1
|
Stead SM, Edwards PD, Persad R, Boonstra R, Teichroeb JA, Palme R, Bowman J. Coping with extreme free cortisol levels: Seasonal stress axis changes in sympatric North American flying squirrels. Gen Comp Endocrinol 2024; 349:114467. [PMID: 38342330 DOI: 10.1016/j.ygcen.2024.114467] [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: 12/07/2023] [Revised: 01/18/2024] [Accepted: 02/03/2024] [Indexed: 02/13/2024]
Abstract
Most environments exhibit predictable yearly changes, permitting animals to anticipate them. The hypothalamic-pituitary-adrenal (HPA) axis is a key physiological pathway that enables animals to cope with such changes. Monitoring glucocorticoid (the end products of the HPA axis) levels in wild animals throughout the year can improve our understanding of how this pathway responds to different conditions. For this study, we collected 18 months of data on two species of North American flying squirrels (Glaucomys sabrinus and G. volans) living in a southern Ontario forest where temperature and food availability fluctuate dramatically throughout the year. These squirrels are active year-round, nest communally, and rely on scatter hoarded foods in the winter months. Flying squirrels have extremely high levels of free plasma cortisol relative to other mammals, but it is unknown how these levels are affected by environmental and reproductive factors. For both species, our goals were to (1) validate an enzyme immunoassay (EIA) to measure their fecal glucocorticoid metabolite (FGM) concentrations and (2) assess yearly differences, seasonal changes, and the influence of sex, reproduction, and ambient temperature on FGM concentrations in each species. In the lab, we successfully validated the use of antibody 5α-pregnane-3β, 11β, 21-triol-20-one EIA for FGM analysis in both species. In the field, neither sex nor reproductive status (breeding condition or not) were linked to FGM concentrations in either species. FGM concentrations were higher in autumn compared to the spring and summer. There were no other seasonal differences. We discuss possible explanations for the autumn peak in FGM concentrations (increased energy expenditure and social nesting changes), as well as outline possible avenues for future research. Understanding how individuals and populations respond to environmental change is a critical goal in evolutionary ecology, particularly in the context of a rapidly changing Anthropocene.
Collapse
Affiliation(s)
- Samantha M Stead
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada.
| | - Phoebe D Edwards
- Department of Psychology, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Rebekah Persad
- Environmental & Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Julie A Teichroeb
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Rupert Palme
- Department of Biological Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Jeff Bowman
- Environmental & Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada; Wildlife Research & Monitoring Section, Ontario Ministry of Natural Resources & Forestry, Trent University, Peterborough, Ontario, Canada
| |
Collapse
|
2
|
Dantzer B. Frank Beach Award Winner: The centrality of the hypothalamic-pituitary-adrenal axis in dealing with environmental change across temporal scales. Horm Behav 2023; 150:105311. [PMID: 36707334 DOI: 10.1016/j.yhbeh.2023.105311] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 01/02/2023] [Accepted: 01/06/2023] [Indexed: 01/26/2023]
Abstract
Understanding if and how individuals and populations cope with environmental change is an enduring question in evolutionary ecology that has renewed importance given the pace of change in the Anthropocene. Two evolutionary strategies of coping with environmental change may be particularly important in rapidly changing environments: adaptive phenotypic plasticity and/or bet hedging. Adaptive plasticity could enable individuals to match their phenotypes to the expected environment if there is an accurate cue predicting the selective environment. Diversifying bet hedging involves the production of seemingly random phenotypes in an unpredictable environment, some of which may be adaptive. Here, I review the central role of the hypothalamic-pituitary-adrenal (HPA) axis and glucocorticoids (GCs) in enabling vertebrates to cope with environmental change through adaptive plasticity and bet hedging. I first describe how the HPA axis mediates three types of adaptive plasticity to cope with environmental change (evasion, tolerance, recovery) over short timescales (e.g., 1-3 generations) before discussing how the implications of GCs on phenotype integration may depend upon the timescale under consideration. GCs can promote adaptive phenotypic integration, but their effects on phenotypic co-variation could also limit the dimensions of phenotypic space explored by animals over longer timescales. Finally, I discuss how organismal responses to environmental stressors can act as a bet hedging mechanism and therefore enhance evolvability by increasing genetic or phenotypic variability or reducing patterns of genetic and phenotypic co-variance. Together, this emphasizes the crucial role of the HPA axis in understanding fundamental questions in evolutionary ecology.
Collapse
Affiliation(s)
- Ben Dantzer
- Department of Psychology, University of Michigan, MI 48109 Ann Arbor, MI, USA; Department of Ecology and Evolutionary Biology, University of Michigan, MI 48109, Ann Arbor, MI, USA.
| |
Collapse
|
3
|
Karaer MC, Čebulj-Kadunc N, Snoj T. Stress in wildlife: comparison of the stress response among domestic, captive, and free-ranging animals. Front Vet Sci 2023; 10:1167016. [PMID: 37138925 PMCID: PMC10150102 DOI: 10.3389/fvets.2023.1167016] [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: 02/15/2023] [Accepted: 03/30/2023] [Indexed: 05/05/2023] Open
Abstract
The stress response, which involves joint activity of the nervous and endocrine systems, is one of the basic adaptive mechanisms that ensures the survival of the individual. The activation of the sympathetic nervous system, the sympathetic-adrenal-medullary axis, and the hypothalamic-pituitary-adrenal axis enables organisms to respond to endogenous and exogenous challenges. Repeated short-term stress leads to long-term stress, which disrupts physiological homeostasis. Unlike domestic animals, wild animals are not protected from environmental and weather influences or treated for diseases. In addition, climate change, habitat fragmentation and loss, and urban stressors (such as light, noise and chemical pollution; xenobiotics; traffic; and buildings) affect individual wildlife and populations. In this review, we have attempted to depict the magnitude of the stress response in wildlife and related domestic animals as well as in captive and free-ranging animals. The intensity of the stress response can be estimated by determining the concentration of glucocorticoids in body fluids, tissues, and excreta. A comparison of results from different studies suggests that domestic animals have lower fecal and hair glucocorticoid concentrations than related wild animals. Additionally, fecal and hair glucocorticoid concentrations in captive animals are higher than in free-ranging animals of the same species. As there are limited data on this topic, we cannot draw definitive conclusions about glucocorticoid concentration and stress response. Further studies are needed to clarify these issues.
Collapse
Affiliation(s)
- Mina Cansu Karaer
- Food and Agriculture Vocational School, Çankiri Karatekin University, Çankiri, Türkiye
| | - Nina Čebulj-Kadunc
- Veterinary Faculty, Institute of Preclinical Sciences, University of Ljubljana, Gerbičeva, Ljubljana, Slovenia
| | - Tomaž Snoj
- Veterinary Faculty, Institute of Preclinical Sciences, University of Ljubljana, Gerbičeva, Ljubljana, Slovenia
- *Correspondence: Tomaž Snoj
| |
Collapse
|
4
|
Petrullo L, Delaney D, Boutin S, McAdam AG, Lane JE, Boonstra R, Palme R, Dantzer B. The glucocorticoid response to environmental change is not specific to agents of natural selection in wild red squirrels. Horm Behav 2022; 146:105262. [PMID: 36191397 DOI: 10.1016/j.yhbeh.2022.105262] [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: 06/14/2022] [Revised: 08/30/2022] [Accepted: 09/07/2022] [Indexed: 11/04/2022]
Abstract
Evolutionary endocrinology aims to understand how natural selection shapes endocrine systems and the degree to which endocrine systems themselves can induce phenotypic responses to environmental changes. Such responses may be specialized in that they reflect past selection for responsiveness only to those ecological factors that ultimately influence natural selection. Alternatively, endocrine responses may be broad and generalized, allowing organisms to cope with a variety of environmental changes simultaneously. Here, we empirically tested whether the endocrine response of female North American red squirrels (Tamiasciurus hudsonicus) was specialized or generalized. We first quantified the direction and magnitude of natural selection acting on three female life history traits (parturition date, litter size, offspring postnatal growth rate) during 32 years of fluctuations in four potential ecological agents of selection (food availability, conspecific density, predator abundance, and temperature). Only three of the four variables (food, density, and predators) affected patterns of natural selection on female life history traits. We then quantified fecal glucocorticoid metabolites (FGMs) across 7 years and found that all four environmental variables, regardless of their effects on patterns of selection, were associated with glucocorticoid production. Our results provide support for a generalized, rather than specific, glucocorticoid response to environmental change that can integrate across multiple co-occurring environmental stressors.
Collapse
Affiliation(s)
- Lauren Petrullo
- Department of Psychology, University of Michigan, Ann Arbor, MI 48108, USA.
| | - David Delaney
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Andrew G McAdam
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, Centre for the Neurobiology of Stress, University of Toronto Scarborough, Toronto, ON M1C 1A6, Canada
| | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterina ̈rplatz 1, Vienna 1210, Austria
| | - Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI 48108, USA; Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48108, USA
| |
Collapse
|
5
|
Kamgang VW, Bennett NC, van der Goot AC, Majelantle TL, Ganswindt A. Patterns of faecal glucocorticoid metabolite levels in captive roan antelope (Hippotragus equinus) in relation to reproductive status and season. Gen Comp Endocrinol 2022; 325:114052. [PMID: 35568230 DOI: 10.1016/j.ygcen.2022.114052] [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: 02/27/2021] [Revised: 02/19/2022] [Accepted: 05/07/2022] [Indexed: 11/18/2022]
Abstract
Populations of roan antelope (Hippotragus equinus) in southern Africa have experienced a drastic decline over the past few decades and this situation has led to the development of intensive breeding programmes to support conservation efforts. However, little is known about related welfare aspects, including stress-related physiological biomarkers. The present study set out to establish a non-invasive method to monitor faecal glucocorticoid metabolite (fGCM) concentrations as a measure of stress and determine fGCM concentrations in relation to male reproductive activity and female reproductive status in the roan antelope. An adrenocorticotrophic hormone challenge was performed using two adult roan antelope (one male and one female) at Lapalala Wilderness Nature Reserve, South Africa, to determine the suitability of five enzyme immunoassays (EIA) for monitoring adrenocortical function in roan antelope. An 11-oxoaetiocholanolone I EIA detecting 11,17 dioxoandrostanes performed best showing 17-20 folds increases in fGCM concentrations after 12 h-17 h post-injection. The identified EIA was then used to monitor fGCM concentrations during active and non-active reproductive periods in males (n = 3), and during periods of cyclicity, gestation, and postpartum in females (n = 10). Males showed an overall 80% increase in fGCM concentrations when reproductively active and females showed a progressively significant increase in fGCM levels throughout pregnancy, with overall fGCM concentrations being 1.5 to 2.6-fold higher than the respective fGCM concentrations during periods of postpartum and cyclicity, respectively. Furthermore, fGCM concentrations remained above baseline for up to 21 days post-partum. A correlation between ecological parameters (rainfall and temperature) and fGCM concentrations revealed elevated fGCM concentrations during the dry season for males, but not females. The non-invasive method validated in this study provides a valuable tool to quantify stress-related biomarkers in roan antelope, and findings can be used to support management decisions in conservation breeding facilities.
Collapse
Affiliation(s)
- Vanessa W Kamgang
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield 0028, South Africa.
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield 0028, South Africa
| | - Annemieke C van der Goot
- Lapalala Wilderness Nature Reserve, Vaalwater 0530, South Africa; Melkrivier Wildlife Veterinary Services, Melkrivier, Vaalwater 0530, South Africa
| | - Tshepiso L Majelantle
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield 0028, South Africa
| | - Andre Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Hatfield 0028, South Africa
| |
Collapse
|
6
|
O'Brien SL, Irian CG, Bentley GE, Lacey EA. Sex, not social behavior, predicts fecal glucocorticoid metabolite concentrations in a facultatively social rodent, the highland tuco-tuco (Ctenomys opimus). Horm Behav 2022; 141:105152. [PMID: 35286897 DOI: 10.1016/j.yhbeh.2022.105152] [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: 10/22/2021] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 11/24/2022]
Abstract
Social relationships may influence circulating glucocorticoid levels, particularly in group-living species in which individuals regularly engage in interactions with conspecifics. The effects of such interactions appear to vary, with greater social contact being associated with increased glucocorticoid concentrations in some species but decreased concentrations in others. These distinct responses raise intriguing questions regarding relationships among social behavior, individual phenotypes, and glucocorticoid physiology. To explore such relationships in a free-living mammal with a dynamic social organization, we quantified variation in baseline glucocorticoids in a population of highland tuco-tucos (Ctenomys opimus) from Jujuy Province, Argentina. These subterranean rodents are facultatively social, with lone and group-living individuals regularly occurring within the same population. To assess potential endocrine correlates of this behavioral variability, we examined differences in baseline fecal glucocorticoid metabolite (fGCm) concentrations as a function of social group size and composition as well as several metrics of social behavior derived from social network analyses. Despite marked variability in social relationships among the 37 (12 male, 25 female) free-living tuco-tucos sampled, none of the measures of social behavior examined were significant predictors of variation in fGCm concentrations. In contrast, individual variation in glucocorticoid metabolites was best explained by sex, with males having higher fGCm concentrations than females. These analyses provide the first characterization of the glucocorticoid physiology of highland tuco-tucos and underscore the potential importance of intrinsic phenotypic factors (e.g., sex) in shaping glucocorticoid variation in free-living mammals.
