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Campbell CR, Manser M, Shiratori M, Williams K, Barreiro L, Clutton-Brock T, Tung J. A female-biased gene expression signature of dominance in cooperatively breeding meerkats. Mol Ecol 2024:e17467. [PMID: 39021304 DOI: 10.1111/mec.17467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 04/27/2024] [Accepted: 07/03/2024] [Indexed: 07/20/2024]
Abstract
Dominance is a primary determinant of social dynamics and resource access in social animals. Recent studies show that dominance is also reflected in the gene regulatory profiles of peripheral immune cells. However, the strength and direction of this relationship differs across the species and sex combinations investigated, potentially due to variation in the predictors and energetic consequences of dominance status. Here, we investigated the association between social status and gene expression in the blood of wild meerkats (Suricata suricatta; n = 113 individuals), including in response to lipopolysaccharide, Gardiquimod (an agonist of TLR7, which detects single-stranded RNA in vivo) and glucocorticoid stimulation. Meerkats are cooperatively breeding social carnivores in which breeding females physically outcompete other females to suppress reproduction, resulting in high reproductive skew. They therefore present an opportunity to disentangle the effects of social dominance from those of sex per se. We identify a sex-specific signature of dominance, including 1045 differentially expressed genes in females but none in males. Dominant females exhibit elevated activity in innate immune pathways and a larger fold-change response to LPS challenge. Based on these results and a preliminary comparison to other mammals, we speculate that the gene regulatory signature of social status in the immune system depends on the determinants and energetic costs of social dominance, such that it is most pronounced in hierarchies where physical competition is important and reproductive skew is large. Such a pattern has the potential to mediate life history trade-offs between investment in reproduction versus somatic maintenance.
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Affiliation(s)
- C Ryan Campbell
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
| | - Marta Manser
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Kalahari Research Centre, Kuruman River Reserve, Northern Cape, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Mari Shiratori
- Section of Genetic Medicine, Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Kelly Williams
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
| | - Luis Barreiro
- Section of Genetic Medicine, Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Tim Clutton-Brock
- Kalahari Research Centre, Kuruman River Reserve, Northern Cape, South Africa
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
- Large Animal Research Group, Department of Zoology, University of Cambridge, Cambridge, UK
| | - Jenny Tung
- Department of Evolutionary Anthropology, Duke University, Durham, North Carolina, USA
- Department of Biology, Duke University, Durham, North Carolina, USA
- Duke Population Research Institute, Duke University, Durham, North Carolina, USA
- Department of Primate Behavior and Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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2
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Rystrom TL, Richter SH, Sachser N, Kaiser S. Social niche shapes social behavior and cortisol concentrations during adolescence in female guinea pigs. Horm Behav 2024; 162:105539. [PMID: 38608380 DOI: 10.1016/j.yhbeh.2024.105539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 03/07/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024]
Abstract
Individualized social niches arise in social groups, resulting in divergent social behavior profiles among group members. During sensitive life phases, the individualized social niche can profoundly impact the development of social behavior and associated phenotypes such as hormone (e.g. cortisol) concentrations. Focusing on adolescence, we investigated the relationship between the individualized social niche, social behavior, and cortisol concentrations (baseline and responsiveness) in female guinea pigs. Females were pair-housed in early adolescence (initial social pair formation), and a social niche transition was induced after six weeks by replacing the partner with either a larger or smaller female. Regarding social behavior, dominance status was associated with aggression in both the initial social pairs and after the social niche transition, and the results suggest that aggression was rapidly and completely reshaped after the social niche transition. Meanwhile, submissive behavior was rapidly reshaped after the social niche transition, but this was incomplete. The dominance status attained in the initial social pair affected the extent of submissive behavior after the social niche transition, and this effect was still detected three weeks after the social niche transition. Regarding cortisol concentrations, higher baseline cortisol concentrations were measured in dominant females in the initial social pairs. After the social niche transition, cortisol responsiveness significantly increased for the females paired with a larger, older female relative to those paired with a smaller, younger female. These findings demonstrate that the social niche during adolescence plays a significant role in shaping behavior and hormone concentrations in females.
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Affiliation(s)
- Taylor L Rystrom
- Department of Behavioural Biology, University of Münster, Münster, Germany; Münster Graduate School of Evolution, University of Münster, Münster, Germany.
| | - S Helene Richter
- Department of Behavioural Biology, University of Münster, Münster, Germany; Münster Graduate School of Evolution, University of Münster, Münster, Germany.
| | - Norbert Sachser
- Department of Behavioural Biology, University of Münster, Münster, Germany; Münster Graduate School of Evolution, University of Münster, Münster, Germany.
| | - Sylvia Kaiser
- Department of Behavioural Biology, University of Münster, Münster, Germany; Münster Graduate School of Evolution, University of Münster, Münster, Germany.
