1
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Simonis MC, Hartzler LK, Turner GG, Scafini MR, Johnson JS, Rúa MA. Capture rates of Eptesicus fuscus increase following white-nose syndrome across the eastern US. Ecol Evol 2024; 14:e11523. [PMID: 38932974 PMCID: PMC11199122 DOI: 10.1002/ece3.11523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 04/25/2024] [Accepted: 05/21/2024] [Indexed: 06/28/2024] Open
Abstract
Emerging infectious diseases threaten wildlife globally. While the effects of infectious diseases on hosts with severe infections and high mortality rates often receive considerable attention, effects on hosts that persist despite infection are less frequently studied. To understand how persisting host populations change in the face of disease, we quantified changes to the capture rates of Eptesicus fuscus (big brown bats), a persisting species susceptible to infection by the invasive fungal pathogen Pseudogymnoascus destructans (Pd; causative agent for white-nose syndrome), across the eastern US using a 30-year dataset. Capture rates of male and female E. fuscus increased from preinvasion to pathogen establishment years, with greater increases to the capture rates of females than males. Among females, capture rates of pregnant and post-lactating females increased by pathogen establishment. We outline potential mechanisms for these broad demographic changes in E. fuscus capture rates (i.e., increases to foraging from energy deficits created by Pd infection, increases to relative abundance, or changes to reproductive cycles), and suggest future research for identifying mechanisms for increasing capture rates across the eastern US. These data highlight the importance of understanding how populations of persisting host species change following pathogen invasion across a broad spatial scale. Understanding changes to population composition following pathogen invasion can identify broad ecological patterns across space and time, and open new avenues for research to identify drivers of those patterns.
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Affiliation(s)
- Molly C. Simonis
- Environmental Sciences PhD ProgramWright State UniversityDaytonOhioUSA
- School of Biological SciencesUniversity of OklahomaNormanOklahomaUSA
| | - Lynn K. Hartzler
- Environmental Sciences PhD ProgramWright State UniversityDaytonOhioUSA
- Department of Biological SciencesWright State UniversityDaytonOhioUSA
| | - Gregory G. Turner
- Pennsylvania Game Commission Bureau of Wildlife ManagementHarrisburgPennsylvaniaUSA
| | - Michael R. Scafini
- Pennsylvania Game Commission Bureau of Wildlife ManagementHarrisburgPennsylvaniaUSA
| | - Joseph S. Johnson
- School of Information TechnologyUniversity of CincinnatiCincinnatiOhioUSA
| | - Megan A. Rúa
- Environmental Sciences PhD ProgramWright State UniversityDaytonOhioUSA
- Department of Biological SciencesWright State UniversityDaytonOhioUSA
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2
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Car C, Gilles A, Goujon E, Muller MLD, Camoin L, Frelon S, Burraco P, Granjeaud S, Baudelet E, Audebert S, Orizaola G, Armengaud J, Tenenhaus A, Garali I, Bonzom JM, Armant O. Population transcriptogenomics highlights impaired metabolism and small population sizes in tree frogs living in the Chernobyl Exclusion Zone. BMC Biol 2023; 21:164. [PMID: 37525144 PMCID: PMC10391870 DOI: 10.1186/s12915-023-01659-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 07/03/2023] [Indexed: 08/02/2023] Open
Abstract
BACKGROUND Individual functional modifications shape the ability of wildlife populations to cope with anthropogenic environmental changes. But instead of adaptive response, human-altered environments can generate a succession of deleterious functional changes leading to the extinction of the population. To study how persistent anthropogenic changes impacted local species' population status, we characterised population structure, genetic diversity and individual response of gene expression in the tree frog Hyla orientalis along a gradient of radioactive contamination around the Chernobyl nuclear power plant. RESULTS We detected lower effective population size in populations most exposed to ionizing radiation in the Chernobyl Exclusion Zone that is not compensated by migrations from surrounding areas. We also highlighted a decreased body condition of frogs living in the most contaminated area, a distinctive transcriptomics signature and stop-gained mutations in genes involved in energy metabolism. While the association with dose will remain correlational until further experiments, a body of evidence suggests the direct or indirect involvement of radiation exposure in these changes. CONCLUSIONS Despite ongoing migration and lower total dose rates absorbed than at the time of the accident, our results demonstrate that Hyla orientalis specimens living in the Chernobyl Exclusion Zone are still undergoing deleterious changes, emphasizing the long-term impacts of the nuclear disaster.
