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Oates BA, Monteith KL, Goheen JR, Merkle JA, Fralick GL, Kauffman MJ. Detecting Resource Limitation in a Large Herbivore Population Is Enhanced With Measures of Nutritional Condition. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2020.522174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Resource limitation at the population level is a function of forage quality and its abundance relative to its per capita availability, which in turn, determines nutritional condition of individuals. Effects of resource limitation on population dynamics in ungulates often occur through predictable and sequential changes in vital rates, which can enable assessments of how resource limitation influences population growth. We tested theoretical predictions of bottom-up (i.e., resource limitation) forcing on moose (Alces alces) through the lens of vital rates by quantifying the relative influence of intrinsic measures of nutritional condition and extrinsic measures of remotely sensed environmental data on demographic rates. We measured rates of pregnancy, parturition, juvenile, and adult survival for 82 adult females in a population where predators largely were absent. Life stage simulation analyses (LSAs) indicated that interannual fluctuations in adult survival contributed to most of the variability in λ. We then extended the LSA to estimate vital rates as a function of bottom-up covariates to evaluate their influence on λ. We detected weak signatures of effects from environmental covariates that were remotely sensed and spatially explicit to each seasonal range. Instead, nutritional condition strongly influenced rates of pregnancy, parturition, and overwinter survival of adults, clearly implicating resource limitation on λ. Our findings depart from the classic life-history paradigm of population dynamics in ungulates in that adult survival was highly variable and generated most of the variability in population growth rates. At the surface, lack of variation explained by environmental covariates may suggest weak evidence of resource limitation in the population, when nutritional condition actually underpinned most demographics. We suggest that variability in vital rates and effects of resource limitation may depend on context more than previously appreciated, and density dependence can obfuscate the relationships between remotely sensed data and demographic rates.
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2
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Ohmer MEB, Costantini D, Czirják GÁ, Downs CJ, Ferguson LV, Flies A, Franklin CE, Kayigwe AN, Knutie S, Richards-Zawacki CL, Cramp RL. Applied ecoimmunology: using immunological tools to improve conservation efforts in a changing world. CONSERVATION PHYSIOLOGY 2021; 9:coab074. [PMID: 34512994 PMCID: PMC8422949 DOI: 10.1093/conphys/coab074] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/27/2021] [Accepted: 08/09/2021] [Indexed: 05/11/2023]
Abstract
Ecoimmunology is a rapidly developing field that explores how the environment shapes immune function, which in turn influences host-parasite relationships and disease outcomes. Host immune defence is a key fitness determinant because it underlies the capacity of animals to resist or tolerate potential infections. Importantly, immune function can be suppressed, depressed, reconfigured or stimulated by exposure to rapidly changing environmental drivers like temperature, pollutants and food availability. Thus, hosts may experience trade-offs resulting from altered investment in immune function under environmental stressors. As such, approaches in ecoimmunology can provide powerful tools to assist in the conservation of wildlife. Here, we provide case studies that explore the diverse ways that ecoimmunology can inform and advance conservation efforts, from understanding how Galapagos finches will fare with introduced parasites, to using methods from human oncology to design vaccines against a transmissible cancer in Tasmanian devils. In addition, we discuss the future of ecoimmunology and present 10 questions that can help guide this emerging field to better inform conservation decisions and biodiversity protection. From better linking changes in immune function to disease outcomes under different environmental conditions, to understanding how individual variation contributes to disease dynamics in wild populations, there is immense potential for ecoimmunology to inform the conservation of imperilled hosts in the face of new and re-emerging pathogens, in addition to improving the detection and management of emerging potential zoonoses.
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Affiliation(s)
- Michel E B Ohmer
- Living Earth Collaborative, Washington University in St. Louis, MO 63130, USA
| | - David Costantini
- Unité Physiologie Moléculaire et Adaptation (PhyMA), Muséum National d’Histoire Naturelle, CNRS, 57 Rue Cuvier, CP32, 75005, Paris, France
| | - Gábor Á Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany
| | - Cynthia J Downs
- Department of Environmental Biology, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210, USA
| | - Laura V Ferguson
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Andy Flies
- Menzies Institute for Medical Research, University of Tasmania, Tasmania 7001, Australia
| | - Craig E Franklin
- School of Biological Sciences, The University of Queensland, Queensland 4072, Australia
| | - Ahab N Kayigwe
- Menzies Institute for Medical Research, University of Tasmania, Tasmania 7001, Australia
| | - Sarah Knutie
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06268, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06268, USA
| | | | - Rebecca L Cramp
- School of Biological Sciences, The University of Queensland, Queensland 4072, Australia
- Corresponding author: School of Biological Sciences, The University of Queensland, Queensland 4072, Australia.
