1
|
Kernen L, Rieder J, Duus A, Holbech H, Segner H, Bailey C. Thymus development in the zebrafish (Danio rerio) from an ecoimmunology perspective. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:805-819. [PMID: 33306886 DOI: 10.1002/jez.2435] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/27/2020] [Accepted: 11/23/2020] [Indexed: 01/21/2023]
Abstract
The thymus is present in all gnathostome vertebrates and is an essential organ for the adaptive immune system via the generation of functional mature T-cells. Over the life span of mammals, the thymus undergoes morphological and functional alterations, including an age-related involution, which in humans starts in early life. Life history tradeoffs have been suggested as possible reasons for thymus involution. While in teleost fish, only a few studies have investigated alterations of thymus structure and function over different life stages, resulting in a fragmented database. Here, we investigated the thymus growth of zebrafish (Danio rerio) from early life, throughout puberty and reproductive stage, up to 1-year-old. We assessed thymus growth by histological and morphometric analyses and thymocyte numbers. Thymus function was assessed by measuring the transcripts of the thymocyte marker genes, ikaros, tcrα, and tcrδ. Additionally, we analyzed gonad maturity and tail homogenate vitellogenin concentrations to align thymus status with the status of the reproductive system. Our results showed that the zebrafish thymus, in contrast to the human thymus, grew strongly during early life and puberty but started to undergo involution when the fish reached the reproductive age. The involution was characterized by reduced thymus area and thymocyte number, altered histoarchitecture, and decreasing thymocyte marker gene transcript levels. Our findings suggest that age-related changes of the zebrafish thymus do exist and could be partly explained in terms of resource tradeoffs, but also in terms of the ontogenetically late development of a functional adaptive immune system in teleosts.
Collapse
Affiliation(s)
- Larissa Kernen
- Centre for Fish and Wildlife Health, University of Bern, Bern, Switzerland
| | - Jessica Rieder
- Centre for Fish and Wildlife Health, University of Bern, Bern, Switzerland
| | - Annette Duus
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Henrik Holbech
- Department of Biology, University of Southern Denmark, Odense, Denmark
| | - Helmut Segner
- Centre for Fish and Wildlife Health, University of Bern, Bern, Switzerland
| | - Christyn Bailey
- Fish Immunology and Pathology Group, Centro de Investigación en Sanidad Animal (CISA-INIA), Madrid, Spain
| |
Collapse
|
2
|
Absence of reproduction-immunity trade-off in male Drosophila melanogaster evolving under differential sexual selection. BMC Evol Biol 2020; 20:13. [PMID: 31992187 PMCID: PMC6988192 DOI: 10.1186/s12862-019-1574-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/30/2019] [Indexed: 11/24/2022] Open
Abstract
Background The theory of trade-off suggests that limited resources should lead to trade-off in resource intensive traits such as, immunity related and sexually selected traits in males. Alternatively, sexual exaggerations can also act as an honest indicator of underlying immunocompetence, leading to positive correlations between these traits. Evidences in support of either hypothesis in invertebrates are equivocal. Whereas several studies have addressed this question, few have used naturally occurring pathogens and realized post infection realized immunity (e.g., survivorship) to assay the fitness correlations between these two sets of traits. Results Adopting an experimental evolution approach, we evolved replicate populations of Drosophila melanogaster under high and low sexual selection regimes for over a hundred generations and found the following in virgin and mated males in three separate assays:
Post infection survivorship against two natural pathogens - Pseudomonas entomophila (Pe) and Staphylococcus succinus (Ss): Mated males survived better against Pe, but were no different than virgins against Ss. Bacterial clearance ability against a third natural pathogen Providencia rettgeri (Pr): Mated males had significantly lower CFUs than virgins.
However, sexual selection history had no effect on realized immunity of either virgin or mated males. Conclusion We show that while mating can affect realized immunity in a pathogen specific way, sexual selection did not affect the same. The results highlight that complex polygenic traits such as immunity and reproductive traits not necessarily evolve following a binary trade-off model. We also stress the importance natural pathogens while studying sexual selection-immunity correlations.
Collapse
|
3
|
Andreasson F, Hegemann A, Nord A, Nilsson JÅ. Experimental facilitation of heat loss affects work rate and innate immune function in a breeding passerine bird. J Exp Biol 2020; 223:jeb.219790. [DOI: 10.1242/jeb.219790] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 03/11/2020] [Indexed: 01/06/2023]
Abstract
The capacity to get rid of excess heat produced during hard work is a possible constraint on parental effort during reproduction (heat dissipation limit [HDL] theory). We released hard-working blue tits (Cyanistes caeruleus) from this constraint by experimentally removing ventral plumage. We then assessed if this changed their reproductive effort (feeding rate and nestling size) and levels of self-maintenance (change in body mass and innate immune function). Feather-clipped females reduced the number of feeding visits and increased levels of constitutive innate immunity compared to unclipped females but did not fledge smaller nestlings. Thus, they increased self-maintenance without compromising current reproductive output. In contrast, feather-clipping did not affect the number of feeding visits or innate immune function in males, despite increased heat loss rate. Our results show that analyses of physiological parameters, such as constitutive innate immune function, can be important when trying to understand sources of variation in investment in self-maintenance versus reproductive effort and that risk of overheating can influence innate immune function during reproduction.
Collapse
Affiliation(s)
- Fredrik Andreasson
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
| | - Arne Hegemann
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
| | - Andreas Nord
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
- Scottish Centre for Ecology and the Natural Environment, Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Rowardennan G63 0AW, UK
| | - Jan-Åke Nilsson
- Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden
| |
Collapse
|
4
|
Negrín Dastis JO, Milne R, Guichard F, Derry AM. Phenotype-environment mismatch in metapopulations-Implications for the maintenance of maladaptation at the regional scale. Evol Appl 2019; 12:1475-1486. [PMID: 31417628 PMCID: PMC6691211 DOI: 10.1111/eva.12833] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 06/02/2019] [Accepted: 06/11/2019] [Indexed: 01/23/2023] Open
Abstract
Maladaptation is widespread in natural populations. However, maladaptation has most often been associated with absolute population decline in local habitats rather than on a spectrum of relative fitness variation that can assist natural populations in their persistence at larger regional scales. We report results from a field experiment that tested for relative maladaptation between-pond habitats with spatial heterogeneity and (a)symmetric selection in pH. In the experiment, we quantified relative maladaptation in a copepod metapopulation as a mismatch between the mean population phenotype and the optimal trait value that would maximize mean population fitness under either stable or fluctuating pH environmental conditions. To complement the field experiment, we constructed a metapopulation model that addressed both relative (distance from the optimum) and absolute (negative population growth) maladaptation, with the aim of forecasting maladaptation to pH at the regional scale in relation to spatial structure (environmental heterogeneity and connectivity) and temporal environmental fluctuations. The results from our experiment indicated that maladaptation to pH at the regional scale depended on the asymmetry of the fitness surface at the local level. The results from our metapopulation model revealed how dispersal and (a)symmetric selection can operate on the fitness surface to maintain maladaptive phenotype-environment mismatch at local and regional scales in a metapopulation. Environmental stochasticity resulted in the maintenance of maladaptation that was robust to dispersal, but also revealed an interaction between the asymmetry in selection and environmental correlation. Our findings emphasize the importance of maladaptation for planning conservation strategies that can support adaptive potential in fragmented and changing landscapes.
Collapse
Affiliation(s)
- Jorge Octavio Negrín Dastis
- Départment des sciences biologiquesUniversité du Québec à Montréal (UQAM)MontréalQuébecCanada
- Groupe de recherche interuniversitaire en limnologie et en environnement aquatique (GRIL)MontréalCanada
| | - Russell Milne
- Department of BiologyMcGill UniversityMontréalQuébecCanada
| | | | - Alison Margaret Derry
- Départment des sciences biologiquesUniversité du Québec à Montréal (UQAM)MontréalQuébecCanada
- Groupe de recherche interuniversitaire en limnologie et en environnement aquatique (GRIL)MontréalCanada
| |
Collapse
|
5
|
Pathirana NUK, Meegaskumbura M, Rajakaruna RS. Infection sequence alters disease severity-Effects of the sequential exposure of two larval trematodes to Polypedates cruciger tadpoles. Ecol Evol 2019; 9:6220-6230. [PMID: 31236216 PMCID: PMC6580301 DOI: 10.1002/ece3.5180] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 12/25/2018] [Accepted: 01/02/2019] [Indexed: 11/10/2022] Open
Abstract
Multiple pathogens coexist in nature, and hence, host species often encounter several pathogens simultaneously. The sequence in which the host encounters the parasites influences interactions between parasites and host pathology. Here, the effects of infection by two cercaria (larvae of trematodes) types, pleurolophocercous cercaria of Acanthostomum burminis and a furcocercous cercaria, on the tadpoles of common hourglass tree frog (Polypedates cruciger) were examined. Ten days posthatch, tadpoles (Gosner stage 27/28) were used for infection exposures. First, in a single infection each cercaria type was introduced to the tadpoles separately. Second, coinfection of the two cercaria was carried out by alternating the sequences of exposure. For all the experiments, appropriate controls were instituted. Tadpoles of all groups exposed to parasites had lower survival levels compared to controls. Among the four groups exposed, the highest survival was observed in the coinfection when furcocercous was introduced first (82.5%). The lowest survival was observed in the coinfection when the A. burminis cercaria was introduced first (65.0%). In the coinfections, when A. burminis was introduced prior to furcocercous, survival of the tadpoles was reduced by 17.0% compared to the exposures of furcocercous prior to A. burminis. Prior infection with A. burminis induced negative effect on the host with an increased infection severity, while prior infection with furcocercous had reduced infection severity than lone exposures. These results suggest that furcocercous infections can be beneficial for hosts challenged with A. burminis provided that A. burminis exposure occurs second. None of the treatments had an effect on the growth of the tadpoles, but lengthening of developmental period was observed in some exposures. All exposed tadpoles developed malformations which were exclusively axial-kyphosis and scoliosis. However, there was no difference in the number of malformed individuals in the single infection (19.0%-25.0%) compared to coinfection (20.0%-22.5%) or between coinfections. The results suggest that the sequence of parasite exposure affects host-parasite interactions and hence the disease outcomes. Understanding the effects of coinfection on disease outcomes for hosts provides insight into disease dynamics.