Collapse
Affiliation(s)
- Shannon L O'Brien
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA; Department of Integrative Biology, University of California, Berkeley, CA 94720, USA.
| | - Christian G Irian
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA
| | - George E Bentley
- Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| | - Eileen A Lacey
- Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720, USA; Department of Integrative Biology, University of California, Berkeley, CA 94720, USA
| |
Collapse
|
7
|
Santicchia F, Wauters LA, Tranquillo C, Villa F, Dantzer B, Palme R, Preatoni D, Martinoli A. Invasive alien species as an environmental stressor and its effects on coping style in a native competitor, the Eurasian red squirrel. Horm Behav 2022; 140:105127. [PMID: 35121301 DOI: 10.1016/j.yhbeh.2022.105127] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 11/15/2021] [Accepted: 01/24/2022] [Indexed: 01/17/2023]
Abstract
Free-living animals cope with environmental stressors through physiological and behavioural responses. According to the unidimensional model, these responses are integrated within a coping style: proactive individuals (bold, active-explorative and social) have a lower hypothalamic-pituitary-adrenal (HPA) axis reactivity than reactive ones (shy, less active-explorative, less social). These associations may change when individuals are exposed to human-induced rapid environmental change (HIREC), such as the introduction of invasive alien species (IAS). Here, we studied Eurasian red squirrels to investigate the relationship between personality traits and one integrated measure of HPA axis activity, both in areas uncolonized (natural populations) and colonized by an IAS, the Eastern grey squirrel (invaded populations). We expected an association between physiological and behavioural responses, and that activity, exploration and social tendency would covary, forming a behavioural syndrome in natural populations, while competition with the IAS was predicted to disrupt these associations. We used faecal glucocorticoid metabolites (FGMs) as an integrated measure of adrenocortical activity, and measured the levels of four personality traits (exploration, activity, activity-exploration and social tendency) with an open field test and a mirror image stimulation test. We found no correlation between FGMs and personality traits, neither in natural nor invaded populations. However, we found correlations among personality traits in areas without interspecific competition, indicating a behavioural syndrome, which was disrupted in invaded populations. This is one of the few studies showing that an IAS, acting as an environmental stressor, alters a native species' behavioural syndrome, but does not influence its coping style.
Collapse
Affiliation(s)
- Francesca Santicchia
- Environment Analysis and Management Unit, Guido Tosi Research Group, Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy.
| | - Lucas Armand Wauters
- Environment Analysis and Management Unit, Guido Tosi Research Group, Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy; Evolutionary Ecology Group, Department of Biology, University of Antwerp, Campus Drie Eiken Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Claudia Tranquillo
- Environment Analysis and Management Unit, Guido Tosi Research Group, Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Federica Villa
- Environment Analysis and Management Unit, Guido Tosi Research Group, Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Ben Dantzer
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109, USA; Department of Ecology and Evolutionary Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109, USA
| | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria
| | - Damiano Preatoni
- Environment Analysis and Management Unit, Guido Tosi Research Group, Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Adriano Martinoli
- Environment Analysis and Management Unit, Guido Tosi Research Group, Department of Theoretical and Applied Sciences, Università degli Studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| |
Collapse
|
8
|
Donini V, Iacona E, Pedrotti L, Macho-Maschler S, Palme R, Corlatti L. Temporal stability of fecal cortisol metabolites in mountain-dwelling ungulates. Naturwissenschaften 2022; 109:20. [PMID: 35325316 PMCID: PMC8948117 DOI: 10.1007/s00114-022-01792-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 11/27/2022]
Abstract
Fecal cortisol metabolites (FCMs) are widely used to track stress responses in wildlife and captive species. Rules of thumb suggest that samples should be collected as soon as possible after defecation, to avoid decay of FCMs. To date, however, only a few studies investigated the stability of defecated FCMs over time, and most of them were conducted in controlled laboratory conditions. Here, we investigated the stability of FCMs over seven consecutive days, in two mountain-dwelling ungulates, under natural environmental conditions using a semi-experimental approach. Fecal samples from Northern chamois Rupicapra rupicapra (n = 24) and red deer Cervus elaphus (n = 22) were collected in summer of 2020 within the Stelvio National Park, Italy, and placed in an open area above 2000 m a.s.l. For the next 7 days, we collected a portion of each sample, and all sub-samples were analyzed with an 11-oxoetiocholanolone enzyme immunoassay. Exposure, temperature, and precipitation were fitted as covariates in non-linear generalized mixed models to assess FCM variation over time, and competing models were selected using AICc. For chamois, the best model included only time as a predictor, while for red deer, it included time, precipitation, and exposure. For both species, FCM values decreased rapidly from the first days after deposition until the fourth day. For red deer, in northern-exposed samples, FCM values decreased slower than in south-exposed ones; furthermore, FCM values increased with increasing precipitation. Our results offer a solid methodological basis to wildlife researchers and practitioners interested in the investigation of the ecological factors affecting stress variation in wildlife and support the recommendation to collect samples as fresh as possible, to avoid misleading inference. Further studies are necessary to evaluate the stability of FCMs when other enzyme immunoassays are used.
Collapse
Affiliation(s)
- Valerio Donini
- Stelvio National Park - ERSAF Lombardia, Via De Simoni 42, 23032, Bormio, Italy
| | - Elisa Iacona
- Stelvio National Park - ERSAF Lombardia, Via De Simoni 42, 23032, Bormio, Italy
| | - Luca Pedrotti
- Stelvio National Park - ERSAF Lombardia, Via De Simoni 42, 23032, Bormio, Italy
- Stelvio National Park - Autonomous Province of Trento, Via Roma 65, 38024, Cogolo di Peio, Italy
| | - Sabine Macho-Maschler
- Department of Biomedical Sciences, Unit of Physiology, Pathophysiology and Experimental Endocrinology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Rupert Palme
- Department of Biomedical Sciences, Unit of Physiology, Pathophysiology and Experimental Endocrinology, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Luca Corlatti
- Stelvio National Park - ERSAF Lombardia, Via De Simoni 42, 23032, Bormio, Italy.
- Chair of Wildlife Ecology and Management, University of Freiburg, Tennenbacher Straße 4, 79106, Freiburg, Germany.
| |
Collapse
|
9
|
Glucocorticoids coordinate changes in gut microbiome composition in wild North American red squirrels. Sci Rep 2022; 12:2605. [PMID: 35173201 PMCID: PMC8850573 DOI: 10.1038/s41598-022-06359-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/24/2022] [Indexed: 12/31/2022] Open
Abstract
The gut microbiome impacts host health and fitness, in part through the diversification of gut metabolic function and pathogen protection. Elevations in glucocorticoids (GCs) appear to reduce gut microbiome diversity in experimental studies, suggesting that a loss of microbial diversity may be a negative consequence of increased GCs. However, given that ecological factors like food availability and population density may independently influence both GCs and microbial diversity, understanding how these factors structure the GC-microbiome relationship is crucial to interpreting its significance in wild populations. Here, we used an ecological framework to investigate the relationship between GCs and gut microbiome diversity in wild North American red squirrels (Tamiasciurus hudsonicus). As expected, higher GCs predicted lower gut microbiome diversity and an increase in metabolic taxa. Surprisingly, but in line with prior empirical studies on wild animals, gastrointestinal pathogens decreased as GCs increased. Both dietary heterogeneity and an upcoming food pulse exhibited direct effects on gut microbiome diversity, whereas conspecific density and reproductive activity impacted diversity indirectly via changes in host GCs. Our results provide evidence of a gut–brain axis in wild red squirrels and highlight the importance of situating the GC-gut microbiome relationship within an ecological framework.
Collapse
|
10
|
Zhang VY, Buck CL. Seasonal patterns in behavior and glucocorticoid secretion of a specialist Holarctic tree squirrel (Sciurus aberti). J Comp Physiol B 2022; 192:541-559. [DOI: 10.1007/s00360-022-01429-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 01/10/2022] [Accepted: 01/26/2022] [Indexed: 10/19/2022]
|
11
|
Shimamoto T. Validation and utility of hair cortisol analysis as a measure of long-term physiological stress in the Pallas's squirrel Callosciurus erythraeus. Gen Comp Endocrinol 2022; 316:113944. [PMID: 34826428 DOI: 10.1016/j.ygcen.2021.113944] [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: 05/14/2021] [Revised: 09/08/2021] [Accepted: 11/18/2021] [Indexed: 11/15/2022]
Abstract
In various mammalian species, there has been an increase in the use of hair cortisol analysis to evaluate long-term stress. This trend is because of some advantages relative to the standard tools, such as hormone analysis using blood, urine, or feces. Here, I carried out assay validation and adrenocorticotrophic hormone (ACTH) challenge to measure long-term stress in Pallas's squirrel Callosciurus erythraeus. In addition, I investigated the effects of sex, body condition, season, and reproductive conditions on hair cortisol concentrations (HCC) in free-living individuals. The assay validation was reported in this study. Hair cortisol concentrations in squirrels given repeated ACTH injections were significantly higher than those that received a single-ACTH injection and a saline injection. I found a negative effect of body condition on adult HCC. In contrast, body condition had a positive effect on HCC in juveniles. I found no effects of other factors in either adult or juvenile squirrels. Furthermore, although I investigated whether reproductive conditions, such as pregnancy, lactation, and non-breeding in females or testis size in males, affected HCC, I found that there were no effects of reproductive conditions. This study validated the assay and utility of hair cortisol analysis to assess long-term stress, and continuous investigation of the relationship between HCC and fitness is important for determining whether hair cortisol analysis is a reliable method for estimating population health in Pallas's squirrels.
Collapse
Affiliation(s)
- Tatsuki Shimamoto
- Department of Veterinary Nursing and Technology, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino, Tokyo 180-8602, Japan.
| |
Collapse
|
12
|
Guo Z, Li S, Wu J, Zhu X, Zhang Y. Maternal Deprivation Increased Vulnerability to Depression in Adult Rats Through DRD2 Promoter Methylation in the Ventral Tegmental Area. Front Psychiatry 2022; 13:827667. [PMID: 35308874 PMCID: PMC8924051 DOI: 10.3389/fpsyt.2022.827667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/21/2022] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE Early life adversity is a risk factor for depression in adulthood; however, the underlying mechanisms are not well understood. This study aims to investigate the effect of DNA methylation of DRD2 gene on early life stress-induced depression in adult rats. METHODS Newborn Sprague-Dawley rats were randomly assigned to four groups: maternal deprivation group (MD), chronic unpredictable stress (CUS) group, maternal deprivation plus chronic unpredictable stress (MD/CUS) group, and normal control group (NOR). Behaviors were measured by open field test (OFT), sucrose preference test (SPT), and Original Research Article forced swimming test (FST). Fecal CORT level was detected by ELISA. Bisulfite amplicon sequencing PCR was used to assess methylation levels of DRD2 promoter. RESULTS CUS and MD/CUS rats had a significantly shorter total distance, longer immobility time, and higher CORT level, while MD and MD/CUS rats had a significantly lower percentage of central distance, more feces, lower rate of sucrose preference, and lower levels of DRD2 protein and mRNA in the VTA than NOR rats. CUS rats showed a significantly higher DRD2 mRNA and protein levels in the VTA than NOR rats. CUS, MD, and MD/CUS rats showed a significantly higher level of DRD2 promoter methylation than NOR rats. CORT level was significantly correlated with the sucrose preference rate in SPT, the immobility time in FST, the total distance, and the number of fecal pellets in OFT. DRD2 protein level was significantly correlated with the sucrose preference rate and the number of fecal pellets. DRD2 mRNA level was significantly correlated with the percentage of central distance and the number of fecal pellets in OFT. The level of DRD2 promoter methylation was significantly correlated with the sucrose preference rate, immobility time, total distance, the percentage of central distance, and the number of fecal pellets. CONCLUSIONS Early life MD increased vulnerability to stress-induced depressive-like behavior in adult rats. Enhanced DRD2 promoter methylation in the VTA may increase the susceptibility to depression.
