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Grebe NM, Eckardt W, Stoinski TS, Umuhoza R, Santymire RM, Rosenbaum S. An empirical comparison of several commercial enzyme immunoassays for the non-invasive assessment of adrenocortical and gonadal function in mountain gorillas. Gen Comp Endocrinol 2023; 342:114351. [PMID: 37532156 DOI: 10.1016/j.ygcen.2023.114351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 06/29/2023] [Accepted: 07/27/2023] [Indexed: 08/04/2023]
Abstract
Wildlife researchers seeking to non-invasively examine endocrine function in their study species are presented with a dense and technical 'garden of forking paths' to navigate between collecting a biological sample and obtaining a final measurement. In particular, the choice of which enzyme immunoassay (EIA) to use with collected fecal samples, out of the many options offered by different manufacturers and research laboratories, may be one of the most consequential for final results. However, guidance for making this decision is still emerging. With this gap in mind, we performed a head-to-head comparison of results obtained from four different EIAs for fecal glucocorticoid metabolites (FGCMs), and three different EIAs for fecal androgen metabolites (FAMs), applied to the same set of fecal samples collected from the mountain gorillas (Gorilla beringei beringei) monitored by the Dian Fossey Gorilla Fund in Volcanoes National Park, Rwanda. We provide a) an analytical validation of the different EIAs via tests of parallelism and linearity; b) an estimate of inter-assay correlation between EIA kits designed for the same metabolites; and c) a test of the kits' ecological validity, in which we examine how well each captures endocrine changes following events that theory predicts should result in elevated FGCM and/or FAM concentrations. Our results show that kits differ to some degree in their performance; at the same time, nearly all assays exhibited at least moderate evidence of validity and covariance with others for the same analyte. Our findings, which differ somewhat from similar comparisons performed in other species, demonstrate the need to directly assess assay performance in a species- and context-specific manner as part of efforts to develop the burgeoning discipline of wildlife endocrinology.
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Affiliation(s)
- Nicholas M Grebe
- Department of Anthropology, University of Michigan, Ann Arbor MI, United States.
| | | | | | | | - Rachel M Santymire
- Department of Biology, Georgia State University, Atlanta GA, United States
| | - Stacy Rosenbaum
- Department of Anthropology, University of Michigan, Ann Arbor MI, United States
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2
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Beaman JE, Mulligan C, Moore C, Mitchell D, Narayan E, Burke da Silva K. Resident wild koalas show resilience to large-scale translocation of bushfire-rescued koalas. Conserv Physiol 2023; 11:coac088. [PMID: 36726864 PMCID: PMC9885738 DOI: 10.1093/conphys/coac088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/11/2022] [Accepted: 01/12/2023] [Indexed: 06/18/2023]
Abstract
Wildlife translocation is increasingly utilized as a conservation management action, to mitigate the immediate negative effects of habitat loss and fragmentation (e.g. from land clearing or bushfires). Previous research has shown that stress responses can help or hinder survival in translocated wildlife and determine the efficacy of translocation as a conservation action. Yet these translocated animals are only one side of the equation, with translocation also potentially impacting the animals in the recipient population. We measured physiological markers of stress (faecal cortisol metabolite concentrations and neutrophil-lymphocyte ratios) and assessed health condition in a wild koala population one year after a major translocation of bushfire-rescued koalas on Kangaroo Island. We expected to find a high population density at the site (>0.75 koalas per hectare) and that resident koalas would show signs of chronic stress and ill health as a result of territorial conflict over food trees and reproductive opportunities. In contrast, we found that only one-fifth of the population remaining at the site were translocated koalas. The overall population density was also much lower (0.21 koalas per hectare) than anticipated. With no evidence of mass mortality at the site, we suggest that the majority of translocated koalas dispersed away from the site. Our stress marker measurements did not differ between the wild koalas and a sample of captive (non-display) koalas at the nearby Kangaroo Island Wildlife Park and were generally low compared to other studies. Veterinary examinations found that most koalas were in good body condition with very few diagnostic indicators of systemic ill health. Overall, our results suggest that, if there is adequate landscape-scale habitat connectivity and opportunity for dispersal, translocated koalas are likely to disperse from the site of release, with limited impacts on recipient koala populations at translocation release sites.
