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Sauer EL, Connelly C, Perrine W, Love AC, DuRant SE. Male pathology regardless of behaviour drives transmission in an avian host-pathogen system. J Anim Ecol 2024; 93:36-44. [PMID: 38044497 DOI: 10.1111/1365-2656.14026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 10/04/2023] [Indexed: 12/05/2023]
Abstract
Host sex is an important source of heterogeneity in the severity of epidemics. Pinpointing the mechanisms causing this heterogeneity can be difficult because differences in behaviour among sexes (e.g. greater territorial aggression in males) can bias exposure risk, obfuscating the role of immune function, which can lead to differences in pathology, in driving differential susceptibility between sexes. Thus, sex-biased transmission driven by differences in immune function independent of behaviour is poorly understood, especially in non-mammalian systems. Here we examine the previously unexplored potential for male-biased pathology to affect transmission using an avian host-pathogen system. We employ a sex-dependent multistate transmission model parameterized with isolated, individual-based experimental exposures of domestic canaries and experimental transmission data of house finches. The experiment revealed that male birds have shorter incubation periods, longer recovery periods, higher pathogen burdens and greater disease pathology than females. Our model revealed that male-biased pathology led to epidemic size rapidly increasing with the proportion of male birds, with a nearly 10-fold increase in total epidemic size from an all-female to an all-male simulation. Our results demonstrate that female-biased resistance, independent of male behaviour, can drive sex-dependent transmission in wildlife, indicating that sex-based differences in immune function, not just differences in exposure risk, can shape epidemic dynamics.
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Affiliation(s)
- Erin L Sauer
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Chloe Connelly
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Weston Perrine
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
| | - Ashely C Love
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
- Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Sarah E DuRant
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
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Smyth KN, Caruso NM, Davies CS, Clutton-Brock TH, Drea CM. Social and endocrine correlates of immune function in meerkats: implications for the immunocompetence handicap hypothesis. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180435. [PMID: 30225031 PMCID: PMC6124081 DOI: 10.1098/rsos.180435] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/25/2018] [Indexed: 06/08/2023]
Abstract
Social status can mediate effects on the immune system, with profound consequences for individual health; nevertheless, most investigators of status-related disparities in free-ranging animals have used faecal parasite burdens to proxy immune function in the males of male-dominant species. We instead use direct measures of innate immune function (complement and natural antibodies) to examine status-related immunocompetence in both sexes of a female-dominant species. The meerkat is a unique model for such a study because it is a cooperatively breeding species in which status-related differences are extreme, evident in reproductive skew, morphology, behaviour, communication and physiology, including that dominant females naturally express the greatest total androgen (androstenedione plus testosterone) concentrations. We found that, relative to subordinates, dominant animals had reduced serum bacteria-killing abilities; also, relative to subordinate females, dominant females had reduced haemolytic complement activities. Irrespective of an individual's sex or social status, androstenedione concentrations (but not body condition, age or reproductive activity) negatively predicted concurrent immunocompetence. Thus, dominant meerkats of both sexes are immunocompromised. Moreover, in female meerkats, androstenedione perhaps acting directly or via local conversion, may exert a double-edged effect of promoting dominance and reproductive success at the cost of increased parasitism and reduced immune function. Given the prominent signalling of dominance in female meerkats, these findings may relate to the immunocompetence handicap hypothesis (ICHH); however, our data would suggest that the endocrine mechanism underlying the ICHH need not be mediated solely by testosterone and might explain trade-offs in females, as well as in males.