Collapse
Affiliation(s)
- Nuwandi U. K. Pathirana
- Department of ZoologyUniversity of PeradeniyaPeradeniyaSri Lanka
- Postgraduate Institute of ScienceUniversity of PeradeniyaPeradeniyaSri Lanka
- Freshwater Fish Group and Fish Health Unit, Centre for Sustainable Aquatic Ecosystems, School of Veterinary & Life SciencesMurdoch UniversityPerthAustralia
| | - Madhava Meegaskumbura
- Guangxi Key Laboratory of Forest Ecology & Conservation, College of ForestryGuangxi UniversityNanningChina
- Department of Molecular Biology and Bio‐technologyUniversity of PeradeniyaPeradeniyaSri Lanka
| | | |
Collapse
|
6
|
RAMIREZ‐OTAROLA N, ESPINOZA J, KALERGIS AM, SABAT P. Response to lipopolysaccharide inOctodon deguspups produces age‐related sickness behavior but does not have effects in juveniles. Integr Zool 2019; 14:235-247. [DOI: 10.1111/1749-4877.12329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Natalia RAMIREZ‐OTAROLA
- Department of Ecological Sciences, Science FacultyUniversidad de Chile Santiago Chile
- Department of Ecology, Center of Applied Ecology & Sustainability, Biological Sciences FacultyPontificia Universidad Católica de Chile Santiago Chile
| | - Janyra ESPINOZA
- Millennium Institute Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias BiológicasPontificia Universidad Católica de Chile Santiago Chile
| | - Alexis M. KALERGIS
- Millennium Institute Immunology and Immunotherapy, Departamento de Genética Molecular y Microbiología, Facultad de Ciencias BiológicasPontificia Universidad Católica de Chile Santiago Chile
- Departamento de Endocrinología, Facultad de MedicinaPontificia Universidad Católica de Chile Santiago Chile
| | - Pablo SABAT
- Department of Ecological Sciences, Science FacultyUniversidad de Chile Santiago Chile
- Department of Ecology, Center of Applied Ecology & Sustainability, Biological Sciences FacultyPontificia Universidad Católica de Chile Santiago Chile
| |
Collapse
|
7
|
Erazo D, Gottdenker NL, González C, Guhl F, Cuellar M, Kieran TJ, Glenn TC, Umaña JD, Cordovez J. Generalist host species drive Trypanosoma cruzi vector infection in oil palm plantations in the Orinoco region, Colombia. Parasit Vectors 2019; 12:274. [PMID: 31138275 PMCID: PMC6540391 DOI: 10.1186/s13071-019-3519-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 05/20/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Oil palm plantation establishment in Colombia has the potential to impact Chagas disease transmission by increasing the distribution range of Rhodnius prolixus. In fact, previous studies have reported Trypanosoma cruzi natural infection in R. prolixus captured in oil palms (Elaeis guineensis) in the Orinoco region, Colombia. The aim of this study is to understand T. cruzi infection in vectors in oil palm plantations relative to community composition and host dietary specialization by analyzing vector blood meals and comparing these results to vectors captured in a native palm tree species, Attalea butyracea. METHODS Rhodnius prolixus nymphs (n = 316) were collected from A. butyracea and E. guineensis palms in Tauramena, Casanare, Colombia. Vector blood meals from these nymphs were determined by amplifying and sequencing a vertebrate-specific 12S rRNA gene fragment. RESULTS Eighteen vertebrate species were identified and pigs (Sus scrofa) made up the highest proportion of blood meals in both habitats, followed by house mouse (Mus musculus) and opossum (Didelphis marsupialis). Individual bugs feeding only from generalist mammal species had the highest predicted vector infection rate, suggesting that generalist mammalian species are more competent hosts for T. cruzi infection . CONCLUSIONS Oil palm plantations and A. butyracea palms found in altered areas provide a similar quality habitat for R. prolixus populations in terms of blood meal availability. Both habitats showed similarities in vector infection rate and potential host species, representing a single T. cruzi transmission scenario at the introduced oil palm plantation and native Attalea palm interface.
Collapse
Affiliation(s)
- Diana Erazo
- Grupo de Investigación en Biología Matemática y Computacional (BIOMAC), Universidad de los Andes, Bogota, Colombia
| | - Nicole L. Gottdenker
- Department of Pathology, School of Veterinary Medicine, The University of Georgia, Athens, GA USA
| | - Camila González
- Centro de Investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Facultad de Ciencias, Universidad de los Andes, Bogotá, Colombia
| | - Felipe Guhl
- Centro de Investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Facultad de Ciencias, Universidad de los Andes, Bogotá, Colombia
| | - Monica Cuellar
- Grupo de Investigación en Ingeniería Biomédica (GIB), Universidad de los Andes, Bogota, Colombia
| | - Troy J. Kieran
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA USA
| | - Travis C. Glenn
- Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA USA
| | - Juan D. Umaña
- Grupo de Investigación en Biología Matemática y Computacional (BIOMAC), Universidad de los Andes, Bogota, Colombia
| | - Juan Cordovez
- Grupo de Investigación en Biología Matemática y Computacional (BIOMAC), Universidad de los Andes, Bogota, Colombia
| |
Collapse
|
8
|
Nwaogu CJ, Cresswell W, Versteegh MA, Tieleman BI. Seasonal differences in baseline innate immune function are better explained by environment than annual cycle stage in a year-round breeding tropical songbird. J Anim Ecol 2019; 88:537-553. [PMID: 30659607 PMCID: PMC6849850 DOI: 10.1111/1365-2656.12948] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 11/21/2018] [Indexed: 11/29/2022]
Abstract
Seasonal variation in innate immunity is often attributed to either temporal environmental variation or to life-history trade-offs that arise from specific annual cycle stages but decoupling them is difficult in natural populations. Here, we effectively decouple seasonal environmental variation from annual cycle stage effects by exploiting cross-seasonal breeding and moult in the tropical Common Bulbul Pycnonotus barbatus. We test how annual cycle stage interacts with a key seasonal environmental variable, rainfall, to determine immunity at population and individual level. If immune challenge varies with precipitation, we might expect immune function to be higher in the wet season due to increased environmental productivity. If breeding or moult imposes resource constraints on birds, depending on or independent of precipitation, we might expect lower immune indices during breeding or moult. We sampled blood from 818 birds in four annual cycle stage categories: breeding, moult, simultaneous breeding and moulting, or neither. We quantified indices of innate immunity (haptoglobin, nitric oxide (NOx ) and ovotransferrin concentrations, and haemagglutination and haemolysis titres) over two annual cycles of wet and dry seasons. Environment (but not annual cycle stage or interactions between both) explained variation in all immune indices, except NOx . NOx concentration differed between annual cycle stages but not between seasons. However, within the wet season, haptoglobin, NOx , ovotransferrin and haemolysis differed significantly between breeding and non-breeding females. Aside from some recorded inconsistencies, population level results were largely similar to results within individuals that were measured repeatedly. Unexpectedly, most immune indices were higher in the dry season and during breeding. Higher immune indices may be explained if fewer or poorer quality resources force birds to increase social contact, thereby exposing individuals to novel antigens and increased infection risk, independently of environmental productivity. Breeding birds may also show higher immunity if less immune-competent and/or infected females omit breeding. We conclude that seasonal environmental variation impacts immunity more directly in natural animal populations than via resource trade-offs. In addition, immune indices were more often variable within than among individuals, but some indices are characteristic of individuals, and so may offer selective advantages if heritable.
Collapse
Affiliation(s)
- Chima J. Nwaogu
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
- School of BiologyUniversity of St AndrewsSt Andrews FifeUK
- A.P. Leventis Ornithological Research InstituteJosNigeria
| | - Will Cresswell
- School of BiologyUniversity of St AndrewsSt Andrews FifeUK
- A.P. Leventis Ornithological Research InstituteJosNigeria
| | - Maaike A. Versteegh
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - B. Irene Tieleman
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| |
Collapse
|
9
|
Merlo J, Cutrera AP, Zenuto RR. Assessment of Trade-Offs between Simultaneous Immune Challenges in a Slow-Living Subterranean Rodent. Physiol Biochem Zool 2019; 92:92-105. [PMID: 30601103 DOI: 10.1086/701320] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The coexistence of two or more infectious agents in the same host is common in nature. Given this, the study of trade-offs within the immune system itself is key to understanding how immune defenses act in wild species in their natural environment. Here we assessed the possible trade-off between an inflammatory response (induced by phytohemagglutinin [PHA]; involving innate and adaptive responses in the study species) and an antibody response (induced by sheep red blood cells [SRBC]; adaptive response) in a slow-living subterranean rodent, the Talas tuco-tuco (Ctenomys talarum Thomas, 1898). According to life-history theory, slow-living species should rely more heavily on adaptive immunity, which develops more slowly than an innate response but is beneficial against repeated infections. Individual physiological condition (estimated by measuring levels of infection and immune, nutritional, and stress parameters) was analyzed during immune challenges. Contrary to what was expected, we found that the magnitude and energetic costs of both immune responses were similar when stimulated alone or simultaneously. Variation in natural antibodies, neutrophils, basophils, total leukocytes, and the ratio of neutrophils to lymphocytes in relation to the different treatments was also detected. In particular, natural antibodies were negatively affected by the induction of both immune challenges simultaneously and an increase of neutrophil counts was detected in all animals with the exception of those challenged with SRBC, while the pattern of variation of basophils, total leukocytes, and ratio of neutrophils to lymphocytes was not clearly associated with any triggered immune response. In general, our results suggest the absence of an energetic or resource-based trade-off between the immune responses triggered by PHA and SRBC in C. talarum.