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3
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LaDue CA, Hunt KE, Kiso WK, Freeman EW. Hormonal variation and temporal dynamics of musth in Asian elephants ( Elephas maximus) are associated with age, body condition and the social environment. CONSERVATION PHYSIOLOGY 2023; 11:coad019. [PMID: 38026805 PMCID: PMC10660383 DOI: 10.1093/conphys/coad019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 12/01/2023]
Abstract
The sustainability of endangered Asian elephants in human care is threatened in part by low breeding success and concerns over individual animal wellbeing. Male elephants have received less research attention compared to females, yet males deserve special consideration due to their unique reproductive biology (particularly the sexual state of "musth") and the complex interaction of physiological, environmental, and social pressures they face. We measured fecal androgen metabolites (FAMs), fecal glucocorticoid metabolites (FGMs), and fecal triiodothyronine metabolites (FT3s) collected weekly over approximately 12 months from 26 male Asian elephants housed in zoos across the US, hypothesizing that FAM, FGM, and FT3 concentrations would be associated with temporal correlates of musth and would vary further with intrinsic (musth status, age, body condition) and extrinsic (social environment) factors. The duration of each musth episode was positively associated with exposure to male conspecifics and negatively associated with body condition. Further, elevated FAM concentrations were associated with social exposure, age, and body condition, and FGM concentrations also varied with age and body condition. FT3 concentrations were not associated with any factor we measured. We also identified periods of lower FAM concentration than confirmed musth episodes (but still higher than baseline FAM concentrations) that we termed "elevated FAM episodes." The durations of these episodes were negatively correlated with exposure to other male elephants. Together, these results provide evidence that hormone profiles (including those that are predicted to change around musth) vary significantly between male Asian elephants in a way that may be attributed to intrinsic and extrinsic factors. Studies like these serve to enhance the sustainability of ex-situ populations by providing wildlife managers with information to enhance the health, welfare, and reproduction of threatened species like Asian elephants.
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Affiliation(s)
- Chase A LaDue
- Department of Environmental Science and Policy, 4400 University Drive, MSN 5F2, George Mason University, Fairfax, VA 22030, USA
- Oklahoma City Zoo and Botanical Garden, 2000 Remington Place, Oklahoma City, OK 73111, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, 10900 University Boulevard, Manassas, VA 20110, USA
- Smithsonian-Mason School of Conservation, 1500 Remount Road, Front Royal, VA 22630, USA
| | - Wendy K Kiso
- White Oak Conservation Foundation, 581705 White Oak Road, Yulee, FL 32097, USA
- Colossal Biosciences, 3309 Elm Street, Dallas, TX 75226, USA
| | - Elizabeth W Freeman
- School of Integrative Studies, 4400 University Drive, MSN 5D3, George Mason University, Fairfax, VA 22030, USA
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4
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Drea CM, Davies CS. Meerkat manners: Endocrine mediation of female dominance and reproductive control in a cooperative breeder. Horm Behav 2022; 145:105245. [PMID: 35988450 DOI: 10.1016/j.yhbeh.2022.105245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/18/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022]
Abstract
This article is part of a Special Issue (Hormones and Hierarchies). To gain more balanced understanding of sexual selection and mammalian sexual differentiation processes, this review addresses behavioral sex differences and hormonal mediators of intrasexual competition in the meerkat (Suricata suricatta) - a cooperative breeder unusual among vertebrates in its female aggression, degree of reproductive skew, and phenotypic divergence. Focused on the evolution, function, mechanism, and development of female dominance, the male remains a key reference point throughout. Integrated review of endocrine function does not support routine physiological suppression in subordinates of either sex, but instead a ramp up of weight, reproduction, aggression, and sex steroids, particularly androgens, in dominant females. Important and timely questions about female competition are thus addressed by shifting emphasis from mediators of reproductive suppression to mediators of reproductive control, and from organizational and activational roles of androgens in males to their roles in females. Unusually, we ask not only how inequity is maintained, but how dominance is acquired within a lifetime and across generations. Antiandrogens administered in the field to males and pregnant dominant females confirm the importance of androgen-mediated food competition. Moreover, effects of maternal endocrine milieu on offspring development reveal a heritable, androgenic route to female aggression, likely promoting reproductive priority along dominant matrilines. Integrating endocrine measures with long-term behavioral, ecological, morphological, and life-history data on normative and experimental individuals, across life stages and generations, provides better appreciation of the role of naturally circulating androgens in regulating the female phenotype, and sheds new light on the evolution of female dominance, reproductive inequity, and cooperative breeding.
