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Moore SE, Siwertsson A, Lafferty KD, Kuris AM, Soldánová M, Morton D, Primicerio R, Amundsen PA. Parasites alter food-web topology of a subarctic lake food web and its pelagic and benthic compartments. Oecologia 2024; 204:257-277. [PMID: 38326516 PMCID: PMC10907417 DOI: 10.1007/s00442-023-05503-w] [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: 12/10/2023] [Indexed: 02/09/2024]
Abstract
We compared three sets of highly resolved food webs with and without parasites for a subarctic lake system corresponding to its pelagic and benthic compartments and the whole-lake food web. Key topological food-web metrics were calculated for each set of compartments to explore the role parasites play in food-web topology in these highly contrasting webs. After controlling for effects from differences in web size, we observed similar responses to the addition of parasites in both the pelagic and benthic compartments demonstrated by increases in trophic levels, linkage density, connectance, generality, and vulnerability despite the contrasting composition of free-living and parasitic species between the two compartments. Similar effects on food-web topology can be expected with the inclusion of parasites, regardless of the physical characteristics and taxonomic community compositions of contrasting environments. Additionally, similar increases in key topological metrics were found in the whole-lake food web that combines the pelagic and benthic webs, effects that are comparable to parasite food-web analyses from other systems. These changes in topological metrics are a result of the unique properties of parasites as infectious agents and the links they participate in. Trematodes were key contributors to these results, as these parasites have distinct characteristics in aquatic systems that introduce new link types and increase the food web's generality and vulnerability disproportionate to other parasites. Our analysis highlights the importance of incorporating parasites, especially trophically transmitted parasites, into food webs as they significantly alter key topological metrics and are thus essential for understanding an ecosystem's structure and functioning.
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Affiliation(s)
- Shannon E Moore
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway.
| | - Anna Siwertsson
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Kevin D Lafferty
- U.S. Geological Survey, Western Ecological Research Center, at Marine Science Institute, University of California, Santa Barbara, CA, USA
| | - Armand M Kuris
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
| | - Miroslava Soldánová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, 370 05, Ceske Budejovice, Czech Republic
| | - Dana Morton
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA, USA
| | - Raul Primicerio
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
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2
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Moscovitz S, Glassner H, Wokam Njomgang RM, Aflalo ED, Ovadia O, Sagi A. Community composition of invasive, outbreak, and non-pest snail species along a source spring-to-fishpond gradient in a spatially structured aquacultural region. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 351:119653. [PMID: 38070421 DOI: 10.1016/j.jenvman.2023.119653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 11/16/2023] [Accepted: 11/16/2023] [Indexed: 01/14/2024]
Abstract
Agricultural lands are integrated into and interact with natural areas. Such is the case of Emek HaMa'ayanot, northern Israel, comprising a springs-rich area characterized by multiple land-uses, including spring-water-based aquaculture, recreational springs, and nature reserves. Aquacultural farms suffer from pest snails that carry fish disease; in the study region, these species are invasive (Thiara scabra, Tarebia granifera, Pseudosuccinea columella) and outbreak endemic (Melanoides tuberculata). Previous snail control efforts have focused on individual fishponds without considering management on larger environmental scales in the waterways from the source springs to the fish farms. To broaden our understanding of the status of the pest snail problem in the study area prior to suggesting environmental managerial solutions, we quantified changes in the community composition of snail species along the springs-to-fishponds gradients in a spatially explicit system. We found a remarkable increase in pest snail abundances along these gradients, indicating that pest snails might be invading upstream towards the springs. There were always nearly 100% pest snails in the endpoint sites for water tracks that ended in fishponds. Moreover, pest snails dominated the site when it was used as a fishpond, even though the site was also a spring. In contrast, in a water track that does not end in a fish farm, the relative abundances of non-pest snail species was similar between the source spring and the downstream endpoint, in spite of an increase in pest snail abundance at a midpoint site. These results suggest that invasive pest snails are actively moving upstream and that the fishponds have a marked upstream effect on the ability of non-pest snails to resist pest species invasions. We suggest further investigation of possible strategies for biocontrol of the observed invasion of the snails into natural areas as a basis for environmental management efforts. Finally, the observations made during this study could have practical global implications for snail management in aquaculture and agriculture, and for the control of snails and snail vectors implicated in animal and human diseases.
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Affiliation(s)
- Sharon Moscovitz
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, 84105, Israel
| | - Hanoch Glassner
- Eden Research Station, Mobile Post Beit Shean, 11710, Israel
| | | | - Eliahu D Aflalo
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, 84105, Israel; Department of Life Sciences, Achva Academic College, Mobile Post Shikmim, 79800, Israel
| | - Ofer Ovadia
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, 84105, Israel; Goldman Sonnenfeldt School of Sustainability and Climate Change, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, 84105, Israel.
| | - Amir Sagi
- Department of Life Sciences, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, 84105, Israel; National Institute for Biotechnology in the Negev (NIBN), Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva, 84105, Israel.
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3
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Sharpe DMT, Valverde MP, De León LF, Hendry AP, Torchin ME. Biological invasions alter the structure of a tropical freshwater food web. Ecology 2023; 104:e4173. [PMID: 37768609 DOI: 10.1002/ecy.4173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023]
Abstract
Biological invasions are expected to alter food web structure, but there are limited empirical data directly comparing invaded versus uninvaded food webs, particularly in species-rich, tropical systems. We characterize for the first time the food web of Lake Gatun-a diverse and highly invaded tropical freshwater lake within the Panama Canal. We used stable isotope analysis to reconstruct the trophic structure of the fish community of Lake Gatun and to compare it to that of a minimally invaded reference lake, Lake Bayano. We found significant differences between the trophic structures of these two Neotropical lakes, notably that Lake Gatun's fish community was characterized by a longer food chain, greater isotopic diversity, a broader range of trophic positions and body sizes, and shifts in the isotopic positions of several native taxa relative to Lake Bayano. The degree of isotopic overlap between native and non-native trophic guilds in Lake Gatun was variable, with herbivores exhibiting the lowest (20%-29%) overlap and carnivores the greatest (81%-100%). Overall, our results provide some of the first empirical evidence for the ways in which multiple introduced and native species may partition isotopic space in a species-rich tropical freshwater food web.
