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Sugianto NA, Newman C, Macdonald DW, Buesching CD. Effects of weather and social factors on hormone levels in the European badger (Meles meles). ZOOLOGY 2023; 158:126093. [PMID: 37149943 DOI: 10.1016/j.zool.2023.126093] [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: 12/09/2022] [Revised: 03/31/2023] [Accepted: 04/27/2023] [Indexed: 05/09/2023]
Abstract
Animals in the wild continually experience changes in environmental and social conditions, which they respond to with behavioural, physiological and morphological adaptations related to individual phenotypic quality. During unfavourable environmental conditions, reproduction can be traded-off against self-maintenance, mediated through changes in reproductive hormone levels. Using the European badger (Meles meles) as a model species, we examine how testosterone in males and oestrogens in females respond to marked deviations in weather from the long-term mean (rainfall and temperature, where badger earthworm food supply is weather dependent), and to social factors (number of adult males and females per social group and total adults in the population), in relation to age, weight and head-body length. Across seasons, testosterone levels correlated postively with body weight and rainfall variability, whereas oestrone correlated positively with population density, but negatively with temperature variability. Restricting analyses to the mating season (spring), heavier males had higher testosterone levels and longer females had higher oestradiol levels. Spring oestrone levels were lower when temperatures were above normal. That we see these effects for this generally adaptive species with a broad bioclimatic niche serves to highlight that climatic effects (especially with the threat of anthropogenic climate change) on reproductive physiology warrant careful attention in a conservation context.
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Affiliation(s)
- N A Sugianto
- School of Biosciences, University of Birmingham, Birmingham, UK; Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney OX13 5QL, UK.
| | - C Newman
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney OX13 5QL, UK; Cook's Lake Farming Forestry and Wildlife Inc (Ecological Consultancy), Queens County, Nova Scotia, Canada
| | - D W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney OX13 5QL, UK
| | - C D Buesching
- Cook's Lake Farming Forestry and Wildlife Inc (Ecological Consultancy), Queens County, Nova Scotia, Canada; Department of Biology, Irving K. Barber Faculty of Sciences, The University of British Columbia, Okanagan, Kelowna, British Columbia, Canada
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Fokidis HB, Brock T, Newman C, Macdonald DW, Buesching CD. Assessing chronic stress in wild mammals using claw-derived cortisol: a validation using European badgers ( Meles meles). CONSERVATION PHYSIOLOGY 2023; 11:coad024. [PMID: 37179707 PMCID: PMC10171820 DOI: 10.1093/conphys/coad024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 01/26/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023]
Abstract
Measuring stress experienced by wild mammals is increasingly important in the context of human-induced rapid environmental change and initiatives to mitigate human-wildlife conflicts. Glucocorticoids (GC), such as cortisol, mediate responses by promoting physiological adjustments during environmental perturbations. Measuring cortisol is a popular technique; however, this often reveals only recent short-term stress such as that incurred by restraining the animal to sample blood, corrupting the veracity of this approach. Here we present a protocol using claw cortisol, compared with hair cortisol, as a long-term stress bio-indicator, which circumvents this constraint, where claw tissue archives the individual's GC concentration over preceding weeks. We then correlate our findings against detailed knowledge of European badger life history stressors. Based on a solid-phase extraction method, we assessed how claw cortisol concentrations related to season and badger sex, age and body-condition using a combination of generalized linear mixed models (GLMM) (n = 668 samples from 273 unique individuals) followed by finer scale mixed models for repeated measures (MMRM) (n = 152 re-captured individuals). Claw and hair cortisol assays achieved high accuracy, precision and repeatability, with similar sensitivity. The top GLMM model for claw cortisol included age, sex, season and the sex*season interaction. Overall, claw cortisol levels were significantly higher among males than females, but strongly influenced by season, where females had higher levels than males in autumn. The top fine scale MMRM model included sex, age and body condition, with claw cortisol significantly higher in males, older and thinner individuals. Hair cortisol was more variable than claw; nevertheless, there was a positive correlation after removing 34 outliers. We discuss strong support for these stress-related claw cortisol patterns from previous studies of badger biology. Given the potential of this technique, we conclude that it has broad application in conservation biology.
