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Tédonzong LRD, Ndju'u MBM, Tchamba M, Angwafo TE, Lens L, Tagg N, Willie J. The influence of vegetation structure on sleeping site selection by chimpanzees (Pan troglodytes troglodytes). Am J Primatol 2023:e23505. [PMID: 37157167 DOI: 10.1002/ajp.23505] [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: 12/24/2021] [Revised: 04/17/2023] [Accepted: 04/29/2023] [Indexed: 05/10/2023]
Abstract
Sleep is an important aspect of great ape life; these animals build sleeping platforms every night. In a community of chimpanzees, each subgroup selects a sleeping site where each individual builds a sleeping platform, mostly on a tree. Previous studies have measured the heights of sleeping platforms and sleeping trees to test the predation avoidance and thermoregulation hypotheses of sleeping site selection. However, it remains unclear how components of vegetation structure (vertical and horizontal) together determine the selection of sleeping sites by chimpanzees. Using botanical inventories around sleeping sites in a tropical rainforest of Cameroon, we found that chimpanzees preferentially sleep in trees measuring 40-50 cm in diameter. Regarding height, on average, sleeping trees measured 26 m and sleeping platforms were built at 16 m. To build sleeping platforms, chimpanzees preferred four tree species, which represent less than 3% of tree species in the study area. We demonstrate that the variation in abundance of tree species and the vertical and horizontal structure of the vegetation drive chimpanzee sleeping site selection. It was previously thought that preference for vegetation types was the driver of sleeping site selection in chimpanzees. However, results from this study indicate that the importance of vegetation types in sleeping site selection depends on their botanical characteristics including the variation in tree size, the abundance of all trees, the abundance of sleeping trees, and the occurrence of preferred sleeping tree species, which predict sleeping site selection. The height and diameter of trees are considered by chimpanzees when selecting a particular tree for sleeping and when selecting a site with a specific vertical structure. In addition to tree height, the abundance of smaller neighboring trees may also play a role in the chimpanzee antipredation strategy. Our results demonstrate that chimpanzees consider several vegetation parameters to establish sleeping sites.
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Affiliation(s)
- Luc Roscelin Dongmo Tédonzong
- Projet Grands Singes (PGS), Yaoundé, Cameroon
- Centre for Research and Conservation (CRC), Royal Zoological Society of Antwerp (RZSA), Antwerp, Belgium
- Section on Great Apes, Primate Specialist Group, IUCN Species Survival Commission, Yaoundé, Cameroon
| | | | - Martin Tchamba
- Department of Forestry, University of Dschang, Dschang, Cameroon
| | | | - Luc Lens
- Department of Biology, Ghent University (UGent), Ghent, Belgium
| | - Nikki Tagg
- Projet Grands Singes (PGS), Yaoundé, Cameroon
- Centre for Research and Conservation (CRC), Royal Zoological Society of Antwerp (RZSA), Antwerp, Belgium
| | - Jacob Willie
- Projet Grands Singes (PGS), Yaoundé, Cameroon
- Centre for Research and Conservation (CRC), Royal Zoological Society of Antwerp (RZSA), Antwerp, Belgium
- Department of Biology, Ghent University (UGent), Ghent, Belgium
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Antonovics J, Amoroso CR, Bruns E, Hood M. Host density shapes the relative contribution of vector-based and aerial transmission of a pathogenic fungus. Ecology 2022; 104:e3970. [PMID: 36576452 PMCID: PMC10073241 DOI: 10.1002/ecy.3970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 11/22/2022] [Accepted: 11/29/2022] [Indexed: 12/29/2022]
Abstract
Pathogen transmission mode is a key determinant of epidemiological outcomes. Theory shows that host density can influence the spread of pathogens differentially depending on their mode of transmission. Host density could therefore play an important role in determining the pathogen transmission mode. We tested theoretical expectations using floral arrays of the alpine carnation Dianthus pavonius in field experiments of spore dispersal of the anther-smut fungus, Microbotryum, by vector (pollinator)-based floral transmission and passive aerial transmission at a range of host densities. Pollinators deposited fewer spores per plant at high host density than at lower density (ranging from a 0.2-2 m spacing between plants), and vector-based spore deposition at higher densities declined more steeply with distance from diseased plant sources. In contrast, while aerial spore deposition declined with distance from the diseased source, the steepness of this decline was independent of host density. Our study indicates that the amount and distance of vector-based transmission are likely to be a nonmonotonic function of host density as a result of vector behavior, which is not readily encapsulated by fixed dispersal functions. We conclude that the spatial spread of pathogens by vectors is likely to be greater at lower and intermediate densities, whereas the spatial spread of aerially transmitted pathogens would be greater at high densities. These contrasting patterns could lead to differential importance of each transmission mode in terms of its contribution to subsequent infections across host densities.