Collapse
|
10
|
Hwang J, Kim Y, Lee S, Kim N, Chun M, Lee H, Gottdenker N. Anthropogenic food provisioning and immune phenotype: Association among supplemental food, body condition, and immunological parameters in urban environments. Ecol Evol 2018; 8:3037-3046. [PMID: 29531715 PMCID: PMC5838038 DOI: 10.1002/ece3.3814] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 11/06/2017] [Accepted: 12/11/2017] [Indexed: 11/23/2022] Open
Abstract
Direct or indirect supplemental feeding of free-ranging animals occurs worldwide, resulting in significant impacts on population density or altered demographic processes. Another potential impact of increased energy intake from supplemental feeding is altered immunocompetence. As immune system maintenance is energetically costly, there may be trade-offs between immune responses and other energy-demanding physiological processes in individual animals. Although increased availability of food sources through supplemental feeding is expected to increase the overall immunocompetence of animals, empirical data verifying the association between supplemental feeding and different immune parameters are lacking. Understanding the potential influence of supplemental feeding on immune phenotypes is critical, as it may also impact host-pathogen dynamics in free-ranging animals. Using urban stray cats as a study model, we tested for associations between the intensity of supplemental feeding due to cat caretaker activity (CCA); body condition; and immune phenotype (bacterial killing assay (BKA), immunoglobulin G (IgG) concentration, and leukocyte counts). Significantly higher bacterial killing ability was observed in cats from high CCA districts, whereas higher IgG concentration and eosinophil counts were observed in cats from low CCA districts. Other leukocyte counts and body condition indices showed no significant association with CCA. We observed varying patterns of different immune components in relation to supplemental feeding. Out data suggest that supplemental feeding influences immune phenotype, not only by means of energy provisioning, but also by potentially reducing exposure rates to parasite infections through stray cat behavioral changes.
Collapse
Affiliation(s)
- Jusun Hwang
- Department of Veterinary PathologyCollege of Veterinary MedicineUniversity of GeorgiaAthensGAUSA
- College of Veterinary MedicineSeoul National UniversitySeoulKorea
| | - Yongbaek Kim
- College of Veterinary MedicineSeoul National UniversitySeoulKorea
| | - Sang‐Won Lee
- College of Veterinary MedicineKon‐Kuk UniversitySeoulKorea
| | - Na‐Yon Kim
- College of Veterinary MedicineSeoul National UniversitySeoulKorea
| | - Myung‐Sun Chun
- College of Veterinary MedicineSeoul National UniversitySeoulKorea
| | - Hang Lee
- College of Veterinary MedicineSeoul National UniversitySeoulKorea
| | - Nicole Gottdenker
- Department of Veterinary PathologyCollege of Veterinary MedicineUniversity of GeorgiaAthensGAUSA
| |
Collapse
|
11
|
Austen EJ, Rowe L, Stinchcombe JR, Forrest JRK. Explaining the apparent paradox of persistent selection for early flowering. THE NEW PHYTOLOGIST 2017; 215:929-934. [PMID: 28418161 DOI: 10.1111/nph.14580] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Decades of observation in natural plant populations have revealed pervasive phenotypic selection for early flowering onset. This consistent pattern seems at odds with life-history theory, which predicts stabilizing selection on age and size at reproduction. Why is selection for later flowering rare? Moreover, extensive evidence demonstrates that flowering time can and does evolve. What maintains ongoing directional selection for early flowering? Several non-mutually exclusive processes can help to reconcile the apparent paradox of selection for early flowering. We outline four: selection through other fitness components may counter observed fecundity selection for early flowering; asymmetry in the flowering-time-fitness function may make selection for later flowering hard to detect; flowering time and fitness may be condition-dependent; and selection on flowering duration is largely unaccounted for. In this Viewpoint, we develop these four mechanisms, and highlight areas where further study will improve our understanding of flowering-time evolution.
Collapse
Affiliation(s)
- Emily J Austen
- Biology Department, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Locke Rowe
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S3B2, Canada
| | - John R Stinchcombe
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S3B2, Canada
- Koffler Scientific Reserve at Joker's Hill, University of Toronto, Toronto, ON, L7B 1K5, Canada
| | | |
Collapse
|
12
|
Modelling the influence of host community composition in a sylvatic Trypanosoma cruzi system. Parasitology 2017; 144:1881-1889. [PMID: 28701240 DOI: 10.1017/s0031182017001287] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Species composition of wild reservoir hosts can influence the transmission and maintenance of multi-host vector borne pathogens. The 'pace of life' hypothesis proposes that the life history strategy of reservoir hosts can influence pathogen transmission of vector borne generalist pathogens. We use empirical data to parameterize a mathematical model that investigates the impacts of host life history traits on vector transmission dynamics of the vector-borne multi-host parasite Trypanosoma cruzi in habitats characterized by different degrees of deforestation and varying host community structure. The model considers susceptible and infected vector and host populations. When comparing the proportion of vectors infected with T. cruzi predicted by the model with empirical data, we found a trend of increasing vector infection as anthropogenic landscape disturbance increases for both data and model output. The model's vector infection rates were significantly lower than empirical results, but when incorporating host congenital transmission in the model, vector infection approaches field data. We conclude that intervened habitats associated with r-selected host species communities predict higher proportions of infected vectors.
Collapse
|
13
|
Brodie ED, Janzen FJ. ON THE ASSIGNMENT OF FITNESS VALUES IN STATISTICAL ANALYSES OF SELECTION. Evolution 2017; 50:437-442. [DOI: 10.1111/j.1558-5646.1996.tb04505.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/1994] [Accepted: 11/02/1994] [Indexed: 12/01/2022]
Affiliation(s)
- Edmund D. Brodie
- Center for Ecology, Evolution and Behavior School of Biological Sciences, University of Kentucky Lexington Kentucky 40506‐0225
| | - Fredric J. Janzen
- Department of Zoology and Genetics Iowa State University Ames Iowa 50011
| |
Collapse
|
14
|
Hayes JP, Garland T. THE EVOLUTION OF ENDOTHERMY: TESTING THE AEROBIC CAPACITY MODEL. Evolution 2017; 49:836-847. [PMID: 28564873 DOI: 10.1111/j.1558-5646.1995.tb02320.x] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/1994] [Accepted: 07/27/1994] [Indexed: 11/26/2022]
Abstract
One of the most important events in vertebrate evolution was the acquisition of endothermy, the ability to use metabolic heat production to elevate body temperature above environmental temperature. Several verbal models have been proposed to explain the selective factors leading to the evolution of endothermy. Of these, the aerobic capacity model has received the most attention in recent years. The aerobic capacity model postulates that selection acted mainly to increase maximal aerobic capacity (or associated behavioral abilities) and that elevated resting metabolic rate evolved as a correlated response. Here we evaluate the implicit evolutionary and genetic assumptions of the aerobic capacity model. In light of this evaluation, we assess the utility of phenotypic and genetic correlations for testing the aerobic capacity model. Collectively, the available intraspecific data for terrestrial vertebrates support the notion of a positive phenotypic correlation between resting and maximal rates of oxygen consumption within species. Interspecific analyses provide mixed support for this phenotypic correlation. We argue, however, that assessments of phenotypic or genetic correlations within species and evolutionary correlations among species (from comparative data) are of limited utility, because they may not be able to distinguish between the aerobic capacity model and plausible alternatives, such as selection acting directly on aspects of thermoregulatory abilities. We suggest six sources of information that may help shed light on the selective factors important during the evolution of high aerobic metabolic rates and, ultimately, the attainment of endothermy. Of particular interest will be attempts to determine, using a combination of mechanistic physiological and quantitative-genetic approaches, whether a positive genetic correlation between resting and maximal rates of oxygen consumption is an ineluctable feature of vertebrate physiology.
Collapse
Affiliation(s)
- Jack P Hayes
- Department of Biology, University of Nevada, Reno, Nevada, 89557-0015
| | - Theodore Garland
- Department of Zoology, University of Wisconsin, Madison, Wisconsin, 53706
| |
Collapse
|
15
|
The effect of short-term food restriction on the metabolic cost of the acute phase response in the fish-eating Myotis (Myotis vivesi). Mamm Biol 2017. [DOI: 10.1016/j.mambio.2016.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
16
|
Muriel J, Pérez-Rodríguez L, Ortiz-Santaliestra ME, Puerta M, Gil D. Sex-Specific Effects of High Yolk Androgen Levels on Constitutive and Cell-Mediated Immune Responses in Nestlings of an Altricial Passerine. Physiol Biochem Zool 2017; 90:106-117. [DOI: 10.1086/688445] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
|
17
|
Reynolds RJ, de los Campos G, Egan SP, Ott JR. Modelling heterogeneity among fitness functions using random regression. Methods Ecol Evol 2016; 7:70-79. [PMID: 26949509 PMCID: PMC4776641 DOI: 10.1111/2041-210x.12440] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Summary
Statistical approaches for testing hypotheses of heterogeneity in fitness functions are needed to accommodate studies of phenotypic selection with repeated sampling across study units, populations or years. In this study, we tested directly for among‐population variation in complex fitness functions and demonstrate a new approach for locating the region of the trait distribution where variation in fitness and traits is greatest.