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3
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Albery GF, Newman C, Ross JB, MacDonald DW, Bansal S, Buesching C. Negative density-dependent parasitism in a group-living carnivore. Proc Biol Sci 2020; 287:20202655. [PMID: 33323092 PMCID: PMC7779509 DOI: 10.1098/rspb.2020.2655] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 11/23/2020] [Indexed: 12/12/2022] Open
Abstract
Animals living at high population densities commonly experience greater exposure to disease, leading to increased parasite burdens. However, social animals can benefit immunologically and hygienically from cooperation, and individuals may alter their socio-spatial behaviour in response to infection, both of which could counteract density-related increases in exposure. Consequently, the costs and benefits of sociality for disease are often uncertain. Here, we use a long-term study of a wild European badger population (Meles meles) to investigate how within-population variation in host density determines infection with multiple parasites. Four out of five parasite taxa exhibited consistent spatial hotspots of infection, which peaked among badgers living in areas of low local population density. Combined movement, survival, spatial and social network analyses revealed that parasite avoidance was the likely cause of this negative density dependence, with possible roles for localized mortality, encounter-dilution effects, and micronutrient-enhanced immunity. These findings demonstrate that animals can organize their societies in space to minimize parasite infection, with important implications for badger behavioural ecology and for the control of badger-associated diseases.
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Affiliation(s)
| | - Chris Newman
- Wildlife Conservation Research Unit, The Recanati-Kaplan Centre, Department of Zoology, University of Oxford, Oxford, UK
| | - Julius Bright Ross
- Wildlife Conservation Research Unit, The Recanati-Kaplan Centre, Department of Zoology, University of Oxford, Oxford, UK
| | - David W. MacDonald
- Wildlife Conservation Research Unit, The Recanati-Kaplan Centre, Department of Zoology, University of Oxford, Oxford, UK
| | - Shweta Bansal
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Christina Buesching
- Wildlife Conservation Research Unit, The Recanati-Kaplan Centre, Department of Zoology, University of Oxford, Oxford, UK
- Irving K. Barber Faculty of Sciences, Okanagan Department of Biology, The University of British Columbia, Kelowna, British Columbia, Canada
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Schultz EM, Gunning CE, Cornelius JM, Reichard DG, Klasing KC, Hahn TP. Patterns of annual and seasonal immune investment in a temporal reproductive opportunist. Proc Biol Sci 2020; 287:20192993. [PMID: 32576107 PMCID: PMC7329054 DOI: 10.1098/rspb.2019.2993] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/01/2020] [Indexed: 02/07/2023] Open
Abstract
Historically, investigations of how organismal investments in immunity fluctuate in response to environmental and physiological changes have focused on seasonally breeding organisms that confine reproduction to seasons with relatively unchallenging environmental conditions and abundant resources. The red crossbill, Loxia curvirostra, is a songbird that can breed opportunistically if conifer seeds are abundant, on both short, cold, and long, warm days, providing an ideal system to investigate environmental and reproductive effects on immunity. In this study, we measured inter- and intra-annual variation in complement, natural antibodies, PIT54 and leucocytes in crossbills across four summers (2010-2013) and multiple seasons within 1 year (summer 2011-spring 2012). Overall, we observed substantial changes in crossbill immune investment among summers, with interannual variation driven largely by food resources, while variation across multiple seasons within a single cone year was less pronounced and lacked a dominant predictor of immune investment. However, we found weak evidence that physiological processes (e.g. reproductive condition, moult) or abiotic factors (e.g. temperature, precipitation) affect immune investment. Collectively, this study suggests that a reproductively flexible organism may be able to invest in both reproduction and survival-related processes, potentially by exploiting rich patches with abundant resources. More broadly, these results emphasize the need for more longitudinal studies of trade-offs associated with immune investment.