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Affiliation(s)
- Diana M T Sharpe
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
- Department of Biology, McGill University, Montréal, Québec, Canada
- Smithsonian Tropical Research Institute, Panama City, Panama
| | - Marisol P Valverde
- Department of Biology, McGill University, Montréal, Québec, Canada
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Luis F De León
- Smithsonian Tropical Research Institute, Panama City, Panama
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts, USA
- Instituto de Investigaciones Cientificas y Servicios de Alta Tecnologia, Centro de Biodiversidad y Descubrimiento de Drogas, Panama City, Panama
| | - Andrew P Hendry
- Department of Biology, McGill University, Montréal, Québec, Canada
| | - Mark E Torchin
- Smithsonian Tropical Research Institute, Panama City, Panama
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4
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Kotowych N, Smalås A, Amundsen PA, Primicerio R. Climate warming accelerates somatic growth of an Arctic fish species in high-latitude lakes. Sci Rep 2023; 13:16749. [PMID: 37798382 PMCID: PMC10556027 DOI: 10.1038/s41598-023-43654-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 09/26/2023] [Indexed: 10/07/2023] Open
Abstract
High-latitude aquatic ecosystems are responding to rapid climate warming. A longer ice-free season with higher water temperatures may accelerate somatic growth in lake ectotherms, leading to widespread ecological implications. In fish, rising temperatures are expected to boost rates of food intake and conversion, and predictions based on empirical relationships between temperature and growth suggest a substantial increase in fish growth rates during the last decades. Fish abundance negatively affects growth by limiting food availability. This field study addresses the effects of climate warming on growth of a subarctic population of Arctic charr (Salvelinus alpinus (L.) over nearly 40 years. Juvenile growth of 680 individuals of Arctic charr, was reconstructed by sclerochronological analysis using sagittal otoliths sampled annually from the early 1980s to 2016. Statistical modelling revealed a positive effect of water temperature, and a negative effect of abundance on somatic growth in juvenile individuals. Temperature dependence in growth was significant for average and fast-growing individuals across all investigated age classes. These findings suggest that, as temperatures rise, somatic growth of Arctic charr will increase in high latitude lakes. Climate warming will thus influence cold water fish life history and size-structured interactions, with important consequences for their populations and ecosystems.
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Affiliation(s)
- Nicholas Kotowych
- Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Aslak Smalås
- Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, Tromsø, Norway.
| | - Per-Arne Amundsen
- Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Raul Primicerio
- Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, Tromsø, Norway
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5
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Vagnon C, Pomeranz J, Loheac B, Vallat M, Guillard J, Raymond JC, Sentis A, Frossard V. Changes in vertical and horizontal diversities mediated by the size structure of introduced fish collectively shape food-web stability. Ecol Lett 2023; 26:1752-1764. [PMID: 37492003 DOI: 10.1111/ele.14290] [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: 02/06/2023] [Revised: 07/05/2023] [Accepted: 07/10/2023] [Indexed: 07/27/2023]
Abstract
Species introductions can alter local food-web structure by changing the vertical or horizontal diversity within communities, largely driven by their body size distributions. Increasing vertical and horizontal diversities is predicted to have opposing effects on stability. However, their interactive effects remain largely overlooked. We investigated the independent and collective effects of vertical and horizontal diversities on food-web stability in alpine lakes stocked with variable body size distributions of introduced fish species. Introduced predators destabilize food-webs by increasing vertical diversity through food chain lengthening. Alternatively, increasing horizontal diversity results in more stable food-web topologies. A non-linear interaction between vertical and horizontal diversities suggests that increasing vertical diversity is most destabilizing when horizontal diversity is low. Our findings suggest that the size structure of introduced predators drives their impacts on stability by modifying the structure of food-webs, and highlights the interactive effects of vertical and horizontal diversities on stability.
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Affiliation(s)
- Chloé Vagnon
- Université Savoie Mont Blanc, INRAE, UMR CARRTEL, Thonon-les-Bains, France
- Pôle R&D Ecosystèmes Lacustres (ECLA), OFB-INRAE-USMB, Aix-en-Provence, France
| | | | - Bertrand Loheac
- Fédération de Savoie pour la Pêche et la Protection du Milieu Aquatique (FDPPMA 73), Saint-Alban-Leysse, France
| | - Manuel Vallat
- Fédération de Savoie pour la Pêche et la Protection du Milieu Aquatique (FDPPMA 73), Saint-Alban-Leysse, France
| | - Jean Guillard
- Université Savoie Mont Blanc, INRAE, UMR CARRTEL, Thonon-les-Bains, France
- Pôle R&D Ecosystèmes Lacustres (ECLA), OFB-INRAE-USMB, Aix-en-Provence, France
| | - Jean-Claude Raymond
- Pôle R&D Ecosystèmes Lacustres (ECLA), OFB-INRAE-USMB, Aix-en-Provence, France
- Office Française pour la Biodiversité, Unité Spécialisée Milieux Lacustres, Thonon-les-Bains, France
| | - Arnaud Sentis
- Pôle R&D Ecosystèmes Lacustres (ECLA), OFB-INRAE-USMB, Aix-en-Provence, France
- INRAE, Université Aix Marseille, UMR RECOVER, Aix-en-Provence, France
| | - Victor Frossard
- Université Savoie Mont Blanc, INRAE, UMR CARRTEL, Thonon-les-Bains, France
- Pôle R&D Ecosystèmes Lacustres (ECLA), OFB-INRAE-USMB, Aix-en-Provence, France
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6
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Henriksen EH, Frainer A, Poulin R, Knudsen R, Amundsen P. Ectoparasites population dynamics are affected by host body size but not host density or water temperature in a 32‐year long time series. OIKOS 2022. [DOI: 10.1111/oik.09328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Eirik H. Henriksen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - André Frainer
- Norwegian Inst. for Nature Research (NINA), Framsenteret Tromsø Norway
| | | | - Rune Knudsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Per‐Arne Amundsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
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7
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Ho HC, Brodersen J, Gossner MM, Graham CH, Kaeser S, Reji Chacko M, Seehausen O, Zimmermann NE, Pellissier L, Altermatt F. Blue and green food webs respond differently to elevation and land use. Nat Commun 2022; 13:6415. [PMID: 36302854 PMCID: PMC9613893 DOI: 10.1038/s41467-022-34132-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 10/14/2022] [Indexed: 12/25/2022] Open
Abstract
While aquatic (blue) and terrestrial (green) food webs are parts of the same landscape, it remains unclear whether they respond similarly to shared environmental gradients. We use empirical community data from hundreds of sites across Switzerland and a synthesis of interaction information in the form of a metaweb to show that inferred blue and green food webs have different structural and ecological properties along elevation and among various land-use types. Specifically, in green food webs, their modular structure increases with elevation and the overlap of consumers' diet niche decreases, while the opposite pattern is observed in blue food webs. Such differences between blue and green food webs are particularly pronounced in farmland-dominated habitats, indicating that anthropogenic habitat modification modulates the climatic effects on food webs but differently in blue versus green systems. These findings indicate general structural differences between blue and green food webs and suggest their potential divergent future alterations through land-use or climatic changes.
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Affiliation(s)
- Hsi-Cheng Ho
- Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600, Dübendorf, Switzerland.
| | - Jakob Brodersen
- Department Fish Ecology and Evolution, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Seestrasse 79, CH-6047, Kastanienbaum, Switzerland
| | - Martin M Gossner
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Universitätstrasse 16, CH-8092, Zürich, Switzerland
| | - Catherine H Graham
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Silvana Kaeser
- Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600, Dübendorf, Switzerland
| | - Merin Reji Chacko
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Universitätstrasse 16, CH-8092, Zürich, Switzerland
| | - Ole Seehausen
- Department Fish Ecology and Evolution, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Seestrasse 79, CH-6047, Kastanienbaum, Switzerland
- Division Aquatic Ecology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, CH-3012, Bern, Switzerland
| | - Niklaus E Zimmermann
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Universitätstrasse 16, CH-8092, Zürich, Switzerland
| | - Loïc Pellissier
- WSL Swiss Federal Research Institute, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
- Department of Environmental Systems Science, Institute of Terrestrial Ecosystems, ETH Zürich, Universitätstrasse 16, CH-8092, Zürich, Switzerland
| | - Florian Altermatt
- Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600, Dübendorf, Switzerland.