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Affiliation(s)
- Kendra N. Smyth
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Nicholas M. Caruso
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA
| | - Charli S. Davies
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Tim H. Clutton-Brock
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
- Department of Zoology, University of Cambridge, Cambridge, UK
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Christine M. Drea
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Biology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
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Ebensperger LA, Correa LA, León C, Ramírez‐Estrada J, Abades S, Villegas Á, Hayes LD. The modulating role of group stability on fitness effects of group size is different in females and males of a communally rearing rodent. J Anim Ecol 2016; 85:1502-1515. [DOI: 10.1111/1365-2656.12566] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/13/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Luis A. Ebensperger
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Loreto A. Correa
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Cecilia León
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Juan Ramírez‐Estrada
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Sebastian Abades
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
- Instituto de Ecología y Biodiversidad (IEB) Las Palmeras 3425 Santiago Chile
| | - Álvaro Villegas
- Departamento de Ecología Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Loren D. Hayes
- Department of Biology, Geology and Environmental Sciences University of Tennessee at Chattanooga Chattanooga TN 37403 USA
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Tarvin KA, Wong LJ, Lumpkin DC, Schroeder GM, D'Andrea D, Meade S, Rivers P, Murphy TG. Dynamic Status Signal Reflects Outcome of Social Interactions, but Not Energetic Stress. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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5
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Demas GE, Carlton ED. Ecoimmunology for psychoneuroimmunologists: Considering context in neuroendocrine-immune-behavior interactions. Brain Behav Immun 2015; 44:9-16. [PMID: 25218837 PMCID: PMC4275338 DOI: 10.1016/j.bbi.2014.09.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 08/26/2014] [Accepted: 09/01/2014] [Indexed: 02/06/2023] Open
Abstract
The study of immunity has become an important area of investigation for researchers in a wide range of areas outside the traditional discipline of immunology. For the last several decades, psychoneuroimmunology (PNI) has strived to identify key interactions among the nervous, endocrine and immune systems and behavior. More recently, the field of ecological immunology (ecoimmunology) has been established within the perspectives of ecology and evolutionary biology, sharing with PNI an appreciation of the environmental influences on immune function. The primary goal of ecoimmunology is to understand immune function within a broadly integrative, organismal context, typically from an ultimate, evolutionary perspective. To accomplish this ecoimmunology, like PNI, has become a broadly integrative field of investigation, combining diverse approaches from evolution and ecology to endocrinology and neurobiology. The disciplines of PNI and ecoimmunology, with their unique yet complementary perspectives and methodologies, have much to offer one another. Researchers in both fields, however, remain largely unaware of each other's findings despite attempts at integration. The goal of this review is to share with psychoneuroimmunologists and other mechanistically-oriented researchers some of the core concepts and principles, as well as relevant recent findings, within ecoimmunology with the hope that this information will prove relevant to their own research programs. More broadly, our goal is to attempt to integrate both the proximate and ultimate perspectives offered by PNI and ecoimmunology respectively into a common theoretical framework for understanding neuro-endocrine-immune interactions and behavior in a larger ecological, evolutionary context.
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Affiliation(s)
- Gregory E Demas
- Department of Biology, Program in Neuroscience and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA.
| | - Elizabeth D Carlton
- Department of Biology, Program in Neuroscience and Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
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Moyers S, Kosarski K, Adelman J, Hawley D. Interactions between social behaviour and the acute phase immune response in house finches. BEHAVIOUR 2015. [DOI: 10.1163/1568539x-00003312] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In social organisms, immune-mediated behavioural changes (sickness behaviours) can both influence and respond to social dynamics. We tested whether social status in house finches (Haemorhous mexicanus) modulates the acute phase response or aggressive interactions with flockmates. We treated subordinate or dominant finches within captive flocks with lipopolysaccharide (LPS) to stimulate an acute phase response (APR), and quantified mass loss, activity, foraging behaviours, and agonistic interactions. Subordinate finches lost more mass than dominants in response to LPS, but social status did not influence the expression of sickness behaviours (activity and foraging) upon LPS injection. LPS-injected subordinate birds experienced reduced aggression from mid-ranking but not dominant flockmates, indicating status-mediated effects of sickness behaviour on agonistic interactions. Our results suggest that social status in house finches influences one component of the APR (mass loss) and can interact with the APR to modulate intraspecific agonistic interactions in ways likely relevant for disease transmission.