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Affiliation(s)
- Elizabeth M. Schultz
- Department of Neurobiology, Physiology, and Behaviour, University of California Davis, Davis, CA, USA
| | - Christian E. Gunning
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Affiliated Scholar, Department of Mathematics and Statistics, Kenyon College, Gambier, OH, USA
| | - Jamie M. Cornelius
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | | | - Kirk C. Klasing
- Department of Animal Science, University of California Davis, Davis, CA, USA
| | - Thomas P. Hahn
- Department of Neurobiology, Physiology, and Behaviour, University of California Davis, Davis, CA, USA
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5
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Merems JL, Shipley LA, Levi T, Ruprecht J, Clark DA, Wisdom MJ, Jackson NJ, Stewart KM, Long RA. Nutritional-Landscape Models Link Habitat Use to Condition of Mule Deer (Odocoileus hemionus). Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00098] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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6
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Becker DJ, Downs CJ, Martin LB. Multi-Scale Drivers of Immunological Variation and Consequences for Infectious Disease Dynamics. Integr Comp Biol 2020; 59:1129-1137. [PMID: 31559436 DOI: 10.1093/icb/icz138] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The immune system is the primary barrier to parasite infection, replication, and transmission following exposure, and variation in immunity can accordingly manifest in heterogeneity in traits that govern population-level infectious disease dynamics. While much work in ecoimmunology has focused on individual-level determinants of host immune defense (e.g., reproductive status and body condition), an ongoing challenge remains to understand the broader evolutionary and ecological contexts of this variation (e.g., phylogenetic relatedness and landscape heterogeneity) and to connect these differences into epidemiological frameworks. Ultimately, such efforts could illuminate general principles about the drivers of host defense and improve predictions and control of infectious disease. Here, we highlight recent work that synthesizes the complex drivers of immunological variation across biological scales of organization and scales these within-host differences to population-level infection outcomes. Such studies note the limitations involved in making species-level comparisons of immune phenotypes, stress the importance of spatial scale for immunology research, showcase several statistical tools for translating within-host data into epidemiological parameters, and provide theoretical frameworks for linking within- and between-host scales of infection processes. Building from these studies, we highlight several promising avenues for continued work, including the application of machine learning tools and phylogenetically controlled meta-analyses to immunology data and quantifying the joint spatial and temporal dependencies in immune defense using range expansions as model systems. We also emphasize the use of organismal traits (e.g., host tolerance, competence, and resistance) as a way to interlink various scales of analysis. Such continued collaboration and disciplinary cross-talk among ecoimmunology, disease ecology, and mathematical modeling will facilitate an improved understanding of the multi-scale drivers and consequences of variation in host defense.
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Affiliation(s)
- Daniel J Becker
- Department of Biology, Indiana University, Bloomington, IN 47405, USA.,Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA 30602, USA
| | - Cynthia J Downs
- Department of Biology, Hamilton College, Clinton, NY 13323, USA
| | - Lynn B Martin
- Department of Global and Planetary Health, University of South Florida, Tampa, FL 33620, USA
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7
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Albery GF, Becker DJ, Kenyon F, Nussey DH, Pemberton JM. The Fine-Scale Landscape of Immunity and Parasitism in a Wild Ungulate Population. Integr Comp Biol 2020; 59:1165-1175. [PMID: 30942858 DOI: 10.1093/icb/icz016] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Spatial heterogeneity in susceptibility and exposure to parasites is a common source of confounding variation in disease ecology studies. However, it is not known whether spatial autocorrelation acts on immunity at small scales, within wild animal populations, and whether this predicts spatial patterns in infection. Here we used a well-mixed wild population of individually recognized red deer (Cervus elaphus) inhabiting a heterogeneous landscape to investigate fine-scale spatial patterns of immunity and parasitism. We noninvasively collected 842 fecal samples from 141 females with known ranging behavior over 2 years. We quantified total and helminth-specific mucosal antibodies and counted propagules of three gastrointestinal helminth taxa. These data were analyzed with linear mixed models using the Integrated Nested Laplace Approximation, using a Stochastic Partial Differentiation Equation approach to control for and quantify spatial autocorrelation. We also investigated whether spatial patterns of immunity and parasitism changed seasonally. We discovered substantial spatial heterogeneity in general and helminth-specific antibody levels and parasitism with two helminth taxa, all of which exhibited contrasting seasonal variation in their spatial patterns. Notably, Fasciola hepatica intensity appeared to be strongly influenced by the presence of wet grazing areas, and antibody hotspots did not correlate with distributions of any parasites. Our results suggest that spatial heterogeneity may be an important factor affecting immunity and parasitism in a wide range of study systems. We discuss these findings with regards to the design of sampling regimes and public health interventions, and suggest that disease ecology studies investigate spatial heterogeneity more regularly to enhance their results, even when examining small geographic areas.
