and Lafferty 2004;Morley and Lewis 2007) and the environmental impacts of global warming (Poulin 2006;Poulin and Mouritsen 2006).…”

“…In spite of their significant roles in freshwater trophic webs both as grazers and prey and in parasite transmission, there is a lack of quantitative information on the composition and structure of larval communities in mollusc hosts within individual freshwater ecosystems in Europe (but see Faltýnková et al 2008b;Soldánová et al 2010). The numerous faunistic studies listed in Faltýnková et al (2007Faltýnková et al ( , 2008a and Żbikowska and Nowak (2009) report summed data on the parasite richness and prevalence in these hosts over large temporal and spatial scales or both.…”