Collapse
Affiliation(s)
- Zhenli Guo
- Medical Psychological Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Shansi Li
- Medical Psychological Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Jialing Wu
- Medical Psychological Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Xiongzhao Zhu
- Medical Psychological Center, The Second Xiangya Hospital, Central South University, Changsha, China.,Medical Psychological Institute of Central South University, Central South University, Changsha, China.,National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yi Zhang
- Medical Psychological Center, The Second Xiangya Hospital, Central South University, Changsha, China.,Medical Psychological Institute of Central South University, Central South University, Changsha, China.,National Clinical Research Center for Mental Disorders, The Second Xiangya Hospital, Central South University, Changsha, China
| |
Collapse
|
13
|
Dantzer B, Boutin S, Lane JE, McAdam AG. Integrative Studies of the Effects of Mothers on Offspring: An Example from Wild North American Red Squirrels. ADVANCES IN NEUROBIOLOGY 2022; 27:269-296. [PMID: 36169819 DOI: 10.1007/978-3-030-97762-7_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Animal species vary in whether they provide parental care or the type of care provided, and this variation in parental care among species has been a common focus of comparative studies. However, the proximate causes and ultimate consequences of within-species variation in parental care have been less studied. Most studies about the impacts of within-species variation in parental care on parental fitness have been in primates, whereas studies in laboratory rodents have been invaluable for understanding what causes inter-individual variation in parental care and its influence on offspring characteristics. We integrated both of these perspectives in our long-term study of North American red squirrels (Tamiasciurus hudsonicus) in the Yukon, Canada, where we have focused on understanding the impacts of mothers on offspring. This includes documenting the impacts that mothers or the maternal environment itself has on their offspring, identifying how changes in maternal physiology impact offspring characteristics, the presence of individual variation in maternal attentiveness toward offspring before weaning and its fitness consequences, and postweaning maternal care and its fitness consequences. We provide an overview of these contributions to understanding the impacts mothers have on their offspring in red squirrels using an integrative framework and contrast them with studies in the laboratory.
Collapse
Affiliation(s)
- Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA.
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Andrew G McAdam
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| |
Collapse
|
14
|
Josefson CC, Skibiel AL. Changes in maternal fecal corticosterone metabolites across lactation and in response to chronic stress. Gen Comp Endocrinol 2021; 314:113916. [PMID: 34555412 DOI: 10.1016/j.ygcen.2021.113916] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 11/26/2022]
Abstract
Maternal exposure to stressors during lactation has previously been demonstrated to impact various aspects of milk synthesis and to have long-term physiological effects on offspring. Much of the current literature investigating the effects of stress during lactation has used acute stressors, and the studies investigating the effects of chronic stressors largely focus on neurological changes. Further, temporal variation in glucocorticoids across lactation in response to stressors has rarely been assessed. The present work uses a novel male intruder paradigm to model the effects of chronic stress on maternal fecal corticosterone metabolites (FCMs) in Sprague-Dawley rats across lactation. FCM levels were elevated in chronically-stressed mothers relative to the control group. Further, FCMs in the stress group were time-dependent either due to repeated exposure to the stressor or lactation stage. Together, this work demonstrates the efficacy of this established paradigm in increasing circulating glucocorticoids in lactating rats. These results highlight the need for repeated temporal sampling, as glucocorticoid levels in response to a chronic stressor may change across lactation.
Collapse
Affiliation(s)
- Chloe C Josefson
- Department of Animal, Veterinary and Food Sciences, University of Idaho, 875 Perimeter Dr., MS 2330, Moscow, ID 83844-2330, USA.
| | - Amy L Skibiel
- Department of Animal, Veterinary and Food Sciences, University of Idaho, 875 Perimeter Dr., MS 2330, Moscow, ID 83844-2330, USA.
| |
Collapse
|
15
|
Maly MA, Edwards KL, Koester DC, Farin CE, Crosier AE. Assessing puberty in female cheetahs (Acinonyx jubatus) via faecal hormone metabolites and body weight. Reprod Fertil Dev 2021; 33:841-854. [PMID: 34844663 DOI: 10.1071/rd21169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 10/29/2021] [Indexed: 11/23/2022] Open
Abstract
With fewer than 7500 cheetahs remaining in the wild, ex situ cheetah populations serve as an insurance policy against extinction and a resource to study species' biology. This study aimed to identify the age of pubertal onset in ex situ female cheetahs using non-invasive faecal steroid hormone monitoring and body weights. Faecal samples from nine female cheetahs were collected two to three times weekly from 2 to 36months of age and body weights were recorded every 3months. Faecal oestrogen metabolites (FOM) and faecal glucocorticoid metabolites (FGM) were analysed using enzyme immunoassays and samples were categorised into 6-month intervals to compare endocrine characteristics. Faecal hormone and body weight data were analysed using generalised linear mixed models. Age was a significant predictor of mean and baseline FOM concentrations, number of FOM peaks, mean and maximum FOM peak concentrations and the number of cycles. Female cheetahs aged 24-30months exhibited a marked rise in mean FOM concentration and the number of FOM peaks and cycles increased with age until 24-30months. Females attained adult body weight by 21months of age. Mean and baseline FGM concentrations were highest at the 0-6 and 12-18months of age groups and did not follow the same FOM patterns. Based on body weight data, the FOM concentrations and peak patterning, females were considered pubertal from 24 to 30months of age. Characterisation of cheetah puberty has direct and significant implications for the improvement of management and reproductive success of cheetahs under human care. This information is particularly informative for identifying important windows of development, littermate dispersal and breeding introductions.
Collapse
Affiliation(s)
- Morgan A Maly
- Center for Species Survival, Smithsonian Conservation Biology Institute, Front Royal, VA 22630, USA; and Genetics Program, Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA; and Genetics Program, Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
| | - Katie L Edwards
- Center for Species Survival, Smithsonian Conservation Biology Institute, Front Royal, VA 22630, USA; and North of England Zoological Society, Chester Zoo, Upton-by-Chester CH2 1LH, UK
| | - Diana C Koester
- Department of Conservation and Science, Cleveland Metroparks Zoo, Cleveland, OH 44109, USA
| | - Charlotte E Farin
- Department of Animal Science, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Adrienne E Crosier
- Center for Species Survival, Smithsonian Conservation Biology Institute, Front Royal, VA 22630, USA
| |
Collapse
|
16
|
Medger K, Prins A, Lutermann H, Ganswindt A, Ganswindt SB, Bennett NC. Repeatability of daily profiles of baseline glucocorticoid metabolites measured in the urine and faeces of eastern rock sengis (Elephantulus myurus). Gen Comp Endocrinol 2021; 312:113857. [PMID: 34284023 DOI: 10.1016/j.ygcen.2021.113857] [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: 12/29/2020] [Revised: 06/24/2021] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
Repeatability of hormone concentrations is of great interest for studies investigating the evolution of hormonal traits. Particularly the repeatability of glucocorticoids (GCs) in response to a stressor is frequently investigated, but often only point (initial and/or response value), or single measures are used. A new method takes into account the entire individual hormone profile and generates an individual profile repeatability (PR) score. The method was developed for response profiles, but it may also be valuable for baseline values in species with diurnal changes in hormone concentrations. GCs are determined in a variety of matrices, and repeatability can vary considerably depending on the matrix. We investigated the repeatability of baseline GC metabolite (GCM) concentrations measured in urine (uGCM) and faeces (fGCM) of captive eastern rock sengis (Elephantulus myurus) using the more traditional linear mixed model approach and the PR method. GCMs were assessed over 24 h and measurements were repeated twice with two weeks between replicates. A diurnal rhythm in GCM concentrations associated with the activity period of the sengis was found in urine, but not in the faeces. Urinary GCM concentrations exhibited a moderate repeatability, whereas the repeatability of fGCM concentrations was low. Urinary GCM concentrations and their repeatability differed between the sexes; with higher concentrations and lower PR scores in females. No such sex differences were apparent for fGCM concentrations and the PR score was not able to characterise repeatability of fGCM concentrations, which were lacking a distinct profile. The PR score enabled a successful quantification of the repeatability of the diurnal uGCM profiles. Hormone profile, sex and sample matrix can affect hormonal traits considerably and the results may be obscured if these factors are not carefully considered.
Collapse
Affiliation(s)
- Katarina Medger
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.
| | - André Prins
- Mammal Research Institute, 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
| | - André Ganswindt
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Stefanie B Ganswindt
- 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
| |
Collapse
|
17
|
Bleke CA, Gese EM, French SS. Variations, validations, degradations, and noninvasive determination of pregnancy using fecal steroid metabolites in free-ranging pronghorn. Gen Comp Endocrinol 2021; 312:113841. [PMID: 34217705 DOI: 10.1016/j.ygcen.2021.113841] [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: 12/31/2020] [Revised: 06/26/2021] [Accepted: 06/29/2021] [Indexed: 10/21/2022]
Abstract
Pregnancy status is a key parameter used to assess reproductive performance of a species as it represents a starting point for measuring vital rates. Vital rates allow managers to determine trends in populations such as neonate survival and recruitment; two important factors in ungulate population growth rates. Techniques to determine pregnancy have generally involved capture and restraint of the animal to obtain blood samples for determining serum hormone levels. Non-invasive pregnancy assessment, via feces, eliminates any hazards between handler and animal, as well as removes handling-induced physiological biases. Using noninvasive fecal sampling, we conducted hormone validations, investigated pregnancy rates, and determined hormone degradation rates across five subpopulations of pronghorn (Antilocapra americana) in Idaho. Samples were collected during April-May of 2018 and 2019 from adult pronghorn of known sex and age class. Metabolites of testosterone, cortisol, 17β-estradiol, and progesterone were measured in fecal samples, and concentrations of estradiol and progesterone were examined for pregnancy determination. Average fecal progesterone metabolite (FPM) levels of pregnant females were more than double compared to levels of nonpregnant females. Fecal estrogen metabolite (FEM) levels did not differ during concurrent sampling. The largest difference in FPM levels between pregnant and nonpregnant females began on 28 April. Pregnancy determination sampling showed average FPM levels for all five subpopulations were significantly different than the nonpregnant female validation group. Nonetheless, pregnancy rates for some subpopulations lacked conclusive estimates due to early fecal sampling. Fecal glucocorticoid metabolites (FGM) levels significantly differed between pregnant females and male pronghorn, but did not differ from nonpregnant females. Degradation rates of FPM and FGM differed across days, with values for FPM from Day 1 being significantly different from all subsequent days, and after Day 9 for FGM, demonstrating the requirement of fresh samples to accurately measure hormone concentrations. We concluded that a noninvasive method to diagnosis pregnancy is possible in pronghorn via progesterone metabolites if fresh samples are collected during late gestation.