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Affiliation(s)
- Gregory F Albery
- Institute of Evolutionary Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Daniel J Becker
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Fiona Kenyon
- Pentlands Science Park, Moredun Research Institute, Bush Loan, Midlothian EH26 0PZ, UK
| | - Daniel H Nussey
- Institute of Evolutionary Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Josephine M Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3FL, UK
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8
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Smiley RA, Rittenhouse CD, Mong TW, Monteith KL. Assessing Nutritional Condition of Mule Deer Using a Photographic Index. WILDLIFE SOC B 2020. [DOI: 10.1002/wsb.1070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Rachel A. Smiley
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the EnvironmentUniversity of Connecticut 1376 Storrs Road, Unit 4087 Storrs CT 06269‐4087 USA
| | - Chadwick D. Rittenhouse
- Wildlife and Fisheries Conservation Center, Department of Natural Resources and the EnvironmentUniversity of Connecticut 1376 Storrs Road, Unit 4087 Storrs CT 06269‐4087 USA
| | - Tony W. Mong
- Wyoming Game and Fish Department 2820 State Highway 120 Cody WY 82414 USA
| | - Kevin L. Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and PhysiologyUniversity of Wyoming 804 East Fremont Street Laramie WY 82072 USA
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9
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LaSharr TN, Long RA, Heffelfinger JR, Bleich VC, Krausman PR, Bowyer RT, Shannon JM, Klaver RW, Brewer CE, Cox M, Holland AA, Hubbs A, Lehman CP, Muir JD, Sterling B, Monteith KL. Hunting and mountain sheep: Do current harvest practices affect horn growth? Evol Appl 2019; 12:1823-1836. [PMID: 31548860 PMCID: PMC6752155 DOI: 10.1111/eva.12841] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/04/2019] [Accepted: 07/06/2019] [Indexed: 11/27/2022] Open
Abstract
The influence of human harvest on evolution of secondary sexual characteristics has implications for sustainable management of wildlife populations. The phenotypic consequences of selectively removing males with large horns or antlers from ungulate populations have been a topic of heightened concern in recent years. Harvest can affect size of horn-like structures in two ways: (a) shifting age structure toward younger age classes, which can reduce the mean size of horn-like structures, or (b) selecting against genes that produce large, fast-growing males. We evaluated effects of age, climatic and forage conditions, and metrics of harvest on horn size and growth of mountain sheep (Ovis canadensis ssp.) in 72 hunt areas across North America from 1981 to 2016. In 50% of hunt areas, changes in mean horn size during the study period were related to changes in age structure of harvested sheep. Environmental conditions explained directional changes in horn growth in 28% of hunt areas, 7% of which did not exhibit change before accounting for effects of the environment. After accounting for age and environment, horn size of mountain sheep was stable or increasing in the majority (~78%) of hunt areas. Age-specific horn size declined in 44% of hunt areas where harvest was regulated solely by morphological criteria, which supports the notion that harvest practices that are simultaneously selective and intensive might lead to changes in horn growth. Nevertheless, phenotypic consequences are not a foregone conclusion in the face of selective harvest; over half of the hunt areas with highly selective and intensive harvest did not exhibit age-specific declines in horn size. Our results demonstrate that while harvest regimes are an important consideration, horn growth of harvested male mountain sheep has remained largely stable, indicating that changes in horn growth patterns are an unlikely consequence of harvest across most of North America.
