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Angst P, Haag CR, Ben-Ami F, Fields PD, Ebert D. Genome-Wide Allele Frequency Changes Reveal That Dynamic Metapopulations Evolve Differently. Mol Biol Evol 2024; 41:msae128. [PMID: 38935572 PMCID: PMC11229820 DOI: 10.1093/molbev/msae128] [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: 02/14/2024] [Revised: 06/14/2024] [Accepted: 06/20/2024] [Indexed: 06/29/2024] Open
Abstract
Two important characteristics of metapopulations are extinction-(re)colonization dynamics and gene flow between subpopulations. These processes can cause strong shifts in genome-wide allele frequencies that are generally not observed in "classical" (large, stable, and panmictic) populations. Subpopulations founded by one or a few individuals, the so-called propagule model, are initially expected to show intermediate allele frequencies at polymorphic sites until natural selection and genetic drift drive allele frequencies toward a mutation-selection-drift equilibrium characterized by a negative exponential-like distribution of the site frequency spectrum. We followed changes in site frequency spectrum distribution in a natural metapopulation of the cyclically parthenogenetic pond-dwelling microcrustacean Daphnia magna using biannual pool-seq samples collected over a 5-yr period from 118 ponds occupied by subpopulations of known age. As expected under the propagule model, site frequency spectra in newly founded subpopulations trended toward intermediate allele frequencies and shifted toward right-skewed distributions as the populations aged. Immigration and subsequent hybrid vigor altered this dynamic. We show that the analysis of site frequency spectrum dynamics is a powerful approach to understand evolution in metapopulations. It allowed us to disentangle evolutionary processes occurring in a natural metapopulation, where many subpopulations evolve in parallel. Thereby, stochastic processes like founder and immigration events lead to a pattern of subpopulation divergence, while genetic drift leads to converging site frequency spectrum distributions in the persisting subpopulations. The observed processes are well explained by the propagule model and highlight that metapopulations evolve differently from classical populations.
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Affiliation(s)
- Pascal Angst
- Department of Environmental Sciences, Zoology, University of Basel, Basel 4051, Switzerland
| | - Christoph R Haag
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, Montpellier 34293, France
- Tvärminne Zoological Station, University of Helsinki, Hanko 10900, Finland
| | - Frida Ben-Ami
- Tvärminne Zoological Station, University of Helsinki, Hanko 10900, Finland
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel 4051, Switzerland
- Tvärminne Zoological Station, University of Helsinki, Hanko 10900, Finland
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel 4051, Switzerland
- Tvärminne Zoological Station, University of Helsinki, Hanko 10900, Finland
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2
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Hargan KE, Duda MP, Michelutti N, Blais JM, Smol JP. Assessing long-term diatom changes in sub-Arctic ponds receiving high fluxes of seabird nutrients. Ecol Evol 2024; 14:e11034. [PMID: 38371864 PMCID: PMC10870249 DOI: 10.1002/ece3.11034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 01/23/2024] [Accepted: 02/01/2024] [Indexed: 02/20/2024] Open
Abstract
Algal bioindicators, such as diatoms, often show subdued responses to eutrophication in Arctic lakes because climate-related changes (e.g., ice cover) tend to be the overriding factors influencing assemblage composition. Here, we examined how sub-Arctic ponds historically receiving high nutrient inputs from nesting seabirds have responded to recent climate change. We present diatom data obtained from 12 sediment cores in seaduck-affected ponds located on islands through Hudson Strait, Canada. All study cores show consistently elevated values of sedimentary ẟ15N, an established proxy for tracking marine-derived nutrients, indicating seabirds have been present on these islands for at least the duration of the sediment records (~100 to 400 years). We document diverse epiphytic diatom assemblages to the base of all sediment cores, which is in marked contrast to seabird-free Arctic ponds-these oligotrophic sites typically record epilithic diatom flora prior to recent warming. Diatoms are likely responding indirectly to seabird nutrients via habitat as nutrients promote the growth of mosses supporting epiphytic diatom communities. This masks the typical diatom response to increased warming in the Arctic, which also results in habitat changes and the growth of mosses around the pond edges. Changes in sedimentary chlorophyll a were not consistently synchronous with large changes in ẟ15N values, suggesting that primary production in ponds is not responding linearly to changes in seabird-derived nitrogen. Across all ponds, we recorded shifts in diatom epiphytic assemblages (e.g., increases in % relative abundance of many Nitzschia species) that often align with increases in chlorophyll a. The changes in diatoms and chlorophyll a, although variable, are most likely driven by climate change as they are generally consistent with longer ice-free conditions and growing seasons. Together, our results show that to effectively use diatoms in animal population reconstructions across the sub-Arctic and Arctic, a strong understanding of eutrophication and climate change, based on supplementary proxies, is also required.