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Affiliation(s)
- H Bobby Fokidis
- Corresponding author: Department of Biology, Rollins College, Winter Park, Florida, USA.
| | - Taylor Brock
- Department of Biology, Rollins College, 1000 Holt Avenue, Winter Park, Florida, 32789-4499, USA
| | - Chris Newman
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abindgon Rd, Tubney, OX13 5QL, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Tubney House, Abindgon Rd, Tubney, OX13 5QL, UK
| | - Christina D Buesching
- Irving K. Barber Faculty of Science, University of British Columbia, Okanagan campus, 3187 University Way, Kelowna, British Columbia, V1V1V7, Canada
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van Lieshout SHJ, Badás EP, Bright Ross JG, Bretman A, Newman C, Buesching CD, Burke T, Macdonald DW, Dugdale HL. Early-life seasonal, weather and social effects on telomere length in a wild mammal. Mol Ecol 2022; 31:5993-6007. [PMID: 34101279 DOI: 10.1111/mec.16014] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 06/03/2021] [Indexed: 01/31/2023]
Abstract
Early-life environmental conditions can provide a source of individual variation in life-history strategies and senescence patterns. Conditions experienced in early life can be quantified by measuring telomere length, which can act as a biomarker of survival probability in some species. Here, we investigate whether seasonal changes, weather conditions and group size are associated with early-life and/or early-adulthood telomere length in a wild population of European badgers (Meles meles). We found substantial intra-annual changes in telomere length during the first 3 years of life, where within-individual effects showed shorter telomere lengths in the winter following the first spring and a trend for longer telomere lengths in the second spring compared to the first winter. In terms of weather conditions, cubs born in warmer, wetter springs with low rainfall variability had longer early-life (3-12 months old) telomeres. Additionally, cubs born in groups with more cubs had marginally longer early-life telomeres, providing no evidence of resource constraint from cub competition. We also found that the positive association between early-life telomere length and cub survival probability remained when social and weather variables were included. Finally, after sexual maturity, in early adulthood (i.e., 12-36 months) we found no significant association between same-sex adult group size and telomere length (i.e., no effect of intrasexual competition). Overall, we show that controlling for seasonal effects, which are linked to food availability, is important in telomere length analyses, and that variation in telomere length in badgers reflects early-life conditions and also predicts first year cub survival.
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Affiliation(s)
- Sil H J van Lieshout
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,NERC Environmental Omics Visitor Facility, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Elisa P Badás
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Julius G Bright Ross
- Wildlife Conservation Research Unit, Department of Zoology, The Recanati-Kaplan Centre, University of Oxford, Abingdon, UK
| | - Amanda Bretman
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Chris Newman
- Wildlife Conservation Research Unit, Department of Zoology, The Recanati-Kaplan Centre, University of Oxford, Abingdon, UK
| | - Christina D Buesching
- Wildlife Conservation Research Unit, Department of Zoology, The Recanati-Kaplan Centre, University of Oxford, Abingdon, UK.,Department of Biology, The University of British Columbia, Okanagan, Kelowna, British Columbia, Canada
| | - Terry Burke
- NERC Environmental Omics Visitor Facility, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, The Recanati-Kaplan Centre, University of Oxford, Abingdon, UK
| | - Hannah L Dugdale
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
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Burford B, Wild LA, Schwarz R, Chenoweth EM, Sreenivasan A, Elahi R, Carey N, Hoving HJT, Straley JM, Denny MW. Rapid range expansion of a marine ectotherm reveals the demographic and ecological consequences of short-term variability in seawater temperature and dissolved oxygen. Am Nat 2021; 199:523-550. [DOI: 10.1086/718575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Sugianto NA, Heistermann M, Newman C, Macdonald DW, Buesching CD. Alternative reproductive strategies provide a flexible mechanism for assuring mating success in the European badgers (Meles meles): An investigation from hormonal measures. Gen Comp Endocrinol 2021; 310:113823. [PMID: 34044013 DOI: 10.1016/j.ygcen.2021.113823] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/19/2021] [Accepted: 05/21/2021] [Indexed: 10/21/2022]
Abstract
