scholarly journals Host exposure to symbionts and ecological drift generate divergence in parasite community assembly

2021 ◽  
Author(s):  
Rita L Grunberg ◽  
Brooklynn N Joyner ◽  
Charles E Mitchell
Keyword(s):  
Community Structure ◽  
Community Assembly ◽  
Parasite Community ◽  
Priority Effects ◽  
Treatment Groups ◽  
Host Interactions ◽  
Parasite Communities ◽  
Ecological Selection ◽  
Multiple Processes ◽  
Parasite Infections

The initial colonization of a host by symbionts, ranging from parasites to mutualists, can generate priority effects that alter within-host interactions and the trajectory of parasite community assembly. At the same time, variation in parasite communities among hosts can also stem from stochastic processes. Community ecology theory posits that multiple processes (e.g. dispersal, selection and drift) interact to generate variation in community structure, but these processes are rarely considered simultaneously during community assembly. To test the role of these processes in a parasite community, we experimentally simulated dispersal of three symbionts by factorially inoculating individual plants of tall fescue with two foliar fungal parasites, Colletotrichum cereale and Rhizoctonia solani, and a hypothesized mutualist endophyte, Epichloë coenophiala. We then tracked parasite infections longitudinally in the field. After the initial inoculations, hosts were exposed to a common pool of parasites in the field, which we expected to cause parasite communities to converge towards a similar community state. To test for convergence, we analyzed individual hosts parasite community trajectories in multivariate space. In contrast to our expectation, there was no signal of convergence. Instead, parasite community trajectories generally diverged over time between treatment groups and the magnitude of divergence depended on the symbiont species inoculated. Parasite communities of hosts that were inoculated with only the mutualist, Epichloë, showed significant trends of divergence relative to all other symbiont inoculation treatments. In contrast, hosts inoculated with only Rhizoctonia did not exhibit clear trends of divergence when compared to other parasite inoculations. Further, co-inoculation with both parasite species resulted in faster rates of divergence and greater temporal change in parasite communities relative to hosts inoculated with only the parasite Colletotrichum. As predicted by existing theory, parasite communities showed evidence of drift during the beginning of the experiment, which contributed to among-host divergence in parasite community structure. Overall, these data provide evidence that initial dispersal of symbionts produced persistent changes in parasite community structure via ecological selection, that drift was important during the early stages of parasite community assembly, and together, dispersal, selection and drift resulted in parasite community divergence.

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

2020 ◽  
Author(s):  
Joshua I. Brian ◽  
David C. Aldridge
Keyword(s):  
Community Assembly ◽  
Species Distribution Model ◽  
Freshwater Mussel ◽  
Parasite Load ◽  
Parasite Community ◽  
Careful Consideration ◽  
Environmental Drivers ◽  
Distribution Model ◽  
Parasite Communities ◽  
The Impact

AbstractUnderstanding how environmental drivers influence the construction 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. Here, we utilise a novel host system, the freshwater mussel Anodonta anatina, to investigate how both the presence and abundance of 14 parasite taxa correlate with environmental drivers across 720 replicate parasite infracommunities. Using both redundancy analysis and a joint species distribution model, we model 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. We demonstrate that both niche- and neutral-based factors are important but to varying degrees across parasite species, suggesting that applying generalities to parasite community construction is too simplistic. Further, we show that presence-absence data fails to capture important density-dependent effects of parasite load for parasites with high abundance. Finally, we highlight that predicted parasite interaction networks vary greatly depending on whether abundance or presence-absence data is used. Our results emphasise the multi-faceted nature of parasite community assembly, and that future studies require careful consideration of the data used to infer community structure.