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Affiliation(s)
- Christine M Drea
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708-0383, USA; Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa.
| | - Charli S Davies
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708-0383, USA; Kalahari Research Trust, Kuruman River Reserve, Northern Cape, South Africa
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5
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Dantzer B, Newman AEM. Expanding the frame around social dynamics and glucocorticoids: From hierarchies within the nest to competitive interactions among species. Horm Behav 2022; 144:105204. [PMID: 35689971 DOI: 10.1016/j.yhbeh.2022.105204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/10/2022] [Accepted: 05/18/2022] [Indexed: 11/25/2022]
Abstract
The effect of the social environment on individual state or condition has largely focused on glucocorticoid levels (GCs). As metabolic hormones whose production can be influenced by nutritional, physical, or psychosocial stressors, GCs are a valuable (though singular) measure that may reflect the degree of "stress" experienced by an individual. Most work to date has focused on how social rank influences GCs in group-living species or how predation risk influences GCs in prey. This work has been revealing, but a more comprehensive assessment of the social environment is needed to fully understand how different features of the social environment influence GCs in both group living and non-group living species and across life history stages. Just as there can be intense within-group competition among adult conspecifics, it bears appreciating there can also be competition among siblings from the same brood, among adult conspecifics that do not live in groups, or among heterospecifics. In these situations, dominance hierarchies typically emerge, albeit, do dominants or subordinate individuals or species have higher GCs? We examine the degree of support for hypotheses derived from group-living species about whether differential GCs between dominants and subordinates reflect the "stress of subordination" or "costs of dominance" in these other social contexts. By doing so, we aim to test the generality of these two hypotheses and propose new research directions to broaden the lens that focuses on social hierarchies and GCs.
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Affiliation(s)
- Ben Dantzer
- Department of Psychology, University of Michigan, 48109 Ann Arbor, MI, USA; Department of Ecology and Evolutionary Biology, University of Michigan, 48109, Ann Arbor, MI, USA.
| | - Amy E M Newman
- Department of Integrative Biology, University of Guelph, Guelph, ON N1G2W1, Canada
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6
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Brachet MAA, Vullioud P, Ganswindt A, Manser MB, Keller M, Clutton-Brock TH. Parity predicts allonursing in a cooperative breeder. J Mammal 2021. [DOI: 10.1093/jmammal/gyab084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
In some mammals that breed cooperatively, nonbreeding female helpers nurse offspring born to the breeding female in their group, a process known as allonursing. Previous laboratory studies have suggested that primiparous and multiparous females (those that have successfully given birth once or more, respectively) are more likely to contribute to allonursing than nulliparous females (those that have not given birth). In contrast, few field studies have been able to demonstrate whether breeding experience, or parity, affects the likelihood or duration of allonursing. In this study, we investigated whether the likelihood and duration of allonursing by subordinate female meerkats (Suricata suricatta) were associated with variations in their parity (number of pregnancies reaching a viable gestational age) and their immediate pregnancy status. Comparisons showed that nonpregnant nulliparous females were less likely to allonurse than nonpregnant primiparous and multiparous females, although parity was not related to variation in allonursing duration. Parity may enhance the expression of maternal behavior when exposed to foster pups, especially since mammary gland development has been shown to be directly associated with parity in other mammals.
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Affiliation(s)
- Morgane A A Brachet
- Laboratoire de Physiologie de la Reproduction & des Comportements, UMR 7247 INRAE/CNRS/Université de Tours/IFCE, Nouzilly, France
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, 0028, South Africa
| | | | - Andre Ganswindt
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, 0028, South Africa
| | - Marta B Manser
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, 0028, South Africa
- Department of Evolutionary Biology and Environmental Studies, Animal Behaviour, University of Zurich, Zurich, Switzerland
- Kalahari Meerkat Project, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Matthieu Keller
- Laboratoire de Physiologie de la Reproduction & des Comportements, UMR 7247 INRAE/CNRS/Université de Tours/IFCE, Nouzilly, France
| | - Tim H Clutton-Brock
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, 0028, South Africa
- Department of Zoology, University of Cambridge, Cambridge, UK
- Kalahari Meerkat Project, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
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7
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Freeman AR. Female-female reproductive suppression: impacts on signals and behavior. Integr Comp Biol 2021; 61:1827-1840. [PMID: 33871603 DOI: 10.1093/icb/icab027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Female-female reproductive suppression is evident in an array of mammals, including rodents, primates, and carnivores. By suppressing others, breeding females can benefit by reducing competition from other females and their offspring. There are neuroendocrinological changes during suppression which result in altered behavior, reproductive cycling, and communication. This review, which focuses on species in Rodentia, explores the current theoretical frameworks of female-female reproductive suppression, how female presence and rank impacts reproductive suppression, and some of the proposed mechanisms of suppression. Finally, the understudied role of olfactory communication in female-female reproductive suppression is discussed to identify current gaps in our understanding of this topic.