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Affiliation(s)
- Clément Car
- Institut de Radioprotection Et de Sûreté Nucléaire (IRSN), PSE-ENV/SRTE/LECO, Cadarache, France
- PSE-SANTE/SESANE/LRTox, Fontenay Aux Roses, France
| | - André Gilles
- UMR 1467 RECOVER, Aix-Marseille Université, INRAE, Centre Saint-Charles, Marseille, France.
| | - Elen Goujon
- Institut de Radioprotection Et de Sûreté Nucléaire (IRSN), PSE-ENV/SRTE/LECO, Cadarache, France
- PSE-SANTE/SESANE/LRTox, Fontenay Aux Roses, France
- Laboratoire Des Signaux Et Systèmes, Université Paris-Saclay, CNRS, CentraleSupélec, 91190, Gif-Sur-Yvette, France
| | - Marie-Laure Delignette Muller
- Laboratoire de Biométrie Et Biologie Evolutive, UMR 5558, Université de Lyon, Université Lyon 1, CNRS, VetAgro Sup, Villeurbanne, France
| | - Luc Camoin
- Aix-Marseille University, Inserm, CNRS, Institut Paoli-Calmettes, CRCM, Marseille Proteomics, Marseille, France
| | - Sandrine Frelon
- Institut de Radioprotection Et de Sûreté Nucléaire (IRSN), PSE-ENV/SRTE/LECO, Cadarache, France
- PSE-SANTE/SESANE/LRTox, Fontenay Aux Roses, France
| | - Pablo Burraco
- Animal Ecology, Department of Ecology and Genetics, Evolutionary Centre, Uppsala University, 75236, Uppsala, Sweden
- Doñana Biological Station (CSIC), Seville, Spain
| | - Samuel Granjeaud
- Aix-Marseille University, Inserm, CNRS, Institut Paoli-Calmettes, CRCM, Marseille Proteomics, Marseille, France
| | - Emilie Baudelet
- Aix-Marseille University, Inserm, CNRS, Institut Paoli-Calmettes, CRCM, Marseille Proteomics, Marseille, France
| | - Stéphane Audebert
- Aix-Marseille University, Inserm, CNRS, Institut Paoli-Calmettes, CRCM, Marseille Proteomics, Marseille, France
| | - Germán Orizaola
- Animal Ecology, Department of Ecology and Genetics, Evolutionary Centre, Uppsala University, 75236, Uppsala, Sweden
- IMIB-Biodiversity Research Institute, University of Oviedo, 33600, Mieres-Asturias, Spain
- Zoology Unit, Department of Biology of Organisms and Systems, University of Oviedo, 33071, Oviedo-Asturias, Spain
| | - Jean Armengaud
- Département Médicaments Et Technologies Pour La Santé (DMTS), Université Paris-Saclay, CEA, INRAE, SPI, Bagnols-Sur-Cèze, France
| | - Arthur Tenenhaus
- Laboratoire Des Signaux Et Systèmes, Université Paris-Saclay, CNRS, CentraleSupélec, 91190, Gif-Sur-Yvette, France
| | - Imène Garali
- Institut de Radioprotection Et de Sûreté Nucléaire (IRSN), PSE-ENV/SRTE/LECO, Cadarache, France
- PSE-SANTE/SESANE/LRTox, Fontenay Aux Roses, France
| | - Jean-Marc Bonzom
- Institut de Radioprotection Et de Sûreté Nucléaire (IRSN), PSE-ENV/SRTE/LECO, Cadarache, France
- PSE-SANTE/SESANE/LRTox, Fontenay Aux Roses, France
| | - Olivier Armant
- Institut de Radioprotection Et de Sûreté Nucléaire (IRSN), PSE-ENV/SRTE/LECO, Cadarache, France.
- PSE-SANTE/SESANE/LRTox, Fontenay Aux Roses, France.
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3
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Bosch J, Thumsová B, Puschendorf R, Bielby J. Drivers of Batrachochytrium dendrobatidis infection load, with evidence of infection tolerance in adult male toads (Bufo spinosus). Oecologia 2023; 202:165-174. [PMID: 37147397 DOI: 10.1007/s00442-023-05380-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/25/2023] [Indexed: 05/07/2023]
Abstract
Chytridiomycosis is affecting hundreds of amphibian species worldwide, but while in tropical areas, adult individuals have been the focus of most investigations, the exact role played by infection intensity of breeding adults is not well understood in temperate areas. We conducted mark-recapture-capture surveys during spiny common toad breeding seasons from 2006 to 2018 at the site of the first recorded outbreak of chytridiomycosis in Europe, the Peñalara Massif (Sierra de Guadarrama National Park, central Spain), and collected infection samples and several variables related to the reproductive effort of male individuals. We used general linear mixed models to evaluate the contribution of study variables on the infection loads of adult male toads exhibited at their capturing date. We also analysed the differences on several male characteristics between the pond with the largest breeding population against the rest of the ponds. We found that the duration of time spent in the waterbody and the condition of the host predicted infection loads. Animals of good physical condition, that spent longer in water, have higher infection levels than individuals with the opposite set of traits. The pond supporting the largest breeding population housed smaller male toads and in poorer condition. Our results are consistent with a shift in reproductive strategy in response to infection and potentially a strategy of tolerance, rather than resistance to infection. These findings have applications for disease mitigation and theoretical implications related to the trade-offs made and the evolution of traits in response to the disease.
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Affiliation(s)
- Jaime Bosch
- Biodiversity Research Institute (IMIB), CSIC-University of Oviedo-Principality of Asturias, Mieres, Spain.