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Affiliation(s)
- Sahnzi C. Moyers
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Derring Hall Room 2125, Virginia Tech, 1405 Perry Street, Blacksburg, VA 24061-0406, USA
| | - Kara B. Kosarski
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Derring Hall Room 2125, Virginia Tech, 1405 Perry Street, Blacksburg, VA 24061-0406, USA
| | - James S. Adelman
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Derring Hall Room 2125, Virginia Tech, 1405 Perry Street, Blacksburg, VA 24061-0406, USA
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, IA 50011, USA
| | - Dana M. Hawley
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Derring Hall Room 2125, Virginia Tech, 1405 Perry Street, Blacksburg, VA 24061-0406, USA
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Adelman JS, Moore IT, Hawley DM. House finch responses to Mycoplasma gallisepticum infection do not vary with experimentally increased aggression. ACTA ACUST UNITED AC 2014; 323:39-51. [PMID: 25387693 DOI: 10.1002/jez.1894] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Aggression can alter infectious disease dynamics through two, non-exclusive mechanisms: 1) increasing direct contact among hosts and 2) altering hosts' physiological response to pathogens. Here we examined the latter mechanism in a social songbird by manipulating intraspecific aggression in the absence of direct physical contact. We asked whether the extent of aggression an individual experiences alters glucocorticoid levels, androgen levels, and individual responses to infection in an ecologically relevant disease model: house finches (Haemorhous mexicanus) infected with Mycoplasma gallisepticum (MG). Wild-caught male finches were housed in one of three settings, designed to produce increasing levels of aggression: 1) alone, with no neighbor ("no neighbor"), 2) next to a sham-implanted stimulus male ("sham neighbor"), or 3) next to a testosterone-implanted stimulus male ("testosterone neighbor"). Following one week of social treatment, focal males were experimentally infected with MG, which causes severe conjunctivitis and induces sickness behaviors such as lethargy and anorexia. While social treatment increased aggression as predicted, there were no differences among groups in baseline corticosterone levels, total circulating androgens, or responses to infection. Across all focal individuals regardless of social treatment, pre-infection baseline corticosterone levels were negatively associated with the severity of conjunctivitis and sickness behaviors, suggesting that corticosterone may dampen inflammatory responses in this host-pathogen system. However, because corticosterone levels differed based upon population of origin, caution must be taken in interpreting this result. Taken together, these results suggest that in captivity, although aggression does not alter individual responses to MG, corticosterone may play a role in this disease.
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Social interactions modulate the virulence of avian malaria infection. Int J Parasitol 2013; 43:861-7. [PMID: 23792297 DOI: 10.1016/j.ijpara.2013.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/16/2013] [Accepted: 05/20/2013] [Indexed: 02/05/2023]
Abstract
There is an increasing understanding of the context-dependent nature of parasite virulence. Variation in parasite virulence can occur when infected individuals compete with conspecifics that vary in infection status; virulence may be higher when competing with uninfected competitors. In vertebrates with social hierarchies, we propose that these competition-mediated costs of infection may also vary with social status. Dominant individuals have greater competitive ability than competing subordinates, and consequently may pay a lower prevalence-mediated cost of infection. In this study we investigated whether costs of malarial infection were affected by the occurrence of the parasite in competitors and social status in domestic canaries (Serinus canaria). We predicted that infected subordinates competing with non-infected dominants would pay higher costs than infected subordinates competing with infected dominants. We also predicted that these occurrence-mediated costs of infection would be ameliorated in infected dominant birds. We found that social status and the occurrence of parasites in competitors significantly interacted to change haematocrit in infected birds. Namely, subordinate and dominant infected birds differed in haematocrit depending on the infection status of their competitors. However, in contrast to our prediction, dominants fared better with infected subordinates, whereas subordinates fared better with uninfected dominants. Moreover, we found additional effects of parasite occurrence on mortality in canaries. Ultimately, we provide evidence for costs of parasitism mediated by social rank and the occurrence of parasites in competitors in a vertebrate species. This has important implications for our understanding of the evolutionary processes that shape parasite virulence and group living.