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Affiliation(s)
- Angela R Freeman
- Department of Psychology, Cornell University, 211 Uris Hall, Cornell University, Ithaca, NY 14853
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8
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Thorley J. The case for extended lifespan in cooperatively breeding mammals: a re-appraisal. PeerJ 2020; 8:e9214. [PMID: 32477839 PMCID: PMC7243813 DOI: 10.7717/peerj.9214] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 04/27/2020] [Indexed: 12/04/2022] Open
Abstract
Recent comparative studies have suggested that cooperative breeding is associated with increases in maximum lifespan among mammals, replicating a pattern also seen in birds and insects. In this study, we re-examine the case for increased lifespan in mammalian cooperative breeders by analysing a large dataset of maximum longevity records. We did not find any consistent, strong evidence that cooperative breeders have longer lifespans than other mammals after having controlled for variation in body mass, mode of life and data quality. The only possible exception to this general trend is found in the African mole-rats (the Bathyergid family), where all members are relatively long-lived, but where the social, cooperatively breeding species appear to be much longer-lived than the solitary species. However, solitary mole-rat species have rarely been kept in captivity or followed longitudinally in the wild and so it seems likely that their maximum lifespan has been underestimated when compared to the highly researched social species. Although few subterranean mammals have received much attention in a captive or wild setting, current data instead supports a causal role of subterranean living on lifespan extension in mammals.
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Affiliation(s)
- Jack Thorley
- Large Animal Research Group, Department of Zoology, University of Cambridge, Cambridge, UK
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Laver PN, Ganswindt A, Ganswindt SB, Alexander KA. Effect of food limitation and reproductive activity on fecal glucocorticoid metabolite levels in banded mongooses. BMC Ecol 2020; 20:12. [PMID: 32070331 PMCID: PMC7027037 DOI: 10.1186/s12898-020-00280-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 02/05/2020] [Indexed: 11/10/2022] Open
Abstract
Background Glucocorticoids mediate responses to perceived stressors, thereby restoring homeostasis. However, prolonged glucocorticoid elevation may cause homeostatic overload. Using extensive field investigations of banded mongoose (Mungos mungo) groups in northern Botswana, we assessed the influence of reproduction, predation risk, and food limitation on apparent homeostatic overload (n=13 groups, 1542 samples from 268 animals). We experimentally manipulated reproduction and regulated food supply in captive mongooses, and compared their glucocorticoid responses to those obtained from free-living groups. Results At the population level, variation in glucocorticoid levels in free-living mongooses was explained by food limitation: fecal organic matter, recent rainfall, and access to concentrated anthropogenic food resources. Soil macrofauna density and reproductive events explained less and predation risk very little variation in glucocorticoid levels. Reproduction and its associated challenges alone (under regulated feeding conditions) increased glucocorticoid levels 19-fold in a captive group. Among free-living groups, glucocorticoid elevation was seasonal (occurring in late dry season or early wet season when natural food resources were less available), but the timing of peak glucocorticoid production was moderated by access to anthropogenic resources (groups with fewer anthropogenic food sources had peaks earlier in dry seasons). Peak months represented 12- and 16-fold increases in glucocorticoids relative to nadir months with some animals exhibiting 100-fold increases. Relative to the captive group nadir, some free-living groups exhibited 60-fold increases in peak glucocorticoid levels with some animals exhibiting up to 800-fold increases. Most of these animals exhibited 1- to 10-fold increases relative to the captive animal peak. Conclusions Banded mongooses exhibit seasonal chronic glucocorticoid elevation, associated primarily with food limitation and secondarily with reproduction. Magnitude and duration of this elevation suggests that this may be maladaptive for some animals, with possible fitness consequences. In late dry season, this population may face a convergence of stressors (food limitation, agonistic encounters at concentrated food resources, evictions, estrus, mate competition, parturition, and predation pressure on pups), which may induce homeostatic overload.