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Affiliation(s)
- Julian E Beaman
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042
| | - Connor Mulligan
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042
| | - Claire Moore
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042
| | - Dana Mitchell
- Kangaroo Island Wildlife Park, 4068 Playford Hwy, Duncan, South Australia 5223
- Kangaroo Island Koala & Wildlife Rescue Centre, 4068 Playford Hwy, Duncan, South Australia 5223
| | - Edward Narayan
- School of Agriculture and Food Sciences, The University of Queensland, Lawes, Queensland 4343
| | - Karen Burke da Silva
- College of Science and Engineering, Flinders University, Bedford Park, South Australia 5042
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3
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Braga Goncalves I, Radford AN. Experimental evidence that chronic outgroup conflict reduces reproductive success in a cooperatively breeding fish. eLife 2022; 11:72567. [PMID: 36102799 PMCID: PMC9473690 DOI: 10.7554/elife.72567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 08/31/2022] [Indexed: 11/13/2022] Open
Abstract
Conflicts with conspecific outsiders are common in group-living species, from ants to primates, and are argued to be an important selective force in social evolution. However, whilst an extensive empirical literature exists on the behaviour exhibited during and immediately after interactions with rivals, only very few observational studies have considered the cumulative fitness consequences of outgroup conflict. Using a cooperatively breeding fish, the daffodil cichlid (Neolamprologus pulcher), we conducted the first experimental test of the effects of chronic outgroup conflict on reproductive investment and output. ‘Intruded’ groups received long-term simulated territorial intrusions by neighbours that generated consistent group-defence behaviour; matched ‘Control’ groups (each the same size and with the same neighbours as an Intruded group) received no intrusions in the same period. Intruded groups had longer inter-clutch intervals and produced eggs with increasingly less protein than Control groups. Despite the lower egg investment, Intruded groups provided more parental care and achieved similar hatching success to Control groups. Ultimately, however, Intruded groups had fewer and smaller surviving offspring than Control groups at 1-month post-hatching. We therefore provide experimental evidence that outgroup conflict can decrease fitness via cumulative effects on reproductive success, confirming the selective potential of this empirically neglected aspect of sociality.
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Affiliation(s)
| | - Andrew N Radford
- School of Biological Sciences/Life Sciences, University of Bristol
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Petrželková K, Samaš P, Romportl D, Uwamahoro C, Červená B, Pafčo B, Prokopová T, Cameira R, Granjon A, Shapiro A, Bahizi M, Nziza J, Noheri J, Syaluha E, Eckardt W, Ndagijimana F, Šlapeta J, Modrý D, Gilardi K, Muvunyi R, Uwingeli P, Mudakikwa A, Mapilanga J, Kalonji A, Hickey J, Cranfield M. Ecological drivers of helminth infection patterns in the Virunga Massif mountain gorilla population. Int J Parasitol Parasites Wildl 2022; 17:174-184. [PMID: 35145846 PMCID: PMC8802862 DOI: 10.1016/j.ijppaw.2022.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/07/2022] [Accepted: 01/17/2022] [Indexed: 01/16/2023]
Abstract
The Virunga Massif mountain gorilla population has been periodically monitored since the early 1970s, with gradually increasing effort. The population declined drastically in the 1970s, but the numbers stabilized in the 1980s. Since then, the population has been steadily increasing within their limited habitat fragment that is surrounded by a dense human population. We examined fecal samples collected during the Virunga 2015-2016 surveys in monitored and unmonitored gorilla groups and quantified strongylid and tapeworm infections using egg counts per gram to determine environmental and host factors that shape these helminth infections. We showed that higher strongylid infections were present in gorilla groups with smaller size of the 500-m buffered minimum-convex polygon (MCP) of detected nest sites per gorilla group, but in higher gorilla densities and inhabiting vegetation types occurring at higher elevations with higher precipitation and lower temperatures. On the contrary, the impact of monitoring (habituation) was minor, detected in tapeworms and only when in the interaction with environmental variables and MCP area. Our results suggest that the Virunga mountain gorilla population may be partially regulated by strongylid nematodes at higher gorilla densities. New health challenges are probably emerging among mountain gorillas because of the success of conservation efforts, as manifested by significant increases in gorilla numbers in recent decades, but few possibilities for the population expansion due to limited amounts of habitat.