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Dhondt AA, States SL, Dhondt KV, Schat KA. Understanding the origin of seasonal epidemics of mycoplasmal conjunctivitis. J Anim Ecol 2012; 81:996-1003. [PMID: 22524311 DOI: 10.1111/j.1365-2656.2012.01986.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. Many host-pathogen systems show regular seasonal oscillations. 2. Seasonal variation in mycoplasmal conjunctivitis prevalence in house finches is an example of such oscillations. 3. An annual pulse of Mycoplasma gallisepticum-naïve juveniles increasing the number of susceptibles, seasonal changes in flocking behaviour increasing transmission rate and a gradual loss of resistance to reinfection with time are sufficient to model the observed seasonal variation in disease prevalence. Nevertheless, experiments are needed to test the underlying mechanisms. 4. We carried out an 18-month experiment with small groups of birds in large aviaries to test two hypotheses. 5. To test the first hypothesis that an influx of naïve juveniles in a group of recovered adults is sufficient to cause an outbreak, we added eight juveniles to a group of 11 adults that had recovered from an earlier infection. In all, three replicates juveniles became infected, but only after some of the adults relapsed. 6. To test the second hypothesis that reintroduction of M. gallisepticum into a multiage group of previously exposed but fully recovered house finches causes a new outbreak, we inoculated two birds in each group in March of the 2nd year. Contrary to what happens in the wild at that time disease prevalence increased rapidly after reintroduction of M. gallisepticum. 7. We conclude that asymptomatic, recovered adults can initiate an epidemic and transmit M. gallisepticum to naïve house finches and that the reintroduction of M. gallisepticum is sufficient to cause a new outbreak, even at a time of the year when mycoplasmal conjunctivitis is low in free-living birds. Date, as such, seems to be less important to explain seasonal variation in conjunctivitis than the presence of naïve juveniles or the introduction on M. gallisepticum. 8. Seasonality in outbreaks is most likely tightly linked to seasonal variation in bird movements and behaviour.
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Affiliation(s)
- André A Dhondt
- Laboratory of Ornithology, Cornell University, Ithaca, NY 14850, USA.
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10
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The effect of winter sex ratio on immune function and condition in a differential migrant. Physiol Behav 2011; 102:406-13. [DOI: 10.1016/j.physbeh.2010.11.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 10/25/2010] [Accepted: 11/26/2010] [Indexed: 12/22/2022]
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Bouwman KM, Hawley DM. Sickness behaviour acting as an evolutionary trap? Male house finches preferentially feed near diseased conspecifics. Biol Lett 2010; 6:462-5. [PMID: 20164082 DOI: 10.1098/rsbl.2010.0020] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Host behaviour towards infectious conspecifics is a crucial yet overlooked component of pathogen dynamics. Selection is expected to favour individuals who can recognize and avoid infected conspecifics in order to reduce their own risk of infection. However, evidence is scarce and limited to species employing chemical cues. Here, we experimentally examine whether healthy captive house finches (Carpodacus mexicanus) preferentially forage near a same-sex, healthy conspecific versus one infected with the directly transmissible pathogen Mycoplasma gallisepticum (MG), which causes lethargy and visible conjunctivitis. Interestingly, male house finches strongly preferred feeding near diseased conspecifics, while females showed no preference. This sex difference appeared to be the result of lower aggression rates in diseased males, but not in females. The reduced aggression of diseased males may act as an 'evolutionary trap' by presenting a historically beneficial behavioural cue in the context of a new environment, which now includes a recently emerged, potentially fatal pathogen. Since MG can be directly transmitted during feeding, healthy males may inadvertently increase their risk of contracting MG. This behaviour is likely to significantly contribute to the continued persistence of MG epidemics in wild populations.
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Affiliation(s)
- Karen M Bouwman
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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Dhondt KV, Dhondt AA, Ley DH. Effects of route of inoculation onMycoplasma gallisepticuminfection in captive house finches. Avian Pathol 2007; 36:475-9. [DOI: 10.1080/03079450701642016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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HAWLEY DM, JENNELLE CS, SYDENSTRICKER KV, DHONDT AA. Pathogen resistance and immunocompetence covary with social status in house finches (Carpodacus mexicanus). Funct Ecol 2007. [DOI: 10.1111/j.1365-2435.2007.01254.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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