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Affiliation(s)
- Pete N Laver
- Biodiversity and Development Institute, 4 Gunner's Park, Grenville Avenue, Epping 1, Cape Town, 7460, South Africa.
| | - André Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa.,Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.,Centre for Veterinary Wildlife Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
| | - Stefanie B Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa.,Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
| | - Kathleen A Alexander
- Department of Fish and Wildlife Conservation, Virginia Tech, 100 Cheatham Hall, Blacksburg, VA, 24061-0321, USA
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10
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Medger K, Bennett NC, Lutermann H, Ganswindt A. Non-invasive assessment of glucocorticoid and androgen metabolite levels in cooperatively breeding Damaraland mole-rats (Fukomys damarensis). Gen Comp Endocrinol 2018; 266:202-210. [PMID: 29782838 DOI: 10.1016/j.ygcen.2018.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 05/08/2018] [Accepted: 05/17/2018] [Indexed: 10/16/2022]
Abstract
Dominant females of cooperative breeding species often use aggression to suppress reproduction of subordinate females, resulting in subordinates experiencing stress-related increases in glucocorticoid levels, which may cause reproductive down-regulation. This would suggest a general pattern with higher glucocorticoid levels in subordinate compared to dominant individuals; however, the opposite was found in a number of cooperatively breeding species. Furthermore, breeding females of the cooperatively breeding Damaraland mole-rats (Fukomys damarensis) exhibit very high androgen concentrations during the wet season, presumably to support their breeding monopoly. Hormone analysis in Damaraland mole-rats have typically been measured using plasma and urine, but faecal analysis offers additional advantages especially for field studies on this species. The present study examines the suitability of Damaraland mole-rat faecal samples for determining glucocorticoid metabolite (fGCM) and androgen metabolite (fAM) concentrations using enzyme immunoassays. Using these assays, we further evaluated the effects of breeding status on fGCM and fAM concentrations in wild-caught and captive Damaraland mole-rats. Wild-caught breeding and non-breeding males and females exhibited no differences in fAM concentrations. Immunoreactive fGCM concentrations were only high in male breeders and comparatively low in non-breeders and breeding females. Concentrations of fAMs and fGCMs were similar in captive males and females, but fAM concentrations were elevated in captive compared to wild-caught individuals, which may be related to a higher reproductive activity due to removal from the breeding female. The relatively uniform fAM and fGCM concentrations found in wild-caught mole-rats may be explained by a stable colony structure during the dry season during which this study was conducted. Limited dispersal opportunities result in lower aggression and stress levels within a colony and as a result lower fAM and fGCM concentrations.
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Affiliation(s)
- Katarina Medger
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa; SARChI Chair of Mammal Behavioural Ecology and Physiology, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Heike Lutermann
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Andre Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa; Endocrine Research Laboratory, Department of Anatomy and Physiology, Faculty of Veterinary Science, Private Bag X04, Onderstepoort 0110, South Africa
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11
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Physiological mechanisms mediating patterns of reproductive suppression and alloparental care in cooperatively breeding carnivores. Physiol Behav 2018; 193:167-178. [DOI: 10.1016/j.physbeh.2017.11.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 10/14/2017] [Accepted: 11/06/2017] [Indexed: 12/17/2022]
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12
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Smyth KN, Caruso NM, Davies CS, Clutton-Brock TH, Drea CM. Social and endocrine correlates of immune function in meerkats: implications for the immunocompetence handicap hypothesis. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180435. [PMID: 30225031 PMCID: PMC6124081 DOI: 10.1098/rsos.180435] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/25/2018] [Indexed: 06/08/2023]
Abstract
Social status can mediate effects on the immune system, with profound consequences for individual health; nevertheless, most investigators of status-related disparities in free-ranging animals have used faecal parasite burdens to proxy immune function in the males of male-dominant species. We instead use direct measures of innate immune function (complement and natural antibodies) to examine status-related immunocompetence in both sexes of a female-dominant species. The meerkat is a unique model for such a study because it is a cooperatively breeding species in which status-related differences are extreme, evident in reproductive skew, morphology, behaviour, communication and physiology, including that dominant females naturally express the greatest total androgen (androstenedione plus testosterone) concentrations. We found that, relative to subordinates, dominant animals had reduced serum bacteria-killing abilities; also, relative to subordinate females, dominant females had reduced haemolytic complement activities. Irrespective of an individual's sex or social status, androstenedione concentrations (but not body condition, age or reproductive activity) negatively predicted concurrent immunocompetence. Thus, dominant meerkats of both sexes are immunocompromised. Moreover, in female meerkats, androstenedione perhaps acting directly or via local conversion, may exert a double-edged effect of promoting dominance and reproductive success at the cost of increased parasitism and reduced immune function. Given the prominent signalling of dominance in female meerkats, these findings may relate to the immunocompetence handicap hypothesis (ICHH); however, our data would suggest that the endocrine mechanism underlying the ICHH need not be mediated solely by testosterone and might explain trade-offs in females, as well as in males.