Collapse
Affiliation(s)
- Cole A Bleke
- Department of Wildland Resources, Utah State University, Logan, UT 84322, USA.
| | - Eric M Gese
- U.S. Department of Agriculture-Wildlife Services-National Wildlife Research Center, Department of Wildland Resources, Utah State University, Logan, UT 84322, USA.
| | - Susannah S French
- Department of Biology and the Ecology Center, Utah State University, Logan, UT 84322, USA.
| |
Collapse
|
18
|
Jepsen EM, Scheun J, Dehnhard M, Kumar V, Umapathy G, Ganswindt A. Non-invasive monitoring of glucocorticoid metabolite concentrations in native Indian, as well as captive and re-wilded tigers in South Africa. Gen Comp Endocrinol 2021; 308:113783. [PMID: 33862051 DOI: 10.1016/j.ygcen.2021.113783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/19/2021] [Accepted: 04/09/2021] [Indexed: 11/23/2022]
Abstract
Over the last century, wild tiger (Panthera tigris) numbers have declined from over 100 000 individuals to fewer than 4 000, with animals now confined to less than 5% of their historic range due to habitat loss, persecution, inadequate management, and poaching. In contrast, 15 000-20 000 tigers are estimated to be housed in captivity, experiencing conditions vastly different than their wild counterparts. A total of 280 tigers are currently held at 44 different facilities within South Africa, including zoos, semi-captive 're-wilded' populations, and pets; these animals provide a unique opportunity to measure the impact of extrinsic factors, found in exotic habitats, on the adrenocortical activity of tigers. By monitoring and comparing stress-related faecal glucocorticoid metabolite (fGCM) concentrations of tigers housed at different locations, and free ranging tigers in natural tiger reserves, this project aimed to get a better understanding of the impact of extrinsic factors on adrenocortical function as a measure of stress. The results of this study showed no significant difference in fGCM concentrations between captive, re-wilded, and free-ranging tigers with the exception of one site. Furthermore, factors such as sex and season were not significant drivers of fGCM concentrations. One study group had elevated fGCM concentrations, showing population variation in the stress response. This indicates that populations are able to cope with exotic environments, however, as population-specific differences in the stress response exist, we suggest management protocols be created for each population. This study offered the unique opportunity to see how well tigers are faring outside of their native range and if having re-wilded tigers in exotic locations is a potential welfare-acceptable management option for tiger conservation globally.
Collapse
Affiliation(s)
- Emma M Jepsen
- Mammal Research Institute, University of Pretoria, Private Bag X20, Pretoria, South Africa.
| | - Juan Scheun
- Mammal Research Institute, University of Pretoria, Private Bag X20, Pretoria, South Africa; Department of Life and Consumer Sciences, University of South Africa, South Africa; National Zoological Garden, South African National Biodiversity Institute, South Africa
| | - Martin Dehnhard
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Vinod Kumar
- Laboratory for the Conservation of Endangered Species, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Govindhaswamy Umapathy
- Laboratory for the Conservation of Endangered Species, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - André Ganswindt
- Mammal Research Institute, University of Pretoria, Private Bag X20, Pretoria, South Africa
| |
Collapse
|
19
|
Behavioral interactions and glucocorticoid production of Somali wild ass (Equus africanus somaliensis) mothers and foals. Appl Anim Behav Sci 2021. [DOI: 10.1016/j.applanim.2021.105337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
20
|
Moagi LL, Bourne AR, Cunningham SJ, Jansen R, Ngcamphalala CA, Ganswindt A, Ridley AR, McKechnie AE. Hot days are associated with short-term adrenocortical responses in a southern African arid-zone passerine bird. J Exp Biol 2021; 224:268362. [PMID: 34032270 DOI: 10.1242/jeb.242535] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 04/21/2021] [Indexed: 12/15/2022]
Abstract
Relatively little effort has been directed towards elucidating the role of physiological stress pathways in mediating avian responses to global heating. For free-ranging southern pied babblers, Turdoides bicolor, daily maximum air temperatures (Tmax) between ∼35 and ∼40°C result in reduced foraging efficiency, loss of body mass and compromised breeding success. We tested the hypothesis that very hot days are experienced as stressors by quantifying relationships between Tmax and faecal glucocorticoid metabolite (fGCM) levels in naturally excreted droppings. On days when Tmax<38°C, fGCM levels were independent of Tmax (mean±s.d. 140.25±56.92 ng g-1 dry mass). At Tmax>38°C, however, fGCM levels increased linearly with Tmax and averaged 190.79±70.13 ng g-1 dry mass. The effects of Tmax on fGCM levels did not carry over to the following morning, suggesting that very hot days are experienced as acute stressors.
Collapse
Affiliation(s)
- Lesedi L Moagi
- South African Research Chair in Conservation Physiology, National Zoological Garden, South African National Biodiversity Institute, Pretoria 0001, South Africa.,Department of Nature Conservation, Tshwane University of Technology, Pretoria 0001, South Africa
| | - Amanda R Bourne
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa
| | - Susan J Cunningham
- FitzPatrick Institute of African Ornithology, DSI-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa
| | - Raymond Jansen
- Department of Environmental, Water and Earth Sciences, Tshwane University of Technology, Pretoria 0001, South Africa
| | - Celiwe A Ngcamphalala
- South African Research Chair in Conservation Physiology, National Zoological Garden, South African National Biodiversity Institute, Pretoria 0001, South Africa.,DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - André Ganswindt
- Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Amanda R Ridley
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, Crawley, Perth, WA 6009Australia
| | - Andrew E McKechnie
- South African Research Chair in Conservation Physiology, National Zoological Garden, South African National Biodiversity Institute, Pretoria 0001, South Africa.,DSI-NRF Centre of Excellence at the FitzPatrick Institute, Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| |
Collapse
|
21
|
Whipple AL, Ray C, Wasser M, Kitchens JN, Hove AA, Varner J, Wilkening JL. Temporal vs. spatial variation in stress-associated metabolites within a population of climate-sensitive small mammals. CONSERVATION PHYSIOLOGY 2021; 9:coab024. [PMID: 34026212 PMCID: PMC8127223 DOI: 10.1093/conphys/coab024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 02/04/2021] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
Temporal variation in stress might signify changes in an animal's internal or external environment, while spatial variation in stress might signify variation in the quality of the habitats that individual animals experience. Habitat-induced variations in stress might be easiest to detect in highly territorial animals, and especially in species that do not take advantage of common strategies for modulating habitat-induced stress, such as migration (escape in space) or hibernation (escape in time). Spatial and temporal variation in response to potential stressors has received little study in wild animals, especially at scales appropriate for relating stress to specific habitat characteristics. Here, we use the American pika (Ochotona princeps), a territorial small mammal, to investigate stress response within and among territories. For individually territorial animals such as pikas, differences in habitat quality should lead to differences in stress exhibited by territory owners. We indexed stress using stress-associated hormone metabolites in feces collected non-invasively from pika territories every 2 weeks from June to September 2018. We hypothesized that differences in territory quality would lead to spatial differences in mean stress and that seasonal variation in physiology or the physical environment would lead to synchronous variation across territories through time. We used linear mixed-effects models to explore spatiotemporal variation in stress using fixed effects of day-of-year and broad habitat characteristics (elevation, aspect, site), as well as local variation in habitat characteristics hypothesized to affect territory quality for this saxicolous species (talus depth, clast size, available forage types). We found that temporal variation within territories was greater than spatial variation among territories, suggesting that shared seasonal stressors are more influential than differences in individual habitat quality. This approach could be used in other wildlife studies to refine our understanding of habitat quality and its effect on individual stress levels as a driver of population decline.
Collapse
Affiliation(s)
- Ashley L Whipple
- Department of Ecology and Evolutionary Biology, University of
Colorado, Boulder, CO 80309, USA
- Institute of Arctic and Alpine Research, University of
Colorado, Boulder, CO 80303, USA
| | - Chris Ray
- Department of Ecology and Evolutionary Biology, University of
Colorado, Boulder, CO 80309, USA
- Institute of Arctic and Alpine Research, University of
Colorado, Boulder, CO 80303, USA
| | - Max Wasser
- Department of Ecology and Evolutionary Biology, University of
Colorado, Boulder, CO 80309, USA
| | - James N Kitchens
- Department of Biology, Warren Wilson College,
Asheville, NC 28778, USA
| | - Alisa A Hove
- Department of Biology, Warren Wilson College,
Asheville, NC 28778, USA
| | - Johanna Varner
- Department of Biological Sciences, Colorado Mesa
University, Grand Junction, CO 81501, USA
| | - Jennifer L Wilkening
- US Fish and Wildlife Service, Southern Nevada Fish and Wildlife
Office, Las Vegas, NV 89130, USA
| |
Collapse
|
22
|
Veitch JSM, Bowman J, Mastromonaco G, Schulte-Hostedde AI. Corticosterone response by Peromyscus mice to parasites, reproductive season, and age. Gen Comp Endocrinol 2021; 300:113640. [PMID: 33017585 DOI: 10.1016/j.ygcen.2020.113640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/14/2020] [Accepted: 09/28/2020] [Indexed: 01/15/2023]
Abstract
A common response to parasite infestations is increased production of glucocorticoid hormones that regulate immune function. We examined relationships between ectoparasite infestations and fecal corticosterone metabolites (FCM) in deer mice (Peromyscus maniculatus). Furthermore, we experimentally removed fleas to determine if reductions in ectoparasites affected FCM production. Individuals were assigned to control (no flea removal) or treatment (anti-flea application, physical combing) groups and individuals were recaptured to assess changes in FCM concentrations. There was a significant and negative effect of number of anti-flea treatment applications on FCM concentrations of deer mice. However, models including host biology traits and environmental predictors had a better model fit compared to models containing ectoparasite predictors. In particular, there was a significant relationship of deer mouse FCM with date and host age, where glucocorticoid production decreased towards the end of the breeding season and increased with age. Overall, adverse events associated with reproduction and age class, rather than ectoparasites, may be more important to variation in glucocorticoids of deer mice.
Collapse
Affiliation(s)
- Jasmine S M Veitch
- Department of Biology, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON P3E 2C6, Canada. https://www.0000-0003-0010-3475
| | - Jeff Bowman
- Ontario Ministry of Natural Resources and Forestry, Wildlife Research and Monitoring Section, 2140 East Bank Drive, DNA Building, Peterborough, ON K9L 0G2, Canada; Trent University, 1600 East Bank Drive, Peterborough, ON K9L 0G2, Canada
| | - Gabriela Mastromonaco
- Reproductive Sciences, Toronto Zoo, 361A Old Finch Avenue, Toronto, ON M1B 5K7, Canada
| | - Albrecht I Schulte-Hostedde
- Department of Biology, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON P3E 2C6, Canada. https://www.0000-0001-7263-4764
| |
Collapse
|
23
|
Iglesias-Carrasco M, Aich U, Jennions MD, Head ML. Stress in the city: meta-analysis indicates no overall evidence for stress in urban vertebrates. Proc Biol Sci 2020; 287:20201754. [PMID: 33023414 PMCID: PMC7657868 DOI: 10.1098/rspb.2020.1754] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/14/2020] [Indexed: 12/12/2022] Open
Abstract
As cities continue to grow it is increasingly important to understand the long-term responses of wildlife to urban environments. There have been increased efforts to determine whether urbanization imposes chronic stress on wild animals, but empirical evidence is mixed. Here, we conduct a meta-analysis to test whether there is, on average, a detrimental effect of urbanization based on baseline and stress-induced glucocorticoid levels of wild vertebrates. We found no effect of urbanization on glucocorticoid levels, and none of sex, season, life stage, taxon, size of the city nor methodology accounted for variation in the observed effect sizes. At face value, our results suggest that urban areas are no more stressful for wildlife than rural or non-urban areas, but we offer a few reasons why this conclusion could be premature. We propose that refining methods of data collection will improve our understanding of how urbanization affects the health and survival of wildlife.
Collapse
Affiliation(s)
- Maider Iglesias-Carrasco
- Division of Evolution, Ecology and Genetics, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | | | | | | |
Collapse
|
24
|
Zhang VY, Williams CT, Palme R, Buck CL. Glucocorticoids and activity in free-living arctic ground squirrels: Interrelationships between weather, body condition, and reproduction. Horm Behav 2020; 125:104818. [PMID: 32698015 DOI: 10.1016/j.yhbeh.2020.104818] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/25/2020] [Accepted: 07/10/2020] [Indexed: 01/13/2023]
Abstract
The dynamic relationship between glucocorticoids and behavior are not well understood in wild mammals. We investigated how weather, body condition, and reproduction interact to affect cortisol levels and activity patterns in a free-living population of arctic ground squirrels (Urocitellus parryii). As a proxy for foraging and escape behaviors, collar-mounted accelerometers and light loggers were used to measure above-ground activity levels and the amount of time squirrels spent below the surface, respectively. Fecal cortisol metabolites (FCMs) were quantified to assess glucocorticoid secretion in squirrels. Male and female squirrels differed in above-ground activity levels and time spent below-ground across the active season, with males being most active during mating and females most active during lactation. We also found that female, but not male, squirrels exhibited seasonal variation in FCM levels, with concentrations highest during mid-lactation and lowest after the lactation period. In female squirrels, the seasonal relationships between breeding stage, activity, and FCM levels were also consistent with changes in maternal investment and the preparative role that glucocorticoids are hypothesized to play in energy mobilization. Body condition was not associated with FCM levels in squirrels. As predicted, deteriorating weather also influenced FCM levels and activity patterns in squirrels. FCM concentrations were affected by an interaction between temperature and wind speed when seasonal temperatures were lowest. In addition, above-ground activity, but not time spent below-ground, positively correlated with FCM levels. These results suggest that, although ground squirrels avoid inclement weather by remaining below-ground, activation of the stress axis may stimulate foraging activity.