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.
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8
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Merging theory and experiments to predict and understand coextinctions. Trends Ecol Evol 2022; 37:886-898. [DOI: 10.1016/j.tree.2022.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 11/20/2022]
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9
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Llaberia-Robledillo M, Balbuena JA, Sarabeev V, Llopis-Belenguer C. Changes in native and introduced host–parasite networks. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02657-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AbstractIntroduced species can alter the dynamics and structure of a native community. Network analysis provides a tool to study host–parasite interactions that can help to predict the possible impact of biological invasions or other disturbances. In this study, we used weighted bipartite networks to assess differences in the interaction patterns between hosts and helminth parasites of native (Sea of Japan) and invasive (Black Sea and Sea of Azov) populations of Planiliza haematocheilus (Teleostei: Mugilidae). We employed three quantitative network descriptors, connectance, weighted nestedness and modularity, to gain insight into the structure of the host–parasite networks in the native and invaded areas. The role of parasite species in the networks was assessed using the betweenness centrality index. We analyzed networks encompassing the whole helminth community and subsets of species classified by their transmission strategy. The analyses were downscaled to host individual-level to consider intraspecific variation in parasite communities. We found significant differences between networks in the native and invaded areas. The latter presented a higher value of nestedness, which may indicate a co-occurrence between parasite species with many connections in the network and species with fewer interactions within the same individual-host. In addition, modularity was higher in the native area’s networks than those of the invaded area, with subgroups of host individuals that interact more frequently with certain parasite species than with others. Only the networks composed of actively transmitted parasites and ectoparasites did not show significant differences in modularity between the Sea of Azov and the Sea of Japan, which could be due to the introduction of a part of the native community into the invaded environment, with a lower diversity and abundance of species. We show that network analysis provides a valuable tool to illuminate the changes that occur in host–parasite interactions when an invasive species and its parasite community are introduced into a new area.
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10
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Prati S, Henriksen EH, Smalås A, Knudsen R, Klemetsen A, Sánchez-Hernández J, Amundsen PA. The effect of inter‐ and intraspecific competition on individual and population niche widths: a four‐decade study on two interacting salmonids. OIKOS 2021. [DOI: 10.1111/oik.08375] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Sebastian Prati
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Eirik Haugstvedt Henriksen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Aslak Smalås
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Rune Knudsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Anders Klemetsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
| | - Javier Sánchez-Hernández
- Depto de Biología, Geología, Física y Química Inorgánica, Univ. Rey Juan Carlos, Móstoles Madrid Spain
| | - Per-Arne Amundsen
- Dept of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic Univ. of Norway Tromsø Norway
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11
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Runghen R, Poulin R, Monlleó-Borrull C, Llopis-Belenguer C. Network Analysis: Ten Years Shining Light on Host-Parasite Interactions. Trends Parasitol 2021; 37:445-455. [PMID: 33558197 DOI: 10.1016/j.pt.2021.01.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/15/2021] [Accepted: 01/16/2021] [Indexed: 12/24/2022]
Abstract
Biological interactions are key drivers of ecological and evolutionary processes. The complexity of such interactions hinders our understanding of ecological systems and our ability to make effective predictions in changing environments. However, network analysis allows us to better tackle the complexity of ecosystems because it extracts the properties of an ecological system according to the number and distribution of links among interacting entities. The number of studies using network analysis to solve ecological and evolutionary questions in parasitology has increased over the past decade. Here, we synthesise the contribution of network analysis toward disentangling host-parasite processes. Furthermore, we identify current trends in mainstream ecology and novel applications of network analysis that present opportunities for research on host-parasite interactions.
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Affiliation(s)
- Rogini Runghen
- Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag 4800, 8140 Christchurch, New Zealand
| | - Robert Poulin
- Department of Zoology, University of Otago, 340 Great King Street, 9054 Dunedin, New Zealand
| | - Clara Monlleó-Borrull
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, PO Box 22085, ES-46071, Valencia, Spain
| | - Cristina Llopis-Belenguer
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, PO Box 22085, ES-46071, Valencia, Spain.
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12
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Shaw JC, Henriksen EH, Knudsen R, Kuhn JA, Kuris AM, Lafferty KD, Siwertsson A, Soldánová M, Amundsen P. High parasite diversity in the amphipod Gammarus lacustris in a subarctic lake. Ecol Evol 2020; 10:12385-12394. [PMID: 33209296 PMCID: PMC7663964 DOI: 10.1002/ece3.6869] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 02/02/2023] Open
Abstract
Amphipods are often key species in aquatic food webs due to their functional roles in the ecosystem and as intermediate hosts for trophically transmitted parasites. Amphipods can also host many parasite species, yet few studies address the entire parasite community of a gammarid population, precluding a more dynamic understanding of the food web. We set out to identify and quantify the parasite community of Gammarus lacustris to understand the contributions of the amphipod and its parasites to the Takvatn food web. We identified seven parasite taxa: a direct life cycle gregarine, Rotundula sp., and larval stages of two digenean trematode genera, two cestodes, one nematode, and one acanthocephalan. The larval parasites use either birds or fishes as final hosts. Bird parasites predominated, with trematode Plagiorchis sp. having the highest prevalence (69%) and mean abundance (2.7). Fish parasites were also common, including trematodes Crepidostomum spp., nematode Cystidicola farionis, and cestode Cyathocephalus truncatus (prevalences 13, 6, and 3%, respectively). Five parasites depend entirely on G. lacustris to complete their life cycle. At least 11.4% of the overall parasite diversity in the lake was dependent on G. lacustris, and 16% of the helminth diversity required or used the amphipod in their life cycles. These dependencies reveal that in addition to being a key prey item in subarctic lakes, G. lacustris is also an important host for maintaining parasite diversity in such ecosystems.