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Affiliation(s)
- Tayler N. LaSharr
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and PhysiologyUniversity of WyomingLaramieWYUSA
| | - Ryan A. Long
- Department of Fish and Wildlife SciencesUniversity of IdahoMoscowIDUSA
| | | | - Vernon C. Bleich
- Department of Natural Resources and Environmental ScienceUniversity of Nevada RenoRenoNVUSA
| | - Paul R. Krausman
- School of Natural Resources and the EnvironmentUniversity of ArizonaTucsonAZUSA
| | - R. Terry Bowyer
- Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAKUSA
| | | | - Robert W. Klaver
- US Geological Survey, Iowa Cooperative Fish and Wildlife Research Unit, Department of Natural Resource Ecology and ManagementIowa State UniversityAmesIAUSA
| | - Clay E. Brewer
- Western Association of Fish and Wildlife Agencies—Wild Sheep Working GroupTexas Parks and Wildlife DepartmentRochelleTXUSA
| | - Mike Cox
- Nevada Department of WildlifeRenoNVUSA
| | | | - Anne Hubbs
- Alberta Environment and ParksRocky Mountain HouseABCanada
| | | | | | | | - Kevin L. Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and PhysiologyUniversity of WyomingLaramieWYUSA
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10
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Vennum CR, Downs CJ, Hayes JP, Houston I, Collopy MW, Woodbridge B, Briggs CW. Early Life Conditions and Immune Defense in Nestling Swainson's Hawks. Physiol Biochem Zool 2019; 92:419-429. [PMID: 31180801 DOI: 10.1086/704364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The quality of perinatal conditions directly influences the physical and immunological development of nestlings, yet it is inherently variable across space and time. Long-term breeding data for a population of Swainson's hawks (Buteo swainsoni) in northern California show a continuum of territory occupancy and productivity values of individual territories and nests. Here we explore effects of variation among territories on immune system development. We hypothesize that nestlings benefitting from favorable conditions will invest in stronger immune systems, a trait with long-term benefits. We used two immunological assays, a bactericidal assay and a hemolytic-complement activity assay, with leukocyte differentials (heterophil∶lymphocyte ratio) to evaluate the constitutive innate immune system. We examined whether early brood-rearing conditions (i.e., number of siblings, hatch date, endoparasite prevalence) were associated with immunological development. Linear mixed-effects models indicated a positive relationship between extended territory occupancy history-an index of habitat quality-and nestling immune function during years with poorer reproduction. There was no association during an exceptionally good reproductive year. Hence, at least under some circumstances, nestling environments or territory characteristics may affect immune function of nestlings. Our study contributes to the growing body of evidence highlighting the importance of facultative allocation to immune traits using long-term demographic data of a top avian predator.
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11
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Respiratory pathogens and their association with population performance in Montana and Wyoming bighorn sheep populations. PLoS One 2018; 13:e0207780. [PMID: 30475861 PMCID: PMC6257920 DOI: 10.1371/journal.pone.0207780] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 11/06/2018] [Indexed: 11/19/2022] Open
Abstract
Respiratory disease caused by Mycoplasma ovipneumoniae and Pasteurellaceae poses a formidable challenge for bighorn sheep (Ovis canadensis) conservation. All-age epizootics can cause 10–90% mortality and are typically followed by multiple years of enzootic disease in lambs that hinders post-epizootic recovery of populations. The relative frequencies at which these epizootics are caused by the introduction of novel pathogens or expression of historic pathogens that have become resident in the populations is unknown. Our primary objectives were to determine how commonly the pathogens associated with respiratory disease are hosted by bighorn sheep populations and assess demographic characteristics of populations with respect to the presence of different pathogens. We sampled 22 bighorn sheep populations across Montana and Wyoming, USA for Mycoplasma ovipneumoniae and Pasteurellaceae and used data from management agencies to characterize the disease history and demographics of these populations. We tested for associations between lamb:ewe ratios and the presence of different respiratory pathogen species. All study populations hosted Pasteurellaceae and 17 (77%) hosted Mycoplasma ovipneumoniae. Average lamb:ewe ratios for individual populations where both Mycoplasma ovipneumoniae and Pasteurellaceae were detected ranged from 0.14 to 0.40. However, average lamb:ewe ratios were higher in populations where Mycoplasma ovipneumoniae was not detected (0.37, 95% CI: 0.27–0.51) than in populations where it was detected (0.25, 95% CI: 0.21–0.30). These findings suggest that respiratory pathogens are commonly hosted by bighorn sheep populations and often reduce recruitment rates; however ecological factors may interact with the pathogens to determine population-level effects. Elucidation of such factors could provide insights for management approaches that alleviate the effects of respiratory pathogens in bighorn sheep. Nevertheless, minimizing the introduction of novel pathogens from domestic sheep and goats remains imperative to bighorn sheep conservation.
