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Paterson RA, Poulin R, Selbach C. Global analysis of seasonal changes in trematode infection levels reveals weak and variable link to temperature. Oecologia 2024; 204:377-387. [PMID: 37358648 PMCID: PMC10907458 DOI: 10.1007/s00442-023-05408-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/12/2023] [Indexed: 06/27/2023]
Abstract
Seasonal changes in environmental conditions drive phenology, i.e., the annual timing of biological events ranging from the individual to the ecosystem. Phenological patterns and successional abundance cycles have been particularly well studied in temperate freshwater systems, showing strong and predictable synchrony with seasonal changes. However, seasonal successional changes in the abundance of parasites or their infection levels in aquatic hosts have not yet been shown to follow universal patterns. Here, using a compilation of several hundred estimates of spring-to-summer changes in infection by trematodes in their intermediate and definitive hosts, spanning multiple species and habitats, we test for general patterns of seasonal (temperature) driven changes in infection levels. The data include almost as many decreases in infection levels from spring to summer as there are increases, across different host types. Our results reveal that the magnitude of the spring-to-summer change in temperature had a weak positive effect on the concurrent change in prevalence of infection in first intermediate hosts, but no effect on the change in prevalence or abundance of infection in second intermediate or definitive hosts. This was true across habitat types and host taxa, indicating no universal effect of seasonal temperature increase on trematode infections. This surprising variation across systems suggests a predominance of idiosyncratic and species-specific responses in trematode infection levels, at odds with any clear phenological or successional pattern. We discuss possible reasons for the minimal and variable effect of seasonal temperature regimes, and emphasise the challenges this poses for predicting ecosystem responses to future climate change.
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Affiliation(s)
- Rachel A Paterson
- Norwegian Institute for Nature Research, Torgarden, PO Box 5685, 7485, Trondheim, Norway
| | - Robert Poulin
- Department of Zoology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand.
| | - Christian Selbach
- Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Langnes, PO Box 6050, 9037, Tromsø, Norway
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Grunberg RL, Halliday FW, Heckman RW, Joyner BN, O’Keeffe KR, Mitchell CE. Disease decreases variation in host community structure in an old-field grassland. PLoS One 2023; 18:e0293495. [PMID: 37889914 PMCID: PMC10610459 DOI: 10.1371/journal.pone.0293495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023] Open
Abstract
Disease may drive variation in host community structure by modifying the interplay of deterministic and stochastic processes that shape communities. For instance, deterministic processes like ecological selection can benefit species less impacted by disease. When communities have higher levels of disease and disease consistently selects for certain host species, this can reduce variation in host community composition. On the other hand, when host communities are less impacted by disease and selection is weaker, stochastic processes (e.g., drift, dispersal) may play a bigger role in host community structure, which can increase variation among communities. While effects of disease on host community structure have been quantified in field experiments, few have addressed the role of disease in modulating variation in structure among host communities. To address this, we conducted a field experiment spanning three years, using a tractable system: foliar fungal pathogens in an old-field grassland community dominated by the grass Lolium arundinaceum, tall fescue. We reduced foliar fungal disease burden in replicate host communities (experimental plots in intact vegetation) in three fungicide regimens that varied in the seasonal duration of fungicide treatment and included a fungicide-free control. We measured host diversity, biomass, and variation in community structure among replicate communities. Disease reduction generally decreased plant richness and increased aboveground biomass relative to communities experiencing ambient levels of disease. These changes in richness and aboveground biomass were consistent across years despite changes in structure of the plant communities over the experiment's three years. Importantly, disease reduction amplified host community variation, suggesting that disease diminished the degree to which host communities were structured by stochastic processes. These results of experimental disease reduction both highlight the potential importance of stochastic processes in plant communities and reveal the potential for disease to regulate variation in host community structure.