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Affiliation(s)
- Jenny C. Shaw
- Marine Science InstituteUniversity of California Santa BarbaraSanta BarbaraCAUSA
| | - Eirik H. Henriksen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Rune Knudsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Jesper A. Kuhn
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Armand M. Kuris
- Marine Science InstituteUniversity of California Santa BarbaraSanta BarbaraCAUSA
- Department of Ecology, Evolution and Marine BiologyUniversity of CaliforniaSanta BarbaraCAUSA
| | - Kevin D. Lafferty
- Marine Science InstituteUniversity of California Santa BarbaraSanta BarbaraCAUSA
- Western Ecological ResearchU.S. Geological SurveySanta BarbaraCAUSA
| | - Anna Siwertsson
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
- Institute of Marine ResearchEcosystem Processes Research GroupTromsøNorway
| | - Miroslava Soldánová
- Institute of Parasitology, Biology CentreCzech Academy of SciencesČeské BudějoviceCzech Republic
| | - Per‐Arne Amundsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
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Prati S, Henriksen EH, Knudsen R, Amundsen PA. Impacts of ontogenetic dietary shifts on the food-transmitted intestinal parasite communities of two lake salmonids. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2020; 12:155-164. [PMID: 32577375 PMCID: PMC7300134 DOI: 10.1016/j.ijppaw.2020.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/08/2020] [Accepted: 06/08/2020] [Indexed: 11/06/2022]
Abstract
Ontogenetic dietary shifts are common in fish and often impact trophically transmitted parasite communities. How parasite species composition and relative abundances change among size classes, and at what rate these changes occur, is rarely examined. Hosts with a broad trophic niche are potentially exposed to a large variety of parasite species. The degree of ontogenetic changes in parasite species composition versus changes in parasite abundance should suggestively differ between thropically generalist and specialist host species. In the present study, we explore ontogenetic dietary shifts and their impact on species composition and relative abundance of intestinal parasites in two sympatric salmonid fish species, Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) caught in the littoral habitat of a subarctic lake. Our results highlight a close interplay between ontogenetic dietary niche shifts and alterations in the acquisition of trophically transmitted parasites, leading to host-specific differences in the component community of parasites. Ontogenetic changes in the intestinal parasite community related to dietary niche shifts were distinct but less pronounced in Arctic charr than in brown trout due to a broader and more consistent dietary niche of the former and an ontogenetic shift toward piscivory in the latter. At the component community level, changes in parasite assemblages of both host species were driven by a faster increase in the heterogeneity of parasite relative abundance than in the compositional heterogeneity, a pattern that partly may be related to a rather species-poor parasite community of this subarctic study system. Separating compositional heterogeneity from heterogeneity in relative parasite abundance is important to understand how size-dependent variability shapes parasite communities of host populations. Ontogenetic dietary niche shifts generated host-specific differences in the component community of parasites. Ontogenetic changes in the intestinal parasite community were less pronounced in Arctic charr than in brown trout. Heterogeneity of parasite relative abundance increased faster than the compositional heterogeneity.
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Affiliation(s)
- Sebastian Prati
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Muninbakken 21, 9019, Tromsø, Norway
| | - Eirik Haugstvedt Henriksen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Muninbakken 21, 9019, Tromsø, Norway
| | - Rune Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Muninbakken 21, 9019, Tromsø, Norway
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Muninbakken 21, 9019, Tromsø, Norway
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14
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Prati S, Henriksen EH, Knudsen R, Amundsen P. Seasonal dietary shifts enhance parasite transmission to lake salmonids during ice cover. Ecol Evol 2020; 10:4031-4043. [PMID: 32489629 PMCID: PMC7244800 DOI: 10.1002/ece3.6173] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/17/2020] [Accepted: 02/19/2020] [Indexed: 12/19/2022] Open
Abstract
Changes in abiotic and biotic factors between seasons in subarctic lake systems are often profound, potentially affecting the community structure and population dynamics of parasites over the annual cycle. However, few winter studies exist and interactions between fish hosts and their parasites are typically confined to snapshot studies restricted to the summer season whereas host-parasite dynamics during the ice-covered period rarely have been explored. The present study addresses seasonal patterns in the infections of intestinal parasites and their association with the diet of sympatric living Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) in Lake Takvatn, a subarctic lake in northern Norway. In total, 354 Arctic charr and 203 brown trout were sampled from the littoral habitat between June 2017 and May 2018. Six trophically transmitted intestinal parasite taxa were identified and quantified, and their seasonal variations were contrasted with dietary information from both stomachs and intestines of the fish. The winter period proved to be an important transmission window for parasites, with increased prevalence and intensity of amphipod-transmitted parasites in Arctic charr and parasites transmitted through fish prey in brown trout. In Arctic charr, seasonal patterns in parasite infections resulted mainly from temporal changes in diet toward amphipods, whereas host body size and the utilization of fish prey were the main drivers in brown trout. The overall dynamics in the community structure of parasites chiefly mirrored the seasonal dietary shifts of their fish hosts.
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Affiliation(s)
- Sebastian Prati
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Eirik H. Henriksen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Rune Knudsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Per‐Arne Amundsen
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
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15
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Schoeman AL, Joubert TL, du Preez LH, Svitin R. Xenopus laevis as UberXL for nematodes. AFRICAN ZOOLOGY 2020. [DOI: 10.1080/15627020.2019.1681295] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Anneke L Schoeman
- African Amphibian Conservation Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
- Centre of Excellence for Invasion Biology, Department of Botany and Zoology, University of Stellenbosch, Stellenbosch, South Africa
| | - Tracy-Lee Joubert
- African Amphibian Conservation Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Louis H du Preez
- African Amphibian Conservation Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
- South African Institute for Aquatic Biodiversity, Grahamstown, South Africa
| | - Roman Svitin
- African Amphibian Conservation Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
- South African Institute for Aquatic Biodiversity, Grahamstown, South Africa
- Department of Invertebrate Fauna and Systematics, II Schmalhausen Institute of Zoology, Kyiv, Ukraine
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16
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Advances and challenges in modelling the impacts of invasive alien species on aquatic ecosystems. Biol Invasions 2019. [DOI: 10.1007/s10530-019-02160-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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17
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Community Response of Cladocera to Trophic Stress by Biomanipulation in a Shallow Oxbow Lake. WATER 2019. [DOI: 10.3390/w11050929] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Studying contemporary and subfossil Cladocera (Crustacea) communities, we explored the effect of top-down stressors on the cladoceran communities; we are also interested in the coherence of the contemporary and subfossil communities. The studied Cibakháza oxbow lake is in E Hungary, on the left-floodplain of the River Tisza; it is a large, long, and shallow oxbow lake. Three areas of the oxbow lake were distinguished based on the strength of top-down stress: protected area with low top-down stress, biomanipulated area with high top-down stress, and recreational area with moderate top-down stress. Altogether, we identified 28 taxa in the contemporary and subfossil communities in the oxbow lake. We found that the species number of the contemporary Cladocera communities was lower (protected area: 13; biomanipulated area: 9, and recreational area: 14) than in the subfossil communities (protected area: 20; biomanipulated area: 16, and recreational area: 14). Among the environmental variables, we observed differences between the protected and biomanipulated area, while the recreational area showed a transition. Species number, abundances, and Simpson diversity also showed the effect of the fish introduction. There were no differences in beta-diversity among the contemporary and subfossil Cladocera community. The non-metric multidimensional scaling (NMDS) ordination showed that the biomanipulated area in the case of the contemporary communities was separated from the other areas, while in the case of the subfossil communities, there was no separation according to top-down stress. Our results showed that the number of species of contemporary Cladocera communities was lower in each area (3–10; 3–9; 5–9) compared to the subfossil communities (6–17; 7–12; 8–12). However, the highest abundances were found in the biomanipulated area due to the appearance of small-sized Cladocera species. Our findings suggest that the effect of a short-time fish introduction is restorable when the oxbow lake has a protected part.