We modelled heterogeneity in fitness functions among populations by treating regression coefficients of fitness on traits as random variates. We applied random regression using two model specifications, (i) spline‐based curve and (ii) stepwise, to a 2‐year study of selection among 16 populations of the gall wasp, Belonocnema treatae. Log‐likelihood ratio tests of variance components and 10‐fold cross‐validation were used to assess the evidence that selection varied among populations.
Ten‐fold cross‐validation prediction error sums of squares (PSS) indicated that spline‐based fitness functions were population specific and that the strength of evidence for heterogeneity in selection differed between years. Hypothesis testing of variance components from both models was consistent with the PSS results. Both the stepwise model and the local prediction error estimates of spline‐based fitness functions identified the region(s) of the phenotype distribution harbouring the greatest heterogeneity among populations.
The adopted framework advances our understanding of phenotypic selection in natural populations by extending the analysis of spline‐based fitness functions to testing for heterogeneity among study units and isolating the regions of the phenotypic distribution where this variation is most pronounced.
Collapse
Affiliation(s)
- Richard J. Reynolds
- Department of Medicine, Division of Clinical Immunology and
Rheumatology, Department of Biostatistics, University of Alabama at Birmingham,
Birmingham, Alabama 35294; (205-975-9300)
| | - Gustavo de los Campos
- Departments of Epidemiology & Biostatistics, and Statistics,
Michigan State University, East Lansing, MI, 48824, (517-353-8623)
| | - Scott P. Egan
- Department of BioSciences, Rice University, Houston, Texas 77005;
(615-618-6601)
| | - James R. Ott
- Population and Conservation Biology Program, Department of Biology,
Texas State University, San Marcos, Texas 78666, (512-245-2321)
| |
Collapse
|
18
|
Young HS, Dirzo R, Helgen KM, McCauley DJ, Nunn CL, Snyder P, Veblen KE, Zhao S, Ezenwa VO. Large wildlife removal drives immune defence increases in rodents. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12542] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hillary S. Young
- University of California Santa Barbara Santa Barbara California 93106 USA
- Division of Mammals National Museum of Natural History Smithsonian Institution Washington District of Columbia 20013 USA
- Mpala Research Centre Box 555 Nanyuki Kenya
| | - Rodolfo Dirzo
- Department of Biology Stanford University Stanford California 94305 USA
| | - Kristofer M. Helgen
- Division of Mammals National Museum of Natural History Smithsonian Institution Washington District of Columbia 20013 USA
| | - Douglas J. McCauley
- University of California Santa Barbara Santa Barbara California 93106 USA
- Mpala Research Centre Box 555 Nanyuki Kenya
| | - Charles L. Nunn
- Department of Evolutionary Anthropology Duke University Durham North Carolina 27708 USA
- Duke Global Health Institute Duke University Durham North Carolina 27708 USA
| | - Paul Snyder
- Odum School of Ecology and Department of Infectious Diseases College of Veterinary Medicine University of Georgia Athens Georgia 30602 USA
- Department of Integrative Biology Oregon State University Corvallis Oregon 97331 USA
| | - Kari E. Veblen
- Mpala Research Centre Box 555 Nanyuki Kenya
- Department of Wildland Resources and Ecology Center Utah State University Logan Utah 84322 USA
| | - Serena Zhao
- Division of Mammals National Museum of Natural History Smithsonian Institution Washington District of Columbia 20013 USA
- Mpala Research Centre Box 555 Nanyuki Kenya
| | - Vanessa O. Ezenwa
- Mpala Research Centre Box 555 Nanyuki Kenya
- Odum School of Ecology and Department of Infectious Diseases College of Veterinary Medicine University of Georgia Athens Georgia 30602 USA
| |
Collapse
|
19
|
Vera-Massieu C, Brock PM, Godínez-Reyes C, Acevedo-Whitehouse K. Activation of an inflammatory response is context-dependent during early development of the California sea lion. ROYAL SOCIETY OPEN SCIENCE 2015; 2:150108. [PMID: 26064646 PMCID: PMC4448862 DOI: 10.1098/rsos.150108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/01/2015] [Indexed: 05/05/2023]
Abstract
Variations in immune function can arise owing to trade-offs, that is, the allocation of limited resources among costly competing physiological functions. Nevertheless, there is little information regarding the ontogeny of the immune system within an ecological context, and it is still unknown whether development affects the way in which resources are allocated to different immune effectors. We investigated changes in the inflammatory response during early development of the California sea lion (Zalophus californianus) and examined its association with body condition, as a proxy for the availability of energetic resources. We found that the relationship between inflammation and body condition varied according to developmental stage and circulating levels of leucocyte populations, a proxy for current infection. Body condition was related to the magnitude of the inflammatory response during two of the three developmental periods assessed, allowing for the possibility that the availability of pup energetic reserves can limit immune function. For older pups, the ability to mount an inflammatory response was related to their circulating levels of neutrophils and the neutrophil to lymphocyte ratio, implying that the infection status of an individual will influence its ability to respond to a new challenge. Our results suggest that trade-offs may occur within the immune system and highlight the importance of taking into account ontogeny in ecoimmunological studies.
Collapse
Affiliation(s)
- Camila Vera-Massieu
- Unit for Basic and Applied Microbiology, School of Natural Sciences, Autonomous University of Queretaro, Avenida de las Ciencias S/N, Queretaro 76230, México
| | - Patrick M. Brock
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Carlos Godínez-Reyes
- Cabo Pulmo National Park, Comisión Nacional de Áreas Naturales Protegidas, SEMARNAT, La Ribera, BCS, Mexico
| | - Karina Acevedo-Whitehouse
- Unit for Basic and Applied Microbiology, School of Natural Sciences, Autonomous University of Queretaro, Avenida de las Ciencias S/N, Queretaro 76230, México
- The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965, USA
- Author for correspondence: Karina Acevedo-Whitehouse e-mail:
| |
Collapse
|
20
|
Kelly CD. Effect of an immune challenge on the functional performance of male weaponry. Behav Processes 2014; 108:197-203. [PMID: 25444779 DOI: 10.1016/j.beproc.2014.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 10/30/2014] [Accepted: 11/01/2014] [Indexed: 01/11/2023]
Abstract
Theories of parasite-mediated sexual selection predict a positive association between immune function and the expression of sexually selected ornaments. Few studies, however, have investigated how an immune challenge affects the performance of sexually selected weaponry. Male Wellington tree weta (Hemideina crassidens) (Orthoptera: Anostostomatidae) possess enlarged mandibles that are used as weapons in fights for access to females residing in tree galleries. Intense sexual competition appears to have favoured the evolution of alternative male mating strategies in this species as males have a trimorphic phenotype in which weapon size varies across morphotype: 8th instar males have the smallest jaws, 10th instar males have the largest and 9th instar males being intermediate to the other two. After injecting males and females with either lipopolysaccharide (LPS; immune challenge) or saline (control) I measured over a 24h period each weta's body mass to assess whether they responded immunologically to the LPS and their bite force to assess the functional performance of their jaws. Both sexes responded immunologically to the immune-challenge as LPS-injected individuals lost significantly more body mass than saline-injected controls with females losing more mass than males. Female bite force was significantly reduced 8h after LPS-injection whereas male bite force did not significantly decline. Both sexes regained pre-injection functional performance of their jaws 24h after the immune challenge. My results suggest that females trade-off bite force for immune function whereas males do not. This article is part of a Special Issue entitled: insert SI title.
Collapse
Affiliation(s)
- Clint D Kelly
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA; Département des Sciences Biologiques, Université du Québec à Montréal, CP-8888 succursale centre-ville, Montréal, QC, Canada H3C 3P8.
| |
Collapse
|
21
|
Ostfeld RS, Levi T, Jolles AE, Martin LB, Hosseini PR, Keesing F. Life history and demographic drivers of reservoir competence for three tick-borne zoonotic pathogens. PLoS One 2014; 9:e107387. [PMID: 25232722 PMCID: PMC4169396 DOI: 10.1371/journal.pone.0107387] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 08/11/2014] [Indexed: 11/19/2022] Open
Abstract
Animal and plant species differ dramatically in their quality as hosts for multi-host pathogens, but the causes of this variation are poorly understood. A group of small mammals, including small rodents and shrews, are among the most competent natural reservoirs for three tick-borne zoonotic pathogens, Borrelia burgdorferi, Babesia microti, and Anaplasma phagocytophilum, in eastern North America. For a group of nine commonly-infected mammals spanning >2 orders of magnitude in body mass, we asked whether life history features or surrogates for (unknown) encounter rates with ticks, predicted reservoir competence for each pathogen. Life history features associated with a fast pace of life generally were positively correlated with reservoir competence. However, a model comparison approach revealed that host population density, as a proxy for encounter rates between hosts and pathogens, generally received more support than did life history features. The specific life history features and the importance of host population density differed somewhat between the different pathogens. We interpret these results as supporting two alternative but non-exclusive hypotheses for why ecologically widespread, synanthropic species are often the most competent reservoirs for multi-host pathogens. First, multi-host pathogens might adapt to those hosts they are most likely to experience, which are likely to be the most abundant and/or frequently bitten by tick vectors. Second, species with fast life histories might allocate less to certain immune defenses, which could increase their reservoir competence. Results suggest that of the host species that might potentially be exposed, those with comparatively high population densities, small bodies, and fast pace of life will often be keystone reservoirs that should be targeted for surveillance or management.