Collapse
Affiliation(s)
- Victor Y Zhang
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Cory T Williams
- Institute of Arctic Biology and Department of Biology & Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, A-1210 Vienna, Austria
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
| |
Collapse
|
25
|
Assessment of the Stress Response in North American Deermice: Laboratory and Field Validation of Two Enzyme Immunoassays for Fecal Corticosterone Metabolites. Animals (Basel) 2020; 10:ani10071120. [PMID: 32630075 PMCID: PMC7401612 DOI: 10.3390/ani10071120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/20/2020] [Accepted: 06/26/2020] [Indexed: 12/18/2022] Open
Abstract
Simple Summary If we want to employ stress physiology in the management and conservation of wildlife populations, we need robust methods to quantify stress physiology in the field. Although this is typically done with blood glucocorticoids (GCs), scientists now increasingly use fecal cortisol/corticosterone metabolites (FCMs), which are metabolized GCs excreted in feces. However, immunoassays to measure FCMs need to be validated for each species. North American deermice (Peromyscus maniculatus; hereafter deermice) are commonly used in laboratory and field studies. Although a corticosterone radioimmunoassay (RIA) has been validated for deermice, there are no validated enzyme immunoassays (EIAs), which do not require radioactive materials. Through laboratory and field experiments, we validated two EIAs for measuring FCMs in deermice. Researchers can now use these EIAs to evaluate stress physiology in deermice without the need for radioactive materials. Abstract Stress physiology is commonly employed in studies of wildlife ecology and conservation. Accordingly, we need robust and suitable methods to measure stress physiology in the field. Fecal cortisol/corticosterone metabolites (FCMs) are now increasingly being used to non-invasively evaluate adrenocortical activity; a measure of stress physiology. However, immunoassays that measure FCMs must be appropriately validated prior to their use and factors that can influence FCMs, such as trap-induced stress, must be considered. Deermice (Peromyscus maniculatus) are widely used in scientific studies so that developing methods that appropriately measure their adrenocortical activity is critical. In the laboratory, we tested the suitability of two enzyme immunoassays (EIAs; a corticosterone EIA, and a group-specific 5α-pregnane-3β,11β,21-triol-20-one EIA) in deermice by challenging individuals with dexamethasone and adrenocorticotropic hormone (ACTH). We found that dexamethasone suppressed FCM levels within ~10 h post injection whereas ACTH increased FCM levels within ~2 h post injection. In the field, we found that FCM levels generally increased with more time in trap confinement when using both EIAs. Although we acknowledge low sample sizes (N = 4), our results validated the two EIAs for use with FCMs from deermice.
Collapse
|
26
|
Comparison of the Glucocorticoid Concentrations between Three Species of Lemuridae Kept in a Temporary Housing Facility. Animals (Basel) 2020; 10:ani10061013. [PMID: 32532091 PMCID: PMC7341240 DOI: 10.3390/ani10061013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 06/06/2020] [Accepted: 06/08/2020] [Indexed: 01/26/2023] Open
Abstract
We compared the glucocorticoid concentrations in response to various types of potential stressors present during standard operation of a temporary housing facility between three species, namely, ring-tailed lemurs, collared brown lemurs and white-headed lemurs. The levels of faecal glucocorticoid metabolites (FGMs) were measured non-invasively on a daily basis during a 30-day period. A total of 510 faecal samples were collected. Concentrations of immunoreactive glucocorticoid hormone metabolites were measured in the obtained extracts by using an enzyme immunoassay. The polyclonal antibodies used in this assay were directed against the metabolite 11-oxo-etiocholanolone I. We found all three monitored lemur species to respond to specific potentially stressful situations by increasing (p < 0.05) the FGM levels within one to two days after the event. Although housed in the same room, differences in response to potentially stressful situations were found in white-headed lemurs compared to ring-tailed lemurs. Increased mean levels of the FGMs were found more frequently in white-headed lemurs than in ring-tailed lemurs. The results suggest that this species may be more sensitive to changes in its surroundings. In general, the levels of the FGMs showed a similar pattern during 30 days of monitoring suggesting that all groups of lemurs responded in a similar manner to the same events. However, we recorded the differences in the absolute values of glucocorticoid concentrations between the monitored species likely due to the differences in sex ratios in the groups and presence of lactating females in the ring-tailed lemurs.
Collapse
|
27
|
Alekseeva GS, Loshchagina JA, Erofeeva MN, Naidenko SV. Stressed by Maternity: Changes of Cortisol Level in Lactating Domestic Cats. Animals (Basel) 2020; 10:ani10050903. [PMID: 32456071 PMCID: PMC7278448 DOI: 10.3390/ani10050903] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/17/2020] [Accepted: 05/19/2020] [Indexed: 12/18/2022] Open
Abstract
Lactation is the most energetically expensive component of maternal care in mammals. Increased reproductive investment can lead to physiological stress for the mothers, based on the exhaustion of energy resources and increase in glucocorticoids level. This study aimed to estimate the changes in cortisol concentrations during lactation in domestic cats and compared the differences among litter sizes. Eleven females gave birth to 27 litters, which were divided in two groups-small (1-3 kittens) and large (4-7 kittens) litters. Blood samples were collected from each female before mating, after parturition, at 4 and 8 weeks of lactation. We showed that the cortisol level in females changed significantly during lactation-the highest concentrations were observed at the peak of lactation at 4 weeks. Cortisol levels varied significantly among females but did not depend on their maternal experience. We also revealed that there were no differences in cortisol levels between females with small and large litters, but at 4 weeks of lactation, the hormone concentrations were higher in females with small litters. It is likely that these females initially invested less in reproduction, giving birth to fewer offspring.
Collapse
Affiliation(s)
- Galina S. Alekseeva
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 119071 Moscow, Russia; (M.N.E.); (S.V.N.)
- Correspondence:
| | | | - Mariya N. Erofeeva
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 119071 Moscow, Russia; (M.N.E.); (S.V.N.)
| | - Sergey V. Naidenko
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, 119071 Moscow, Russia; (M.N.E.); (S.V.N.)
| |
Collapse
|
28
|
Edwards PD, Mooney SJ, Bosson CO, Toor I, Palme R, Holmes MM, Boonstra R. The stress of being alone: Removal from the colony, but not social subordination, increases fecal cortisol metabolite levels in eusocial naked mole-rats. Horm Behav 2020; 121:104720. [PMID: 32081743 DOI: 10.1016/j.yhbeh.2020.104720] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/06/2020] [Accepted: 02/14/2020] [Indexed: 12/15/2022]
Abstract
In many social species, hierarchical status within the group is associated with differences in basal adrenocortical activity. We examined this relationship in naked mole-rats (Heterocephalus glaber), eusocial rodents with arguably the most extreme social hierarchies of all mammals. This species lives in colonies where breeding is restricted to one socially dominant 'queen' and her male consorts, and all other individuals are reproductively suppressed 'subordinates'. The relationship between cortisol and social status in naked mole-rats has not fully been elucidated, as prior results on this topic have been contradictory. We used non-invasive feces sampling to measure baseline cortisol levels in eight laboratory colonies of naked mole-rats, to either replicate or reject rank differences. First, we successfully validated an assay to measure fecal cortisol metabolites (FCMs). Removal from the colony for the validation experiment, either alone or with an opposite sex conspecific, induced prolonged elevation of FCM levels on a scale of days to weeks. This increase in cortisol did not prevent the removed animals from sexually maturing. In colony-housed animals, we found no relationship between rank in the social hierarchy and FCM levels. Further, queens, breeding males, and reproductively suppressed subordinates all had equivalent FCM levels. We conclude that this species shows little evidence of the 'stress of dominance' or 'stress of subordination' and that reproductive suppression in naked mole-rats is not driven by elevated cortisol levels.
Collapse
Affiliation(s)
- Phoebe D Edwards
- Dept. of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; Dept. of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; Centre for the Neurobiology of Stress, Dept. of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada.
| | - Skyler J Mooney
- Dept. of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Curtis O Bosson
- Centre for the Neurobiology of Stress, Dept. of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada
| | - Ilapreet Toor
- Dept. of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Rupert Palme
- Dept. of Biomedical Sciences, University of Veterinary Medicine, 1210 Vienna, Austria
| | - Melissa M Holmes
- Dept. of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; Dept. of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; Dept. of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Rudy Boonstra
- Dept. of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; Centre for the Neurobiology of Stress, Dept. of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada
| |
Collapse
|
29
|
Medger K, Bennett NC, Prins A, Lutermann H, Ganswindt A. Sex and dose-dependent responses of urinary and faecal glucocorticoid metabolite concentrations following an ACTH challenge in eastern rock sengis (Elephantulus myurus). Comp Biochem Physiol A Mol Integr Physiol 2020; 245:110696. [PMID: 32268194 DOI: 10.1016/j.cbpa.2020.110696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 01/18/2023]
Abstract
Non-invasive methods for measuring glucocorticoids and their metabolites are frequently used in ecological, behavioural and physiological studies of mammals. Using faeces, urine and other matrices for such a measurement has considerable advantages in comparison to more traditional methods, but also requires thorough validation of the methods used. Eastern rock sengis (Elephantulus myurus) are fascinating African mammals and the non-invasive monitoring of the adrenocortical activity opens up new opportunities to study their biology. We were able to validate two assays for measuring urinary (uGCM) and faecal glucocorticoid metabolite (fGCM) concentrations in this species using a dose-dependent challenge with adrenocorticotropic hormone (ACTH). A higher concentration of ACTH elicited higher uGCM and fGCM concentrations in both males and females. Interestingly, uGCM and fGCM concentrations and the responses to ACTH were higher in females than in males and small changes in faecal glucocorticoid metabolites could not be reliably detected in males. In contrast to ACTH, a saline injection did not result in an increase in uGCM or fGCM concentrations. The study also provided insight into when responses to a stressor are likely to be detected in the urine and faeces of sengis and opens up new opportunities to study the stress physiology of this and other sengi species. It further emphasises the importance of thoroughly validating non-invasive methods for measuring hormones in both sexes of a species and for incorporating dose-dependent approaches.
Collapse
Affiliation(s)
- Katarina Medger
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa.
| | - Nigel C Bennett
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa; Department of Zoology and Entomology, SARChI Chair of Mammal Behavioural Ecology and Physiology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - André Prins
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Heike Lutermann
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Andre Ganswindt
- Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa; Endocrine Research Laboratory, Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| |
Collapse
|
30
|
Stewart ND, Mastromonaco GF, Burness G. No island-effect on glucocorticoid levels for a rodent from a near-shore archipelago. PeerJ 2020; 8:e8590. [PMID: 32110493 PMCID: PMC7034373 DOI: 10.7717/peerj.8590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 01/17/2020] [Indexed: 11/20/2022] Open
Abstract
Island rodents are often larger and live at higher population densities than their mainland counterparts, characteristics that have been referred to as "island syndrome". Island syndrome has been well studied, but few studies have tested for island-mainland differences in stress physiology. We evaluated island syndrome within the context of stress physiology of white-footed mice (Peromyscus leucopus) captured from 11 islands and five mainland sites in Thousand Islands National Park, Ontario, Canada. Stress physiology was evaluated by quantifying corticosterone (a stress biomarker), the primary glucocorticoid in mice, from hair and its related metabolites from fecal samples. White-footed mice captured in this near-shore archipelago did not display characteristics of island syndrome, nor differences in levels of hair corticosterone or fecal corticosterone metabolites compared with mainland mice. We suggest that island white-footed mice experience similar degrees of stress in the Thousand Islands compared with the mainland. Although we did not find evidence of island syndrome or differences in glucocorticoid levels, we identified relationships between internal (sex, body mass) and external (season) factors and our hormonal indices of stress in white-footed mice.