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18
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Repeated reduction in parasite diversity in invasive populations of Xenopus laevis: a global experiment in enemy release. Biol Invasions 2019. [DOI: 10.1007/s10530-018-1902-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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Hohenadler MAA, Honka KI, Emde S, Klimpel S, Sures B. First evidence for a possible invasional meltdown among invasive fish parasites. Sci Rep 2018; 8:15085. [PMID: 30305713 PMCID: PMC6180077 DOI: 10.1038/s41598-018-33445-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 09/27/2018] [Indexed: 11/24/2022] Open
Abstract
Biological invasions are frequently studied topics in ecological research. Unfortunately, within invasion ecology parasite-associated aspects such as parasite impacts on new environments and on local host populations are less well-studied. Round gobies migrating from the Ponto-Caspian region into the Rhine River system are heavily infested with the Ponto-Caspian acanthocephalan parasite Pomphorhynchus laevis. As shown by experimental infestations the acanthocephalans occur as pre-adults in host-encapsulated cysts within the internal organs of the migrating gobies, but remain infective for their definitive host chub. Recently, we described the occurrence of larvae of another parasite, the invasive eel swim bladder nematode Anguillicola crassus, in these Pomphorhynchus cysts. In the present study, we could prove the infectivity of the nematode larvae for European eels for the first time. After experimental inoculation of Pomphorhynchus cysts occasionally infested with A. crassus larvae, the nematodes grow to maturity and reproduce whereas all P. laevis were unviable. We therefore postulate that the nematode larvae behave like immunological hitchhikers that follow a “Trojan horse strategy” in order to avoid the paratenic host’s immune response. Accordingly, the interaction between both invasive parasites gives first evidence that the invasional meltdown hypothesis may also apply to parasites.
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Affiliation(s)
- M A A Hohenadler
- Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany
| | - K I Honka
- Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany
| | - S Emde
- Landesamt für Natur, Umwelt und Verbraucherschutz Nordrhein-Westfalen (LANUV), Fisheries Ecology, Heinsberger Str. 53, 57399, Kirchhundem-Albaum, Germany.,Goethe-University, Institute of Ecology, Evolution and Diversity; Senckenberg Gesellschaft für Naturforschung, Senckenberg Biodiversity and Climate Research Centre Frankfurt/Main, Max-von-Laue-Str. 13, 60438 Frankfurt, Germany
| | - S Klimpel
- Goethe-University, Institute of Ecology, Evolution and Diversity; Senckenberg Gesellschaft für Naturforschung, Senckenberg Biodiversity and Climate Research Centre Frankfurt/Main, Max-von-Laue-Str. 13, 60438 Frankfurt, Germany
| | - B Sures
- Aquatic Ecology and Centre for Water and Environmental Research, University of Duisburg-Essen, Universitätsstr. 5, 45141, Essen, Germany. .,Department of Zoology, University of Johannesburg, PO Box 524, Auckland Park, 2006, Johannesburg, South Africa.
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20
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Lagrue C. Impacts of crustacean invasions on parasite dynamics in aquatic ecosystems: A plea for parasite-focused studies. Int J Parasitol Parasites Wildl 2017; 6:364-374. [PMID: 30951574 PMCID: PMC5715223 DOI: 10.1016/j.ijppaw.2017.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 03/31/2017] [Indexed: 11/23/2022]
Abstract
While there is considerable interest in, and good evidence for, the role that parasites play in biological invasions, the potential parallel effects of species introduction on parasite dynamics have clearly received less attention. Indeed, much effort has been focused on how parasites can facilitate or limit invasions, and positively or negatively impact native host species and recipient communities. Contrastingly, the potential consequences of biological invasions for the diversity and dynamics of both native and introduced parasites have been and are still mainly overlooked, although successful invasion by non-native host species may have large, contrasting and unpredictable effects on parasites. This review looks at the links between biological invasions and pathogens, and particularly at crustacean invasions in aquatic ecosystems and their potential effects on native and invasive parasites, and discusses what often remains unknown even from well-documented systems. Aquatic crustaceans are hosts to many parasites and are often invasive. Published studies show that crustacean invasion can have highly contrasting effects on parasite dynamics, even when invasive host and parasite species are phylogenetically close to their native counterparts. These effects seem to be dependent on multiple factors such as host suitability, parasite life-cycle or host-specific resistance to parasitic manipulation. Furthermore, introduced hosts can have drastically contrasting effects on parasite standing crop and transmission, two parameters that should be independently assessed before drawing any conclusion on the potential effects of novel hosts on parasites and the key processes influencing disease dynamics following biological invasions. I conclude by calling for greater recognition of biological invasions' effects on parasite dynamics, more parasite-focused studies and suggest some potential ways to assess these effects.
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21
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Barry J, Newton M, Dodd JA, Evans D, Newton J, Adams CE. The effect of foraging and ontogeny on the prevalence and intensity of the invasive parasite Anguillicola crassus in the European eel Anguilla anguilla. JOURNAL OF FISH DISEASES 2017; 40:1213-1222. [PMID: 28084623 DOI: 10.1111/jfd.12596] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 11/10/2016] [Accepted: 11/10/2016] [Indexed: 06/06/2023]
Abstract
Infection patterns of the invasive Anguillicola crassus nematode were investigated in a population of the European eel Anguilla anguilla where parasite invasion is very recent, Loch Lomond, Scotland. Intensity levels of the parasite were associated with differences in fish ontogeny and trophic ecology. Although eels foraged on both fish and invertebrates, individuals which were smaller and fed on invertebrates (>70% contribution to diet) were found to contain a greater number of swim bladder parasites compared to larger eel with a predominance of fish (>60% contribution) in their diet. Within affected fish, a significant negative relationship was found between fish length and parasite intensity, with smaller individuals having higher parasite intensity than larger individuals. This study indicates that food intake and infection risk are linked in this recently infected host-parasite system. From a management perspective increasing our understanding of how infection intensity and repeated exposure is linked to resource use in an ecosystem is important for the future management of this endangered species in Europe.
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Affiliation(s)
- J Barry
- Scottish Centre for Ecology & the Natural Environment, IBAHCM, University of Glasgow, Glasgow, UK
| | - M Newton
- Scottish Centre for Ecology & the Natural Environment, IBAHCM, University of Glasgow, Glasgow, UK
| | - J A Dodd
- Scottish Centre for Ecology & the Natural Environment, IBAHCM, University of Glasgow, Glasgow, UK
| | - D Evans
- Agri-Food and Biosciences Institute, Belfast, Antrim, UK
| | - J Newton
- NERC Life Sciences Mass Spectrometry Facility, SUERC, East Kilbride, Glasgow, UK
| | - C E Adams
- Scottish Centre for Ecology & the Natural Environment, IBAHCM, University of Glasgow, Glasgow, UK
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22
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Borgstrøm R, Trømborg J, Haugen TO, Rosseland BO. Plerocercoids of the cestode Diphyllobothrium ditremum in brown trout Salmo trutta: substantial increase in infection after establishment of European minnow Phoxinus phoxinus. JOURNAL OF FISH BIOLOGY 2017; 91:912-927. [PMID: 28758219 DOI: 10.1111/jfb.13391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/29/2017] [Indexed: 06/07/2023]
Abstract
This study focuses on plerocercoids of the cestode Diphyllobothrium ditremum in brown trout Salmo trutta from the subalpine lake Øvre Heimdalsvatn in south-central Norway. Salmo trutta was the only fish species in this lake until European minnow Phoxinus phoxinus was registered in 1969. The P. phoxinus population increased substantially in the following years. In contrast with the 1969-1972 period, when plerocercoids of D. ditremum were practically absent in S. trutta, there was a high prevalence and intensity of infection in the 2013 S. trutta samples. Because the life cycle of D. ditremum involves two larval stages, in copepods and salmonids and mature worms in piscivorous birds, such as mergansers and loons, a change in feeding ecology of S. trutta or changes in population densities of copepods, fish or birds might have influenced the infection pattern. No relationships between D. ditremum infection and muscle-tissue δ15 N signature or Hg concentration were found, indicating that infection is not a result of piscivory or cannibalism. Furthermore, consumption of copepods by S. trutta during summer and autumn was low. On the other hand, the number of piscivorous birds has increased, probably due to the presence of P. phoxinus as a new and numerous prey. An increased number of final D. ditremum hosts may have produced a higher output of cestode eggs, resulting in more infected copepods that in turn are consumed by S. trutta. Indirectly, P. phoxinus may therefore have caused the observed increased infection in S. trutta and thereby imposed further negative effects on S. trutta in high mountain areas.