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Affiliation(s)
- K.J. Petrželková
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Czech Republic
- Liberec Zoo, Liberec, Czech Republic
| | - P. Samaš
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - D. Romportl
- Department of Physical Geography and Geoecology, Faculty of Science, Charles University, Prague, Czech Republic
| | | | - B. Červená
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences, Brno, Czech Republic
| | - B. Pafčo
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - T. Prokopová
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences, Brno, Czech Republic
| | - R. Cameira
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences, Brno, Czech Republic
| | - A.C. Granjon
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - A. Shapiro
- Here + There Mapping Solutions, Berlin, Germany
| | - M. Bahizi
- Gorilla Doctors (MGVP, Inc.), Davis, CA, USA
| | - J. Nziza
- Gorilla Doctors (MGVP, Inc.), Davis, CA, USA
| | - J.B. Noheri
- Gorilla Doctors (MGVP, Inc.), Davis, CA, USA
| | | | - W. Eckardt
- Dian Fossey Gorilla Fund, Musanze, Rwanda
| | | | - J. Šlapeta
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, New South Wales 2006, Australia
| | - D. Modrý
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Czech Republic
- Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences, Brno, Czech Republic
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
- Department of Veterinary Sciences/CINeZ, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic
| | - K. Gilardi
- Gorilla Doctors (MGVP, Inc.), Davis, CA, USA
- School of Veterinary Medicine, University of California, Davis, CA, USA
| | - R. Muvunyi
- Rwanda Development Board, Kigali, Rwanda
| | | | | | - J. Mapilanga
- Institut Congolais pour la Conservation de la Nature, Kinshasa, Congo
| | - A. Kalonji
- Institut Congolais pour la Conservation de la Nature, Parc National de Kahuzi Biega, Bukavu, Congo
| | - J.R. Hickey
- International Gorilla Conservation Programme, Kigali, Rwanda
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Rosenbaum S, Eckardt W, Stoinski TS, Umuhoza R, Kuzawa CW, Santymire RM. Group structure, but not dominance rank, predicts fecal androgen metabolite concentrations of wild male mountain gorillas (Gorilla beringei beringei). Am J Primatol 2021; 83:e23295. [PMID: 34223661 DOI: 10.1002/ajp.23295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/24/2021] [Accepted: 06/06/2021] [Indexed: 11/11/2022]
Abstract
Androgens are important mediators of male-male competition in many primate species. Male gorillas' morphology is consistent with a reproductive strategy that relies heavily on androgen-dependent traits (e.g., extreme size and muscle mass). Despite possessing characteristics typical of species with an exclusively single-male group structure, multimale groups with strong dominance hierarchies are common in mountain gorillas. Theory predicts that androgens should mediate their dominance hierarchies, and potentially vary with the type of group males live in. We validated the use of a testosterone enzyme immunoassay (T-EIA R156/7, CJ Munro, UC-Davis) for use with mountain gorilla fecal material by (1) examining individual-level androgen responses to competitive events, and (2) isolating assay-specific hormone metabolites via high-performance liquid chromatography. Males had large (2.6- and 6.5-fold), temporary increases in fecal androgen metabolite (FAM) after competitive events, and most captured metabolites were testosterone or 5α-dihydrotestosterone-like androgens. We then examined the relationship between males' dominance ranks, group type, and FAM concentrations. Males in single-male groups had higher FAM concentrations than males in multimale groups, and a small pool of samples from solitary males suggested they may have lower FAM than group-living peers. However, data from two different time periods (n = 1610 samples) indicated there was no clear relationship between rank and FAM concentrations, confirming results from the larger of two prior studies that measured urinary androgens. These findings highlight the need for additional research to clarify the surprising lack of a dominance hierarchy/androgen relationship in mountain gorillas.
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Affiliation(s)
- Stacy Rosenbaum
- Department of Anthropology, University of Michigan, Ann Arbor, Michigan, USA.,Davee Center for Epidemiology and Endocrinology, Lincoln Park Zoo, Chicago, Illinois, USA
| | - Winnie Eckardt
- Karisoke Research Center, Musanze, Rwanda.,The Dian Fossey Gorilla Fund, Atlanta, Georgia, USA
| | | | | | - Christopher W Kuzawa
- Department of Anthropology, Northwestern University, Evanston, Illinois, USA.,Institute for Policy Research, Northwestern University, Evanston, Illinois, USA
| | - Rachel M Santymire
- Davee Center for Epidemiology and Endocrinology, Lincoln Park Zoo, Chicago, Illinois, USA
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6
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Caillaud D, Eckardt W, Vecellio V, Ndagijimana F, Mucyo JP, Hirwa JP, Stoinski T. Violent encounters between social units hinder the growth of a high-density mountain gorilla population. Sci Adv 2020; 6:6/45/eaba0724. [PMID: 33148636 PMCID: PMC7673674 DOI: 10.1126/sciadv.aba0724] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 08/29/2020] [Indexed: 05/29/2023]
Abstract
Density-dependent processes such as competition for resources, migration, predation, and disease outbreaks limit the growth of natural populations. The analysis of 50 years of mountain gorilla data reveals that social behavior changes observed at high group density may also affect population growth in social species. A sudden increase in social group density observed in 2007 caused a threefold increase in the rate of violent encounters between social units (groups and solitary males). A fivefold increase in the rate of infanticide and seven cases of lethal fights among mature males were subsequently recorded, and the annual subpopulation growth rate declined by half between 2000 and 2017. The increase in infanticide alone explains 57% of this decline. These findings highlight the complex relationship between population density and growth in social species and hold important implications for the management of island populations.