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12
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Smyth KN, Caruso NM, Davies CS, Clutton-Brock TH, Drea CM. Social and endocrine correlates of immune function in meerkats: implications for the immunocompetence handicap hypothesis. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180435. [PMID: 30225031 PMCID: PMC6124081 DOI: 10.1098/rsos.180435] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/25/2018] [Indexed: 06/08/2023]
Abstract
Social status can mediate effects on the immune system, with profound consequences for individual health; nevertheless, most investigators of status-related disparities in free-ranging animals have used faecal parasite burdens to proxy immune function in the males of male-dominant species. We instead use direct measures of innate immune function (complement and natural antibodies) to examine status-related immunocompetence in both sexes of a female-dominant species. The meerkat is a unique model for such a study because it is a cooperatively breeding species in which status-related differences are extreme, evident in reproductive skew, morphology, behaviour, communication and physiology, including that dominant females naturally express the greatest total androgen (androstenedione plus testosterone) concentrations. We found that, relative to subordinates, dominant animals had reduced serum bacteria-killing abilities; also, relative to subordinate females, dominant females had reduced haemolytic complement activities. Irrespective of an individual's sex or social status, androstenedione concentrations (but not body condition, age or reproductive activity) negatively predicted concurrent immunocompetence. Thus, dominant meerkats of both sexes are immunocompromised. Moreover, in female meerkats, androstenedione perhaps acting directly or via local conversion, may exert a double-edged effect of promoting dominance and reproductive success at the cost of increased parasitism and reduced immune function. Given the prominent signalling of dominance in female meerkats, these findings may relate to the immunocompetence handicap hypothesis (ICHH); however, our data would suggest that the endocrine mechanism underlying the ICHH need not be mediated solely by testosterone and might explain trade-offs in females, as well as in males.
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Affiliation(s)
- Kendra N. Smyth
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Nicholas M. Caruso
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA
| | - Charli S. Davies
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Tim H. Clutton-Brock
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
- Department of Zoology, University of Cambridge, Cambridge, UK
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Christine M. Drea
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Biology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
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13
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Downs CJ, Boan BV, Lohuis TD, Stewart KM. Investigating Relationships between Reproduction, Immune Defenses, and Cortisol in Dall Sheep. Front Immunol 2018; 9:105. [PMID: 29445376 PMCID: PMC5797757 DOI: 10.3389/fimmu.2018.00105] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 01/12/2018] [Indexed: 12/25/2022] Open
Abstract
Life-history theory is fundamental to understanding how animals allocate resources among survival, development, and reproduction, and among traits within these categories. Immediate trade-offs occur within a short span of time and, therefore, are more easily detected. Trade-offs, however, can also manifest across stages of the life cycle, a phenomenon known as carryover effects. We investigated trade-offs on both time scales in two populations of Dall sheep (Ovis dalli dalli) in Southcentral Alaska. Specifically, we (i) tested for glucocorticoid-mediated carryover effects from the breeding season on reproductive success and immune defenses during parturition and (ii) tested for trade-offs between immune defenses and reproduction within a season. We observed no relationship between cortisol during mating and pregnancy success; however, we found marginal support for a negative relationship between maternal cortisol and neonate birth weights. Low birth weights, resulting from high maternal cortisol, may result in low survival or low fecundity for the neonate later in life, which could result in overall population decline. We observed a negative relationship between pregnancy and bacterial killing ability, although we observed no relationship between pregnancy and haptoglobin. Study site affected bactericidal capacity and the inflammatory response, indicating the influence of external factors on immune responses, although we could not test hypotheses about the cause of those differences. This study helps advance our understanding of the plasticity and complexity of the immune system and provides insights into the how individual differences in physiology may mediate differences in fitness.
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Affiliation(s)
- Cynthia J. Downs
- Department of Biology, Hamilton College, Clinton, NY, United States
| | - Brianne V. Boan
- Department of Natural Resources and Environmental Sciences, University of Nevada, Reno, NV, United States
| | - Thomas D. Lohuis
- Alaska Department of Fish and Game, Anchorage, AK, United States
| | - Kelley M. Stewart
- Department of Natural Resources and Environmental Sciences, University of Nevada, Reno, NV, United States
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14
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Cheynel L, Lemaître JF, Gaillard JM, Rey B, Bourgoin G, Ferté H, Jégo M, Débias F, Pellerin M, Jacob L, Gilot-Fromont E. Immunosenescence patterns differ between populations but not between sexes in a long-lived mammal. Sci Rep 2017; 7:13700. [PMID: 29057949 PMCID: PMC5651810 DOI: 10.1038/s41598-017-13686-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 09/22/2017] [Indexed: 11/08/2022] Open
Abstract
In animals, physiological mechanisms underlying reproductive and actuarial senescence remain poorly understood. Immunosenescence, the decline in the ability to display an efficient immune response with increasing age, is likely to influence both reproductive and actuarial senescence through increased risk of disease. Evidence for such a link has been reported from laboratory animal models but has been poorly investigated in the wild, where variation in resource acquisitions usually drives life-history trade-offs. We investigated immunosenescence patterns over 7 years in both sexes of two contrasting roe deer populations (Capreolus capreolus). We first measured twelve immune markers to obtain a thorough identification of innate and adaptive components of immunity and assessed, from the same individuals, the age-dependent variation observed in parasitic infections. Although the level of innate traits was maintained at old age, the functional innate immune traits declined with increasing age in one of two populations. In both populations, the production of inflammatory markers increased with advancing age. Finally, the adaptive response declined in late adulthood. The increasing parasite burden with age we reported suggests the effective existence of immunosenescence. Age-specific patterns differed between populations but not between sexes, which indicate that habitat quality could shape age-dependent immune phenotype in the wild.