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Affiliation(s)
- R Borgstrøm
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway
| | - J Trømborg
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway
| | - T O Haugen
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway
| | - B O Rosseland
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway
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23
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Al-Shorbaji F, Roche B, Britton R, Andreou D, Gozlan R. Influence of predation on community resilience to disease. J Anim Ecol 2017; 86:1147-1158. [PMID: 28758196 DOI: 10.1111/1365-2656.12722] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 06/01/2017] [Indexed: 02/05/2023]
Abstract
Outbreaks of generalist pathogens are influenced by host community structure, including population density and species diversity. Within host communities predation can influence pathogen transmission rates, prevalence and impacts. However, the influence of predation on community resilience to outbreaks of generalist pathogens is not fully understood. The role of predation on host community resilience to disease was assessed using an epidemiological multi-host susceptible-exposed-infectious-recovered model. Sphaerothecum destruens, an emerging fungal-like generalist pathogen, was used as a model pathogen. Six cyprinid and salmonid fishes, including an asymptomatic carrier, were selected as model hosts that are known to be impacted by S. destruens, and they were used within a model host community. Pathogen release into the host community was via introduction of the asymptomatic carrier. Mortality from infection, pathogen incubation rate, and host recovery rate were set to a range of evidence-based values in each species and were varied in secondary consumers to predict top-down effects of infection on the resilience of a host community. Predation pressure within the fish community was varied to test its effects on infection prevalence and host survival in the community. Model predictions suggested that predation of the asymptomatic hosts by fishes in the host community was insufficient to eliminate S. destruens. Sphaerothecum destruens persisted in the community due to its rapid transmission from the asymptomatic host to susceptible host fishes. Following transmission, pathogen prevalence in the community was driven by transmission within and between susceptible host fishes, indicating low host community resilience. However, introducing low densities of a highly specific piscivorous fish into the community to pre-date asymptomatic hosts could limit pathogen prevalence in the host community, thus increasing resilience. The model predictions indicate that whilst resilience to this generalist pathogen in the host community was low, this could be increased using management interventions. The results suggest that this model has high utility for predicting community resilience to disease and thus can be applied to other generalist parasites to determine risks of disease emergence.
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Affiliation(s)
- Farah Al-Shorbaji
- Bournemouth University, Faculty of Science and Technology, Dorset, UK
| | - Benjamin Roche
- Unit for Mathematical and Computer Modelling of Complex Systems, Institute of Research for Development, Montpellier, France.,Institut de Recherche pour le Développement UMR MIVEGEC IRD-CNRS-Université de Montpellier, Centre IRD de Montpellier, Montpellier, France
| | - Robert Britton
- Bournemouth University, Faculty of Science and Technology, Dorset, UK
| | - Demetra Andreou
- Bournemouth University, Faculty of Science and Technology, Dorset, UK
| | - Rodolphe Gozlan
- Institut de Recherche pour le Développement UMR MIVEGEC IRD-CNRS-Université de Montpellier, Centre IRD de Montpellier, Montpellier, France.,Institut de Recherche pour le Développement UMR BOREA IRD-MNHN-Université Pierre et Marie Curie, Muséum National d'Histoire Naturelle, Paris Cedex 5, France
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24
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Molecular analyses reveal high species diversity of trematodes in a sub-Arctic lake. Int J Parasitol 2017; 47:327-345. [DOI: 10.1016/j.ijpara.2016.12.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 12/09/2016] [Accepted: 12/12/2016] [Indexed: 02/05/2023]
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25
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Médoc V, Firmat C, Sheath D, Pegg J, Andreou D, Britton J. Parasites and Biological Invasions. ADV ECOL RES 2017. [DOI: 10.1016/bs.aecr.2016.10.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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26
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Kuhn JA, Frainer A, Knudsen R, Kristoffersen R, Amundsen PA. Effects of fish species composition on Diphyllobothrium spp. infections in brown trout - is three-spined stickleback a key species? JOURNAL OF FISH DISEASES 2016; 39:1313-1323. [PMID: 27111407 DOI: 10.1111/jfd.12467] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 12/26/2015] [Accepted: 12/27/2015] [Indexed: 06/05/2023]
Abstract
Subarctic populations of brown trout (Salmo trutta) are often heavily infected with cestodes of the genus Diphyllobothrium, assumedly because of their piscivorous behaviour. This study explores possible associations between availability of fish prey and Diphyllobothrium spp. infections in lacustrine trout populations. Trout in (i) allopatry (group T); (ii) sympatry with Arctic charr (Salvelinus alpinus) (group TC); and (iii) sympatry with charr and three-spined stickleback (Gasterosteus aculeatus) (group TCS) were contrasted. Mean abundance and intensity of Diphyllobothrium spp. were higher in group TCS compared to groups TC and T. Prevalence, however, was similarly higher in groups TCS and TC compared to group T. Zero-altered negative binomial modelling identified the lowest probability of infection in group T and similar probabilities of infection in groups TC and TCS, whereas the highest intensity was predicted in group TCS. The most infected trout were from the group co-occurring with stickleback (TCS), possibly due to a higher availability of fish prey. In conclusion, our study demonstrates elevated Diphyllobothrium spp. infections in lacustrine trout populations where fish prey are available and suggests that highly available and easily caught stickleback prey may play a key role in the transmission of Diphyllobothrium spp. parasite larvae.
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Affiliation(s)
- J A Kuhn
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway.
| | - A Frainer
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - R Knudsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - R Kristoffersen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
| | - P-A Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
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27
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Bozick BA, Real LA. INTEGRATING PARASITES AND PATHOGENS INTO THE STUDY OF GEOGRAPHIC RANGE LIMITS. QUARTERLY REVIEW OF BIOLOGY 2016; 90:361-80. [PMID: 26714350 DOI: 10.1086/683698] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The geographic distributions of all species are limited, and the determining factors that set these limits are of fundamental importance to the fields of ecology and evolutionary biology. Plant and animal ranges have been of primary concern, while those of parasites, which represent much of the Earth's biodiversity, have been neglected. Here, we review the determinants of the geographic ranges of parasites and pathogens, and explore how parasites provide novel systems with which to investigate the ecological and evolutionary processes governing host/parasite spatial distributions. Although there is significant overlap in the causative factors that determine range borders of parasites and free-living species, parasite distributions are additionally constrained by the geographic range and ecology of the host species' population, as well as by evolutionary factors that promote host-parasite coevolution. Recently, parasites have been used to infer population demographic and ecological information about their host organisms and we conclude that this strategy can be further exploited to understand geographic range limitations of both host and parasite populations.