Collapse
Affiliation(s)
- Richard S. Ostfeld
- Cary Institute of Ecosystem Studies, Millbrook, New York, United States of America
- * E-mail:
| | - Taal Levi
- Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, United States of America
| | - Anna E. Jolles
- Departments of Biomedical Sciences and Zoology, Oregon State University, Corvallis, Oregon, United States of America
| | - Lynn B. Martin
- Department of Integrative Biology, University of South Florida, Tampa, Florida, United States of America
| | | | - Felicia Keesing
- Biology Program, Bard College, Annandale-on-Hudson, New York, United States of America
| |
Collapse
|
22
|
Archie EA, Altmann J, Alberts SC. Costs of reproduction in a long-lived female primate: injury risk and wound healing. Behav Ecol Sociobiol 2014; 68:1183-1193. [PMID: 25045201 PMCID: PMC4097819 DOI: 10.1007/s00265-014-1729-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Reproduction is a notoriously costly phase of life, exposing individuals to injury, infectious disease, and energetic tradeoffs. The strength of these costs should be influenced by life history strategies, and in long-lived species, females may be selected to mitigate costs of reproduction because life span is such an important component of their reproductive success. Here we report evidence for two costs of reproduction that may influence survival in wild female baboons-injury risk and delayed wound healing. Based on 29 years of observations in the Amboseli ecosystem, Kenya, we found that wild female baboons experienced the highest risk of injury on days when they were most likely to be ovulating. In addition, lactating females healed from wounds more slowly than pregnant or cycling females, indicating a possible tradeoff between lactation and immune function. We also found variation in injury risk and wound healing with dominance rank and age: older and low-status females were more likely to be injured than younger or high-status females, and older females exhibited slower healing than younger females. Our results support the idea that wild non-human primates experience energetic and immune costs of reproduction, and they help illuminate life history tradeoffs in long-lived species.
Collapse
Affiliation(s)
- Elizabeth A. Archie
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556 USA
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
| | - Jeanne Altmann
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544 USA
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Chiromo Campus, Post Office Box 30197 00100 Nairobi, Kenya
| | - Susan C. Alberts
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
- Department of Biology, Duke University, Durham, NC 27708 USA
| |
Collapse
|
23
|
Kubli SP, MacDougall-Shackleton EA. Developmental Timing of Signals Affects Information Content: Song Complexity but Not Consistency Reflects Innate Immune Strategy in Male Song Sparrows. Am Nat 2014; 183:660-70. [DOI: 10.1086/675757] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
24
|
Meitern R, Sild E, Lind MA, Männiste M, Sepp T, Karu U, Hõrak P. Effects of Endotoxin and Psychological Stress on Redox Physiology, Immunity and Feather Corticosterone in Greenfinches. PLoS One 2013; 8:e67545. [PMID: 23805316 PMCID: PMC3689720 DOI: 10.1371/journal.pone.0067545] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 05/20/2013] [Indexed: 12/24/2022] Open
Abstract
Assessment of costs accompanying activation of immune system and related neuroendocrine pathways is essential for understanding the selective forces operating on these systems. Here we attempted to detect such costs in terms of disruption to redox balance and interference between different immune system components in captive wild-caught greenfinches (Carduelis chloris). Study birds were subjected to an endotoxin-induced inflammatory challenge and temporary exposure to a psychological stressor (an image of a predator) in a 2*2 factorial experiment. Injection of bacterial endotoxin resulted in up-regulation of two markers of antioxidant protection – erythrocyte glutathione, and plasma oxygen radical absorbance (OXY). These findings suggest that inflammatory responses alter redox homeostasis. However, no effect on markers of oxidative damage to proteins or DNA in erythrocytes could be detected. We found no evidence that the endotoxin injection interfered with antibody production against Brucella abortus antigen or the intensity of chronic coccidiosis. The hypothesis of within-immune system trade-offs as a cost of immunity was thus not supported in our model system. We showed for the first time that administration of endotoxin can reduce the level of corticosterone deposited into feathers. This finding suggests a down-regulation of the corticosterone secretion cascade due to an endotoxin-induced immune response, a phenomenon that has not been reported previously. Exposure to the predator image did not affect any of the measured physiological parameters.
Collapse
Affiliation(s)
- Richard Meitern
- Department of Zoology, Institute of Ecology and Earth Sciences, Tartu University, Tartu, Estonia
| | | | | | | | | | | | | |
Collapse
|
25
|
Carter A, DuRant S, Hepp G, Hopkins W. Thermal Challenge Severity Differentially Influences Wound Healing in Wood Duck (Aix sponsa) Ducklings. ACTA ACUST UNITED AC 2013; 319:422-9. [DOI: 10.1002/jez.1805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 12/27/2012] [Accepted: 04/18/2013] [Indexed: 11/09/2022]
Affiliation(s)
- A.W. Carter
- Department of Fish and Wildlife Conservation; Blacksburg; Virginia
| | - S.E. DuRant
- Department of Fish and Wildlife Conservation; Blacksburg; Virginia
| | - G.R. Hepp
- School of Forestry and Wildlife Sciences; Auburn; Alabama
| | - W.A. Hopkins
- Department of Fish and Wildlife Conservation; Blacksburg; Virginia
| |
Collapse
|
26
|
Abad-Gómez JM, Gutiérrez JS, Villegas A, Sánchez-Guzmán JM, Navedo JG, Masero JA. Time course and metabolic costs of a humoral immune response in the little ringed plover Charadrius dubius. Physiol Biochem Zool 2013; 86:354-60. [PMID: 23629885 DOI: 10.1086/670733] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Despite host defense against parasites and pathogens being considered a costly life-history trait, relatively few studies have assessed the energetic cost of immune responsiveness. Knowledge of such energetic costs may help to understand the mechanisms by which trade-offs with other demanding activities occur. The time course and associated metabolic costs of mounting a primary and secondary humoral immune response was examined in little ringed plovers Charadrius dubius challenged with sheep red blood cells. As was expected, the injection with this antigen increased the production of specific antibodies significantly, with peaks 6 d postinjection in both primary and secondary responses. At the peak of secondary antibody response, the antibody production was 29% higher than that observed during the primary response, but the difference was nonsignificant. Mounting the primary response did not significantly increase the resting metabolic rate (RMR) of birds, whereas the secondary response did by 21%, suggesting that the latter was more costly in terms of RMR. In spite of the fact that the primary response did not involve an increase in RMR, birds significantly decreased their body mass. This could imply an internal energy reallocation strategy to cope with the induced immune challenge. Last, we found that RMR and antibody production peaks were not coupled, which could help to conciliate the variable results of previous studies. Collectively, the results of this study support the hypothesis that humoral immunity, especially the secondary response, entails energetic costs that may trade-off with other physiological activities.
Collapse
Affiliation(s)
- José M Abad-Gómez
- Conservation Biology Research Group, Zoology, University of Extremadura, Badajoz, Spain.
| | | | | | | | | | | |
Collapse
|
27
|
Thomason C, Hedrick-Hopper T, Derting T. Social and nutritional stressors: agents for altered immune function in white-footed mice (Peromyscus leucopus). CAN J ZOOL 2013. [DOI: 10.1139/cjz-2012-0319] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
As habitats become more fragmented, population densities and diets of wildlife can change dramatically, contributing to increased stress and incidence of infections and disease. To better understand effects of human disturbance on immunocompetence of wild mammals, we studied individual and combined effects of social and nutritional stress on the health of wild-captured adult male white-footed mice (Peromyscus leucopus (Rafinesque, 1818)), a species that commonly occurs in close proximity to humans. Paired mice had reduced body mass and circulating monocytes, higher serum corticosterone level, and a significantly weaker humoral immune response compared with mice housed individually. Mice fed a 5% protein diet had reduced body mass and circulating monocytes, but no differences in humoral or cellular immune responses compared with mice fed a 30% protein diet. The only interactive effect of the two stresses on immune-related parameters was on mass of the spleen. We hypothesize that reduced humoral immunocompetence in response to acute and chronic social stress likely contributes to increases in disease transmission in high-density populations associated with fragments of habitat. In addition, anthropogenic impacts that limit food availability may be of greater importance to immune function than impacts on food quality.
Collapse
Affiliation(s)
- C.A. Thomason
- Department of Biological Sciences, Murray State University, Murray, KY 42071, USA
| | - T.L. Hedrick-Hopper
- Department of Biological Sciences, Murray State University, Murray, KY 42071, USA
| | - T.L. Derting
- Department of Biological Sciences, Murray State University, Murray, KY 42071, USA
| |
Collapse
|
28
|
Carmona D, Fornoni J. Herbivores can select for mixed defensive strategies in plants. THE NEW PHYTOLOGIST 2013; 197:576-585. [PMID: 23171270 DOI: 10.1111/nph.12023] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 10/01/2012] [Indexed: 06/01/2023]
Abstract
Resistance and tolerance are the most important defense mechanisms against herbivores. Initial theoretical studies considered both mechanisms functionally redundant, but more recent empirical studies suggest that these mechanisms may complement each other, favoring the presence of mixed defense patterns. However, the expectation of redundancy between tolerance and resistance remains unsupported. In this study, we tested this assumption following an ecological genetics field experiment in which the presence/absence of two herbivores (Lema daturaphila and Epitrix parvula) of Datura stramonium were manipulated. In each of three treatments, genotypic selection analyses were performed and selection patterns compared. Our results indicated that selection on resistance and tolerance was significantly different between the two folivores. Tolerance and resistance are not redundant defense strategies in D. stramonium but instead functioned as complementary defenses against both beetle species, favoring the evolution of a mixed defense strategy. Although each herbivore was selected for different defense strategies, the observed average tolerance and resistance were closer to the adaptive peak predicted against E. parvula and both beetles together. In our experimental population, natural selection imposed by herbivores can favor the evolution of mixed defense strategies in plants, accounting for the presence of intermediate levels of tolerance and resistance.