- Centro de Investigación, Seguimiento y Evaluación, Parque Nacional de la Sierra de Guadarrama, Rascafría, Spain.
| | - Barbora Thumsová
- Asociación Herpetológica Española (AHE), Madrid, Spain
- Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain
| | - Robert Puschendorf
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, UK
| | - Jon Bielby
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
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4
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Arguedas V, Barquero MD, Mora JM. Population structure and dynamics, breeding activity and phenology of the blue‐sided treefrog (
Agalychnis annae
). Biotropica 2022. [DOI: 10.1111/btp.13066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Viviana Arguedas
- Carrera de Turismo Ecológico Recinto de Paraíso Sede del Atlántico Universidad de Costa Rica Cartago Costa Rica
- Carrera de Turismo Ecológico Recinto de Tacares Sede de Occidente Universidad de Costa Rica Alajuela Costa Rica
| | | | - José Manuel Mora
- Carrera de Gestión Ecoturística Sede Central Universidad Técnica Nacional Alajuela Costa Rica
- Department of Biology and Museum of Vertebrate Biology Portland State University Portland Oregon USA
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5
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Valenzuela-Sánchez A, Azat C, Cunningham AA, Delgado S, Bacigalupe LD, Beltrand J, Serrano JM, Sentenac H, Haddow N, Toledo V, Schmidt BR, Cayuela H. Interpopulation differences in male reproductive effort drive the population dynamics of a host exposed to an emerging fungal pathogen. J Anim Ecol 2021; 91:308-319. [PMID: 34704260 DOI: 10.1111/1365-2656.13603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 10/04/2021] [Indexed: 11/28/2022]
Abstract
Compensatory recruitment is a key demographic mechanism that has allowed the coexistence of populations of susceptible amphibians with Batrachochytrium dendrobatidis (Bd), a fungus causing one of the most devastating emerging infectious disease ever recorded among vertebrates. However, the underlying processes (e.g. density-dependent increase in survival at early life stages, change in reproductive traits) as well as the level of interpopulation variation in this response are poorly known. We explore potential mechanisms of compensatory recruitment in response to Bd infection by taking advantage of an amphibian system where male reproductive traits are easy to quantify in free-living populations. The Southern Darwin's frog Rhinoderma darwinii is a vocal sac-brooding species that exhibits a high susceptibility to lethal Bd infection. Using a 7-year capture-recapture study at four populations with contrasting Bd infection status (one high prevalence, one low prevalence and two Bd-free populations), we evaluated whether Bd-positive populations exhibited a higher adult recruitment and a higher male reproductive effort than Bd-negative populations. We also estimated population growth rates to explore whether recruitment compensated for the negative impacts of Bd on the survival of adults. In addition, we evaluated a potential demographic signal of compensatory recruitment (i.e. positive relationship between the proportion of juveniles and Bd prevalence) in response to Bd infection using raw count data from 13 R. darwinii populations. The high Bd prevalence population exhibited the highest male reproductive effort and the highest recruitment among the four monitored populations. This led to a growing population during the study period despite high mortality of adult hosts. In contrast, males from the population with low Bd prevalence had a low reproductive effort and this population, which had the lowest adult recruitment, was declining during the study period despite adults having a higher survival in comparison to the high Bd prevalence population. We also found a demographic signal of compensatory recruitment in response to Bd infection in our broader analysis of 13 R. darwinii populations. Our study underlines the importance of interpopulation variation in life-history strategies on the fate of host populations after infectious disease emergence. Our results also suggest that an increase in reproductive effort can be one of the processes underlying compensatory recruitment in populations of Bd-susceptible amphibians.
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Affiliation(s)
- Andrés Valenzuela-Sánchez
- ONG Ranita de Darwin, Valdivia, Chile.,Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia, Chile.,Sustainability Research Centre & PhD in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile
| | - Claudio Azat
- Sustainability Research Centre & PhD in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile
| | | | | | - Leonardo D Bacigalupe
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | | | - José M Serrano
- ONG Ranita de Darwin, Valdivia, Chile.,Museo de Zoología 'Alfonso L. Herrera', Departamento Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Hugo Sentenac
- Institute of Zoology, Zoological Society of London, London, UK.,Royal Veterinary College, University of London, London, UK
| | - Natashja Haddow
- Sustainability Research Centre & PhD in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile.,Institute of Zoology, Zoological Society of London, London, UK.,Royal Veterinary College, University of London, London, UK
| | | | - Benedikt R Schmidt
- Info fauna karch, Neuchâtel, Switzerland.,Institut für Evolutionsbiologie und Umweltwissenschaften, Universität Zürich, Zürich, Switzerland
| | - Hugo Cayuela
- Department of Ecology and Evolution, Biophore, University of Lausanne, Lausanne, Switzerland
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6
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Brannelly LA, Webb RJ, Jiang Z, Berger L, Skerratt LF, Grogan LF. Declining amphibians might be evolving increased reproductive effort in the face of devastating disease. Evolution 2021; 75:2555-2567. [PMID: 34383313 DOI: 10.1111/evo.14327] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 07/08/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022]
Abstract
The devastating infectious disease chytridiomycosis has caused declines of amphibians across the globe, yet some populations are persisting and even recovering. One understudied effect of wildlife disease is changes in reproductive effort. Here, we aimed to understand if the disease has plastic effects on reproduction and if reproductive effort could evolve with disease endemism. We compared the effects of experimental pathogen exposure (trait plasticity) and population-level disease history (evolution in trait baseline) on reproductive effort using gametogenesis as a proxy in the declining and endangered frog Litoria verreauxii alpina. We found that unexposed males from disease-endemic populations had higher reproductive effort, which is consistent with an evolutionary response to chytridiomycosis. We also found evidence of trait plasticity, where males and females were affected differently by infection: pathogen exposed males had higher reproductive effort (larger testes), whereas females had reduced reproductive effort (smaller and fewer developed eggs) regardless of the population of origin. Infectious diseases can cause plastic changes in the reproductive effort at an individual level, and population-level disease exposure can result in changes to baseline reproductive effort; therefore, individual- and population-level effects of disease should be considered when designing management and conservation programs for threatened and declining species.