Collapse
Affiliation(s)
- Nathan D Stewart
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario, Canada
| | | | - Gary Burness
- Department of Biology, Trent University, Peterborough, Ontario, Canada
| |
Collapse
|
31
|
van Kesteren F, Delehanty B, Westrick SE, Palme R, Boonstra R, Lane JE, Boutin S, McAdam AG, Dantzer B. Experimental Increases in Glucocorticoids Alter Function of the HPA Axis in Wild Red Squirrels without Negatively Impacting Survival and Reproduction. Physiol Biochem Zool 2020; 92:445-458. [PMID: 31365306 DOI: 10.1086/705121] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Hormones such as glucocorticoids (colloquially referred to as "stress hormones") have important effects on animal behavior and life-history traits, yet most of this understanding has come through correlative studies. While experimental studies offer the ability to assign causality, there are important methodological concerns that are often not considered when manipulating hormones, including glucocorticoids, in wild animals. In this study, we examined how experimental elevations of cortisol concentrations in wild North American red squirrels (Tamiasciurus hudsonicus) affected their hypothalamic-pituitary-adrenal (HPA) axis reactivity and life-history traits, including body mass, litter survival, and adult survival. The effects of exogenous cortisol on plasma cortisol concentrations depended on the time between treatment consumption and blood sampling. In the first 9 h after consumption of exogenous cortisol, individuals had significantly higher true baseline plasma cortisol concentrations, but adrenal gland function was impaired as indicated by their dampened response to capture and handling and to injections of adrenocorticotropic hormone compared to controls. Approximately 24 h after consumption of exogenous cortisol, individuals had much lower plasma cortisol concentrations than controls, but adrenal function was restored. Corticosteroid-binding globulin (CBG) concentrations were also significantly reduced in squirrels treated with cortisol. Despite these profound shifts in the functionality of the HPA axis, squirrel body mass, offspring survival, and adult survival were unaffected by experimental increases in cortisol concentrations. Our results highlight that even short-term experimental increases in glucocorticoids can affect adrenal gland functioning and CBG concentrations but without other side effects.
Collapse
|
32
|
Kozlowski CP, Clawitter H, Guglielmino A, Schamel J, Baker S, Franklin AD, Powell D, Coonan TJ, Asa CS. Factors Affecting Glucocorticoid and Thyroid Hormone Production of Island Foxes. J Wildl Manage 2019. [DOI: 10.1002/jwmg.21808] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Corinne P. Kozlowski
- Department of Reproductive and Behavioral SciencesSaint Louis Zoo St. Louis MO 63110 USA
| | - Helen Clawitter
- Department of Reproductive and Behavioral SciencesSaint Louis Zoo St. Louis MO 63110 USA
| | - Angela Guglielmino
- Department of Ecology and Evolutionary BiologyUniversity of California Los Angeles CA 90095 USA
| | | | - Stacy Baker
- Channel Islands National Park Ventura CA 93001 USA
| | | | - David Powell
- Department of Reproductive and Behavioral SciencesSaint Louis Zoo St. Louis MO 63110 USA
| | | | - Cheryl S. Asa
- Department of Reproductive and Behavioral SciencesSaint Louis Zoo St. Louis MO 63110 USA
| |
Collapse
|
33
|
Franchini M, Prandi A, Filacorda S, Pezzin EN, Fanin Y, Comin A. Cortisol in hair: a comparison between wild and feral cats in the north-eastern Alps. EUR J WILDLIFE RES 2019. [DOI: 10.1007/s10344-019-1330-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
34
|
Hammond TT, Vo M, Burton CT, Surber LL, Lacey EA, Smith JE. Physiological and behavioral responses to anthropogenic stressors in a human-tolerant mammal. J Mammal 2019. [DOI: 10.1093/jmammal/gyz134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Abstract
As humans continue to alter natural habitats, many wild animals are facing novel suites of environmental stimuli. These changes, including increased human–wildlife interactions, may exert sublethal impacts on wildlife such as alterations in stress physiology and behavior. California ground squirrels (Otospermophilus beecheyi) occur in human-modified as well as more pristine environments, where they face a variety of anthropogenic and naturally occurring threats. This makes this species a valuable model for examining the effects of diverse challenges on the physiology and behavior of free-living mammals. To explore potential sublethal effects of habitat modification on O. beecheyi, we compared body masses, behaviors, and fecal glucocorticoid metabolite (FGM) levels for free-living squirrels in human-disturbed versus undisturbed habitats. Prior to these analyses, we validated the use of FGMs in this species by exposing captive O. beecheyi to pharmacological and handling challenges; both challenges produced significant increases in FGMs in the study animals. While FGM responses were repeatable within captive individuals, responses by free-living animals were more variable, perhaps reflecting a greater range of life-history traits and environmental conditions within natural populations of squirrels. Animals from our human-disturbed study site had significantly higher FGMs, significantly lower body masses, and were significantly less behaviorally reactive to humans than those from our more pristine study site. Thus, despite frequent exposure of California ground squirrels to human impacts, anthropogenic stressors appear to influence stress physiology and other phenotypic traits in this species. These findings suggest that even human-tolerant mammalian species may experience important sublethal consequences due to human modifications of natural habitats.
Collapse
Affiliation(s)
- Talisin T Hammond
- San Diego Zoo Institute for Conservation Research, Escondido, CA, USA
- Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA, USA
| | - Minnie Vo
- Biology Department, Mills College, Oakland, CA, USA
| | | | | | - Eileen A Lacey
- Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA, USA
| | | |
Collapse
|
35
|
Hunt KE, Robbins J, Buck CL, Bérubé M, Rolland RM. Evaluation of fecal hormones for noninvasive research on reproduction and stress in humpback whales (Megaptera novaeangliae). Gen Comp Endocrinol 2019; 280:24-34. [PMID: 30951726 DOI: 10.1016/j.ygcen.2019.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 03/22/2019] [Accepted: 04/01/2019] [Indexed: 01/05/2023]
Abstract
Fecal hormone analysis shows high potential for noninvasive assessment of population-level patterns in stress and reproduction of marine mammals. However, the marine environment presents unique challenges for fecal sample collection. Data are still lacking on collection methodology and assay validations for most species, particularly for those mysticete whales that have variable diets. In this study we tested collection techniques for fecal samples of free-swimming humpback whales (Megaptera novaeangliae), and validated immunoassays for five steroid and thyroid hormones. Resulting data were used for preliminary physiological validations, i.e., comparisons to independently confirmed sex and reproductive state. Pregnant females had significantly higher fecal progestins and glucocorticoids than did other demographic categories of whales. Two possible cases of previously undetected pregnancies were noted. Males had significantly higher fecal testosterone metabolites than nonpregnant females. Fecal glucocorticoids were significantly elevated in pregnant females and mature males compared to nonpregnant females. Calf fecal samples had elevated concentrations of all fecal hormones. Fecal thyroid hormones showed a significant seasonal decline from spring to summer. Though sample sizes were small, and sampling was necessarily opportunistic, these patterns indicate that noninvasive fecal hormone analysis may facilitate studies of reproduction, stress and potentially energetics in humpback whales.
Collapse
Affiliation(s)
- Kathleen E Hunt
- Anderson Cabot Center for Ocean Life, New England Aquarium, Central Wharf, New England, Boston, MA 02110, USA; Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
| | - Jooke Robbins
- Center for Coastal Studies, 5 Holway Avenue, Provincetown, MA 02657, USA
| | - C Loren Buck
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Martine Bérubé
- Center for Coastal Studies, 5 Holway Avenue, Provincetown, MA 02657, USA; Marine Evolution and Conservation, Groningen Institute of Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Rosalind M Rolland
- Anderson Cabot Center for Ocean Life, New England Aquarium, Central Wharf, New England, Boston, MA 02110, USA
| |
Collapse
|
36
|
Santicchia F, Wauters LA, Dantzer B, Westrick SE, Ferrari N, Romeo C, Palme R, Preatoni DG, Martinoli A. Relationships between personality traits and the physiological stress response in a wild mammal. Curr Zool 2019; 66:197-204. [PMID: 32440278 PMCID: PMC7233610 DOI: 10.1093/cz/zoz040] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 08/06/2019] [Indexed: 01/01/2023] Open
Abstract
Glucocorticoids (GCs) are involved in the regulation of an animal's energetic state. Under stressful situations, they are part of the neuroendocrine response to cope with environmental challenges. Animals react to aversive stimuli also through behavioral responses, defined as coping styles. Both in captive and wild populations, individuals differ in their behavior along a proactive-reactive continuum. Proactive animals exhibit a bold, active-explorative and social personality, whereas reactive ones are shy, less active-explorative and less social. Here, we test the hypothesis that personality traits and physiological responses to stressors covary, with more proactive individuals having a less pronounced GC stress response. In wild populations of invasive gray squirrels Sciurus carolinensis, we measured fecal glucocorticoid metabolites (FGMs), an integrated measure of circulating GCs, and 3 personality traits (activity, sociability, and exploration) derived from open field test (OFT) and mirror image stimulation (MIS) test. Gray squirrels had higher FGMs in Autumn than in Winter and males with scrotal testes had higher FGMs than nonbreeding males. Personality varied with body mass and population density. Squirrels expressed more activity-exploration at higher than at lower density and heavier squirrels had higher scores for activity-exploration than animals that weighed less. Variation in FGM concentrations was not correlated with the expression of the 3 personality traits. Hence, our results do not support a strong association between the behavioral and physiological stress responses but show that in wild populations, where animals experience varying environmental conditions, the GC endocrine response and the expression of personality are uncorrelated traits among individuals.
Collapse
Affiliation(s)
- Francesca Santicchia
- Department of Theoretical and Applied Sciences, Environment Analysis and Management Unit - Guido Tosi Research Group - Università degli Studi dell'Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
| | - Lucas A Wauters
- Department of Theoretical and Applied Sciences, Environment Analysis and Management Unit - Guido Tosi Research Group - Università degli Studi dell'Insubria, Via J. H. Dunant 3, 21100 Varese, Italy.,Department of Biology, Evolutionary Ecology Group, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Ben Dantzer
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, 830 North University, Ann Arbor, MI 48109, USA
| | - Sarah E Westrick
- Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109, USA
| | - Nicola Ferrari
- Department of Veterinary Medicine, Università degli Studi di Milano, Via Celoria 10, 20133 Milano, Italy.,Centro di Ricerca Coordinata Epidemiologia e Sorveglianza Molecolare delle Infezioni, Università degli Studi di Milano, Milano, Italy
| | - Claudia Romeo
- Department of Veterinary Medicine, Università degli Studi di Milano, Via Celoria 10, 20133 Milano, Italy
| | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria
| | - Damiano G Preatoni
- Department of Theoretical and Applied Sciences, Environment Analysis and Management Unit - Guido Tosi Research Group - Università degli Studi dell'Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
| | - Adriano Martinoli
- Department of Theoretical and Applied Sciences, Environment Analysis and Management Unit - Guido Tosi Research Group - Università degli Studi dell'Insubria, Via J. H. Dunant 3, 21100 Varese, Italy
| |
Collapse
|
37
|
Westrick SE, van Kesteren F, Palme R, Boonstra R, Lane JE, Boutin S, McAdam AG, Dantzer B. Stress activity is not predictive of coping style in North American red squirrels. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2728-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
38
|
Guindre-Parker S, Mcadam AG, van Kesteren F, Palme R, Boonstra R, Boutin S, Lane JE, Dantzer B. Individual variation in phenotypic plasticity of the stress axis. Biol Lett 2019; 15:20190260. [PMID: 31337294 DOI: 10.1098/rsbl.2019.0260] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Phenotypic plasticity-one individual's capacity for phenotypic variation under different environments-is critical for organisms facing fluctuating conditions within their lifetime. North American red squirrels (Tamiasciurus hudsonicus) experience drastic among-year fluctuations in conspecific density. This shapes juvenile competition over vacant territories and overwinter survival. To help young cope with competition at high densities, mothers can increase offspring growth rates via a glucocorticoid-mediated maternal effect. However, this effect is only adaptive under high densities, and faster growth often comes at a cost to longevity. While red squirrels can adjust hormones in response to fluctuating density, the degree to which mothers differ in glucocorticoid plasticity across changing densities remains unknown. Findings from our reaction norm approach revealed significant individual variation not only in a female red squirrel's mean endocrine phenotype but also in endocrine plasticity in response to changes in local density. Future work on proximate and ultimate drivers of variation in endocrine plasticity and maternal effects is needed, particularly in free-living animals experiencing fluctuating environments.