Collapse
Affiliation(s)
- Diego Carmona
- Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, México, Distrito Federal, 04510, México
| | - Juan Fornoni
- Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, México, Distrito Federal, 04510, México
| |
Collapse
|
29
|
Schulte-Hostedde AI, Bowman J, Nituch LA. Dynamic spleen mass in wild and domestic American mink. Biol J Linn Soc Lond 2012. [DOI: 10.1111/j.1095-8312.2012.01961.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
| | - Jeff Bowman
- Ontario Ministry of Natural Resources; Trent University; DNA Building 2140 East Bank Drive Peterborough ON Canada K9J 7B8
| | - Larissa A. Nituch
- Ontario Ministry of Natural Resources; Trent University; DNA Building 2140 East Bank Drive Peterborough ON Canada K9J 7B8
| |
Collapse
|
30
|
Abstract
Social status can have striking effects on health in humans and other animals, but the causes often are unknown. In male vertebrates, status-related differences in health may be influenced by correlates of male social status that suppress immune responses. Immunosuppressive correlates of low social status may include chronic social stress, poor physical condition, and old age; the immunosuppressive correlates of high status may include high testosterone and energetic costs of reproduction. Here we test whether these correlates could create status-related differences in immune function by measuring the incidence of illness and injury and then examining healing rates in a 27-y data set of natural injuries and illnesses in wild baboon males. We found no evidence that the high testosterone and intense reproductive effort associated with high rank suppress immune responses. Instead, high-ranking males were less likely to become ill, and they recovered more quickly than low-ranking males, even controlling for differences in age. Notably, alpha males, who experience high glucocorticoids, as well as the highest testosterone and reproductive effort, healed significantly faster than other males, even other high-ranking males. We discuss why alpha males seem to escape from the immunosuppressive costs of glucocorticoids but low-ranking males do not, including the idea that glucocorticoids' effects depend on an individual's physiological and social context.
Collapse
Affiliation(s)
- Elizabeth A. Archie
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556
| | - Jeanne Altmann
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Chiromo Campus, Nairobi, Kenya; and
| | - Susan C. Alberts
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
- Department of Biology, Duke University, Durham, NC 27708
| |
Collapse
|
31
|
Schwanz LE, Previtali MA, Gomes-Solecki M, Brisson D, Ostfeld RS. Immunochallenge reduces risk sensitivity during foraging in white-footed mice. Anim Behav 2012. [DOI: 10.1016/j.anbehav.2011.10.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
32
|
Palacios MG, Cunnick JE, Winkler DW, Vleck CM. Interrelations among immune defense indexes reflect major components of the immune system in a free-living vertebrate. Physiol Biochem Zool 2011; 85:1-10. [PMID: 22237284 DOI: 10.1086/663311] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Understanding the relationships among immune components in free-living animals is a challenge in ecoimmunology, and it is important not only for selecting the immune assays to be used but also for more knowledgeable interpretation of results. In this study, we investigated the relationships among six immune defense indexes commonly used by ecoimmunologists and measured simultaneously in individual free-living tree swallows. Three main axes of variation in immune function were identified using a principal components analysis, representing variation in T-cell, B-cell, and innate immunity. Measures within each axis tended to be positively correlated among individuals, while measures in different axes were uncorrelated. A trade-off between T-cell function and B-cell function became apparent only when variation among individuals in body condition, age, and general quality was taken into account. Interestingly, the level of natural antibodies, a component of innate immunity, showed the strongest association with components of acquired B-cell function, possibly reflecting a common underlying genetic mechanism, as has been documented in poultry. Our results indicate that despite the complexity of the immune system, important insights can be gained by using the currently available assays but in a more comprehensive approach than has generally been used in the field of ecoimmunology.
Collapse
Affiliation(s)
- Maria G Palacios
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011, USA.
| | | | | | | |
Collapse
|
33
|
Clairardin SG, Barnett CA, Sakaluk SK, Thompson CF. Experimentally increased in ovo testosterone leads to increased plasma bactericidal activity and decreased cutaneous immune response in nestling house wrens. J Exp Biol 2011; 214:2778-82. [DOI: 10.1242/jeb.054833] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
SUMMARY
Maternally derived testosterone in the eggs of birds may benefit nestlings by increasing various aspects of their growth, condition and behavioral development, but these benefits may come at a cost, including suppression of immune responsiveness. Experiments on a variety of species in which in ovo levels of testosterone have been experimentally increased have produced mixed results; some have found increased growth and suppressed immune function of nestlings whereas others have found the opposite. In an attempt to clarify the relationship between in ovo testosterone and nestling size, mass, health state and immune responsiveness, we experimentally increased levels of testosterone in the eggs of house wrens (Troglodytes aedon). We simultaneously determined the size, mass, hematocrit (a measure of health state), cutaneous immune response to phytohaemagglutinin and plasma bactericidal activity of nestlings near the time of fledging. We predicted that nestlings hatching from testosterone-injected eggs would exhibit lower immune responsiveness, but achieve greater mass, size and condition, than nestlings hatching from vehicle-injected control eggs. Instead, we found that nestlings hatching from testosterone-injected eggs had a weaker cutaneous immune response but greater bactericidal activity than those hatching from control eggs. They did not, however, differ significantly in mass, size or hematocrit from controls. These results suggest that experimentally increased in ovo testosterone induced a trade-off between bactericidal activity and the cutaneous immune response. The opposite responses by two different measures of immune function to experimentally increased in ovo testosterone underscore the importance of including multiple immune assays when investigating the potential for trade-offs with the immune system and other physiological functions.
Collapse
Affiliation(s)
- Sandrine G. Clairardin
- Behavior, Ecology, Evolution, and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA
| | - Craig A. Barnett
- Behavior, Ecology, Evolution, and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA
| | - Scott K. Sakaluk
- Behavior, Ecology, Evolution, and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA
| | - Charles F. Thompson
- Behavior, Ecology, Evolution, and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA
| |
Collapse
|
34
|
Schulte-Hostedde AI, Elsasser SC. Spleen mass, body condition, and parasite load in male American mink (Neovison vison). J Mammal 2011. [DOI: 10.1644/10-mamm-a-020.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
|
35
|
Salvador AR, Guivier E, Xuéreb A, Chaval Y, Cadet P, Poulle ML, Sironen T, Voutilainen L, Henttonen H, Cosson JF, Charbonnel N. Concomitant influence of helminth infection and landscape on the distribution of Puumala hantavirus in its reservoir, Myodes glareolus. BMC Microbiol 2011; 11:30. [PMID: 21303497 PMCID: PMC3040693 DOI: 10.1186/1471-2180-11-30] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Accepted: 02/08/2011] [Indexed: 12/22/2022] Open
Abstract
Background Puumala virus, the agent of nephropathia epidemica (NE), is the most prevalent hantavirus in Europe. The risk for human infection seems to be strongly correlated with the prevalence of Puumala virus (PUUV) in populations of its reservoir host species, the bank vole Myodes glareolus. In humans, the infection risks of major viral diseases are affected by the presence of helminth infections. We therefore proposed to analyse the influence of both helminth community and landscape on the prevalence of PUUV among bank vole populations in the Ardennes, a PUUV endemic area in France. Results Among the 313 voles analysed, 37 had anti-PUUV antibodies. Twelve gastro-intestinal helminth species were recorded among all voles sampled. We showed that PUUV seroprevalence strongly increased with age or sexual maturity, especially in the northern forests (massif des Ardennes). The helminth community structure significantly differed between this part and the woods or hedgerows of the southern cretes pre-ardennaises. Using PUUV RNA quantification, we identified significant coinfections between PUUV and gastro-intestinal helminths in the northern forests only. More specifically, PUUV infection was positively associated with the presence of Heligmosomum mixtum, and in a lesser extent, Aonchotheca muris-sylvatici. The viral load of PUUV infected individuals tended to be higher in voles coinfected with H. mixtum. It was significantly lower in voles coinfected with A. muris-sylvatici, reflecting the influence of age on these latter infections. Conclusions This is the first study to emphasize hantavirus - helminth coinfections in natural populations. It also highlights the importance to consider landscape when searching for such associations. We have shown that landscape characteristics strongly influence helminth community structure as well as PUUV distribution. False associations might therefore be evidenced if geographic patterns of helminths or PUUV repartition are not previously identified. Moreover, our work revealed that interactions between helminths and landscape enhance/deplete the occurrence of coinfections between PUUV and H. mixtum or A. muris-sylvatici. Further experimental analyses and long-term individual surveys are now required to confirm these correlative results, and to ascertain the causal links between helminth and PUUV infection risks.