Helminth communities of fish as ecological indicators of lake health

Parasitology ◽  
2012 ◽  
Vol 140 (3) ◽  
pp. 352-360 ◽  
Author(s):  
HUMAIRA BASHIR SHAH ◽  
A. R. YOUSUF ◽  
M. Z. CHISHTI ◽  
FAYAZ AHMAD
Keyword(s):  
Community Structure ◽  
Trophic Status ◽  
Parasite Community ◽  
Ambient Conditions ◽  
Component Level ◽  
Pollution Levels ◽  
Parasite Communities ◽  
Mediated Effects ◽  
Community Data ◽  
Trophic Gradients

SUMMARYThis paper deals largely with the dynamics and changes in the helminth parasite communities of fish along the trophic gradient of lakes. The use of parasitological community data as a bioindicator of environmental health underlines the need to study parasite communities at comparable localities with known pollution levels. The comparison of the conditions in different habitats might be helpful to differentiate between normal fluctuations in ambient conditions and pollution-mediated effects. Therefore, the present study was designed to examine the community structure of parasites in snow trout (Schizothorax niger Heckel) inhabiting 3 lakes of contrasting trophic status in Kashmir. The idea of selecting the lakes, namely Anchar (strongly hypereutrophic), Dal (eutrophic) and Manasbal (mesotrophic) for this study was intentional as they depict different trophic gradients and exhibit the desirable pattern which was a prerequisite for this study. The findings presented in this article suggest an apparent lake-wise gradient in community structure, as the increase in trematode and cestode infections in Anchar was markedly greater, to levels clearly distinguishable from those in the other two water bodies. We conclude that human-induced eutrophication of lakes modifies the parasite community at component level and community-level studies on parasites may provide information on health status of lakes.

Helminth communities of yellow perch (Perca flavescens (Mitchill)): determinants of pattern

2000 ◽  
Vol 78 (4) ◽  
pp. 538-555 ◽  
Author(s):  
J P Carney ◽  
T A Dick
Keyword(s):  
Community Structure ◽  
Yellow Perch ◽  
Trophic Status ◽  
Lake Michigan ◽  
Parasite Species ◽  
Local Level ◽  
Perca Flavescens ◽  
Parasite Community ◽  
Green Bay ◽  
Parasite Communities

Twenty-eight parasite species were recorded from 504 yellow perch (Perca flavescens) collected from Dauphin Lake and Beaufort Lake, Manitoba, and Lake Winnebago, Green Bay, and Lake Michigan, Wisconsin. Four parasite species, Diplostomum spp., Urocleidus adspectus, Proteocephalus pearsei, and Raphidascaris acus, occurred in perch from all localities. Infracommunities and component communities were low in richness. The Dauphin Lake and Beaufort Lake samples had the richest parasite communities, while those in the Green Bay and Lake Michigan samples were the least rich. The effect of host size and age on parasite community structure was equivocal. A positive association between P. pearsei and Bothriocephalus cuspidatus and more multispecies infracommunities than expected provide evidence of nonrandom associations in the Manitoba samples, while the Wisconsin infracommunities were random associations. Significant infracommunity nestedness in all samples indicated nonrandom community organization and structure. Parasite faunas were richer in samples with complex invertebrate communities than in samples with complex fish communities. The trophic status of the aquatic system indirectly affected the parasite communities by limiting the variety of potential intermediate hosts. Predictions regarding relationships between parasite community structure and lake trophic status were not supported. We show that predictable patterns at the fine-scale local level of the parasite infracommunity and component communities of perch are best explained by a rich invertebrate community upon which the host feeds.

scholarly journals Halfway up the trophic chain: development of parasite communities in the sparid fish Boops boops

Parasitology ◽  
2007 ◽  
Vol 135 (2) ◽  
pp. 257-268 ◽  
Author(s):  
A. PÉREZ-DEL OLMO ◽  
M. FERNÁNDEZ ◽  
J. A. RAGA ◽  
A. KOSTADINOVA ◽  
R. POULIN
Keyword(s):  
Community Structure ◽  
Species Abundance ◽  
Parasite Community ◽  
Life Cycles ◽  
Trophic Chain ◽  
Age Cohorts ◽  
Parasite Communities ◽  
Sparid Fish ◽  
Key Species ◽  
Boops Boops

SUMMARYWe examined the patterns of composition and structure of parasite communities in the Mediterranean sparid fish Boops boops along a gradient of fish sizes, using a large sample from a single population. We tested the hypothesis that species forming the core of the bogue parasite fauna (i.e. species which have a wide geographical range and are responsible for recognizable community structure) appear early in the fish ontogeny. The sequential community development observed supported the prediction that core species appear in the fish population earlier than rare and stochastic species. There was also a strong correlation between the order of ‘arrival’ of the species and their overall prevalence. Six key species were responsible for recognizable community structure across size/age cohorts; the addition to this baseline community of key parasite species resulted in a nested structure that is linked to differential species abundance rather than fish size. Information on the life-cycles, distribution and host range of the parasites is used to explain the observed patterns of parasite community structure. We conclude that the small mouth size of B. boops coupled with suction feeding may provide a setting for passive sampling as a mechanism leading to non-random parasite community structure.