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Affiliation(s)
- Laura A Brannelly
- One Health Research Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Rebecca J Webb
- One Health Research Group, School of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
| | - Zhixuan Jiang
- One Health Research Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Lee Berger
- One Health Research Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Lee F Skerratt
- One Health Research Group, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - Laura F Grogan
- Environmental Futures Research Institute, Griffith University, Southport, Queensland, Australia.,Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
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7
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Brannelly LA, McCallum HI, Grogan LF, Briggs CJ, Ribas MP, Hollanders M, Sasso T, Familiar López M, Newell DA, Kilpatrick AM. Mechanisms underlying host persistence following amphibian disease emergence determine appropriate management strategies. Ecol Lett 2020; 24:130-148. [PMID: 33067922 DOI: 10.1111/ele.13621] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/18/2020] [Accepted: 09/08/2020] [Indexed: 12/19/2022]
Abstract
Emerging infectious diseases have caused many species declines, changes in communities and even extinctions. There are also many species that persist following devastating declines due to disease. The broad mechanisms that enable host persistence following declines include evolution of resistance or tolerance, changes in immunity and behaviour, compensatory recruitment, pathogen attenuation, environmental refugia, density-dependent transmission and changes in community composition. Here we examine the case of chytridiomycosis, the most important wildlife disease of the past century. We review the full breadth of mechanisms allowing host persistence, and synthesise research on host, pathogen, environmental and community factors driving persistence following chytridiomycosis-related declines and overview the current evidence and the information required to support each mechanism. We found that for most species the mechanisms facilitating persistence have not been identified. We illustrate how the mechanisms that drive long-term host population dynamics determine the most effective conservation management strategies. Therefore, understanding mechanisms of host persistence is important because many species continue to be threatened by disease, some of which will require intervention. The conceptual framework we describe is broadly applicable to other novel disease systems.
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Affiliation(s)
- Laura A Brannelly
- Veterinary BioSciences, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Vic, 3030, Australia
| | - Hamish I McCallum
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia
| | - Laura F Grogan
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia.,Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Cheryl J Briggs
- Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Maria P Ribas
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia.,Wildlife Conservation Medicine Research Group, Departament de Medicina i Cirurgia Animals, Universitat Autònoma de Barcelona, Bellaterra, 08193, Spain
| | - Matthijs Hollanders
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Thais Sasso
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, Qld., 4111, Australia
| | - Mariel Familiar López
- School of Environment and Sciences, Griffith University, Gold Coast, Qld., 4215, Australia
| | - David A Newell
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, 2480, Australia
| | - Auston M Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
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8
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Hudson AL, Moatt JP, Vale PF. Terminal investment strategies following infection are dependent on diet. J Evol Biol 2019; 33:309-317. [DOI: 10.1111/jeb.13566] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 10/30/2019] [Accepted: 11/04/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Ali L. Hudson
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Joshua P. Moatt
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
| | - Pedro F. Vale
- Institute of Evolutionary Biology School of Biological Sciences University of Edinburgh Edinburgh UK
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9
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Doherty‐Bone TM, Cunningham AA, Fisher MC, Garner TWJ, Ghosh P, Gower DJ, Verster R, Weldon C. Amphibian chytrid fungus in Africa – realigning hypotheses and the research paradigm. Anim Conserv 2019. [DOI: 10.1111/acv.12538] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- T. M. Doherty‐Bone
- Conservation Programs Royal Zoological Society of Scotland Edinburgh UK
- Department of Life Sciences Natural History Museum London UK
| | | | - M. C. Fisher
- School of Public Health Imperial College London London UK
| | - T. W. J. Garner
- Institute of Zoology Zoological Society of London London UK
- Unit for Environmental Sciences and Management North‐West University Potchefstroom South Africa
| | - P. Ghosh
- School of Public Health Imperial College London London UK
- Unit for Environmental Sciences and Management North‐West University Potchefstroom South Africa
| | - D. J. Gower
- Department of Life Sciences Natural History Museum London UK
| | - R. Verster
- Unit for Environmental Sciences and Management North‐West University Potchefstroom South Africa
| | - C. Weldon
- Unit for Environmental Sciences and Management North‐West University Potchefstroom South Africa
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10
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Kirk D, Shea D, Start D. Host traits and competitive ability jointly structure disease dynamics and community assembly. J Anim Ecol 2019; 88:1379-1391. [PMID: 31120552 DOI: 10.1111/1365-2656.13028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 04/03/2019] [Indexed: 01/13/2023]
Abstract