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28
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Invaded Invaders: Infection of Invasive Brown Treesnakes on Guam by an Exotic Larval Cestode with a Life Cycle Comprised of Non-Native Hosts. PLoS One 2015; 10:e0143718. [PMID: 26699614 PMCID: PMC4689450 DOI: 10.1371/journal.pone.0143718] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 11/09/2015] [Indexed: 11/28/2022] Open
Abstract
Background Multiple host introductions to the same non-native environment have the potential to complete life cycles of parasites incidentally transported with them. Our goal was to identify a recently detected parasitic flatworm in the invasive Brown Treesnake (Boiga irregularis) on the remote Pacific island of Guam. We considered possible factors influencing parasite transmission, and tested for correlations between infection status and potential indicators of host fitness. We used genetic data from the parasite and information about the native ranges of other possible non-native hosts to hypothesize how it arrived on Guam and how its life cycle may be currently supported. Methods We identified the parasite by comparing larval morphology and mtDNA sequences with other Pseudophyllid tapeworms. We assessed probability of infection in individual snakes using logistic regression and examined different factors influencing presence of parasites in hosts. Results We identified the parasite as the pseudophyllid cestode Spirometra erinaceieuropaei, with all sampled worms from multiple snakes sharing a single mtDNA haplotype. Infection appears to be limited to the only freshwater watershed on the island, where infection prevalence was high (77.5%). Larger snakes had a higher probability of being infected, consistent with the chronic nature of such infections. While infection status was positively correlated with body condition, infected snakes tended to have lower intra-peritoneal fat body mass, potentially indicating a negative effect on energy stores. Conclusions We discovered that B. irregularis inhabiting a small area of forested habitat in a freshwater watershed on Guam are often infected by a novel parasite of Asian origin. While further work is needed, this species of Spirometra, itself a non-native species, likely depends on a suite of recently introduced hosts from different parts of the world to complete the life cycle. This baseline study provides little evidence of any effects on host fitness, but additional data are needed to more thoroughly explore the consequences of infection in this invasive snake population.
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Three-spined stickleback Gasterosteus aculeatus, as a possible paratenic host for salmonid nematodes in a subarctic lake. Parasitol Res 2015; 115:1335-8. [PMID: 26650345 DOI: 10.1007/s00436-015-4854-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/27/2015] [Indexed: 10/22/2022]
Abstract
In Takvatn, a subarctic lake in northern Norway, 35 of 162 three-spined sticklebacks examined were infected with 106 specimens of third-stage larvae of Philonema oncorhynchi. The prevalence and mean intensity of P. oncorhynchi were 10 % and 2.0 in 2013 and 24 % and 3.0 in 2014, respectively. A single specimen of Cystidicola farionis was found in an additional sample. While the latter is considered an accidental infection, three-spined sticklebacks may function as paratenic hosts of P. oncorhynchi, potentially enhancing its transmission to salmonids due to their central role in the lacustrine food web of this subarctic lake.
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Sánchez-Hernández J, Cobo F, Amundsen PA. Food Web Topology in High Mountain Lakes. PLoS One 2015; 10:e0143016. [PMID: 26571235 PMCID: PMC4646624 DOI: 10.1371/journal.pone.0143016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/29/2015] [Indexed: 12/02/2022] Open
Abstract
Although diversity and limnology of alpine lake systems are well studied, their food web structure and properties have rarely been addressed. Here, the topological food webs of three high mountain lakes in Central Spain were examined. We first addressed the pelagic networks of the lakes, and then we explored how food web topology changed when benthic biota was included to establish complete trophic networks. We conducted a literature search to compare our alpine lacustrine food webs and their structural metrics with those of 18 published lentic webs using a meta-analytic approach. The comparison revealed that the food webs in alpine lakes are relatively simple, in terms of structural network properties (linkage density and connectance), in comparison with lowland lakes, but no great differences were found among pelagic networks. The studied high mountain food webs were dominated by a high proportion of omnivores and species at intermediate trophic levels. Omnivores can exploit resources at multiple trophic levels, and this characteristic might reduce competition among interacting species. Accordingly, the trophic overlap, measured as trophic similarity, was very low in all three systems. Thus, these alpine networks are characterized by many omnivorous consumers with numerous prey species and few consumers with a single or few prey and with low competitive interactions among species. The present study emphasizes the ecological significance of omnivores in high mountain lakes as promoters of network stability and as central players in energy flow pathways via food partitioning and enabling energy mobility among trophic levels.
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Affiliation(s)
- Javier Sánchez-Hernández
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
- Department of Zoology and Physical Anthropology, Faculty of Biology, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Fernando Cobo
- Department of Zoology and Physical Anthropology, Faculty of Biology, University of Santiago de Compostela, Santiago de Compostela, Spain
- Station of Hydrobiology “Encoro do Con”, Castroagudín s/n, 36617 Vilagarcía de Arousa, Pontevedra, Spain
| | - Per-Arne Amundsen
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway
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Kuhn JA, Kristoffersen R, Knudsen R, Jakobsen J, Marcogliese DJ, Locke SA, Primicerio R, Amundsen PA. Parasite communities of two three-spined stickleback populations in subarctic Norway—effects of a small spatial-scale host introduction. Parasitol Res 2015; 114:1327-39. [DOI: 10.1007/s00436-015-4309-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 01/07/2015] [Indexed: 12/31/2022]
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Parasite species richness and its effect on persistence in food webs. J Theor Biol 2015; 364:377-82. [DOI: 10.1016/j.jtbi.2014.09.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 09/23/2014] [Accepted: 09/24/2014] [Indexed: 11/23/2022]
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Lymbery AJ, Morine M, Kanani HG, Beatty SJ, Morgan DL. Co-invaders: The effects of alien parasites on native hosts. Int J Parasitol Parasites Wildl 2014; 3:171-7. [PMID: 25180161 PMCID: PMC4145144 DOI: 10.1016/j.ijppaw.2014.04.002] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 04/09/2014] [Accepted: 04/09/2014] [Indexed: 01/30/2023]
Abstract
We define co-introduced parasites as those which have been transported with an alien host to a new locality, outside of their natural range, and co-invading parasites as those which have been co-introduced and then spread to new, native hosts. Of 98 published studies of co-introductions, over 50% of hosts were freshwater fishes and 49% of parasites were helminths. Although we would expect parasites with simple, direct life cycles to be much more likely to be introduced and establish in a new locality, a substantial proportion (36%) of co-introductions were of parasites with an indirect life cycle. Seventy-eight per cent of co-introduced parasites were found in native host species and can therefore be classed as co-invaders. Host switching was equally common among parasites with direct and indirect life cycles. The magnitude of the threat posed to native species by co-invaders will depend, among other things, on parasite virulence. In 16 cases where co-introduced parasites have switched to native hosts and information was available on relative virulence, 14 (85%) were more virulent in native hosts than in the co-introduced alien host. We argue that this does not necessarily support the naïve host theory that co-invading parasites will have greater pathogenic effects in native hosts with which they have no coevolutionary history, but may instead be a consequence of the greater likelihood for parasites with lower virulence in their natural host to be co-introduced.