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Affiliation(s)
- Damien Caillaud
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA.
- Department of Anthropology, University of California, Davis, One Shields Ave., Davis, CA 95616, USA
| | - Winnie Eckardt
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Veronica Vecellio
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Felix Ndagijimana
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Jean-Pierre Mucyo
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Jean-Paul Hirwa
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Tara Stoinski
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA.
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7
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Scherpenhuizen JM, Narayan EJ, Quinn JC. Timed environmental exposure indicates sample stability for reliable noninvasive measurement of fecal cortisol metabolite concentrations in sheep. Domest Anim Endocrinol 2020; 72:106423. [PMID: 32272317 DOI: 10.1016/j.domaniend.2019.106423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 10/26/2019] [Accepted: 12/03/2019] [Indexed: 10/25/2022]
Abstract
The use of noninvasive techniques to evaluate stress responses in animals has become an increasingly popular method of animal welfare assessment in both production animals and wildlife. In particular, using fecal samples to measure fecal cortisol metabolites (FCMs) as a quantitative measure has proven ideal as samples can be collected remote to the animal after defecation without the need for invasive procedures. Colorimetric enzyme immunoassays (EIAs) have been shown to have a high level of selectivity and sensitivity for FCM concentration analysis, equivalent to the traditionally used radioimmunoassay. Regardless of the assay system used, species- and sample-specific validation must be undertaken to ensure the reliability of results, particularly where sampling is undertaken in a novel species or where environmental conditions might impact FCM stability in the fecal sample. To determine the limit of environmental exposure acceptable for analysis of FCM concentrations in ovine scat samples collected from a paddock under conditions of stable heat and humidity, this study quantified FCMs in ovine feces shortly after defecation (2-7 h) and after timed environmental exposure (1-9 d). Samples were determined to show stable FCM concentrations for up to 5 d by this analysis. Understanding the impacts of environmental exposure, and therefore the viability of remote fecal collection methods for quantitative analysis of FCM by EIA, is important to assess the utility of noninvasive measures of endocrine status in animals where the exact timing of defecation may not be known.
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Affiliation(s)
- J M Scherpenhuizen
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales 2678, Australia; Graham Centre for Agricultural Innovation (Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga, New South Wales 2560, Australia.
| | - E J Narayan
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales 2678, Australia
| | - J C Quinn
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales 2678, Australia; Graham Centre for Agricultural Innovation (Charles Sturt University and NSW Department of Primary Industries), Wagga Wagga, New South Wales 2560, Australia
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8
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Mirville MO, Ridley AR, Samedi JPM, Vecellio V, Ndagijimana F, Stoinski TS, Grueter CC. Intragroup Behavioral Changes Following Intergroup Conflict in Mountain Gorillas (Gorilla beringei beringei). INT J PRIMATOL 2020. [DOI: 10.1007/s10764-020-00130-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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9
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Eckardt W, Stoinski TS, Rosenbaum S, Santymire R. Social and ecological factors alter stress physiology of Virunga mountain gorillas ( Gorilla beringei beringei). Ecol Evol 2019; 9:5248-5259. [PMID: 31110676 PMCID: PMC6509442 DOI: 10.1002/ece3.5115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 02/05/2019] [Accepted: 03/01/2019] [Indexed: 11/12/2022] Open
Abstract
Living in a rapidly changing environment can alter stress physiology at the population level, with negative impacts on health, reproductive rates, and mortality that may ultimately result in species decline. Small, isolated animal populations where genetic diversity is low are at particular risks, such as endangered Virunga mountain gorillas (Gorilla beringei beringei). Along with climate change-associated environmental shifts that are affecting the entire population, subpopulations of the Virunga gorillas have recently experienced extreme changes in their social environment. As the growing population moves closer to the forest's carrying capacity, the gorillas are coping with rising population density, increased frequencies of interactions between social units, and changing habitat use (e.g., more overlapping home ranges and routine ranging at higher elevations). Using noninvasive monitoring of fecal glucocorticoid metabolites (FGM) on 115 habituated Virunga gorillas, we investigated how social and ecological variation are related to baseline FGM levels, to better understand the adaptive capacity of mountain gorillas and monitor potential physiological indicators of population decline risks. Generalized linear mixed models revealed elevated mean monthly baseline FGM levels in months with higher rainfall and higher mean maximum and minimum temperature, suggesting that Virunga gorillas might be sensitive to predicted warming and rainfall trends involving longer, warmer dry seasons and more concentrated and extreme rainfall occurrences. Exclusive use of smaller home range areas was linked to elevated baseline FGM levels, which may reflect reduced feeding efficiency and increased travel efforts to actively avoid neighboring groups. The potential for additive effects of stress-inducing factors could have short- and long-term impacts on the reproduction, health, and ultimately survival of the Virunga gorilla population. The ongoing effects of environmental changes and population dynamics must be closely monitored and used to develop effective long-term conservation strategies that can help address these risk factors.