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Affiliation(s)
- Rita L. Grunberg
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Fletcher W. Halliday
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Robert W. Heckman
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Brooklynn N. Joyner
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Kayleigh R. O’Keeffe
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Charles E. Mitchell
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Environment, Ecology and Energy Program, University of North Carolina, Chapel Hill, North Carolina, United States of America
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Sures B, Nachev M, Schwelm J, Grabner D, Selbach C. Environmental parasitology: stressor effects on aquatic parasites. Trends Parasitol 2023; 39:461-474. [PMID: 37061443 DOI: 10.1016/j.pt.2023.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/07/2023] [Accepted: 03/10/2023] [Indexed: 04/17/2023]
Abstract
Anthropogenic stressors are causing fundamental changes in aquatic habitats and to the organisms inhabiting these ecosystems. Yet, we are still far from understanding the diverse responses of parasites and their hosts to these environmental stressors and predicting how these stressors will affect host-parasite communities. Here, we provide an overview of the impacts of major stressors affecting aquatic ecosystems in the Anthropocene (habitat alteration, global warming, and pollution) and highlight their consequences for aquatic parasites at multiple levels of organisation, from the individual to the community level. We provide directions and ideas for future research to better understand responses to stressors in aquatic host-parasite systems.
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Affiliation(s)
- Bernd Sures
- Aquatic Ecology, University of Duisburg-Essen, Essen, Germany; Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany; Research Center One Health Ruhr, Research Alliance Ruhr, University Duisburg-Essen, Essen, Germany.
| | - Milen Nachev
- Aquatic Ecology, University of Duisburg-Essen, Essen, Germany; Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany
| | - Jessica Schwelm
- Aquatic Ecology, University of Duisburg-Essen, Essen, Germany; Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany; Research Center One Health Ruhr, Research Alliance Ruhr, University Duisburg-Essen, Essen, Germany
| | - Daniel Grabner
- Aquatic Ecology, University of Duisburg-Essen, Essen, Germany; Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany
| | - Christian Selbach
- Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany; Freshwater Ecology Group, Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, Tromsø, Norway
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Changes in Snail Chemical Profiles through Host-Parasite Interactions. Mol Biochem Parasitol 2022; 249:111464. [DOI: 10.1016/j.molbiopara.2022.111464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/17/2022] [Accepted: 02/24/2022] [Indexed: 11/21/2022]
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Díaz-Morales DM, Bommarito C, Vajedsamiei J, Grabner DS, Rilov G, Wahl M, Sures B. Heat sensitivity of first host and cercariae may restrict parasite transmission in a warming sea. Sci Rep 2022; 12:1174. [PMID: 35064187 PMCID: PMC8782892 DOI: 10.1038/s41598-022-05139-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 01/03/2022] [Indexed: 12/01/2022] Open
Abstract
To predict global warming impacts on parasitism, we should describe the thermal tolerance of all players in host-parasite systems. Complex life-cycle parasites such as trematodes are of particular interest since they can drive complex ecological changes. This study evaluates the net response to temperature of the infective larval stage of Himasthla elongata, a parasite inhabiting the southwestern Baltic Sea. The thermal sensitivity of (i) the infected and uninfected first intermediate host (Littorina littorea) and (ii) the cercarial emergence, survival, self-propelling, encystment, and infection capacity to the second intermediate host (Mytilus edulis sensu lato) were examined. We found that infection by the trematode rendered the gastropod more susceptible to elevated temperatures representing warm summer events in the region. At 22 °C, cercarial emergence and infectivity were at their optimum while cercarial survival was shortened, narrowing the time window for successful mussel infection. Faster out-of-host encystment occurred at increasing temperatures. After correcting the cercarial emergence and infectivity for the temperature-specific gastropod survival, we found that warming induces net adverse effects on the trematode transmission to the bivalve host. The findings suggest that gastropod and cercariae mortality, as a tradeoff for the emergence and infectivity, will hamper the possibility for trematodes to flourish in a warming ocean.
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Affiliation(s)
- Dakeishla M Díaz-Morales
- Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany.
| | - Claudia Bommarito
- Benthic and Experimental Ecology Department, GEOMAR, Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Jahangir Vajedsamiei
- Benthic and Experimental Ecology Department, GEOMAR, Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Daniel S Grabner
- Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany
| | - Gil Rilov
- Israel Oceanographic and Limnological Research, National Institute of Oceanography, P.O. Box 8030, 31080, Haifa, Israel
- Marine Biology Department, The Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, 31905, Haifa, Israel
| | - Martin Wahl
- Benthic and Experimental Ecology Department, GEOMAR, Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Bernd Sures
- Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Essen, Germany
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