Collapse
Affiliation(s)
- Alexis Ribas Salvador
- Laboratori de Parasitologia, Departament de Microbiologia i Parasitologia Sanitaries, Facultat de Farmacia, Universitat de Barcelona, Barcelona, Spain
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Cucco M, Pellegrino I, Malacarne G. Immune challenge affects female condition and egg size in the grey partridge. ACTA ACUST UNITED AC 2011; 313:597-604. [PMID: 20665708 DOI: 10.1002/jez.635] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
As maintenance of the immune system is energetically costly and resource-limited, trade-offs among immune function, body condition, and reproductive allocation are expected. In this study, we experimentally test the possible trade-off between immune response, self maintenance, and reproductive output in breeding grey partridges Perdix perdix. Before laying, half the females were immune challenged with a novel antigen vaccine (Newcastle disease virus, NDV). The challenged females showed a higher erythrosedimentation rate, a serum parameter related to worsened health conditions, but their cell-mediated immune reaction (PHA test) did not differ from that of controls. The NDV-treated females laid smaller eggs (mass, length, and breadth), while the concentrations of antibacterial substances (lysozyme and avidin, two enzymes that confer innate antibacterial immunity) were unrelated to the hen's immune challenge. Our study suggests that an immune challenge can have physiological consequences in terms of self-maintenance and reproductive allocation to the egg.
Collapse
Affiliation(s)
- Marco Cucco
- University of Piemonte Orientale, DiSAV, Alessandria, Italy.
| | | | | |
Collapse
|
37
|
Schwanz LE, Voordouw MJ, Brisson D, Ostfeld RS. Borrelia burgdorferiHas Minimal Impact on the Lyme Disease Reservoir HostPeromyscus leucopus. Vector Borne Zoonotic Dis 2011; 11:117-24. [DOI: 10.1089/vbz.2009.0215] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Maarten J. Voordouw
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Dustin Brisson
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania
| | | |
Collapse
|
38
|
Affiliation(s)
- Raoul K. Boughton
- Avian Ecology, Archbold Biological Station, 123 Main Drive, Venus, Florida, USA
| | - Gerrit Joop
- Institute of Integrative Biology,
Experimental Ecology, ETH Zürich, CH‐8092 Zürich, Switzerland
| | - Sophie A.O. Armitage
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, D‐48149 Münster, Germany
| |
Collapse
|
39
|
Schwanz LE, Brisson D, Gomes-Solecki M, Ostfeld RS. Linking disease and community ecology through behavioural indicators: immunochallenge of white-footed mice and its ecological impacts. J Anim Ecol 2011; 80:204-14. [PMID: 20796206 PMCID: PMC10056715 DOI: 10.1111/j.1365-2656.2010.01745.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. Pathogens and immune challenges can induce changes in host phenotype in ways that indirectly impact important community interactions, including those that affect host-pathogen interactions. 2. To explore host behavioural response to immune challenge, we exposed wild white-footed mice (Peromyscus leucopus) to an immunogen from an endemic, zoonotic pathogen, the spirochete Borrelia burgdorferi. White-footed mice are a major reservoir host of Lyme disease (LD) spirochetes in northeastern USA and an abundant member of forest communities. The activity patterns, foraging behaviour, and space use of white-footed mice have implications for population growth rates of community members upon which mice incidentally prey (i.e. gypsy moths and native thrushes), as well as potentially determining host-vector encounter rates and human risk of LD. 3. Immunochallenge led to specific humoral (antibody) and cellular (i.e. elevated neutrophils and eosinophils) immune responses, supporting use of the immunogen as a surrogate for pathogenic infection. 4. Immunochallenged mice had reduced wheel-running activity early in the night when measured in the lab. However, mouse activity, as measured by track plates in natural field experiments, did not differ between mice exposed to the immunogen and unexposed mice. 5. Foraging behaviour of wild mice in the field - assessed with giving-up densities of seed at artificial feeding stations - was affected by exposure to the immunogen. Whereas immunochallenge did not influence whether foraging mice gained information on patch quality while foraging, it led to reductions in predator avoidance during foraging, suggesting that the proportion of space used by foraging mice may be greater as a result of immunochallenge. This increased space use is predicted to increase encounter rates with patchily distributed LD vectors (ticks) and with incidental prey items. 6. Thus, immunochallenge in white-footed mice, and potentially pathogenic infection, have the potential to indirectly impact community interactions, including those important for pathogen transmission.
Collapse
Affiliation(s)
- Lisa E Schwanz
- Cary Institute of Ecosystem Studies, PO Box AB, Millbrook, NY 12545, USA.
| | | | | | | |
Collapse
|
40
|
Bourgeon S, Kauffmann M, Geiger S, Raclot T, Robin JP. Relationships between metabolic status, corticosterone secretion and maintenance of innate and adaptive humoral immunities in fasted re-fed mallards. J Exp Biol 2010; 213:3810-8. [DOI: 10.1242/jeb.045484] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
The prolonged exposure of birds to environmental stressors known to affect energy status and glucocorticoid secretion may have several physiological consequences including a decrease in immunocompetence, further compromising the survival of individuals. However, the relationships between these parameters remain poorly understood. To this end, changes in body energy content, plasma corticosterone, adaptive (total plasma immunoglobulin Y; IgY) and innate (natural antibodies; NAbs) immune systems were assessed in female mallards (Anas plathyrhynchos) throughout prolonged fasts of different intensities and subsequent re-feeding. Plasma IgY and NAb scores were decreased by 36% and 50%, respectively, during phase II of fasting (protein-sparing phase) and by up to 40% and 80%, respectively, during phase III (protein-wasting phase), indicating a selective regulation of immune function. These results are consistent with the hypothesis of a trade-off between immune function and other energy-demanding activities. However, despite full repletion of fuel reserves and NAbs, only 76% of initial IgY levels were recovered, further supporting a trade-off between innate and adaptive branches of immunity. Although fasting induced significant increases in corticosterone levels to up to 6 times higher than baseline levels during phase III, baseline levels were recovered within 1 day of re-feeding. Our data do not support the hypothesis of a direct regulation of immunocompetence by corticosterone, at least during periods of energy repletion. Finally, the mismatch between the kinetics of body fuels and the two arms of the immune system during fasting and re-feeding suggests that variations in immune system components do not strictly covary with body mass under fluctuating food conditions.
Collapse
Affiliation(s)
- Sophie Bourgeon
- Norwegian Institute for Nature Research (NINA), The Polar Environmental Centre, NO-9296, Tromsø, Norway
| | - Marion Kauffmann
- Université de Strasbourg, IPHC, 23 rue Becquerel, 67087 Strasbourg, France
- CNRS, UMR7178, 67037 Strasbourg, France
| | - Sylvie Geiger
- Université de Strasbourg, IPHC, 23 rue Becquerel, 67087 Strasbourg, France
- CNRS, UMR7178, 67037 Strasbourg, France
| | - Thierry Raclot
- Université de Strasbourg, IPHC, 23 rue Becquerel, 67087 Strasbourg, France
- CNRS, UMR7178, 67037 Strasbourg, France
| | - Jean-Patrice Robin
- Université de Strasbourg, IPHC, 23 rue Becquerel, 67087 Strasbourg, France
- CNRS, UMR7178, 67037 Strasbourg, France
| |
Collapse
|
41
|
Tobler M, Hasselquist D, Smith HG, Sandell MI. Short- and long-term consequences of prenatal testosterone for immune function: an experimental study in the zebra finch. Behav Ecol Sociobiol 2009. [DOI: 10.1007/s00265-009-0889-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
42
|
Gasparini J, Piault R, Bize P, Roulin A. Synergistic and antagonistic interaction between different branches of the immune system is related to melanin-based coloration in nestling tawny owls. J Evol Biol 2009; 22:2348-53. [PMID: 19796085 DOI: 10.1111/j.1420-9101.2009.01831.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
When exposed to parasites, hosts often mount energetically expensive immune responses, and this may alter resource allocation between competing life history traits including other components of the immune system. Here, we investigated whether a humoral immune challenge towards a vaccine reduces or enhances the cutaneous immune responses towards an injection of lipopolysaccharid (LPS, innate immunity) and phytohaemagglutinin (PHA, T-cell immunity) in nestling tawny owls in interaction with the degree of plumage melanin-based coloration. The humoral immune challenge enhanced the response to LPS similarly in differently coloured nestlings. In contrast, the same humoral immune challenge enhanced immune response to PHA in dark reddish melanic nestlings while reducing it in pale reddish melanic nestlings. Our results highlight that both antagonistic and synergistic interactions can take place among branches of immune system, and that the sign and magnitude of these interactions can vary with immune responses involved and the degree of melanin-based coloration.
Collapse
Affiliation(s)
- J Gasparini
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
| | | | | | | |
Collapse
|
43
|
Armbruster WS, Pélabon C, Hansen TF, Bolstad GH. Macroevolutionary patterns of pollination accuracy: a comparison of three genera. THE NEW PHYTOLOGIST 2009; 183:600-617. [PMID: 19594697 DOI: 10.1111/j.1469-8137.2009.02930.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We hypothesize that pollination efficiency selects for equal distances between the pollinator reward and the anthers, and the stigmas, creating an adaptive ridge. We predict that this fitness surface governs the divergence of many plant species. We use the theory of adaptive accuracy, precision and mean optimality to assess how close populations lie to the hypothesized adaptive ridge and which factors contribute to departure from the optimum. Patterns of accuracy of pollen placement and receipt were compared across species in three study systems, Dalechampia (Euphorbiaceae), Collinsieae (Plantaginaceae) and Stylidium (Stylidiaceae), in order to assess the roles of stamen/stigma imprecision and population mean departure from the optimum in the generation of floral inaccuracy. We found that population mean departure from the optimum was the most important factor in Dalechampia, female imprecision and departure from the optimum were about equally important factors in Collinsieae, and stamen and stigma imprecision were equally important in Stylidium, with virtually no departure from the optimum. Possible reasons for imprecision and departure from the optimum were assessed using phylogenetically informed methods, indicating important roles of limited floral integration in the generation of imprecision, and conflicting selective pressures, associated with outcrossing, in the generation of departure from the optimum.