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Affiliation(s)
| | - Matthew P. Duda
- Paleoecological Environmental Assessment and Research Laboratory, Department of BiologyQueen's UniversityKingstonOntarioCanada
| | - Neal Michelutti
- Paleoecological Environmental Assessment and Research Laboratory, Department of BiologyQueen's UniversityKingstonOntarioCanada
| | - Jules M. Blais
- Department of BiologyUniversity of OttawaOttawaOntarioCanada
| | - John P. Smol
- Paleoecological Environmental Assessment and Research Laboratory, Department of BiologyQueen's UniversityKingstonOntarioCanada
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Luo M, Wang S, Saavedra S, Ebert D, Altermatt F. Multispecies coexistence in fragmented landscapes. Proc Natl Acad Sci U S A 2022; 119:e2201503119. [PMID: 36067285 PMCID: PMC9477233 DOI: 10.1073/pnas.2201503119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 08/03/2022] [Indexed: 11/18/2022] Open
Abstract
Spatial dynamics have long been recognized as an important driver of biodiversity. However, our understanding of species' coexistence under realistic landscape configurations has been limited by lack of adequate analytical tools. To fill this gap, we develop a spatially explicit metacommunity model of multiple competing species and derive analytical criteria for their coexistence in fragmented heterogeneous landscapes. Specifically, we propose measures of niche and fitness differences for metacommunities, which clarify how spatial dynamics and habitat configuration interact with local competition to determine coexistence of species. We parameterize our model with a Bayesian approach using a 36-y time-series dataset of three Daphnia species in a rockpool metacommunity covering >500 patches. Our results illustrate the emergence of interspecific variation in extinction and recolonization processes, including their dependencies on habitat size and environmental temperature. We find that such interspecific variation contributes to the coexistence of Daphnia species by reducing fitness differences and increasing niche differences. Additionally, our parameterized model allows separating the effects of habitat destruction and temperature change on species extinction. By integrating coexistence theory and metacommunity theory, our study provides platforms to increase our understanding of species' coexistence in fragmented heterogeneous landscapes and the response of biodiversity to environmental changes.
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Affiliation(s)
- Mingyu Luo
- Institute of Ecology, Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, 100871 Beijing, China
| | - Shaopeng Wang
- Institute of Ecology, Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Sciences, Peking University, 100871 Beijing, China
| | - Serguei Saavedra
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, CH-4051 Basel, Switzerland
- Tvärminne Zoological Station, University of Helsinki, 10900 Hanko, Finland
| | - Florian Altermatt
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, CH-8057 Zürich, Switzerland
- Department of Aquatic Ecology, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland
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4
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Cabalzar AP, Fields PD, Kato Y, Watanabe H, Ebert D. Parasite-mediated selection in a natural metapopulation of Daphnia magna. Mol Ecol 2019; 28:4770-4785. [PMID: 31591747 DOI: 10.1111/mec.15260] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/17/2019] [Accepted: 09/27/2019] [Indexed: 01/03/2023]
Abstract
Parasite-mediated selection varying across time and space in metapopulations is expected to result in host local adaptation and the maintenance of genetic diversity in disease-related traits. However, nonadaptive processes like migration and extinction-(re)colonization dynamics might interfere with adaptive evolution. Understanding how adaptive and nonadaptive processes interact to shape genetic variability in life-history and disease-related traits can provide important insights into their evolution in subdivided populations. Here we investigate signatures of spatially fluctuating, parasite-mediated selection in a natural metapopulation of Daphnia magna. Host genotypes from infected and uninfected populations were genotyped at microsatellite markers, and phenotyped for life-history and disease traits in common garden experiments. Combining phenotypic and genotypic data a QST -FST -like analysis was conducted to test for signatures of parasite mediated selection. We observed high variation within and among populations for phenotypic traits, but neither an indication of host local adaptation nor a cost of resistance. Infected populations have a higher gene diversity (Hs) than uninfected populations and Hs is strongly positively correlated with fitness. These results suggest a strong parasite effect on reducing population level inbreeding. We discuss how stochastic processes related to frequent extinction-(re)colonization dynamics as well as host and parasite migration impede the evolution of resistance in the infected populations. We suggest that the genetic and phenotypic patterns of variation are a product of dynamic changes in the host gene pool caused by the interaction of colonization bottlenecks, inbreeding, immigration, hybrid vigor, rare host genotype advantage and parasitism. Our study highlights the effect of the parasite in ameliorating the negative fitness consequences caused by the high drift load in this metapopulation.