Parasitism and competition are both ubiquitous interactions in ecological communities. The ability of host species to interact directly via competition and indirectly through shared parasites suggests that host traits related to competition and parasitism are likely important in structuring communities and disease dynamics. Specifically, those host traits affecting competition and those mediating parasitism are often correlated either because of trade-offs (in resource acquisition or resource allocation) or condition dependence, yet the consequences of these trait relationships for community and epidemiological dynamics are poorly understood. We conducted a literature review of parasite-related host traits-competitive ability relationships. We found that transmission-competitive ability relationships were most often reported, and that superior competitors exhibited elevated transmission relative to their less-competitive counterparts in nearly 80% of the cases. We also found a significant number of virulence-competitive ability and parasite shedding-competitive ability relationships. We investigated these links by altering the relationship between host competitive ability and three parasite-related traits (transmission, virulence and parasite shedding rates) in a simple model, incorporating competitive asymmetries in a multi-host community. We show that these relationships can lead to a range of different communities. For example, depending on the strength and direction of these distinct trait relationships, we observed communities with anywhere from high parasite prevalence to complete parasite extinction, and either one, two or the maximum of three host species coexisting. Our results suggest that parasite-competitive ability relationships may be common in nature, that further integration of these relationships can produce novel and unexpected community and disease dynamics, and that generalizations may allow for the prediction of how parasitism and competition jointly structure disease and diversity in natural communities.
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Affiliation(s)
- Devin Kirk
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Dylan Shea
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Denon Start
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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11
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Bower DS, Brannelly LA, McDonald CA, Webb RJ, Greenspan SE, Vickers M, Gardner MG, Greenlees MJ. A review of the role of parasites in the ecology of reptiles and amphibians. AUSTRAL ECOL 2018. [DOI: 10.1111/aec.12695] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Deborah S. Bower
- College of Science and Engineering; James Cook University; Townsville Queensland 4811 Australia
- School of Environmental and Rural Science; University of New England; Armidale New South Wales Australia
| | - Laura A. Brannelly
- Department of Biological Sciences; University of Pittsburgh; Pittsburgh Pennsylvania USA
| | - Cait A. McDonald
- Department of Ecology and Evolutionary Biology; Cornell University; Ithaca New York USA
| | - Rebecca J. Webb
- College of Public Health, Medical and Veterinary Sciences; James Cook University; Townsville Queensland Australia
| | - Sasha E. Greenspan
- Department of Biological Sciences; University of Alabama; Tuscaloosa Alabama USA
| | - Mathew Vickers
- College of Science and Engineering; James Cook University; Townsville Queensland 4811 Australia
| | - Michael G. Gardner
- College of Science and Engineering; Flinders University; Adelaide South Australia Australia
- Evolutionary Biology Unit; South Australian Museum; Adelaide South Australia Australia
| | - Matthew J. Greenlees
- School of Life and Environmental Sciences; University of Sydney; Sydney New South Wales Australia
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12
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Duffield KR, Hampton KJ, Houslay TM, Hunt J, Rapkin J, Sakaluk SK, Sadd BM. Age‐dependent variation in the terminal investment threshold in male crickets. Evolution 2018; 72:578-589. [DOI: 10.1111/evo.13443] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/26/2018] [Accepted: 01/29/2018] [Indexed: 01/17/2023]
Affiliation(s)
- Kristin R. Duffield
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
| | - Kylie J. Hampton
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
| | - Thomas M. Houslay
- Center for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn TR10 9FE United Kingdom
| | - John Hunt
- Center for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn TR10 9FE United Kingdom
- School of Science and Health and Hawkesbury Institute for the Environment, Western Sydney University Penrith NSW 2751 Australia
| | - James Rapkin
- Center for Ecology and Conservation, College of Life and Environmental Sciences University of Exeter Penryn TR10 9FE United Kingdom
| | - Scott K. Sakaluk
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
| | - Ben M. Sadd
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences Illinois State University Normal Illinois 61761
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13
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Abstract
Although reproductive strategies can be influenced by a variety of intrinsic and extrinsic factors, life history theory provides a rigorous framework for explaining variation in reproductive effort. The terminal investment hypothesis proposes that a decreased expectation of future reproduction (as might arise from a mortality threat) should precipitate increased investment in current reproduction. Terminal investment has been widely studied, and a variety of intrinsic and extrinsic cues that elicit such a response have been identified across an array of taxa. Although terminal investment is often treated as a static strategy, the level at which a cue of decreased future reproduction is sufficient to trigger increased current reproductive effort (i.e., the terminal investment threshold) may depend on context, including the internal state of the organism or its current external environment, independent of the cue that triggers a shift in reproductive investment. Here, we review empirical studies that address the terminal investment hypothesis, exploring both the intrinsic and extrinsic factors that mediate its expression. Based on these studies, we propose a novel framework within which to view the strategy of terminal investment, incorporating factors that influence an individual's residual reproductive value beyond a terminal investment trigger - the dynamic terminal investment threshold.