Collapse
Affiliation(s)
- W Scott Armbruster
- School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK
- Department of Biology, NTNU, N-7491, Trondheim, Norway
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA
| | - Christophe Pélabon
- Centre for Conservation Biology, Department of Biology, NTNU, N-7491, Trondheim, Norway
| | - Thomas F Hansen
- Centre for Ecological and Evolutionary Synthesis, Department of Biology, University of Oslo, PO Box 1066, N-0316 Oslo, Norway
| | - Geir H Bolstad
- Centre for Conservation Biology, Department of Biology, NTNU, N-7491, Trondheim, Norway
| |
Collapse
|
44
|
Arriero E. Rearing environment effects on immune defence in blue tit Cyanistes caeruleus nestlings. Oecologia 2009; 159:697-704. [DOI: 10.1007/s00442-008-1253-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 11/26/2008] [Indexed: 11/24/2022]
|
45
|
Humoral immune response suppresses reproductive physiology in male Brandt's voles (Lasiopodomys brandtii). ZOOLOGY 2008; 112:69-75. [PMID: 19041232 DOI: 10.1016/j.zool.2008.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 02/15/2008] [Accepted: 04/09/2008] [Indexed: 11/21/2022]
Abstract
In order to evaluate the potential costs of humoral immune response, which is important for survival in small wild mammals, we studied the physiological function of adult male Brandt's voles (Lasiopodomys brandtii) challenged with human immunoglobulin G (IgG). Compared with controls, the immunochallenged voles showed significantly higher antibody levels 15 days after injection. Serum testosterone levels, and mass of testes and epididymides were lower in immunochallenged voles than in control animals. Body mass remained stable during the course of the experiment. Total and digestible energy intake showed a transient decrease following IgG injection, while resting metabolic rate (RMR) increased. Taken together, these data suggest a shift in metabolic priorities in response to immune challenge. Our results provide evidence that mounting a humoral immune response to an immunological challenge may have fitness costs in male Brandt's voles.
Collapse
|
46
|
Roosting ecology and variation in adaptive and innate immune system function in the Brazilian free-tailed bat (Tadarida brasiliensis). J Comp Physiol B 2008; 179:315-23. [PMID: 19002470 PMCID: PMC7087743 DOI: 10.1007/s00360-008-0315-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 10/12/2008] [Accepted: 10/14/2008] [Indexed: 11/24/2022]
Abstract
Bats have recently been implicated as reservoirs of important emerging diseases. However, few studies have examined immune responses in bats, and even fewer have evaluated these responses in an ecological context. We examined aspects of both innate and adaptive immune response in adult female Brazilian free-tailed bats (Tadarida brasiliensis) at four maternity roosts (two natural caves and two human-made bridges) in south-central Texas. Immune measurements included in vitro bactericidal ability of whole blood and in vivo T cell mediated response to mitogenic challenge. Bactericidal activity in T. brasiliensis varied with roosting ecology, but appears to be sensitive to colony-level effects. Blood from females living at one cave had significantly lower bactericidal ability than blood from females at three other sites. T cell mediated response in this species was associated with variation in roost ecology, with females from two caves having greater responses than females from two bridges. T cell mediated response and bactericidal activity were negatively correlated with one another within individuals that were tested for both. Variation in immunological response of T. brasiliensis is important for understanding the influence of the environment on the frequency and distribution of immunologically competent individuals and for understanding disease-host dynamics in this and other colonial species.
Collapse
|
47
|
Calsbeek R, Bonneaud C, Smith TB. Differential fitness effects of immunocompetence and neighbourhood density in alternative female lizard morphs. J Anim Ecol 2008; 77:103-9. [PMID: 18177330 DOI: 10.1111/j.1365-2656.2007.01320.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. A growing number of studies demonstrate that natural selection acts on traits important in whole animal performance and physiology. 2. Here we describe a heritable polymorphism in female dorsal pattern in the lizard Anolis sagrei (Dumeril & Bibron 1837). 3. Morphs did not differ in body size or habitat use (perch diameter), however, we show that the social environment, estimated by the number of female neighbours, had different selective effects on alternative morphs in nature. 4. We show that morphs displayed a significantly different immune response to phytohaemagglutinin. Furthermore, natural selection differentially acted on combinations of female morph and immunocompetence, favouring high levels of immune function in one morph and low levels of immune function in the other. 5. We discuss the possibility that morph-specific investments in life-history traits may lead to correlational selection between traits, even when those traits are likely to be determined by different genetic loci.
Collapse
Affiliation(s)
- Ryan Calsbeek
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA.
| | | | | |
Collapse
|
48
|
Forsman AM, Vogel LA, Sakaluk SK, Grindstaff JL, Thompson CF. Immune-challenged house wren broods differ in the relative strengths of their responses among different axes of the immune system. J Evol Biol 2008; 21:873-8. [PMID: 18298497 DOI: 10.1111/j.1420-9101.2008.01503.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Single components of the immune system are widely used to assess immune function in free-living vertebrates. However, as different immunological components are triggered by different types of threats and may be regulated independently, there is little reason to assume that they should respond similarly if challenged. We investigated whether three commonly assayed immune responses, cutaneous immune activity (phytohaemagglutinin assay), antibody response (tetanus toxoid immunization), and plasma bactericidal activity (Escherichia coli killing) are positively related in nestling house wrens (Troglodytes aedon). Multivariate analysis revealed significant differences in overall immune responsiveness among broods (i.e. nests), primarily attributable to differences in plasma bactericidal activity. Among broods, humoral immune response was negatively related to cutaneous immune activity and positively related to plasma bactericidal activity. We found no significant relationships among these measures of immunity among individual nestlings within broods. Our results suggest that different broods (i.e. families) invest differentially in the various branches of the immune system. Further study is needed to characterize the roles of maternal, genetic and environmental effects on the expression of this physiological bias.
Collapse
Affiliation(s)
- A M Forsman
- Department of Biological Sciences, Illinois State University, Normal, IL, USA.
| | | | | | | | | |
Collapse
|
49
|
Martin LB, Weil ZM, Nelson RJ. Seasonal changes in vertebrate immune activity: mediation by physiological trade-offs. Philos Trans R Soc Lond B Biol Sci 2008; 363:321-39. [PMID: 17638690 PMCID: PMC2606753 DOI: 10.1098/rstb.2007.2142] [Citation(s) in RCA: 367] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Animals living in temporally dynamic environments experience variation in resource availability, climate and threat of infection over the course of the year. Thus, to survive and reproduce successfully, these organisms must allocate resources among competing physiological systems in such a way as to maximize fitness in changing environments. Here, we review evidence supporting the hypothesis that physiological trade-offs, particularly those between the reproductive and immune systems, mediate part of the seasonal changes detected in the immune defences of many vertebrates. Abundant recent work has detected significant energetic and nutritional costs of immune defence. Sometimes these physiological costs are sufficiently large to affect fitness (e.g. reproductive output, growth or survival), indicating that selection for appropriate allocation strategies probably occurred in the past. Because hormones often orchestrate allocations among physiological systems, the endocrine mediators of seasonal changes in immune activity are discussed. Many hormones, including melatonin, glucocorticoids and androgens have extensive and consistent effects on the immune system, and they change in systematic fashions over the year. Finally, a modified framework within which to conduct future studies in ecological immunology is proposed, viz. a heightened appreciation of the complex but intelligible nature of the vertebrate immune system. Although other factors besides trade-offs undoubtedly influence seasonal variation in immune defence in animals, a growing literature supports a role for physiological trade-offs and the fitness consequences they sometimes produce.
Collapse
Affiliation(s)
- Lynn B Martin
- Departments of Psychology and Neuroscience, The Ohio State University, Columbus, OH 43210, USA.
| | | | | |
Collapse
|
50
|
Abstract
Immune activity is variable within and among vertebrates despite the potentially large fitness costs of pathogens to their hosts. From the perspective of life history theory, immunological variability may be the consequence of counterbalancing investments in immune defense against other expensive physiological processes, namely, reproduction. In the present study, we tested the hypothesis that immune defense among captive-bred, disease-free Peromyscus mice would be influenced by their reproductive life history strategies. Specifically, we expected that small species that reproduce prolifically and mature rapidly (i.e., fast pace of life) would favor inexpensive, nonspecific immune defenses to promote reproductive proclivity. Alternatively, we expected that large species that mature slowly and invest modestly in reproduction over multiple events (i.e., slow pace of life) would favor developmentally expensive, specific immune defenses and avoid cheap, nonspecific ones because such defenses are predisposed to self-damage. We found that species exhibited either strong ability to kill (gram-negative) bacteria, a developmentally inexpensive defense, or strong ability to produce antibodies against a novel protein, a developmentally expensive defense, but not both. Cell-mediated inflammation also varied significantly among species, but in a unique fashion relative to bacteria killing or antibody production; wound healing was comparatively similar among species. These results indicate that Peromyscus species use immune strategies that are constrained to a dominant axis, but this axis is not determined solely by reproductive pace of life. Further comparisons, ideally with broader phylogenetic coverage, could identify what ecological and evolutionary forces produce the pattern we detected. Importantly, our study indicates that species may not be differentially immunocompetent; rather, they use unique defense strategies to prevent infection.
Collapse
Affiliation(s)
- Lynn B Martin
- Department of Psychology, Ohio State University, Columbus, Ohio 43210, USA.
| | | | | |
Collapse
|