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Affiliation(s)
- Alan J. Lymbery
- Freshwater Fish Group and Fish Health Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch 6150, Western Australia, Australia
| | - Mikayla Morine
- Freshwater Fish Group and Fish Health Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch 6150, Western Australia, Australia
| | - Hosna Gholipour Kanani
- Freshwater Fish Group and Fish Health Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch 6150, Western Australia, Australia
- Fisheries Department, Faculty of Agriculture, Gonbad Kavous University, Iran
| | - Stephen J. Beatty
- Freshwater Fish Group and Fish Health Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch 6150, Western Australia, Australia
| | - David L. Morgan
- Freshwater Fish Group and Fish Health Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch 6150, Western Australia, Australia
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Rasconi S, Grami B, Niquil N, Jobard M, Sime-Ngando T. Parasitic chytrids sustain zooplankton growth during inedible algal bloom. Front Microbiol 2014; 5:229. [PMID: 24904543 PMCID: PMC4033230 DOI: 10.3389/fmicb.2014.00229] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/29/2014] [Indexed: 11/13/2022] Open
Abstract
This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modeling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modeling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the impact of parasites on food web function through grazers and recyclers. During blooms of "inedible" algae (unexploited by planktonic herbivores), the epidemic growth of chytrids channeled 19-20% of the primary production in both lakes through the production of grazer exploitable zoospores. The parasitic throughput represented 50% and 57% of the zooplankton diet, respectively, in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties such as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin.
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Affiliation(s)
- Serena Rasconi
- CNRS UMR 6250, UMRi 7266, LIENSs, Université de La Rochelle La Rochelle, France
| | - Boutheina Grami
- CNRS UMR 6250, UMRi 7266, LIENSs, Université de La Rochelle La Rochelle, France
| | - Nathalie Niquil
- CNRS UMR 6250, UMRi 7266, LIENSs, Université de La Rochelle La Rochelle, France
| | - Marlène Jobard
- CNRS UMR 6023, LMGE, Clermont Université Aubière Cedex, France
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Locke SA, Bulté G, Marcogliese DJ, Forbes MR. Altered trophic pathway and parasitism in a native predator (Lepomis gibbosus) feeding on introduced prey (Dreissena polymorpha). Oecologia 2014; 175:315-24. [PMID: 24562470 DOI: 10.1007/s00442-014-2898-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 01/25/2014] [Indexed: 10/25/2022]
Abstract
Populations of invasive species tend to have fewer parasites in their introduced ranges than in their native ranges and are also thought to have fewer parasites than native prey. This 'release' from parasites has unstudied implications for native predators feeding on exotic prey. In particular, shifts from native to exotic prey should reduce levels of trophically transmitted parasites. We tested this hypothesis in native populations of pumpkinseed sunfish (Lepomis gibbosus) in Lake Opinicon, where fish stomach contents were studied intensively in the 1970s, prior to the appearance of exotic zebra mussels (Dreissena polymorpha) in the mid-1990s. Zebra mussels were common in stomachs of present-day pumpkinseeds, and stable isotopes of carbon and nitrogen confirmed their importance in long-term diets. Because historical parasite data were not available in Lake Opinicon, we also surveyed stomach contents and parasites in pumpkinseed in both Lake Opinicon and an ecologically similar, neighboring lake where zebra mussels were absent. Stomach contents of pumpkinseed in the companion lake did not differ from those of pre-invasion fish from Lake Opinicon. The companion lake, therefore, served as a surrogate "pre-invasion" reference to assess effects of zebra mussel consumption on parasites in pumpkinseed. Trophically transmitted parasites were less species-rich and abundant in Lake Opinicon, where fish fed on zebra mussels, although factors other than zebra mussel consumption may contribute to these differences. Predation on zebra mussels has clearly contributed to a novel trophic coupling between littoral and pelagic food webs in Lake Opinicon.
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Affiliation(s)
- Sean A Locke
- Aquatic Biodiversity Section, Watershed Hydrology and Ecology Research Division, Water Science and Technology Directorate, Science and Technology Branch, St. Lawrence Centre, Environment Canada, 105 McGill, 7th floor, Montreal, QC, H2Y 2E7, Canada,
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Dunne JA, Lafferty KD, Dobson AP, Hechinger RF, Kuris AM, Martinez ND, McLaughlin JP, Mouritsen KN, Poulin R, Reise K, Stouffer DB, Thieltges DW, Williams RJ, Zander CD. Parasites affect food web structure primarily through increased diversity and complexity. PLoS Biol 2013; 11:e1001579. [PMID: 23776404 PMCID: PMC3679000 DOI: 10.1371/journal.pbio.1001579] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 05/01/2013] [Indexed: 01/11/2023] Open
Abstract
Parasites primarily affect food web structure through changes to diversity and complexity. However, compared to free-living species, their life-history traits lead to more complex feeding niches and altered motifs. Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites “dominate” food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites' roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites' feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic organization, identifies limitations of current food web models, and provides direction for future structural and dynamical models. Food webs are networks of feeding interactions among species. Although parasites comprise a large proportion of species diversity, they have generally been underrepresented in food web data and analyses. Previous analyses of the few datasets that contain parasites have indicated that their inclusion alters network structure. However, it is unclear whether those alterations were a result of unique roles that parasites play, or resulted from the changes in diversity and complexity that would happen when any type of species is added to a food web. In this study, we analyzed many aspects of the network structure of seven highly resolved coastal estuary or marine food webs with parasites. In most cases, we found that including parasites in the analysis results in generic changes to food web structure that would be expected with increased diversity and complexity. However, in terms of specific patterns of links in the food web (“motifs”) and the breadth and contiguity of feeding niches, parasites do appear to alter structure in ways that result from unique traits—in particular, their close physical intimacy with their hosts, their complex life cycles, and their small body sizes. Thus, this study disentangles unique from generic effects of parasites on food web organization, providing better understanding of similarities and differences between parasites and free-living species in their roles as consumers and resources.
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Affiliation(s)
- Jennifer A Dunne
- Santa Fe Institute, Santa Fe, New Mexico, United States of America.
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Thieltges DW, Amundsen PA, Hechinger RF, Johnson PTJ, Lafferty KD, Mouritsen KN, Preston DL, Reise K, Zander CD, Poulin R. Parasites as prey in aquatic food webs: implications for predator infection and parasite transmission. OIKOS 2013. [DOI: 10.1111/j.1600-0706.2013.00243.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Introduced parasites in food webs: new species, shifting structures? Trends Ecol Evol 2013; 28:93-9. [DOI: 10.1016/j.tree.2012.08.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 08/20/2012] [Accepted: 08/21/2012] [Indexed: 11/21/2022]
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Abstract
Past models have suggested host-parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought.
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Affiliation(s)
- Kevin D Lafferty
- Western Ecological Research Center, US Geological Survey, c/o Marine Science Institute, University of California, Santa Barbara, CA 93106, USA.
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