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14
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Brannelly LA, Webb R, Skerratt LF, Berger L. Amphibians with infectious disease increase their reproductive effort: evidence for the terminal investment hypothesis. Open Biol 2017; 6:rsob.150251. [PMID: 27358291 PMCID: PMC4929933 DOI: 10.1098/rsob.150251] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 06/01/2016] [Indexed: 12/13/2022] Open
Abstract
Mounting an immune response to fight disease is costly for an organism and can reduce investment in another life-history trait, such as reproduction. The terminal investment hypothesis predicts that an organism will increase reproductive effort when threatened by disease. The reproductive fitness of amphibians infected with the deadly fungal pathogen Batrachochytrium dendrobatidis (Bd) is largely unknown. In this study, we explored gametogenesis in two endangered and susceptible frog species, Pseudophryne corroboree and Litoria verreauxii alpina. Gametogenesis, both oogenesis and spermatogenesis, increased when animals were experimentally infected with Bd. In P. corroboree, infected males have thicker germinal epithelium, and a larger proportion of spermatocytes. In L. v. alpina, infected males had more spermatic cell bundles in total, and a larger proportion of spermatozoa bundles. In female L. v. alpina, ovaries and oviducts were larger in infected animals, and there were more cells present within the ovaries. Terminal investment has consequences for the evolution of disease resistance in declining species. If infected animals are increasing reproductive efforts and producing more offspring before succumbing to disease, it is possible that population-level selection for disease resistance will be minimized.
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Affiliation(s)
- Laura A Brannelly
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
| | - Rebecca Webb
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Lee Berger
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
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15
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Scheele BC, Skerratt LF, Hunter DA, Banks SC, Pierson JC, Driscoll DA, Byrne PG, Berger L. Disease-associated change in an amphibian life-history trait. Oecologia 2017; 184:825-833. [DOI: 10.1007/s00442-017-3911-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 07/06/2017] [Indexed: 11/30/2022]
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16
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Abstract
Reproduction of amphibians includes ovulation, spermiation, fertilization, oviposition, larval stage and development, and metamorphosis. A problem at any stage could lead to reproductive failure. To stimulate reproduction, environmental conditions must be arranged to simulate changes in natural habits. Reproductive life history is well documented in amphibians; a thorough knowledge of this subject will aid the practitioner in diagnosis and treatment. Technologies for artificial reproduction are developing rapidly, and some protocols may be transferable to privately kept or endangered species. Reproductive tract disorders are rarely described; no bacterial or viral diseases are known that specifically target the amphibian reproductive system.
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17
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Maceda-Veiga A, Green AJ, Poulin R, Lagrue C. Body Condition Peaks at Intermediate Parasite Loads in the Common Bully Gobiomorphus cotidianus. PLoS One 2016; 11:e0168992. [PMID: 28030606 PMCID: PMC5193454 DOI: 10.1371/journal.pone.0168992] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 12/09/2016] [Indexed: 12/26/2022] Open
Abstract
Most ecologists and conservationists perceive parasitic infections as deleterious for the hosts. Their effects, however, depend on many factors including host body condition, parasite load and the life cycle of the parasite. More research into how multiple parasite taxa affect host body condition is required and will help us to better understand host-parasite coevolution. We used body condition indices, based on mass-length relationships, to test the effects that abundances and biomasses of six parasite taxa (five trematodes, Apatemon sp., Tylodelphys sp., Stegodexamene anguillae, Telogaster opisthorchis, Coitocaecum parvum, and the nematode Eustrongylides sp.) with different modes of transmission have on the body condition of their intermediate or final fish host, the common bully Gobiomorphus cotidianus in New Zealand. We used two alternative body condition methods, the Scaled Mass Index (SMI) and Fulton's condition factor. General linear and hierarchical partitioning models consistently showed that fish body condition varied strongly across three lakes and seasons, and that most parasites did not have an effect on the two body condition indices. However, fish body condition showed a highly significant humpbacked relationship with the total abundance of all six parasite taxa, mostly driven by Apatemon sp. and S. anguillae, indicating that the effects of these parasites can range from positive to negative as abundance increases. Such a response was also evident in models including total parasite biomass. Our methodological comparison supports the SMI as the most robust mass-length method to examine the effects of parasitic infections on fish body condition, and suggests that linear, negative relationships between host condition and parasite load should not be assumed.