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Affiliation(s)
- L Cheynel
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France.
| | - J-F Lemaître
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France
| | - J-M Gaillard
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France
| | - B Rey
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France
| | - G Bourgoin
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France
- Université de Lyon, VetAgro Sup, Marcy-l'Etoile, France
| | - H Ferté
- EA 4688 "VECPAR", UFR Pharmacie, Université de Reims Champagne-Ardenne, Reims, France
| | - M Jégo
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France
| | - F Débias
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France
| | - M Pellerin
- Office National de la Chasse et de la Faune Sauvage, Centre National de Recherches Appliquées sur les Cervidés-Sanglier, Bar-le-Duc, France
| | - L Jacob
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France
| | - E Gilot-Fromont
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR 5558, F-69622, Villeurbanne, France
- Université de Lyon, VetAgro Sup, Marcy-l'Etoile, France
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15
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Monteith KL, Long RA, Stephenson TR, Bleich VC, Bowyer RT, Lasharr TN. Horn size and nutrition in mountain sheep: Can ewe handle the truth? J Wildl Manage 2017. [DOI: 10.1002/jwmg.21338] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kevin L. Monteith
- Haub School of Environment and Natural Resources, Wyoming Cooperative Fish and Wildlife Research UnitDepartment of Zoology and Physiology, University of Wyoming 804 East Fremont St. Laramie WY 82072 USA
| | - Ryan A. Long
- Department of Fish and Wildlife SciencesUniversity of Idaho 875 Perimeter Dr., MS 1142 Moscow ID 83844 USA
| | - Thomas R. Stephenson
- Sierra Nevada Bighorn Sheep Recovery ProgramCalifornia Department of Fish and Wildlife 787 North Main Street, Suite 220 Bishop CA 93514 USA
| | - Vernon C. Bleich
- Department of Natural Resources and Environmental ScienceUniversity of Nevada Reno Mail Stop 186, 1664 North Virginia Street Reno NV 89557 USA
| | - R. Terry Bowyer
- Institute of Arctic BiologyUniversity of Alaska Fairbanks Box 757000 Fairbanks AK 99775 USA
| | - Tayler N. Lasharr
- Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and PhysiologyUniversity of Wyoming Dept. 3166, 1000 E. University Ave Laramie WY 82071 USA
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16
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MacColl E, Vanesky K, Buck JA, Dudek BM, Eagles-Smith CA, Heath JA, Herring G, Vennum C, Downs CJ. Correlates of immune defenses in golden eagle nestlings. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2017; 327:243-253. [PMID: 29356454 DOI: 10.1002/jez.2081] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/30/2017] [Accepted: 06/21/2017] [Indexed: 11/07/2022]
Abstract
An individual's investment in constitutive immune defenses depends on both intrinsic and extrinsic factors. We examined how Leucocytozoon parasite presence, body condition (scaled mass), heterophil-to-lymphocyte (H:L) ratio, sex, and age affected immune defenses in golden eagle (Aquila chrysaetos) nestlings from three regions: California, Oregon, and Idaho. We quantified hemolytic-complement activity and bacterial killing ability, two measures of constitutive immunity. Body condition and age did not affect immune defenses. However, eagles with lower H:L ratios had lower complement activity, corroborating other findings that animals in better condition sometimes invest less in constitutive immunity. In addition, eagles with Leucocytozoon infections had higher concentrations of circulating complement proteins but not elevated opsonizing proteins for all microbes, and eagles from Oregon had significantly higher constitutive immunity than those from California or Idaho. We posit that Oregon eagles might have elevated immune defenses because they are exposed to more endoparasites than eagles from California or Idaho, and our results confirmed that the OR region has the highest rate of Leucocytozoon infections. Our study examined immune function in a free-living, long-lived raptor species, whereas most avian ecoimmunological research focuses on passerines. Thus, our research informs a broad perspective regarding the evolutionary and environmental pressures on immune function in birds.
