An efficient photograph-based quantitative method for assessing castrating trematode parasites in bivalve molluscs

Brian, Joshua I.; Aldridge, David C.

doi:10.1017/s0031182020001213

Cited by 12 publications

(10 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Jokela et al., 1993; Walker, 2017), particularly for the virulent R. campanula (Müller et al., 2015; Taskinen et al., 1994), but these studies still record native mussels being able to reproduce at low infection intensities. We have also previously recorded gravid mussels at low infection intensities of R. campanula (Brian & Aldridge, 2021), suggesting that understanding the degree of infection is as important as understanding its presence (Brian & Aldridge, 2020). Nevertheless, our results highlight that even intermediate infection intensities are correlated with mussel castration, showing the need to understand the presence and distribution of this highly virulent parasite across individuals and populations.…”

Section: Discussionmentioning

confidence: 87%

“…Error bars represent standard 95% confidence intervals. (c) The average infection intensity (percentage of the gonad filled with trematode tissue, following Brian & Aldridge, 2020) of mussels at BC and OW. Only infected mussels were included.…”

Section: Resultsmentioning

confidence: 99%

“…anatina was inspected under a dissecting microscope to identify the presence of encysted larvae and eggs of the parasitic mite Unionicola intermedia (henceforth referred to as mites ), and scored as a binary presence/absence. We then inspected the gonad of the mussel to identify and quantify infection with the digenean Rhipidocotyle campanula (henceforth referred to as trematodes ), following Brian and Aldridge (2020). Briefly, we removed the visceral mass and made an incision c .…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Population‐level effects of parasitism on a freshwater ecosystem engineer, the unionid mussel Anodonta anatina

et al. 2021

Self Cite

View full text Add to dashboard Cite

Parasites can negatively affect hosts at individual, population, and species‐level scales. However, the link between individual‐ and population‐level impacts is often poorly understood. In particular, the population‐level response to parasitism may alter wider ecosystem dynamics if animals with ecosystem engineering capabilities are infected. Here, we examine the effects of parasitism on a freshwater ecosystem engineer, the unionid mussel Anodonta anatina, at two different sites. We study three common parasites: the digenean trematode Rhipidocotyle campanula; the unionicolid mite Unionicola intermedia; and the ectoparasitic invasive zebra mussel Dreissena polymorpha. As well as demonstrating the individual‐level effects of parasitism on the native host mussel, we construct a simple model to estimate the reduction in population‐level reproductive output caused by parasites. We show that both infection prevalence and intensity were population‐specific, with one site having more than three times as many native mussels infected by trematodes and mites than the other, but more than four times fewer mussels afflicted by invasive zebra mussels. Negative reproductive consequences for individual host mussels were documented as a result of parasitism, with trematodes causing castration at both sites. Mites were also correlated with a reduction in the viability of larval offspring (glochidia) by more than 25%, but only at one site, suggesting some potential impacts of parasitism may be population specific. The population‐level model shows that parasitism alone reduces larval output of the two populations by 10% and 13%, respectively. Our study takes the important step of scaling individual‐level effects of parasitism to population‐level processes, and highlights the influence that parasites may have in the population dynamics of unionid mussels. Given the ecosystem engineering capabilities of A. anatina, such effects may have important impacts on the wider biota. Even at relatively low prevalences, the observed effects of parasites on native mussel populations suggests that parasitism must be considered in the conservation of freshwater mussels, one of the world's most globally imperilled faunal groups. Further, understanding how the effects of parasitism on individual hosts scales to the ecosystem level is a crucial and unaddressed question in freshwater biology.

show abstract

Section: Discussionmentioning

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Population‐level effects of parasitism on a freshwater ecosystem engineer, the unionid mussel Anodonta anatina

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…An increased emphasis on invertebrates may facilitate this, especially with the advent of new methods to accurately quantify infection in these hosts (e.g. Brian & Aldridge, 2020). In addition, we have shown that detailed knowledge of parasite life histories is an important but often overlooked aspect of predicting community structure.…”