Collapse
Affiliation(s)
- Sarah Guindre-Parker
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada.,Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Andrew G Mcadam
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | | | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Scarborough, Ontario, Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
39
|
The role of steroid hormones and individual traits in food intake in the wood mouse (Apodemus sylvaticus). Naturwissenschaften 2019; 106:36. [PMID: 31203436 DOI: 10.1007/s00114-019-1628-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 05/21/2019] [Accepted: 05/24/2019] [Indexed: 10/26/2022]
Abstract
Availability of food resources affects animal survival and reproduction. Thus, coping with changes in food availability is one of the most crucial behavioural and physiological processes in wildlife. Food intake is a key concept in animal ecology that is directly conditioned by food quality and abundance or diet choice, but may also vary according to individual-related factors (e.g. foraging behaviours, social rank or energy-demanding periods) and the influence of the endocrine system on energy metabolism. Here, we studied food intake in relation to individual characteristics (sex, breeding condition and age) and whether steroid hormones (testosterone and corticosterone metabolites) mediate food intake in wild wood mouse (Apodemus sylvaticus). Field work was carried out in February-March 2014 in Monte de Valdelatas (Madrid, Spain). Wood mice were live-trapped for 10 consecutive days in four independent plots. Traps were baited with 4 g of toasted corn and food intake was calculated by subtracting the remaining bait found inside traps. Fresh faecal samples from 130 different wood mice were collected and faecal testosterone and corticosterone metabolites (FTM and FCM, respectively) were analysed by enzyme immunoassays. Food intake was higher in females than males, probably due to greater energy requirements. Non-breeders and young individuals also showed a higher food intake. These individuals usually hold a lower social rank which is associated to limited food resources because of dominants; thus, increased food intake may be a result of freely exploit food bait inside traps while avoiding risky competition. In addition, food intake negatively correlated with FTM levels and positively with FCM levels indicating that both hormones have an active role mediating food intake in the wood mouse. Our data suggest that food intake is a function of both individual traits and the endocrine system that accordingly respond throughout different energy-demanding periods.
Collapse
|
40
|
Crill C, Janz DM, Kusch JM, Santymire RM, Heyer GP, Shury TK, Lane JE. Investigation of the utility of feces and hair as non-invasive measures of glucocorticoids in wild black-tailed prairie dogs (Cynomys ludovicianus). Gen Comp Endocrinol 2019; 275:15-24. [PMID: 30735671 DOI: 10.1016/j.ygcen.2019.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 01/26/2019] [Accepted: 02/04/2019] [Indexed: 10/27/2022]
Abstract
Non-invasive measures of glucocorticoid (GC) hormones and their metabolites, particularly in feces and hair, are gaining popularity as wildlife management tools, but species-specific validations of these tools remain rare. We report the results of a validation on black-tailed prairie dogs (Cynomys ludovicianus), a highly social engineer of the grasslands ecosystem that has experienced recent population declines. We captured adult female prairie dogs and brought them into temporary captivity to conduct an adrenocorticotropic hormone (ACTH) stimulation test, assessing the relationship between plasma GC and fecal glucocorticoid metabolite (FGM) levels following a single injection of a low (4 IU/kg) or high dose (12 IU/kg) of ACTH, compared to a single injection of saline. We also gave repeated injections of ACTH to adult females to assess whether this would result in an increase of hair cortisol concentrations, compared with control individuals repeatedly injected with saline. A single injection of ACTH at either low or high dose peaked plasma cortisol levels after 30 min, and thereafter the cortisol levels declined until 120 min, where they returned to pre-treatment levels comparable to those of the saline injected group. Despite the significant elevation of plasma cortisol in the treatment groups following ACTH injection, the elevation of FGM levels in the treatment groups were not significantly different from those in the control group over the following 12 h. Repeated injection of a high dose of ACTH failed to increase hair cortisol concentration in treatment animals. Instead, hair cortisol levels remained comparable to the pre-treatment mean, despite an increase in post-treatment hair cortisol levels seen in the saline-injected group. The magnitude of increase in the saline control group was comparable to natural seasonal variation seen in unmanipulated individuals. These results highlight that while measurement of GCs and their metabolites in feces and hair are potentially valuable conservation tools for black-tailed prairie dogs, further validation work is required before these matrices can be to real-world conservation applications.
Collapse
Affiliation(s)
- Colleen Crill
- Department of Biology, University of Saskatchewan, Canada.
| | - David M Janz
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, Canada
| | | | - Rachel M Santymire
- Davee Center for Epidemiology and Endocrinology, Lincoln Park Zoo, United States
| | | | | | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Canada
| |
Collapse
|
41
|
Edwards PD, Dean EK, Palme R, Boonstra R. Assessing space use in meadow voles: the relationship to reproduction and the stress axis. J Mammal 2018. [DOI: 10.1093/jmammal/gyy161] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Abstract
Voles are key mammals in understanding how social interactions can affect large-scale population processes. Previous studies have shown that at high population densities, meadow voles (Microtus pennsylvanicus) have a lower proportion of breeding animals, higher average corticosterone levels, and can be limited by female territorial spacing. Based on this, we compared corticosterone levels and spatial use between breeding and nonbreeding free-ranging adult meadow voles within populations. We measured intrasexual spatial overlap to examine if breeding females minimize occupying the same areas as other females, and noninvasively assessed corticosterone levels using fecal corticosterone metabolites (FCMs). We found that female meadow voles have much lower intrasexual spatial overlap than males, even though both sexes have similar range sizes, and that females have generally higher FCM levels than males. However, breeding and nonbreeding females did not differ from one another in spatial use or in FCM levels. Conversely, reproductive classes of males differed greatly in all measures: nonbreeding males had FCM levels that were two times higher than those of breeding males, occupied a smaller range, and had lower spatial overlap, indicating they were moving less widely than breeding males. We additionally validated an enzyme immunoassay for noninvasively measuring FCMs in meadow voles. The assay was successful in detecting an increase in corticosterone stimulated by adrenocorticotropic hormone injection; however, dexamethasone did not induce negative feedback. FCMs reflect circulating corticosterone levels approximately 5 h prior. These results highlight differences in FCMs and spacing in meadow voles related to sex and reproductive status, and reflect the respective strategies males and females employ during the breeding season.
Collapse
Affiliation(s)
- Phoebe D Edwards
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Erik K Dean
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| |
Collapse
|
42
|
Palme R. Non-invasive measurement of glucocorticoids: Advances and problems. Physiol Behav 2018; 199:229-243. [PMID: 30468744 DOI: 10.1016/j.physbeh.2018.11.021] [Citation(s) in RCA: 310] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/16/2018] [Accepted: 11/16/2018] [Indexed: 01/19/2023]
Abstract
Glucocorticoids (GCs; i.e. cortisol/corticosterone) are a central component of the stress response and thus their measurement is frequently used to evaluate the impact of stressful situations. Their metabolites from faeces of various animal species are more and more taken as a non-invasive aid to assess GC release and thus adrenocortical activity. The current literature review includes an extensive collection (1327 papers) and evaluation (see also Supplementary Tables) of the literature on faecal cortisol/corticosterone metabolite (FCM) analysis published to date. It aims at giving reference for researchers interested in implementing FCM analysis into their study or seeking to improve such methods by providing background knowledge on GC metabolism and excretion, conveying insights into methodological issues and stating caveats of FCM analysis and by highlighting prerequisites for and some examples of a successful application of such methods. Collecting faecal samples and analysing FCMs may appear simple and straightforward, but researchers have to select and apply methods correctly. They also need to be aware of the many pitfalls and potentially confounding factors and, last but not least, have to carefully interpret results. Applied properly, measurement of FCMs is a powerful non-invasive tool in a variety of research areas, such as (stress) biology, ethology, ecology, animal conservation and welfare, but also biomedicine.
Collapse
Affiliation(s)
- Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology, Department of Biomedical Sciences, University of Veterinary Medicine, Veterinärplatz 1, 1210 Vienna, Austria.
| |
Collapse
|
43
|
Maly MA, Edwards KL, Farin CE, Koester DC, Crosier AE. Assessing puberty in ex situ male cheetahs (Acinonyx jubatus) via fecal hormone metabolites and body weights. Gen Comp Endocrinol 2018; 268:22-33. [PMID: 30026021 DOI: 10.1016/j.ygcen.2018.07.011] [Citation(s) in RCA: 3] [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: 10/04/2017] [Revised: 07/10/2018] [Accepted: 07/15/2018] [Indexed: 01/28/2023]
Abstract
Cheetahs are one of the most heavily studied felid species, with numerous publications on health, disease, and reproductive physiology produced over the last 30 years. Despite this relatively long history of research, there is a paucity of crucial biological data, such as pubertal onset, which has direct and significant applications to improved management of ex situ cheetah populations. This study aimed to determine age of pubertal onset in ex situ male cheetahs using non-invasive fecal steroid hormone monitoring and body weights. Fecal samples from 12 male cheetahs from four institutions were collected 2-3 times weekly from 1 to 42 months of age. Fecal androgen and glucocorticoid metabolites were analyzed using enzyme immunoassays previously validated for use with cheetah feces. Animal body weights were recorded monthly. Fecal hormone and body weight data were analyzed using generalized linear mixed models. Androgen concentrations exhibited an increase to levels similar to those observed in adult males by 18-24 months of age, and males attained adult body weights by 21 months of age. Based on these weight data and the initial increase in androgens toward adult concentrations, males were considered pubertal from 18 to 24 months of age. Glucocorticoid concentrations and amplitude of concentration over baseline were also increased during this period. Knowledge about the physiological changes associated with puberty is useful for management and improving reproductive success of cheetah populations under human care, particularly for determining timing of litter separation from dam, littermate dispersal and when to introduce potential breeding pairs.
Collapse
Affiliation(s)
- Morgan A Maly
- Center for Species Survival, Department of Reproductive Sciences, Smithsonian Conservation Biology Institute, 1500 Remount Road, Front Royal, VA 22630, United States; Department of Animal Science, College of Agriculture and Life Sciences, North Carolina State University, 123 Polk Hall, 120 Broughton Drive, Raleigh, NC 27695, United States
| | - Katie L Edwards
- Center for Species Survival, Department of Reproductive Sciences, Smithsonian Conservation Biology Institute, 1500 Remount Road, Front Royal, VA 22630, United States
| | - Charlotte E Farin
- Department of Animal Science, College of Agriculture and Life Sciences, North Carolina State University, 123 Polk Hall, 120 Broughton Drive, Raleigh, NC 27695, United States
| | - Diana C Koester
- Department of Conservation and Science, Cleveland Metroparks Zoo, 3900 Wildlife Way, Cleveland, OH 44109, United States
| | - Adrienne E Crosier
- Center for Species Survival, Department of Reproductive Sciences, Smithsonian Conservation Biology Institute, 1500 Remount Road, Front Royal, VA 22630, United States.
| |
Collapse
|
44
|
Hammond TT, Palme R, Lacey EA. Glucocorticoid-environment relationships align with responses to environmental change in two co-occurring congeners. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2018; 28:1683-1693. [PMID: 30043471 DOI: 10.1002/eap.1781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 06/08/2018] [Accepted: 06/20/2018] [Indexed: 06/08/2023]
Abstract
As more species undergo range shifts in response to climate change, it is increasingly important to understand the factors that determine an organism's realized niche. Physiological limits imposed by abiotic factors constrain the distributions of many species. Because glucocorticoids are essential to the maintenance of physiological homeostasis, identifying glucocorticoid-environment relationships may generate critical insights into both limits on species distributions and potential responses to environmental change. We explored relationships between variability in baseline glucocorticoids and sensitivity to environmental conditions in two chipmunk species characterized by divergent patterns of spatial, genetic, and morphological change over the past century. Specifically, we investigated whether the alpine chipmunk (Tamias alpinus), which has undergone pronounced changes, displays greater glucocorticoid sensitivity to environmental parameters than the lodgepole chipmunk (T. speciosus), which has exhibited little change over the same interval. From 2013 to 2015, we collected environmental data and fecal glucocorticoid metabolite (FGM) samples from these species. Using generalized linear mixed models and a model averaging approach, we examined the impacts of environmental and individual phenotypic parameters on FGMs. We found pronounced interspecific differences, with environmental parameters being better predictors of FGMs in T. alpinus. FGMs in this species were particularly elevated in less climatically suitable habitats and in areas with higher maximum daily temperatures. Individual phenotypic traits were not predictive of FGMs in T. alpinus, although they were highly predictive for T. speciosus. Collectively, these findings support the hypothesis that T. alpinus is more sensitive to environmental change. More generally, our results suggest that both phenotypic attributes and environmental conditions contribute to FGM responses but that the relative contributions of these factors differ among taxa, including among closely related species. Finally, our analyses underscore the value of glucocorticoids as bioindicators of sensitivity to environmental change in species for which the factors affecting stress physiology have been assessed.
