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Desai B, Bhowmik T, Srinivasan R, Whitaker N, Ghosal R. Monitoring the stress physiology of free-ranging mugger crocodiles ( Crocodylus palustris) across diverse habitats within Central Gujarat, India. CONSERVATION PHYSIOLOGY 2024; 12:coae035. [PMID: 38840751 PMCID: PMC11151695 DOI: 10.1093/conphys/coae035] [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: 11/29/2023] [Revised: 05/03/2024] [Accepted: 05/08/2024] [Indexed: 06/07/2024]
Abstract
Animals face several challenges in their natural environment, and to cope with such conditions, they may exhibit contrasting physiological responses that directly affect their overall well-being and survival. In this study, we assessed physiological responses via faecal glucocorticoid metabolite (fGCM) measurements in free-ranging mugger crocodiles inhabiting diverse habitats in Gujarat, India. We sampled muggers within Charotar, a rural area (Zone A) with local people having high tolerance towards the presence of muggers, and Vadodara, a region having both urban (Zone B) and rural (Zone C) areas with high levels of human-mugger conflict (HMC). Further, muggers in Vadodara live in water bodies that are mostly polluted due to sewage disposal from adjoining chemical industries. To measure fGCM (mean ± SEM, ng/g dry faeces) levels in muggers, scats were collected during both breeding (N = 107 scats) and non-breeding (N = 22 scats) seasons from all three zones. We used captive muggers (a focal enclosure) to biologically validate (via capture and restraint) the selected fGCM assay (11-oxoetiocholanolone assay). We showed a significant (P < 0.05) 11-fold increase in fGCM levels between pre-capture (540.9 ± 149.2, N = 11) and post-capture (6259.7 ± 1150.5, N = 11) samples. The validated assay was applied to free-ranging muggers during the breeding season, and Zone A showed significantly (P < 0.05) lower fGCM levels (542.03 ± 71.3) compared to muggers of Zone B (1699.9 ± 180.8) and Zone C (1806.4 ± 243.2), both zones having high levels of HMC with polluted water bodies. A similar contrast in fGCM levels was also observed during the non-breeding season. Overall, the study demonstrated that fGCM levels in muggers varied across habitats, and such variation could be due to a multitude of ecological factors that the species experience in their immediate local environment. Moreover, high fGCM levels in muggers of Vadodara during both breeding and non-breeding seasons may indicate a condition of chronic stress, which could be maladaptive for the species.
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Affiliation(s)
- Brinky Desai
- Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Commerce Six Roads, Navrangpura, Ahmedabad 380009, Gujarat, India
| | - Tathagata Bhowmik
- Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Commerce Six Roads, Navrangpura, Ahmedabad 380009, Gujarat, India
| | - Rohith Srinivasan
- Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Commerce Six Roads, Navrangpura, Ahmedabad 380009, Gujarat, India
| | - Nikhil Whitaker
- Madras Crocodile Bank Trust, Post Bag No 4, Mahabalipuram, Chennai 603104, Tamil Nadu, India
| | - Ratna Ghosal
- Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University, Commerce Six Roads, Navrangpura, Ahmedabad 380009, Gujarat, India
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Behr DM, Hodel FH, Cozzi G, McNutt JW, Ozgul A. Higher Mortality Is Not a Universal Cost of Dispersal: A Case Study in African Wild Dogs. Am Nat 2023; 202:616-629. [PMID: 37963118 DOI: 10.1086/726220] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
AbstractMortality is considered one of the main costs of dispersal. A reliable evaluation of mortality, however, is often hindered by a lack of information about the fate of individuals that disappear under unexplained circumstances (i.e., missing individuals). Here, we addressed this uncertainty by applying a Bayesian mortality analysis that inferred the fate of missing individuals according to information from individuals with known fate. Specifically, we tested the hypothesis that mortality during dispersal is higher than mortality among nondispersers using 32 years of mark-resighting data from a free-ranging population of the endangered African wild dog (Lycaon pictus) in northern Botswana. Contrary to expectations, we found that mortality during dispersal was lower than mortality among nondispersers, indicating that higher mortality is not a universal cost of dispersal. Our findings suggest that group living can incur costs for certain age classes, such as limited access to resources as group density increases, that exceed the mortality costs associated with dispersal. By challenging the accepted expectation of higher mortality during dispersal, we urge for further investigations of this key life history trait and propose a robust statistical approach to reduce bias in mortality estimates.