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Affiliation(s)
| | - Kris Vanesky
- Academy for the Environment, University of Nevada Reno, NV, USA
| | - Jeremy A Buck
- US Fish and Wildlife Service, Oregon Fish and Wildlife Office, Portland, OR, USA
| | - Benjamin M Dudek
- Department of Biological Sciences and Raptor Research Center, Boise State University, Boise, ID, USA
| | - Collin A Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR
| | - Julie A Heath
- Department of Biological Sciences and Raptor Research Center, Boise State University, Boise, ID, USA
| | - Garth Herring
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR
| | - Chris Vennum
- Department of Biology, University of Nevada, Reno, NV, USA
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17
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Garnier R, Cheung CK, Watt KA, Pilkington JG, Pemberton JM, Graham AL. Joint associations of blood plasma proteins with overwinter survival of a large mammal. Ecol Lett 2017; 20:175-183. [DOI: 10.1111/ele.12719] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 10/31/2016] [Accepted: 11/17/2016] [Indexed: 02/02/2023]
Affiliation(s)
- Romain Garnier
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ USA
| | - Christopher K. Cheung
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ USA
| | - Kathryn A. Watt
- Institute of Evolutionary Biology; School of Biological Sciences; University of Edinburgh; Edinburgh UK
| | - Jill G. Pilkington
- Institute of Evolutionary Biology; School of Biological Sciences; University of Edinburgh; Edinburgh UK
| | - Josephine M. Pemberton
- Institute of Evolutionary Biology; School of Biological Sciences; University of Edinburgh; Edinburgh UK
| | - Andrea L. Graham
- Department of Ecology and Evolutionary Biology; Princeton University; Princeton NJ USA
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18
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Neggazi SA, Noreikiene K, Öst M, Jaatinen K. Reproductive investment is connected to innate immunity in a long-lived animal. Oecologia 2016; 182:347-56. [PMID: 27215635 DOI: 10.1007/s00442-016-3657-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 05/11/2016] [Indexed: 02/07/2023]
Abstract
Life-history theory predicts that organisms optimize their resource allocation strategy to maximize lifetime reproductive success. Individuals can flexibly reallocate resources depending on their life-history stage, and environmental and physiological factors, which lead to variable life-history strategies even within species. Physiological trade-offs between immunity and reproduction are particularly relevant for long-lived species that need to balance current reproduction against future survival and reproduction, but their underlying mechanisms are poorly understood. A major unresolved issue is whether the first-line innate immune function is suppressed by reproductive investment. In this paper, we tested if reproductive investment is associated with the suppression of innate immunity, and how this potential trade-off is resolved depending on physiological state and residual reproductive value. We used long-lived capital-breeding female eiders (Somateria mollissima) as a model. We showed that the innate immune response, measured by plasma bacteria-killing capacity (BKC), was negatively associated with increasing reproductive investment, i.e., with increasing clutch size and advancing incubation stage. Females in a better physiological state, as indexed by low heterophil-to-lymphocyte (H/L) ratios, showed higher BKC during early incubation, but this capacity decreased as incubation progressed, whereas females in poorer state showed low BKC capacity throughout incubation. Although plasma BKC generally declined with increasing H/L ratios, this decrease was most pronounced in young females. Our results demonstrate that reproductive investment can suppress constitutive first-line immune defence in a long-lived bird, but the degree of immunosuppression depends on physiological state and age.
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Affiliation(s)
- Sara A Neggazi
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Viikinkaari 1, 00014, Helsinki, Finland
| | - Kristina Noreikiene
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Viikinkaari 1, 00014, Helsinki, Finland.
| | - Markus Öst
- Environmental and Marine Biology, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6, 20520, Turku, Finland.,Coastal Zone Research Team, Novia University of Applied Sciences, Raseborgsvägen 9, 10600, Ekenäs, Finland
| | - Kim Jaatinen
- Coastal Zone Research Team, Novia University of Applied Sciences, Raseborgsvägen 9, 10600, Ekenäs, Finland
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