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Affiliation(s)
- Kendra N. Smyth
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Nicholas M. Caruso
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA
| | - Charli S. Davies
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Tim H. Clutton-Brock
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
- Department of Zoology, University of Cambridge, Cambridge, UK
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Christine M. Drea
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Biology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
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13
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Thorley J, Katlein N, Goddard K, Zöttl M, Clutton-Brock T. Reproduction triggers adaptive increases in body size in female mole-rats. Proc Biol Sci 2018; 285:20180897. [PMID: 29875307 PMCID: PMC6015866 DOI: 10.1098/rspb.2018.0897] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 05/11/2018] [Indexed: 11/12/2022] Open
Abstract
In social mole-rats, breeding females are larger and more elongated than non-breeding female helpers. This status-related morphological divergence is thought to arise from modifications of skeletal growth following the death or removal of the previous breeder and the transition of their successors from a non-breeding to a breeding role. However, it is not clear what changes in growth are involved, whether they are stimulated by the relaxation of reproductive suppression or by changes in breeding status, or whether they are associated with fecundity increases. Here, we show that, in captive Damaraland mole-rats (Fukomys damarensis), where breeding was experimentally controlled in age-matched siblings, individuals changed in size and shape through a lengthening of the lumbar vertebrae when they began breeding. This skeletal remodelling results from changes in breeding status because (i) females removed from a group setting and placed solitarily showed no increases in growth and (ii) females dispersing from natural groups that have not yet bred do not differ in size and shape from helpers in established groups. Growth patterns consequently resemble other social vertebrates where contrasts in size and shape follow the acquisition of the breeding role. Our results also suggest that the increases in female body size provide fecundity benefits. Similar forms of socially responsive growth might be more prevalent in vertebrates than is currently recognized, but the extent to which this is the case, and the implications for the structuring of mammalian dominance hierarchies, are as yet poorly understood.
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Affiliation(s)
- Jack Thorley
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
- Kalahari Research Centre, Kuruman River Reserve, PO Box 64, Van Zylsrus, South Africa
| | - Nathan Katlein
- Kalahari Research Centre, Kuruman River Reserve, PO Box 64, Van Zylsrus, South Africa
| | - Katy Goddard
- Kalahari Research Centre, Kuruman River Reserve, PO Box 64, Van Zylsrus, South Africa
| | - Markus Zöttl
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
- Kalahari Research Centre, Kuruman River Reserve, PO Box 64, Van Zylsrus, South Africa
- Ecology and Evolution in Microbial Model Systems, EEMiS, Department of Biology and Environmental Science, Linnaeus University, 391 Kalmar, Sweden
| | - Tim Clutton-Brock
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
- Kalahari Research Centre, Kuruman River Reserve, PO Box 64, Van Zylsrus, South Africa
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, 0028 Pretoria, South Africa
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Incidence and biomarkers of pregnancy, spontaneous abortion, and neonatal loss during an environmental stressor: Implications for female reproductive suppression in the cooperatively breeding meerkat. Physiol Behav 2018; 193:90-100. [PMID: 29730033 DOI: 10.1016/j.physbeh.2017.11.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/11/2017] [Accepted: 11/11/2017] [Indexed: 11/22/2022]
Abstract
Meerkats are group-living, insectivorous herpestids in which subordinate members provide extensive care for the dominant female's young. In contrast to some cooperative breeders, subordinate female meerkats are physiologically able to reproduce and occasionally do so successfully; their attempts are more frequently 'suppressed' via eviction or infanticide by the dominant female. Spontaneous abortion and neonatal loss occur with some regularity, further negatively impacting reproductive success. Here, we compared the reproductive outcomes and endocrine profiles, including of serum progesterone (P4), serum estradiol (E2), and fecal glucocorticoid metabolites (fGCm), of dominant and subordinate dams residing within their clans in the Kalahari Desert of South Africa. Our study spanned years of drought, which reduced insect abundance and represented a substantial environmental stressor. Meerkat pregnancies were identified at mid-term and culminated either in spontaneous abortions or full-term deliveries, after which pups were either lost prior to emergence from the natal den (usually within 2days of birth) or emerged at 2-3weeks. Neonatal loss exceeded fetal loss for all females, and contributed to narrowing the status-related disparity in female reproductive output seen during less arid periods. Although E2 concentrations were significantly lower in subordinate than dominant females, they were sufficient to support gestation. Absolute E2 concentrations may owe to androgenic precursors that also attain highest concentrations in dominant dams and may mediate aggression underlying female reproductive skew. Pregnancies terminating in fetal loss were marked by significantly lower P4 concentrations in mid-gestation and modestly lower E2 concentrations overall. Consistently high fGCm concentrations further increased across trimesters, particularly (but not consistently) in subordinates and in aborted pregnancies. Environmental stressors may modulate reproductive outcomes in meerkats through their influence on sex steroids and their effects on intragroup competition. The social and eco-physiological factors affecting intraspecific variation in reproductive output, even in obligate cooperative breeders, may be most apparent during extreme conditions, reflecting the benefits of long-term studies for assessing the impact of climate change.