Section: Discussionmentioning

confidence: 99%

Abundance data applied to a novel model invertebrate host shed new light on parasite community assembly in nature

Brian

Aldridge

2021

Journal of Animal Ecology

Self Cite

View full text Add to dashboard Cite

Understanding how environmental drivers influence the assembly of parasite communities, in addition to how parasites may interact at an infracommunity level, are fundamental requirements for the study of parasite ecology. Knowledge of how parasite communities are assembled will help to predict the risk of parasitism for hosts, and model how parasite communities may change under variable conditions. However, studies frequently rely on presence–absence data and examine multiple host species or sites, metrics which may be too coarse to characterise nuanced within‐host patterns. We utilised a novel host system, the freshwater mussel Anodonta anatina, to investigate the drivers of community structure and explore parasite interactions. In addition, we aimed to highlight consistencies and inconsistencies between PA and abundance data. Our analysis incorporated 14 parasite taxa and 720 replicate infracommunities. Using Redundancy Analysis, a joint species distribution model and a Markov random field approach, we modelled the impact of both host‐level and environment‐level characteristics on parasite structure, as well as parasite–parasite correlations after accounting for all other factors. This approach was repeated for both the presence and abundance of all parasites. We demonstrated that the regional species pool, individual host characteristics (mussel length and gravidity) and predicted parasite–parasite interactions are all important but to varying degrees across parasite species, suggesting that applying generalities to parasite community construction is too simplistic. Furthermore, we showed that PA data fail to capture important density‐dependent effects of parasite load for parasites with high abundance, and in general performs poorly for high‐intensity parasites. Host and parasite traits, as well as broader environmental factors, all contribute to parasite community structure, emphasising that an integrated approach is required to study community assembly. However, care must be taken with the data used to infer patterns, as presence‐absence data may lead to incorrect ecological inference.

show abstract

“…Following the removal of gonadal fluid, the mussel was sacrificed by cutting the posterior and anterior adductor muscles and the visceral mass was removed. The gonad was then examined for trematodes and, if present, the percentage of the gonad filled with trematodes was calculated through squashing gonad samples between two slides and calculating the mean trematode area in replicate photographs (Brian & Aldridge, 2020).…”

Section: Methodsmentioning

confidence: 99%

A rapid, non‐destructive method for sampling castrating parasites in endangered bivalve molluscs

Brian

Aldridge

2020

Aquatic Conservation

Self Cite

View full text Add to dashboard Cite

Bivalves are important ecosystem engineers, and there is emerging evidence that many species are afflicted with castrating parasites. Understanding the prevalence of these largely overlooked parasites is crucial in understanding the fundamental biology of bivalves, informing conservation efforts, and providing a wider understanding of host–parasite dynamics. Current techniques to assess the presence of parasites are destructive, making them untenable for endangered or protected populations. This article presents a non‐destructive method of sampling bivalve molluscs (Anodonta anatina) to detect castrating trematodes. Gonadal fluid is removed with a hypodermic needle from bivalves in situ and analysed in a laboratory setting without removing the mollusc from the field; this sampling mechanism has previously been shown not to harm the mollusc. A single 50 μl sample is sufficient to detect both the presence and developmental stage of the trematode with greater than 95% reliability, with all but the lightest infections visible. We recommend that this technique should be used to enhance knowledge on host–parasite dynamics in bivalves, and inform sensible conservation for threatened species.

show abstract

An efficient photograph-based quantitative method for assessing castrating trematode parasites in bivalve molluscs

Cited by 12 publications

References 42 publications

Population‐level effects of parasitism on a freshwater ecosystem engineer, the unionid mussel Anodonta anatina

Population‐level effects of parasitism on a freshwater ecosystem engineer, the unionid mussel Anodonta anatina

Abundance data applied to a novel model invertebrate host shed new light on parasite community assembly in nature

A rapid, non‐destructive method for sampling castrating parasites in endangered bivalve molluscs

Contact Info

Product

Resources

About