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Sen S, Carrera SC, Heistermann M, Potter CB, Baniel A, DeLacey PM, Petrullo L, Lu A, Beehner JC. Social correlates of androgen levels and dispersal age in juvenile male geladas. Horm Behav 2022; 146:105264. [PMID: 36155910 DOI: 10.1016/j.yhbeh.2022.105264] [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: 04/05/2022] [Revised: 09/06/2022] [Accepted: 09/09/2022] [Indexed: 11/23/2022]
Abstract
Androgens offer a window into the timing of important male life history events such as maturation. However, when males are the dispersing sex, piecing together normative androgen profiles across development is challenging because dispersing males are difficult to track. Here, we examined the conditions that may be associated with male androgen status (via fecal androgen metabolites, fAMs) and age at dispersal in wild male geladas (Theropithecus gelada). Gelada male life histories are highly variable - dispersal may occur before sexual maturation, dispersal itself can be immediate or drawn out, and, due to their multi-leveled society, social conditions affecting dispersal can vary for juveniles living in different reproductive units within the same band. Using longitudinal data from known natal males, we examined how androgen levels and age at dispersal were associated with: (1) access to maternal resources (i.e., maternal rank, birth of a younger sibling, experiencing maternal loss), and (2) access to male peers (i.e., number of similar-aged males in their unit). We found that androgens were significantly lower in males with high-ranking mothers (in males >2.5 years of age; infant androgens were unrelated) and that having more male peers in their social group and larger groups overall predicted an earlier age at dispersal. Moreover, dispersal in geladas was not preceded or followed by a surge in androgen levels. Taken together, results suggest that social environments can cause individual variation in androgens and dispersal age. Whether this variation leads to differences in male fitness in later life remains to be determined.
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Affiliation(s)
- Sharmi Sen
- Department of Anthropology, University of Michigan, Ann Arbor, MI 48109-1107, USA.
| | - Sofia C Carrera
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109-1107, USA
| | - Michael Heistermann
- Endocrinology Laboratory, German Primate Center, Leibniz Institute for Primate Research, 37077 Göttingen, Germany
| | - Caitlin Barale Potter
- Cedar Creek Ecosystem Science Reserve, University of Minnesota, St. Paul, MN 55108, USA
| | - Alice Baniel
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ 85281, USA; School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Patricia M DeLacey
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109-1107, USA
| | - Lauren Petrullo
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109-1107, USA
| | - Amy Lu
- Department of Anthropology, Stony Brook University, Stony Brook, NY 11794-4364, USA
| | - Jacinta C Beehner
- Department of Anthropology, University of Michigan, Ann Arbor, MI 48109-1107, USA; Department of Psychology, University of Michigan, Ann Arbor, MI 48109-1107, USA
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Affordable RFID loggers for monitoring animal movement, activity, and behaviour. PLoS One 2022; 17:e0276388. [PMID: 36302036 PMCID: PMC9612574 DOI: 10.1371/journal.pone.0276388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
Effective conservation management strategies require accurate information on the movement patterns and behaviour of wild animals. To collect these data, researchers are increasingly turning to remote sensing technology such as radio-frequency identification (RFID). RFID technology is a powerful tool that has been widely implemented in ecological research to identify and monitor unique individuals, but it bears a substantial price tag, restricting this technology to generously-funded disciplines and projects. To overcome this price hurdle, we provide detailed step-by-step instructions to source the components for, and construct portable RFID loggers in house, at a fraction of the cost (~5%) of commercial RFID units. Here, we assess the performance of these RFID loggers in the field and describe their application in two studies of Australian mammal species; monitoring nest-box use in the Northern quolls (Dasyurus hallucatus) and observing the foraging habits of quenda (Isoodon fusciventer) at feeding stations. The RFID loggers performed well, identifying quenda in >80% of visits, and facilitating the collection of individual-level behavioural data including common metrics such as emergence time, latency to approach, and foraging effort. While the technology itself is not novel, by lowering the cost per unit, our loggers enabled greater sample sizes, increasing statistical power from 0.09 to 0.75 in the quoll study. Further, we outline and provide solutions to the limitations of this design. Our RFID loggers proved an innovative method for collecting accurate behavioural and movement data. With their ability to successfully identify individuals, the RFID loggers described here can act as an alternative or complementary tool to camera traps. These RFID loggers can also be applied in a wide variety of projects which range from monitoring animal welfare or demographic traits to studies of anti-predator responses and animal personality, making them a valuable addition to the modern ecologists’ toolkit.