Selection-pressures differ with population density, but few studies investigate how this can affect reproductive physiology. European badger (Meles meles) density varies from solitary to group-living across their range, with reported mating periods throughout the entire year to specific seasonal periods. Badger reproduction is evolutionarily distinct, interrupting the direct progression from conception to gestation with delayed implantation (DI), allowing for superfecundation (SF). To establish the tactical mating flexibility afforded by DI*SF, we used cross-sectional population-level seasonal variation of circulating sex-steroids for 97 females from a high-density population. Oestradiol was highest in spring among non-parous females, then lower in summer, and remained low during following seasons, suggesting that the mating period was restricted to just spring. Oestrone was consistently higher than oestradiol; it was elevated in spring, lowest during summer, peaked in autumn, and remained elevated for pregnant females in winter. This suggests that oestrone sustains pre-implanted blastocysts throughout DI. Progesterone was low throughout, except during winter pregnancy, associated with implantation and luteal development. In contrast to multiple mating periods reported by lower-density studies, our oestradiol data suggest that, at high-density, females exhibit only one mating period (congruent with testosterone patterns in males studied previously in this same population). While additional mating periods during DI enhance fertility assurance at low-density, at high-density, we propose that when coitus is frequent, fertilisation is assured, precluding the need for further cycles and associated mating risks. This endocrinologically flexible DI*SF mating strategy likely represents a form of balancing selection, allowing badgers to succeed at a range of regional densities.
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Affiliation(s)
- Nadine Adrianna Sugianto
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Oxford, UK; School of Biosciences, University of Birmingham, Birmingham, UK.
| | - Michael Heistermann
- Endocrinology Laboratory, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
| | - Chris Newman
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Oxford, UK; Cook's Lake Farming Forestry and Wildlife Inc (Ecological Consultancy), Queens County, Nova Scotia, Canada
| | - David W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Oxford, UK
| | - Christina D Buesching
- Cook's Lake Farming Forestry and Wildlife Inc (Ecological Consultancy), Queens County, Nova Scotia, Canada; Department of Biology, Irving K. Barber Faculty of Sciences, The University of British Columbia, Kelowna, British Columbia, Canada
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van Lieshout SHJ, Badás EP, Mason MWT, Newman C, Buesching CD, Macdonald DW, Dugdale HL. Social effects on age-related and sex-specific immune cell profiles in a wild mammal. Biol Lett 2020; 16:20200234. [PMID: 32673548 PMCID: PMC7423055 DOI: 10.1098/rsbl.2020.0234] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Evidence for age-related changes in innate and adaptive immune responses is increasing in wild populations. Such changes have been linked to fitness, and knowledge of the factors driving immune response variation is important for understanding the evolution of immunity. Age-related changes in immune profiles may be owing to factors such as immune system development, sex-specific behaviour and responses to environmental conditions. Social environments may also contribute to variation in immunological responses, for example, through transmission of pathogens and stress arising from resource and mate competition. Yet, the impact of the social environment on age-related changes in immune cell profiles is currently understudied in the wild. Here, we tested the relationship between leukocyte cell composition (proportion of neutrophils and lymphocytes [innate and adaptive immunity, respectively] that were lymphocytes) and age, sex and group size in a wild population of European badgers (Meles meles). We found that the proportion of lymphocytes in early life was greater in males in smaller groups compared to larger groups, but with a faster age-related decline in smaller groups. By contrast, the proportion of lymphocytes in females was not significantly related to age or group size. Our results provide evidence of sex-specific age-related changes in immune cell profiles in a wild mammal, which are influenced by the social environment.
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Affiliation(s)
- Sil H J van Lieshout
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Elisa P Badás
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Michael W T Mason
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Chris Newman
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Abingdon, Oxfordshire OX13 5QL, UK
| | - Christina D Buesching
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Abingdon, Oxfordshire OX13 5QL, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, The Recanati-Kaplan Centre, Abingdon, Oxfordshire OX13 5QL, UK
| | - Hannah L Dugdale
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, 9747 AG Groningen, The Netherlands
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