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Affiliation(s)
- Janis Antonovics
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Caroline R Amoroso
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Emily Bruns
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Michael Hood
- Department of Biology, Amherst College, Amherst, Massachusetts, USA
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Smeltzer EA, Stead SM, Li MF, Samson D, Kumpan LT, Teichroeb JA. Social sleepers: The effects of social status on sleep in terrestrial mammals. Horm Behav 2022; 143:105181. [PMID: 35594742 DOI: 10.1016/j.yhbeh.2022.105181] [Citation(s) in RCA: 3] [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: 12/31/2021] [Revised: 04/12/2022] [Accepted: 04/22/2022] [Indexed: 11/18/2022]
Abstract
Social status among group-living mammals can impact access to resources, such as water, food, social support, and mating opportunities, and this differential access to resources can have fitness consequences. Here, we propose that an animal's social status impacts their access to sleep opportunities, as social status may predict when an animal sleeps, where they sleep, who they sleep with, and how well they sleep. Our review of terrestrial mammals examines how sleep architecture and intensity may be impacted by (1) sleeping conditions and (2) the social experience during wakefulness. Sleeping positions vary in thermoregulatory properties, protection from predators, and exposure to parasites. Thus, if dominant individuals have priority of access to sleeping positions, they may benefit from higher quality sleeping conditions and, in turn, better sleep. With respect to waking experiences, we discuss the impacts of stress on sleep, as it has been established that specific social statuses can be characterized by stress-related physiological profiles. While much research has focused on how dominance hierarchies impact access to resources like food and mating opportunities, differential access to sleep opportunities among mammals has been largely ignored despite its potential fitness consequences.
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Affiliation(s)
- E A Smeltzer
- Department of Anthropology, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - S M Stead
- Department of Anthropology, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada.
| | - M F Li
- Department of Anthropology, University of Toronto, 19 Russell St., Toronto, Ontario M5S 2S2, Canada
| | - D Samson
- Department of Anthropology, University of Toronto Mississauga, 3359 Mississauga Rd., Mississauga, Ontario L5L 1C6, Canada
| | - L T Kumpan
- Department of Anthropology, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
| | - J A Teichroeb
- Department of Anthropology, University of Toronto Scarborough, 1265 Military Trail, Scarborough, Ontario M1C 1A4, Canada
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Abstract
The human sleep pattern is paradoxical. Sleep is vital for optimal physical and cognitive performance, yet humans sleep the least of all primates. In addition, consolidated and continuous monophasic sleep is evidently advantageous, yet emerging comparative data sets from small-scale societies show that the phasing of the human pattern of sleep–wake activity is highly variable and characterized by significant nighttime activity. To reconcile these phenomena, the social sleep hypothesis proposes that extant traits of human sleep emerged because of social and technological niche construction. Specifically, sleep sites function as a type of social shelter by way of an extended structure of social groups that increases fitness. Short, high-quality, and flexibly timed sleep likely originated as a response to predation risks while sleeping terrestrially. This practice may have been a necessary preadaptation for migration out of Africa and for survival in ecological niches that penetrate latitudes with the greatest seasonal variation in light and temperature on the planet.
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Affiliation(s)
- David R. Samson
- Department of Anthropology, University of Toronto, Mississauga, Ontario L5L 1C6, Canada
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Group-size effects on virus prevalence depend on the presence of an invasive species. Behav Ecol Sociobiol 2021. [DOI: 10.1007/s00265-021-03040-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Affiliation(s)
- William C McGrew
- School of Psychology and Neuroscience, University of St Andrews, South Street, Fife, St Andrews, KY16 9AJ, Scotland, UK.
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Hernandez-Aguilar RA, Reitan T. Deciding Where to Sleep: Spatial Levels of Nesting Selection in Chimpanzees (Pan troglodytes) Living in Savanna at Issa, Tanzania. INT J PRIMATOL 2020. [DOI: 10.1007/s10764-020-00186-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AbstractTo understand how animals select resources we need to analyze selection at different spatial levels or scales in the habitat. We investigated which physical characteristics of trees (dimensions and structure, e.g., height, trunk diameter, number of branches) determined nesting selection by chimpanzees (Pan troglodytes) on two different spatial scales: individual nesting trees and nesting sites. We also examined whether individual tree selection explained the landscape pattern of nesting site selection. We compared the physical characteristics of actual (N = 132) and potential (N = 242) nesting trees in nesting sites (in 15 plots of 25 m × 25 m) and of all trees in actual and potential nesting sites (N = 763 in 30 plots of 25 m × 25 m). We collected data in May and June 2003 in Issa, a dry and open savanna habitat in Tanzania. Chimpanzees selected both the site they used for nesting in the landscape and the trees they used to build nests within a nesting site, demonstrating two levels of spatial selection in nesting. Site selection was stronger than individual tree selection. Tree height was the most important variable for both nesting site and tree selection in our study, suggesting that chimpanzees selected both safe sites and secure trees for sleeping.
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Traniello JFA, Bakker TCM. Social behavior and disease: supporting science during the pandemic. Behav Ecol Sociobiol 2020; 74:99. [PMID: 32834413 PMCID: PMC7367787 DOI: 10.1007/s00265-020-02882-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- James F A Traniello
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215 USA
| | - Theo C M Bakker
- Institute for Evolutionary Biology and Ecology, University of Bonn, An der Immenburg 1, 53121 Bonn, Germany
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