Collapse
Affiliation(s)
- Talisin T Hammond
- Department of Biological Sciences, University of Pittsburgh, 105 Clapp Hall, Pittsburgh, Pennsylvania, 15260, USA
- Museum of Vertebrate Zoology, University of California Berkeley, 3101 Valley Life Sciences Building, Berkeley, California, 94720-3160, USA
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, Veterinärplatz 1, 1210, Vienna, Austria
| | - Eileen A Lacey
- Museum of Vertebrate Zoology, University of California Berkeley, 3101 Valley Life Sciences Building, Berkeley, California, 94720-3160, USA
| |
Collapse
|
45
|
O'Brien KA, Waterman JM, Anderson WG, Bennett NC. Trade-offs between immunity and testosterone in male African ground squirrels. ACTA ACUST UNITED AC 2018; 221:jeb.177683. [PMID: 29941613 DOI: 10.1242/jeb.177683] [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: 01/19/2018] [Accepted: 06/20/2018] [Indexed: 10/28/2022]
Abstract
The immunocompetence handicap hypothesis (ICHH) proposes that testosterone has both beneficial effects on male reproductive potential and negative effects by suppressing the immune system. However, support for the ICHH has been variable and an alternative hypothesis suggests that testosterone may be acting indirectly via cortisol to suppress immunity (the stress-linked ICHH). A third hypothesis is that increased energetic investment in immunity results in the suppression of testosterone. We tested these hypotheses in male Cape ground squirrels (Xerus inauris) through two separate manipulations: first, by triggering a strong immune response using a lipopolysaccharide (LPS) injection and, secondly, by increasing circulating testosterone using silastic testosterone implants. Responding to an immune challenge significantly reduced testosterone, supporting the immune suppression hypothesis, while increasing circulating testosterone had no effect on immunocompetence, body mass, ectoparasite abundances or cortisol levels, failing to support either the ICHH or stress-linked ICHH. Our results add to the increasing body of literature that challenges the ICHH, and we conclude that the trade-off between testosterone and immunity is mediated through immune activation and not through testosterone in male Cape ground squirrels. Being able to test the ICHH, stress-linked ICHH and immune suppression hypotheses in a free-ranging mammal gives us a unique opportunity to examine the mechanisms mediating this trade-off.
Collapse
Affiliation(s)
- Kelsey A O'Brien
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Jane M Waterman
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada .,Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
| | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
| |
Collapse
|
46
|
Santicchia F, Dantzer B, van Kesteren F, Palme R, Martinoli A, Ferrari N, Wauters LA. Stress in biological invasions: Introduced invasive grey squirrels increase physiological stress in native Eurasian red squirrels. J Anim Ecol 2018; 87:1342-1352. [DOI: 10.1111/1365-2656.12853] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 05/11/2018] [Indexed: 01/10/2023]
Affiliation(s)
- Francesca Santicchia
- Environment Analysis and Management Unit; Guido Tosi Research Group; Department of Theoretical and Applied Sciences; Università degli Studi dell'Insubria; Varese Italy
| | - Ben Dantzer
- Department of Psychology; University of Michigan; Ann Arbor Michigan
- Department of Ecology and Evolutionary Biology; University of Michigan; Ann Arbor Michigan
| | | | - Rupert Palme
- Unit of Physiology, Pathophysiology and Experimental Endocrinology; Department of Biomedical Sciences; University of Veterinary Medicine Vienna; Vienna Austria
| | - Adriano Martinoli
- Environment Analysis and Management Unit; Guido Tosi Research Group; Department of Theoretical and Applied Sciences; Università degli Studi dell'Insubria; Varese Italy
| | - Nicola Ferrari
- Department of Veterinary Sciences and Public Health; Università degli Studi di Milano; Milan Italy
| | - Lucas Armand Wauters
- Environment Analysis and Management Unit; Guido Tosi Research Group; Department of Theoretical and Applied Sciences; Università degli Studi dell'Insubria; Varese Italy
- Department of Biology; Evolutionary Ecology Group; University of Antwerp; Wilrijk Belgium
| |
Collapse
|
47
|
Taff CC, Schoenle LA, Vitousek MN. The repeatability of glucocorticoids: A review and meta-analysis. Gen Comp Endocrinol 2018; 260:136-145. [PMID: 29355531 DOI: 10.1016/j.ygcen.2018.01.011] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/27/2017] [Accepted: 01/11/2018] [Indexed: 12/17/2022]
Abstract
Glucocorticoids are highly conserved hormones that mediate a suite of responses to changing conditions in vertebrates. Recent work has focused on understanding how selection operates on glucocorticoid secretion in natural populations. Because heritability is rarely estimated and difficult to measure in the wild, many studies report within-individual repeatability as an estimate of stable between individual differences in glucocorticoid secretion. We conducted a systematic review and meta-analysis on estimates of within-individual glucocorticoid repeatability to elucidate general patterns of repeatability, and to test for relationships between covariates and estimates of repeatability. To this end, we collected 203 estimates of within-individual glucocorticoid repeatability drawn from 71 separate studies and 55 species. Overall, we found moderate levels of repeatability (0.29). We also found that repeatability varied by sample type. Long-term measures (e.g., fecal and feather samples) and acute stress-induced plasma glucocorticoids had higher repeatability (long-term: 0.44, stress-induced: 0.38), than baseline glucocorticoid levels (0.18). Repeatability also decreased with increasing time between repeated sampling events. Despite significant overall repeatability, there was substantial heterogeneity in estimates from different studies, suggesting that repeatability of glucocorticoid secretion varies substantially across systems and conditions. We discuss the implications of our results for understanding selection on glucocorticoid traits and suggest that continuing work should focus on evaluating the repeatability of within-individual glucocorticoid reaction norms.
Collapse
Affiliation(s)
- Conor C Taff
- Lab of Ornithology and Department of Ecology & Evolutionary Biology, Cornell University, United States.
| | | | - Maren N Vitousek
- Lab of Ornithology and Department of Ecology & Evolutionary Biology, Cornell University, United States
| |
Collapse
|
48
|
Edwards PD, Boonstra R. Glucocorticoids and CBG during pregnancy in mammals: diversity, pattern, and function. Gen Comp Endocrinol 2018; 259:122-130. [PMID: 29155262 DOI: 10.1016/j.ygcen.2017.11.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 11/16/2017] [Accepted: 11/16/2017] [Indexed: 01/17/2023]
Abstract
Pregnancy is one of the defining characteristics of placental mammals. Key in the growth and development of the fetus during pregnancy are the dynamics of glucocorticoids (GCs) and their binding protein,corticosteroid-binding globulin (CBG), which determines how much of the GCs are free and biologically active. Out of more than 5000 species of placental mammals in 19 different orders, our understanding of the dynamics of maternal GCs and CBG during pregnancy is largely limited to the detailed study of 3 groups - sheep, laboratory rodents, and humans. The assumption is often made that what we see in these few species applies to the rest. To examine this generality, we compared patterns of maternal GCs over pregnancy from all placental mammals where data is available: in the blood of 13 species from 5 different orders and in metabolites in excreta in an additional 20 species from 9 orders. We found that maternal free GCs increase by late pregnancy in most taxa. This increase is achieved by either an increase in total GC secretion or a decrease in CBG. A major exception is found in the even-toed ungulates (sheep, cows, etc.) where maternal GCs and CBG remain stable, but where the fetal adrenals mature in late pregnancy and produce the majority of their own GCs. We conclude that patterns of change in maternal GCs and CBG during pregnancy are species-specific but are alternative means to the same end: increased fetal exposure to GCs in late pregnancy, which is essential for development.
Collapse
Affiliation(s)
- Phoebe D Edwards
- Centre for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada.
| | - Rudy Boonstra
- Centre for the Neurobiology of Stress, Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| |
Collapse
|
49
|
McDonald R, Roth J, Anderson W. Prey cortisol affects the usefulness of fecal glucocorticoid metabolite concentration as an indicator of stress in a carnivore. CAN J ZOOL 2018. [DOI: 10.1139/cjz-2017-0065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The noninvasive nature of sample collection makes analysis of fecal hormone concentrations useful for examining endocrine responses in free-living wild animals. Glucocorticoid hormones (i.e., cortisol and corticosterone) are frequently measured as an indicator of activation of the endocrine stress axis. However, many factors may influence glucocorticoid concentrations in feces, and the influence of prey glucocorticoids on concentrations in the feces of predators is rarely considered. We tested whether cortisol consumption influenced concentrations of glucocorticoid metabolites in feces of captive Arctic foxes (Vulpes lagopus (Linnaeus, 1758)) by adding cortisol (5 mg cortisol per kg fox body mass) to the foxes’ diet. Food supplemented with supraphysiological concentrations of cortisol increased fecal glucocorticoid metabolite concentrations of Arctic foxes by 97% in males and 51% in females, compared with controls. In addition, fecal metabolite concentrations in nontreatment samples were higher for females (22.2 ± 3.3 ng·g−1, mean ± SE) than males (13.3 ± 1.5 ng·g−1), suggesting female Arctic foxes may have higher baseline cortisol concentrations or females may be more sensitive to captivity or relocation. These results indicate that prey cortisol can influence measurement of glucocorticoid metabolites in carnivore feces and suggest caution may be needed when interpreting such measurements in wild carnivores.
Collapse
Affiliation(s)
- R.S. McDonald
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - J.D. Roth
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - W.G. Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| |
Collapse
|
50
|
Sánchez-González B, Barja I, Piñeiro A, Hernández-González MC, Silván G, Illera JC, Latorre R. Support vector machines for explaining physiological stress response in Wood mice (Apodemus sylvaticus). Sci Rep 2018; 8:2562. [PMID: 29416078 PMCID: PMC5803235 DOI: 10.1038/s41598-018-20646-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 01/23/2018] [Indexed: 11/08/2022] Open
Abstract
Physiological stress response is a crucial adaptive mechanism for prey species survival. This paper aims to identify the main environmental and/or individual factors better explaining the stress response in Wood mice, Apodemus sylvaticus. We analyzed alterations in fecal glucocorticoid metabolite (FCM) concentration - extensively used as an accurate measure of the physiological stress response - of wild mice fecal samples seasonally collected during three years. Then, support vector machines were built to predict said concentration according to different stressors. These statistical tools appear to be particularly suitable for small datasets with substantial number of dimensions, corroborating that the stress response is an extremely complex process in which multiple factors can simultaneously partake in a context-dependent manner, i.e., the role of each potential stressor varies in time depending on other stressors. However, air-humidity, temperature and body-weight allowed us to explain the FCM fluctuation in 98% of our samples. The relevance of air-humidity and temperature altering FCM level could be linked to the presence of an abundant vegetation cover and, therefore, to food availability and predation risk perception. Body-weight might be related to the stress produced by reproduction and other intraspecific relationships such as social dominance or territorial behavior.
Collapse
Affiliation(s)
- Beatriz Sánchez-González
- Departamento de Biología, Unidad de Zoología, Universidad Autónoma de Madrid, c/Darwin 2, Campus Universitario de Cantoblanco, 28049, Madrid, Spain
| | - Isabel Barja
- Departamento de Biología, Unidad de Zoología, Universidad Autónoma de Madrid, c/Darwin 2, Campus Universitario de Cantoblanco, 28049, Madrid, Spain
| | - Ana Piñeiro
- Departamento de Biología, Unidad de Zoología, Universidad Autónoma de Madrid, c/Darwin 2, Campus Universitario de Cantoblanco, 28049, Madrid, Spain
- Escuela de Medicina Veterinaria, Facultad de Ecología y Recursos Naturales, Universidad Andrés Bello, Santiago de Chile, Chile
| | - M Carmen Hernández-González
- Departamento de Biología, Unidad de Zoología, Universidad Autónoma de Madrid, c/Darwin 2, Campus Universitario de Cantoblanco, 28049, Madrid, Spain
| | - Gema Silván
- Departamento de Fisiología (Fisiología Animal), Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - Juan Carlos Illera
- Departamento de Fisiología (Fisiología Animal), Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain
| | - Roberto Latorre
- Departamento de Ingeniería Informática, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
| |
Collapse
|