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15
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Stress levels of dominants reflect underlying conflicts with subordinates in a cooperatively breeding species. Behav Ecol Sociobiol 2018. [DOI: 10.1007/s00265-018-2484-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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16
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Charpentier MJE, Givalois L, Faurie C, Soghessa O, Simon F, Kappeler PM. Seasonal glucocorticoid production correlates with a suite of small-magnitude environmental, demographic, and physiological effects in mandrills. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 165:20-33. [DOI: 10.1002/ajpa.23329] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/11/2017] [Accepted: 09/18/2017] [Indexed: 11/07/2022]
Affiliation(s)
| | - L. Givalois
- MMDN Lab - U1198, INSERM, University of Montpellier, EPHE; Montpellier France
| | - C. Faurie
- ISEM, Univ. Montpellier, CNRS, IRD, EPHE; Montpellier France
| | | | - F. Simon
- Faculté de Médecine Paris -Diderot; Service de microbiologie CHU Saint Louis; France
| | - P. M. Kappeler
- Behavioral Ecology and Sociobiology Unit; German Primate Center; Gottingen Germany
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17
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Mausbach J, Braga Goncalves I, Heistermann M, Ganswindt A, Manser MB. Meerkat close calling patterns are linked to sex, social category, season and wind, but not fecal glucocorticoid metabolite concentrations. PLoS One 2017; 12:e0175371. [PMID: 28467419 PMCID: PMC5414979 DOI: 10.1371/journal.pone.0175371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 03/24/2017] [Indexed: 01/05/2023] Open
Abstract
It is well established that animal vocalizations can encode information regarding a sender's identity, sex, age, body size, social rank and group membership. However, the association between physiological parameters, particularly stress hormone levels, and vocal behavior is still not well understood. The cooperatively breeding African meerkats (Suricata suricatta) live in family groups with despotic social hierarchies. During foraging, individuals emit close calls that help maintain group cohesion. These contact calls are acoustically distinctive and variable in rate across individuals, yet, information on which factors influence close calling behavior is missing. The aim of this study was to identify proximate factors that influence variation in call rate and acoustic structure of meerkat close calls. Specifically, we investigated whether close calling behavior is associated with sex, age and rank, or stress hormone output (i.e., measured as fecal glucocorticoid metabolite (fGCM) concentrations) as individual traits of the caller, as well as with environmental conditions (weather) and reproductive seasonality. To disentangle the effects of these factors on vocal behavior, we analyzed sound recordings and assessed fGCM concentrations in 64 wild but habituated meerkats from 9 groups during the reproductive and non-reproductive seasons. Dominant females and one-year old males called at significantly higher rates compared to other social categories during the reproductive season. Additionally, dominant females produced close calls with the lowest mean fundamental frequencies (F0) and the longest mean pulse durations. Windy conditions were associated with significantly higher call rates during the non-reproductive season. Fecal GCM concentrations were unrelated to close calling behavior. Our findings suggest that meerkat close calling behavior conveys information regarding the sex and social category of the caller, but shows no association with fGCM concentrations. The change in call rate in response to variation in the social and ecological environments individuals experience indicates some degree of flexibility in vocal production.