scholarly journals Life-cycle mediated effects of urbanization on parasite communities in the estuarine fish, Fundulus heteroclitus

2018 ◽  
Author(s):  
James M. Alfieri ◽  
Tavis K. Anderson
Keyword(s):  
Community Structure ◽  
Life Cycle ◽  
Fundulus Heteroclitus ◽  
Parasite Community ◽  
Estuarine Fish ◽  
Parasite Communities ◽  
Mediated Effects ◽  
Physicochemical Factors ◽  
Primary Parasite ◽  
The Relationship

AbstractThis study examined the relationship between urbanization and parasite community structure in the estuarine fish, Fundulus heteroclitus. We measured landscape and physicochemical factors associated with urbanization at 6 sites from 4 collection periods. Concurrently, we quantified the metazoan parasite community in F. heteroclitus collected at those sites, with 105 fish studied per site during the 4 collection periods. Parasite community composition differed between sites. Variation in the prevalence and intensity of infection of two indirect life-cycle parasites, Lasiocotus minutus and Glossocercus caribaensis, were the primary parasite species that determined this pattern. Sediment potassium and aquatic osmium were the most important physicochemical factors in structuring parasite communities, and habitat dominance was the most important landscape factor. Our data supports the hypothesis that urbanization, acting at both landscape and physicochemical scales, can have a significant impact on parasite community structure. This, however, varied by parasite life history: there was little effect of urbanization on the prevalence and intensity of direct life-cycle parasites, but significant variation was dedicated for indirect life-cycle parasites. This study demonstrates how anthropogenically driven landscape change influences fine-scale parasite population dynamics.

scholarly journals Parasite community structure of cod from Bear Island (Barents Sea) and Pomeranian Bay (Baltic Sea)

2011 ◽  
Vol 32 (3) ◽  
pp. 253-262 ◽  
Author(s):  
Ewa Sobecka ◽  
Ewa Łuczak ◽  
Beata Więcaszek ◽  
Artur Antoszek
Keyword(s):  
Community Structure ◽  
Baltic Sea ◽  
Parasite Species ◽  
Barents Sea ◽  
Parasite Community ◽  
Mean Values ◽  
Parasite Communities ◽  
Higher Taxa ◽  
The Baltic ◽  
Pomeranian Bay

Parasite community structure of cod from Bear Island (Barents Sea) and Pomeranian Bay (Baltic Sea) A total of 142 cods: 60 from the South-East Ground of Bear Island and 82 from the Pomeranian Bay (Baltic Sea) were examined for their ecto- and endoparasites. Twenty different parasite species, comprising one Myxosporea, three Cestoda, four Digenea, seven Nematoda, three Acanthocephala and two Crustacea were found. The parasite component communities comprised 1446 individuals (17 species, six higher taxa) from the Bear Island and 6588 individuals (nine species, three higher taxa) from Pomeranian Bay. The observed parasite host specificity was low, and the intensity in a single fish ranged from one to 279 specimens. The eudominant parasite species were Echinorhynchus gadi, Hemiurus levinseni and Contracaecum osculatum. The dominant parasite communities from the Bear Island were nematodes, but acanthocephalans dominated in cod from the Baltic Sea. It appears that one group of parasites, better adapted for the specific conditions of the macrohabitat, has replaced another. The most prevalent parasites were E. gadi, Anisakis simplex, C. osculatum and Hysterothylacium aduncum, and the mean values of crowding were the highest for E. gadi and Pomphorhynchus laevis. The nematode Camallanus lacustris was noted in this host species for the first time. Only six species of parasites were common to cod from both fishing grounds.