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Affiliation(s)
- Alberto Maceda-Veiga
- Department of Integrative Ecology, Estación Biológica de Doñana-CSIC), Sevilla, Spain
- Institute of Research in Biodiversity (IRBio), Faculty of Biology, University of Barcelona, Barcelona, Spain
- * E-mail:
| | - Andy J. Green
- Department of Wetland Ecology, Estación Biológica de Doñana-CSIC, Sevilla, Spain
| | - Robert Poulin
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Clément Lagrue
- Department of Zoology, University of Otago, Dunedin, New Zealand
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18
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An D, Waldman B. Enhanced call effort in Japanese tree frogs infected by amphibian chytrid fungus. Biol Lett 2016; 12:20160018. [PMID: 26932682 DOI: 10.1098/rsbl.2016.0018] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Some amphibians have evolved resistance to the devastating disease chytridiomycosis, associated with global population declines, but immune defences can be costly. We recorded advertisement calls of male Japanese tree frogs (Hyla japonica) in the field. We then assessed whether individuals were infected by Batrachochytrium dendrobatidis (Bd), the causal agent of the disease. This allowed us to analyse call properties of males as a function of their infection status. Infected males called more rapidly and produced longer calls than uninfected males. This enhanced call effort may reflect pathogen manipulation of host behaviour to foster disease transmission. Alternatively, increased calling may have resulted from selection on infected males to reproduce earlier because of their shortened expected lifespan. Our results raise the possibility that sublethal effects of Bd alter amphibian life histories, which contributes to long-term population declines.
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Affiliation(s)
- Deuknam An
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Bruce Waldman
- Laboratory of Behavioral and Population Ecology, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
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19
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Greenspan SE, Roznik EA, Schwarzkopf L, Alford RA, Pike DA. Robust calling performance in frogs infected by a deadly fungal pathogen. Ecol Evol 2016; 6:5964-72. [PMID: 27547369 PMCID: PMC4983606 DOI: 10.1002/ece3.2256] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 05/25/2016] [Indexed: 11/11/2022] Open
Abstract
Reproduction is an energetically costly behavior for many organisms, including species with mating systems in which males call to attract females. In these species, calling males can often attract more females by displaying more often, with higher intensity, or at certain frequencies. Male frogs attract females almost exclusively by calling, and we know little about how pathogens, including the globally devastating fungus, Batrachochytrium dendrobatidis, influence calling effort and call traits. A previous study demonstrated that the nightly probability of calling by male treefrogs, Litoria rheocola, is elevated when they are in good body condition and are infected by B. dendrobatidis. This suggests that infections may cause males to increase their present investment in mate attraction to compensate for potential decreases in future reproduction. However, if infection by B. dendrobatidis decreases the attractiveness of their calls, infected males might experience decreased reproductive success despite increases in calling effort. We examined whether calls emitted by L. rheocola infected by B. dendrobatidis differed from those of uninfected individuals in duration, pulse rate, dominant frequency, call rate, or intercall interval, the attributes commonly linked to mate choice. We found no effects of fungal infection status or infection intensity on any call attribute. Our results indicate that infected males produce calls similar in all the qualities we measured to those of uninfected males. It is therefore likely that the calls of infected and uninfected males should be equally attractive to females. The increased nightly probability of calling previously demonstrated for infected males in good condition may therefore lead to greater reproductive success than that of uninfected males. This could reduce the effectiveness of natural selection for resistance to infection, but could increase the effectiveness of selection for infection tolerance, the ability to limit the harm caused by infection, such as reductions in body condition.
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Affiliation(s)
- Sasha E Greenspan
- College of Marine and Environmental Sciences James Cook University Townsville Queensland 4811 Australia
| | - Elizabeth A Roznik
- College of Marine and Environmental Sciences James Cook University Townsville Queensland 4811 Australia; Present address: Department of Integrative Biology University of South Florida Tampa Florida 33620
| | - Lin Schwarzkopf
- College of Marine and Environmental Sciences James Cook University Townsville Queensland 4811 Australia
| | - Ross A Alford
- College of Marine and Environmental Sciences James Cook University Townsville Queensland 4811 Australia
| | - David A Pike
- College of Marine and Environmental Sciences James Cook University Townsville Queensland 4811 Australia; Present address: Department of Integrative Biology University of South Florida Tampa Florida 33620
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20
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Grogan LF, Phillott AD, Scheele BC, Berger L, Cashins SD, Bell SC, Puschendorf R, Skerratt LF. Endemicity of chytridiomycosis features pathogen overdispersion. J Anim Ecol 2016; 85:806-16. [PMID: 26847143 DOI: 10.1111/1365-2656.12500] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 01/20/2016] [Indexed: 11/26/2022]
Abstract
Pathogens can be critical drivers of the abundance and distribution of wild animal populations. The presence of an overdispersed pathogen load distribution between hosts (where few hosts harbour heavy parasite burdens and light infections are common) can have an important stabilizing effect on host-pathogen dynamics where infection intensity determines pathogenicity. This may potentially lead to endemicity of an introduced pathogen rather than extirpation of the host and/or pathogen. Overdispersed pathogen load distributions have rarely been considered in wild animal populations as an important component of the infection dynamics of microparasites such as bacteria, viruses, protozoa and fungi. Here we examined the abundance, distribution and transmission of the model fungal pathogen Batrachochytrium dendrobatidis (Bd, cause of amphibian chytridiomycosis) between wild-caught Litoria rheocola (common mist frogs) to investigate the effects of an overdispersed pathogen load distribution on the host population in the wild. We quantified host survival, infection incidence and recovery probabilities relative to infectious burden, and compared the results of models where pathogen overdispersion either was or was not considered an important feature of host-pathogen dynamics. We found the distribution of Bd load between hosts to be highly overdispersed. We found that host survival was related to infection burden and that accounting for pathogen overdispersion allowed us to better understand infection dynamics and their implications for disease control. In addition, we found that the pattern of host infections and recoveries varied markedly with season whereby (i) infections established more in winter, consistent with temperature-dependent effects on fungal growth, and (ii) recoveries (loss of infection) occurred frequently in the field throughout the year but were less likely in winter. Our results suggest that pathogen overdispersion is an important feature of endemic chytridiomycosis and that intensity of infection determines disease impact. These findings have important implications for our understanding of chytridiomycosis dynamics and the application of management strategies for disease mitigation. We recommend quantifying individual infectious burdens rather than infection state where possible in microparasitic diseases.