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Ostreiher R, Mundry R, Heifetz A. Actual versus counterfactual fitness consequences of dispersal decisions in a cooperative breeder. ETHOL ECOL EVOL 2022. [DOI: 10.1080/03949370.2022.2094469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Roni Ostreiher
- Department of Life Science, The Open University of Israel, Raanana, Israel
| | - Roger Mundry
- Platform Bioinformatics and Biostatistics, VetMedUni, Vienna, Austria
- Cognitive Ethology Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany
- Department for Primate Cognition, Georg-August-University Göttingen, Göttingen, Germany
- Leibniz ScienceCampus Primate Cognition, Göttingen, Germany
| | - Aviad Heifetz
- Department of Management and Economics, The Open University of Israel, Raanana, Israel
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Maag N, Paniw M, Cozzi G, Manser M, Clutton-Brock T, Ozgul A. Dispersal decreases survival but increases reproductive opportunities for subordinates in a cooperative breeder. Am Nat 2022; 199:679-690. [DOI: 10.1086/719029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Harrison ND, Maag N, Haverkamp PJ, Ganswindt A, Manser MB, Clutton-Brock TH, Ozgul A, Cozzi G. Behavioural change during dispersal and its relationship to survival and reproduction in a cooperative breeder. J Anim Ecol 2021; 90:2637-2650. [PMID: 34258771 PMCID: PMC8597146 DOI: 10.1111/1365-2656.13569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 07/07/2021] [Indexed: 12/12/2022]
Abstract
The ability of dispersing individuals to adjust their behaviour to changing conditions is instrumental in overcoming challenges and reducing dispersal costs, consequently increasing overall dispersal success. Understanding how dispersers' behaviour and physiology change during the dispersal process, and how they differ from resident individuals, can shed light on the mechanisms by which dispersers increase survival and maximise reproduction. By analysing individual behaviour and concentrations of faecal glucocorticoid metabolites (fGCM), a stress‐associated biomarker, we sought to identify the proximate causes behind differences in survival and reproduction between dispersing and resident meerkats Suricata suricatta. We used data collected on 67 dispersing and 108 resident females to investigate (a) which individual, social and environmental factors are correlated to foraging and vigilance, and whether the role of such factors differs among dispersal phases, and between dispersers and residents; (b) how time allocated to either foraging or vigilance correlated to survival in dispersers and residents and (c) the link between aggression and change in fGCM concentration, and their relationship with reproductive rates in dispersing groups and resident groups with either long‐established or newly established dominant females. Time allocated to foraging increased across dispersal phases, whereas time allocated to vigilance decreased. Time allocated to foraging and vigilance correlated positively and negatively, respectively, with dispersers' group size. We did not find a group size effect for residents. High proportions of time allocated to foraging correlated with high survival, and more so in dispersers, suggesting that maintaining good physical condition may reduce mortality during dispersal. Furthermore, while subordinate individuals rarely reproduced in resident groups, the conception rate of subordinates in newly formed dispersing groups was equal to that of their dominant individuals. Mirroring conception rates, in resident groups, fGCM concentrations were lower in subordinates than in dominants, whereas in disperser groups, fGCM concentrations did not differ between subordinates and dominants. Our results, which highlight the relationship between behavioural and physiological factors and demographic rates, provide insights into some of the mechanisms that individuals of a cooperative species can use to increase overall dispersal success.
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Affiliation(s)
- Natasha D Harrison
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Kalahari Research Centre, Kuruman River Reserve, Van Zylsrus, South Africa
| | - Nino Maag
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Kalahari Research Centre, Kuruman River Reserve, Van Zylsrus, South Africa
| | - Paul J Haverkamp
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - André Ganswindt
- Mammal Research Institute, University of Pretoria, Hatfield, South Africa
| | - Marta B Manser
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Kalahari Research Centre, Kuruman River Reserve, Van Zylsrus, South Africa
| | - Tim H Clutton-Brock
- Kalahari Research Centre, Kuruman River Reserve, Van Zylsrus, South Africa.,Mammal Research Institute, University of Pretoria, Hatfield, South Africa.,Department of Zoology, University of Cambridge, Cambridge, UK
| | - Arpat Ozgul
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Kalahari Research Centre, Kuruman River Reserve, Van Zylsrus, South Africa
| | - Gabriele Cozzi
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Kalahari Research Centre, Kuruman River Reserve, Van Zylsrus, South Africa
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