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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.
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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
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Zhao L, Ji SN, Du XB, Liu JH, Zhang BL, Li PH, Yang YJ, Li BG, Guo YQ, Qi XG. Dynamic foraging strategy adaptation to heterogeneous environments contributes to social aggregation in snub-nosed monkeys. Zool Res 2024; 45:39-54. [PMID: 38114432 PMCID: PMC10839657 DOI: 10.24272/j.issn.2095-8137.2023.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 09/08/2023] [Indexed: 12/21/2023] Open
Abstract
The dynamics of animal social structures are heavily influenced by environmental patterns of competition and cooperation. In folivorous colobine primates, prevailing theories suggest that larger group sizes should be favored in rainforests with a year-round abundance of food, thereby reducing feeding competition. Yet, paradoxically, larger groups are frequently found in high-altitude or high-latitude montane ecosystems characterized by a seasonal scarcity of leaves. This contradiction is posited to arise from cooperative benefits in heterogeneous environments. To investigate this hypothesis, we carried out a six-year field study on two neighboring groups of golden snub-nosed monkey ( Rhinopithecus roxellana), a species representing the northernmost distribution of colobine primates. Results showed that the groups adjusted their movement and habitat selection in response to fluctuating climates and spatiotemporal variability of resources, indicative of a dynamic foraging strategy. Notably, during the cold, resource-scarce conditions in winter, the large group occupied food-rich habitats but did not exhibit significantly longer daily travel distances than the smaller neighboring group. Subsequently, we compiled an eco-behavioral dataset of 52 colobine species to explore their evolutionary trajectories. Analysis of this dataset suggested that the increase in group size may have evolved via home range expansion in response to the cold and heterogeneous climates found at higher altitudes or latitudes. Hence, we developed a multi-benefits framework to interpret the formation of larger groups by integrating environmental heterogeneity. In cold and diverse environments, even smaller groups require larger home ranges to meet their dynamic survival needs. The spatiotemporal distribution of high-quality resources within these expanded home ranges facilitates more frequent interactions between groups, thereby encouraging social aggregation into larger groups. This process enhances the benefits of collaborative actions and reproductive opportunities, while simultaneously optimizing travel costs through a dynamic foraging strategy.
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Affiliation(s)
- Lan Zhao
- College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China
| | - Sheng-Nan Ji
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Xiao-Bing Du
- College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China
| | - Jia-Hui Liu
- College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China
| | - Bo-Lun Zhang
- College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China
| | - Pei-Hua Li
- College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China
| | - Yi-Jun Yang
- College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China
| | - Bao-Guo Li
- College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China
| | - Yan-Qing Guo
- College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China
| | - Xiao-Guang Qi
- College of Life Sciences, Northwest University, Xi'an, Shaanxi 710069, China. E-mail:
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Young C, Robbins MM. Association patterns of female gorillas. Philos Trans R Soc Lond B Biol Sci 2023; 378:20210429. [PMID: 36440560 PMCID: PMC9703218 DOI: 10.1098/rstb.2021.0429] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 08/09/2022] [Indexed: 11/29/2022] Open
Abstract
Social interactions ultimately impact health and fitness in gregarious mammals. However, research focusing on the strength of affiliative interactions has primarily been conducted on female philopatric species. Gorillas provide an interesting counterpoint to previous research as females emigrate multiple times throughout their lives. We compare female-female association strength, duration and consistency in wild mountain (Gorilla beringei beringei) and western gorillas (Gorilla gorilla gorilla). Additionally, we examine whether the alpha male influences female association strength and if these associations are an artefact of both females concurrently in spatial proximity of the alpha male. In this between-species comparison, female gorillas had differentiated association patterns that were consistent on average for 2 years. The alpha males did not influence female association strength, with associations being similar in his presence or absence. Finally, we found more variability in association patterns among mountain gorillas with higher average association scores and higher proportion of 'preferred associates' than western gorillas. The rare dispersal pattern in the Gorilla genus may lead to greater flexibility in female association patterns than in species exhibiting female philopatry and strong kinship bonds. This may echo ancestral human society and provide new evidence to help us understand the evolution of modern human society. This article is part of the theme issue 'Cooperation among women: evolutionary and cross-cultural perspectives'.
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Affiliation(s)
- Christopher Young
- Department of Psychology, Nottingham Trent University, Nottingham NG1 4FQ, UK
- Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Martha M. Robbins
- Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
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Teichroeb JA, Adams FV, Khwaja A, Stapelfeldt K, Stead SM. Tight quarters: ranging and feeding competition in a Colobus angolensis ruwenzorii multilevel society occupying a fragmented habitat. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03166-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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