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Affiliation(s)
- Andrea P Cabalzar
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Yasuhiko Kato
- Department of Biotechnology, Division of Advance Science and Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Hajime Watanabe
- Department of Biotechnology, Division of Advance Science and Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland.,Tvärminne Zoological Station, Tvärminne, Finland
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5
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Cuhra M. Observations of water-fleaDaphnia magnaand avian fecalia in rock pools: is traditional natural history reporting still relevant for science? J NAT HIST 2019. [DOI: 10.1080/00222933.2019.1585587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Marek Cuhra
- Marbank, Institute of Marine Research, Bergen, Norway
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6
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Narr CF, Ebert D, Bastille-Rousseau G, Frost PC. Nutrient availability affects the prevalence of a microsporidian parasite. J Anim Ecol 2019; 88:579-590. [PMID: 30636044 DOI: 10.1111/1365-2656.12945] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 11/12/2018] [Indexed: 11/29/2022]
Abstract
Defining the relationship between nutrients and parasitism is complicated by shifts in host physiology and population density, which can both mediate the effects of host diet on parasites and vice versa. We examined the relationship between nutrient availability and an abundant parasite capable of both horizontal and vertical transmission (Hamiltosporidium tvaerminnensis) of a planktonic crustacean, Daphnia magna, in rock pools on Baltic Sea Skerry islands. We found that the relative availability of nutrients directly affected infection prevalence; parasite prevalence was higher in pools with higher particulate N:P ratios. Infection prevalence was not related to Daphnia population densities. A complementary experiment that examined host responses to an N:P gradient in mesocosms indicated that high N:P ratios can increase spore load in the hosts. We surmise that high N:P food increases Daphnia feeding rate, which increases their contact with parasite spores and leads to higher prevalence and more intense infections. We found no direct evidence that parasite-induced changes in host nutrient use affected nutrient dynamics in pools. However, the relationship between diet N:P and the parasite's prevalence and load is consistent with previously documented patterns of this parasite's effect on host nutrient use. Taken together, this study suggests that high N:P ratios in food may benefit the parasite in multiple ways and could create environments that favour horizontal transmission over vertical transmission for parasites capable of both transmission routes. If so, nutrient limitation could have long-term consequences for host-parasite evolution.