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Affiliation(s)
| | | | - Stacy Rosenbaum
- Departmet of AnthropologyNorthwestern UniversityEvanstonIllinois
- Davee Center for Epidemiology and EndocrinologyLincoln Park ZooChicagoIllinois
| | - Rachel Santymire
- Davee Center for Epidemiology and EndocrinologyLincoln Park ZooChicagoIllinois
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Robbins MM, Robbins AM. Variation in the social organization of gorillas: Life history and socioecological perspectives. Evol Anthropol 2018; 27:218-233. [PMID: 30325554 DOI: 10.1002/evan.21721] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 07/18/2018] [Accepted: 08/06/2018] [Indexed: 01/29/2023]
Abstract
A focus of socioecological research is to understand how ecological, social, and life history factors influence the variability of social organization within and between species. The genus Gorilla exhibits variability in social organization with western gorilla groups being almost exclusively one-male, yet approximately 40% of mountain gorilla groups are multimale. We review five ultimate causes for the variability in social organization within and among gorilla populations: human disturbance, ecological constraints on group size, risk of infanticide, life history patterns, and population density. We find the most evidence for the ecological constraints and life history hypotheses, but an over-riding explanation remains elusive. The variability may hinge on variation in female dispersal patterns, as females seek a group of optimal size and with a good protector male. Our review illustrates the challenges of understanding why the social organization of closely related species may deviate from predictions based on socioecological and life history theory.
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Affiliation(s)
- Martha M Robbins
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Andrew M Robbins
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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11
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Santymire RM, Manjerovic MB, Sacerdote-Velat A. A novel method for the measurement of glucocorticoids in dermal secretions of amphibians. Conserv Physiol 2018; 6:coy008. [PMID: 29479435 PMCID: PMC5814794 DOI: 10.1093/conphys/coy008] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 01/19/2018] [Accepted: 02/05/2018] [Indexed: 05/23/2023]
Abstract
Amphibians have been declining in both diversity and abundance due in large part to habitat degradation and the prevalence of emerging diseases. Although stressors can suppress the immune system, affecting an individual's health and susceptibility to pathogens, established methods for directly collecting stress hormones are not suitable for rapid field use or for use on threatened and endangered species. To overcome these challenges, we are developing an innovative method to collect and measure amphibian glucocorticoid secretions using non-invasive dermal swabs. We tested this methodology using multiple terrestrial, semi-aquatic and fully aquatic species. We swabbed the dorsal side of each animal six times and then induced a stressor of either hand-restraint, ACTH injection, or saline as a control. We then repeated swab collection immediately after the stressor and at 15, 30, 45, 60, 90 and 120 min intervals. Cortisol enzyme immunoassay detected changes in cortisol post-stressor. We also tested this methodology in the field and were successfully able to detect glucocorticoids from multiple species at varying life stages. When using in the field, capture technique should be considered since it may impact stress levels in certain species. Upon further testing, this novel method may be used to greatly increase our understanding of amphibian health especially as disease and environmental changes continue to impact fragile populations.
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Affiliation(s)
- R M Santymire
- Lincoln Park Zoo, Conservation & Science Department, 2001 N. Clark St., Chicago, IL 60614, USA
| | - M B Manjerovic
- Lincoln Park Zoo, Conservation & Science Department, 2001 N. Clark St., Chicago, IL 60614, USA
- Department of Biology, Virginia Military Institute, 301C Maury-Brooke Hall, Lexington, VA 24450, USA
| | - A Sacerdote-Velat
- The Chicago Academy of Sciences, Peggy Notebaert Nature Museum, 2430 North Cannon Drive, Chicago, IL 60614, USA
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