Community structure of fleas within and among populations of three closely related rodent hosts: nestedness and beta-diversity

Parasitology ◽  
2016 ◽  
Vol 143 (10) ◽  
pp. 1268-1278 ◽  
Author(s):  
LUTHER VAN DER MESCHT ◽  
BORIS R. KRASNOV ◽  
CONRAD A. MATTHEE ◽  
SONJA MATTHEE
Keyword(s):  
South Africa ◽  
Community Structure ◽  
Host Species ◽  
Beta Diversity ◽  
Species Turnover ◽  
Spatial Scales ◽  
Parasite Community ◽  
Random Pattern ◽  
Parasite Communities ◽  
Rhabdomys Pumilio

SUMMARYWe studied nestedness and its relationships with beta-diversity in flea communities harboured by three closely related rodent species (Rhabdomys pumilio, Rhabdomys intermedius, Rhabdomys dilectus) at two spatial scales (within and among host populations) in South Africa and asked (a) whether variation in species composition of flea communities within and among host populations follows a non-random pattern; if yes, (b) what are the contributions of nestedness and species turnover to dissimilarity (= beta-diversity) among flea communities at the two scales; and (c) do the degree of nestedness and its contribution to beta-diversity differ among host species (socialvssolitary) and between scales. We found that nestedness in flea assemblages was more pronounced (a) in social than solitary host species and (b) at lower (among host individuals within populations) than at higher scale (among host populations). We also found that higher degree of nestedness was associated with its higher contribution to beta-diversity. Our findings support earlier ideas that parasite community structure results from the processes of parasite accumulation by hosts rather than from the processes acting within parasite communities.

Conservation and Restoration of Grasslands

2018 ◽  
Author(s):  
Brian J. Wilsey
Keyword(s):  
Community Assembly ◽  
Woody Plants ◽  
Woody Plant ◽  
Priority Effects ◽  
Woody Plant Encroachment ◽  
Humpty Dumpty ◽  
Alternate States ◽  
Density And Biomass ◽  
Acid Test ◽  
Stocking Rates

Conservation programs alter herbivore stocking rates and find and protect the remaining areas that have not been plowed or converted to crops. Restoration is an ‘Acid Test’ for ecology. If we fully understand how grassland systems function and assemble after disturbance, then it should be easy to restore them after they have been degraded or destroyed. Alternatively, the idea that restorations will not be equivalent to remnants has been termed the ‘Humpty Dumpty’ hypothesis—once lost, it cannot be put back together again. Community assembly may follow rules, and if these rules are uncovered, then we may be able to accurately predict final species composition after assembly. Priority effects are sometimes found depending on species arrival orders, and they can result in alternate states. Woody plant encroachment is the increase in density and biomass of woody plants, and it is strongly affecting grassland C and water cycles.

scholarly journals The capacity of wastewater treatment plants drives bacterial community structure and its assembly

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Young Kyung Kim ◽  
Keunje Yoo ◽  
Min Sung Kim ◽  
Il Han ◽  
Minjoo Lee ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Community Structure ◽  
Bacterial Community ◽  
Activated Sludge ◽  
Community Assembly ◽  
Bacterial Communities ◽  
Wastewater Treatment Plants ◽  
High Capacity ◽  
Operating Conditions ◽  
Rrna Gene

Abstract Bacterial communities in wastewater treatment plants (WWTPs) affect plant functionality through their role in the removal of pollutants from wastewater. Bacterial communities vary extensively based on plant operating conditions and influent characteristics. The capacity of WWTPs can also affect the bacterial community via variations in the organic or nutrient composition of the influent. Despite the importance considering capacity, the characteristics that control bacterial community assembly are largely unknown. In this study, we discovered that bacterial communities in WWTPs in Korea and Vietnam, which differ remarkably in capacity, exhibit unique structures and interactions that are governed mainly by the capacity of WWTPs. Bacterial communities were analysed using 16S rRNA gene sequencing and exhibited clear differences between the two regions, with these differences being most pronounced in activated sludge. We found that capacity contributed the most to bacterial interactions and community structure, whereas other factors had less impact. Co-occurrence network analysis showed that microorganisms from high-capacity WWTPs are more interrelated than those from low-capacity WWTPs, which corresponds to the tighter clustering of bacterial communities in Korea. These results will contribute to the understanding of bacterial community assembly in activated sludge processing.

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