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Affiliation(s)
- Charlotte F Narr
- Environmental and Life Sciences, Trent University, Peterborough, Ontario, Canada
| | - Dieter Ebert
- Zoological Institute, Basel University, Basel, Switzerland
| | | | - Paul C Frost
- Department of Biology, Trent University, Peterborough, Ontario, Canada
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7
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Mitogenome phylogeographic analysis of a planktonic crustacean. Mol Phylogenet Evol 2018; 129:138-148. [DOI: 10.1016/j.ympev.2018.06.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 06/14/2018] [Accepted: 06/15/2018] [Indexed: 11/17/2022]
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Roulin AC, Mariadassou M, Hall MD, Walser JC, Haag C, Ebert D. High genetic variation in resting-stage production in a metapopulation: Is there evidence for local adaptation? Evolution 2015; 69:2747-56. [DOI: 10.1111/evo.12770] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 07/20/2015] [Accepted: 08/20/2015] [Indexed: 12/23/2022]
Affiliation(s)
- Anne C. Roulin
- Zoological Institute; Basel University; Vesalgasse 1 4051 Basel Switzerland
- Institute of Plant Biology; University of Zurich; Zollikerstrasse 107 8008 Zurich Switzerland
| | | | - Matthew D. Hall
- Zoological Institute; Basel University; Vesalgasse 1 4051 Basel Switzerland
- School of Biological Sciences; Monash University; Melbourne 3800 Australia
| | - Jean-Claude Walser
- Zoological Institute; Basel University; Vesalgasse 1 4051 Basel Switzerland
- Genetic Diversity Centre; Universitätstrasse 16, CHN E 55 8092 Zürich Switzerland
| | - Christoph Haag
- CNRS-UMR5175 CEFE; 1919, Route de Mende 34293 Montpellier France
| | - Dieter Ebert
- Zoological Institute; Basel University; Vesalgasse 1 4051 Basel Switzerland
- Tvärminne Zoological Station; Helsinki University; Hanko Finland
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9
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Fields PD, Reisser C, Dukić M, Haag CR, Ebert D. Genes mirror geography inDaphnia magna. Mol Ecol 2015; 24:4521-36. [DOI: 10.1111/mec.13324] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 07/13/2015] [Accepted: 07/14/2015] [Indexed: 02/06/2023]
Affiliation(s)
- Peter D. Fields
- Zoological Institute; University of Basel; Vesalgasse 1 Basel CH-4051 Switzerland
| | - Céline Reisser
- Centre d'Ecologie Fonctionnelle et Evolutive - UMR 5175; campus CNRS 1919 route de Mende 34293 Montpellier Cedex 5 France
- Department of Biology; Ecology and Evolution; University of Fribourg; Chemin du Muśee 10 1700 Fribourg Switzerland
| | - Marinela Dukić
- Zoological Institute; University of Basel; Vesalgasse 1 Basel CH-4051 Switzerland
| | - Christoph R. Haag
- Centre d'Ecologie Fonctionnelle et Evolutive - UMR 5175; campus CNRS 1919 route de Mende 34293 Montpellier Cedex 5 France
- Department of Biology; Ecology and Evolution; University of Fribourg; Chemin du Muśee 10 1700 Fribourg Switzerland
| | - Dieter Ebert
- Zoological Institute; University of Basel; Vesalgasse 1 Basel CH-4051 Switzerland
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10
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Guttel Y, Ben-Ami F. The maintenance of hybrids by parasitism in a freshwater snail. Int J Parasitol 2014; 44:1001-8. [PMID: 25173837 DOI: 10.1016/j.ijpara.2014.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/09/2014] [Accepted: 06/25/2014] [Indexed: 12/20/2022]
Abstract
Hybrids have often been labelled evolutionary dead-ends due to their lower fertility and viability. However, there is growing awareness that hybridisation between different species may play a constructive role in animal evolution as a means to create variability. Thus, hybridisation and introgression may contribute to adaptive evolution, for example with regards to natural antagonists (parasites, predators, competitors) and adaptation to local environmental conditions. Here we investigated whether parasite intensity contributes to the continuous recreation of hybrids in 74 natural populations of Melanopsis, a complex of freshwater snails with three species. We also examined, under laboratory conditions, whether hybrids and their parental taxa differ in their tolerance of low and high temperatures and salinity levels. Infections were consistently less prevalent in males than in females, and lower in snails from deeper habitats. Infection prevalence in hybrids was significantly lower than in the parental taxa. Low hybrid infection rates could not be explained by sediment type, snail density or geographic distribution of the sampling sites. Interestingly, infected hybrid snails did not show signs of parasite-induced gigantism, whereas all parental taxa did. We found that hybrids mostly coped with extreme temperatures and salinity levels as well as their parental taxa did. Taken together, our results suggest that Melanopsis hybrids perform better in the presence of parasites and environmental stress. This may explain the widespread and long-term occurrence of Melanopsis hybrids as evidenced by paleontological and biogeographic data. Hybridisation may be an adaptive host strategy, reducing infection rates and resisting gigantism.
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Affiliation(s)
- Yonathan Guttel
- Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Frida Ben-Ami
- Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel.
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