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Affiliation(s)
- Laura F Grogan
- One Health Research Group, College of Public Health, Medicine and Veterinary Sciences, James Cook University, 1 James Cook Drive, Townsville City, QLD, 4811, Australia.,Griffith Wildlife Disease Ecology Group, Environmental Futures Research Institute, School of Environment, Griffith University, 170 Kessels Road, Nathan, QLD, 4111, Australia
| | - Andrea D Phillott
- One Health Research Group, College of Public Health, Medicine and Veterinary Sciences, James Cook University, 1 James Cook Drive, Townsville City, QLD, 4811, Australia.,Biological Sciences, Asian University for Women, Mohammed Ali Road, Chittagong, Bangladesh
| | - Benjamin C Scheele
- One Health Research Group, College of Public Health, Medicine and Veterinary Sciences, James Cook University, 1 James Cook Drive, Townsville City, QLD, 4811, Australia.,Fenner School of Environment and Society, College of Medicine, Biology and Environment, Australian National University, Canberra, ACT, 0200, Australia
| | - Lee Berger
- One Health Research Group, College of Public Health, Medicine and Veterinary Sciences, James Cook University, 1 James Cook Drive, Townsville City, QLD, 4811, Australia
| | - Scott D Cashins
- One Health Research Group, College of Public Health, Medicine and Veterinary Sciences, James Cook University, 1 James Cook Drive, Townsville City, QLD, 4811, Australia
| | - Sara C Bell
- One Health Research Group, College of Public Health, Medicine and Veterinary Sciences, James Cook University, 1 James Cook Drive, Townsville City, QLD, 4811, Australia.,Australian Institute of Marine Science, 1526 Cape Cleveland Road, Cape Cleveland, Townsville City, QLD, 4810, Australia
| | - Robert Puschendorf
- School of Biological Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK
| | - Lee F Skerratt
- One Health Research Group, College of Public Health, Medicine and Veterinary Sciences, James Cook University, 1 James Cook Drive, Townsville City, QLD, 4811, Australia
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21
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Roznik EA, Sapsford SJ, Pike DA, Schwarzkopf L, Alford RA. Natural disturbance reduces disease risk in endangered rainforest frog populations. Sci Rep 2015; 5:13472. [PMID: 26294048 PMCID: PMC4544035 DOI: 10.1038/srep13472] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 07/28/2015] [Indexed: 11/27/2022] Open
Abstract
Natural disturbances can drive disease dynamics in animal populations by altering the microclimates experienced by hosts and their pathogens. Many pathogens are highly sensitive to temperature and moisture, and therefore small changes in habitat structure can alter the microclimate in ways that increase or decrease infection prevalence and intensity in host populations. Here we show that a reduction of rainforest canopy cover caused by a severe tropical cyclone decreased the risk of endangered rainforest frogs (Litoria rheocola) becoming infected by a fungal pathogen (Batrachochytrium dendrobatidis). Reductions in canopy cover increased the temperatures and rates of evaporative water loss in frog microhabitats, which reduced B. dendrobatidis infection risk in frogs by an average of 11–28% in cyclone-damaged areas, relative to unaffected areas. Natural disturbances to the rainforest canopy can therefore provide an immediate benefit to frogs by altering the microclimate in ways that reduce infection risk. This could increase host survival and reduce the probability of epidemic disease outbreaks. For amphibian populations under immediate threat from this pathogen, targeted manipulation of canopy cover could increase the availability of warmer, drier microclimates and therefore tip the balance from host extinction to coexistence.
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Affiliation(s)
- Elizabeth A Roznik
- College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Sarah J Sapsford
- College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - David A Pike
- College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Lin Schwarzkopf
- College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Ross A Alford
- College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia
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