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Affiliation(s)
- Jelena Mausbach
- Animal Behaviour, Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Kalahari Meerkat Project, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Ines Braga Goncalves
- Animal Behaviour, Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Kalahari Meerkat Project, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | | | - André Ganswindt
- Endocrine Research Laboratory, Dept. of Anatomy & Physiology, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
- Mammal Research Institute, University of Pretoria, Hatfield, South Africa
| | - Marta B. Manser
- Animal Behaviour, Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Kalahari Meerkat Project, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
- Mammal Research Institute, University of Pretoria, Hatfield, South Africa
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18
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Fitness and hormonal correlates of social and ecological stressors of female yellow-bellied marmots. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2015.11.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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19
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Voellmy IK, Goncalves IB, Barrette MF, Monfort SL, Manser MB. Mean fecal glucocorticoid metabolites are associated with vigilance, whereas immediate cortisol levels better reflect acute anti-predator responses in meerkats. Horm Behav 2014; 66:759-65. [PMID: 25218254 DOI: 10.1016/j.yhbeh.2014.08.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 08/14/2014] [Accepted: 08/27/2014] [Indexed: 11/19/2022]
Abstract
Adrenal hormones likely affect anti-predator behavior in animals. With experimental field studies, we first investigated associations between mean fecal glucocorticoid metabolite (fGC) excretion and vigilance and with behavioral responses to alarm call playbacks in free-ranging meerkats (Suricata suricatta). We then tested how vigilance and behavioral responses to alarm call playbacks were affected in individuals administered exogenous cortisol. We found a positive association between mean fGC concentrations and vigilance behavior, but no relationship with the intensity of behavioral responses to alarm calls. However, in response to alarm call playbacks, individuals administered cortisol took slightly longer to resume foraging than control individuals treated with saline solution. Vigilance behavior, which occurs in the presence and absence of dangerous stimuli, serves to detect and avoid potential dangers, whereas responses to alarm calls serve to avoid immediate predation. Our data show that mean fGC excretion in meerkats was associated with vigilance, as a re-occurring anti-predator behavior over long time periods, and experimentally induced elevations of plasma cortisol affected the response to immediate threats. Together, our results indicate an association between the two types of anti-predator behavior and glucocorticoids, but that the underlying mechanisms may differ. Our study emphasizes the need to consider appropriate measures of adrenal activity specific to different contexts when assessing links between stress physiology and different anti-predator behaviors.
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Affiliation(s)
- Irene K Voellmy
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Kalahari Meerkat Project, Kuruman River Reserve, South Africa
| | - Ines Braga Goncalves
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Kalahari Meerkat Project, Kuruman River Reserve, South Africa
| | - Marie-France Barrette
- Département de Biologie, Université de Sherbrooke, Sherbrooke J1K 2R1, Canada; Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Rd, Front Royal, VA 22630, USA; Kalahari Meerkat Project, Kuruman River Reserve, South Africa
| | - Steven L Monfort
- Smithsonian Conservation Biology Institute, National Zoological Park, 1500 Remount Rd, Front Royal, VA 22630, USA
| | - Marta B Manser
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Mammal Research Institute, Pretoria University, 00002 Pretoria, South Africa; Kalahari Meerkat Project, Kuruman River Reserve, South Africa.
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20
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York CA, Schulte BA. The relationship of dominance, reproductive state and stress in female horses (Equus caballus). Behav Processes 2014; 107:15-21. [DOI: 10.1016/j.beproc.2014.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 05/06/2014] [Accepted: 07/11/2014] [Indexed: 10/25/2022]
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21
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Laver PN, Ganswindt A, Ganswindt SB, Alexander KA. Non-invasive monitoring of glucocorticoid metabolites in banded mongooses (Mungos mungo) in response to physiological and biological challenges. Gen Comp Endocrinol 2012; 179:178-83. [PMID: 22926328 DOI: 10.1016/j.ygcen.2012.08.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 07/27/2012] [Accepted: 08/05/2012] [Indexed: 10/28/2022]
Abstract
Free-ranging banded mongooses are infected by the novel pathogen, Mycobacterium mungi in northern Botswana. A reliable method for determining stress-related physiological responses in banded mongooses will increase our understanding of the stress response in M. mungi infection. Therefore, our aim was to examine the suitability of four enzyme immunoassays (EIAs) for monitoring adrenocortical endocrine function in captive and free-ranging banded mongooses based on fecal glucocorticoid metabolite (FGM) analysis. A conducted adrenocorticotropic hormone challenge revealed suitability of a valid measurement of FGM levels in banded mongoose feces for all four tested EIAs, with an 11-oxoetiocholanolone assay detecting 11,17-dioxoandrostanes (11,17-DOA) performing best. Subsequent analyses using only this EIA showed the expected decrease in FGM concentrations 48 h after administering dexamethasone sodium phosphate. Furthermore, captive mongooses showed higher FGM concentrations during reproductive activity, agonistic encounters and depredation events. Finally, a late-stage, tuberculosis-infected moribund mongoose in a free-ranging troop had a 54-fold elevation in FGM levels relative to the rest of the troop. Measurements of gastrointestinal transit times and FGM metabolism post-defecation indicate that the time delay of FGM excretion approximately corresponded with food transit time and that FGM metabolism is minimal up to 8h post-defecation. The ability to reliably assess adrenocortical endocrine function in banded mongoose now provides a solid basis for advancing our understanding of infectious disease and endocrinology in this species.
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Affiliation(s)
- Peter N Laver
- Department of Fish and Wildlife Conservation, 100 Cheatham Hall, Virginia Tech, Blacksburg, VA 24061-0321, USA.
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