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Walmsley SF, Boutin S, Dantzer B, Lane JE, Coltman DW, McAdam AG. Benefits of living closer to kin vary by genealogical relationship in a territorial mammal. Proc Biol Sci 2023; 290:20221569. [PMID: 36629099 PMCID: PMC9832554 DOI: 10.1098/rspb.2022.1569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/05/2022] [Indexed: 01/12/2023] Open
Abstract
While cooperative interactions among kin are a key building block in the societies of group-living species, their importance for species with more variable social environments is unclear. North American red squirrels (Tamiasciurus hudsonicus) defend individual territories in dynamic neighbourhoods and are known to benefit from living among familiar conspecifics, but not relatives. However, kin-directed behaviours may be restricted to specific genealogical relationships or strongly mediated by geographical distance, masking their influence at broader scales. Using distance between territories as a proxy for the ability of individuals to interact, we estimated the influence of primary kin (parents, offspring, siblings) on the annual survival and reproductive success of red squirrels. This approach revealed associations between fitness and access to kin, but only for certain genealogical relationships and fitness components. For example, females had enhanced annual survival when living closer to their daughters, though the reverse was not true. Most surprising was the finding that males had higher annual reproductive success when living closer to their father, suggesting possible recognition and cooperation among fathers and sons. Together, these findings point to unexpected nuance in the fitness consequences of kinship dynamics for a species that is territorial and largely solitary.
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Affiliation(s)
- Sam F. Walmsley
- Department of Ecology and Evolutionary Biology, University of Colorado, 1900 Pleasant Street, Boulder, CO 80309, USA
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2E9
| | - Ben Dantzer
- Department of Psychology, University of Michigan, 500 South State Street, Ann Arbor, MI 48109, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, 500 South State Street, Ann Arbor, MI 48109, USA
| | - Jeffrey E. Lane
- Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, Canada S7N 5E2
| | - David W. Coltman
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2E9
- Biology Department, Western University, 1151 Richmond Street, London, Ontario, Canada N6A 5B7
| | - Andrew G. McAdam
- Department of Ecology and Evolutionary Biology, University of Colorado, 1900 Pleasant Street, Boulder, CO 80309, USA
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Hare AJ, Newman AE, Dantzer B, Lane JE, Boutin S, Coltman DW, McAdam AG. An independent experiment does not support stress-mediated kin discrimination through red squirrel vocalizations. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sehrsweeney M, Wilson DR, Bain M, Boutin S, Lane JE, McAdam AG, Dantzer B. The effects of stress and glucocorticoids on vocalizations: a test in North American red squirrels. Behav Ecol 2019. [DOI: 10.1093/beheco/arz044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
AbstractAcoustic signaling is an important means by which animals communicate both stable and labile characteristics. Although it is widely appreciated that vocalizations can convey information on labile state, such as fear and aggression, fewer studies have experimentally examined the acoustic expression of stress state. The transmission of such public information about physiological state could have broad implications, potentially influencing the behavior and life-history traits of neighbors. North American red squirrels (Tamiasciurus hudsonicus) produce vocalizations known as rattles that advertise territorial ownership. We examined the influence of changes in physiological stress state on rattle acoustic structure through the application of a stressor (trapping and handling the squirrels) and by provisioning squirrels with exogenous glucocorticoids (GCs). We characterized the acoustic structure of rattles emitted by these squirrels by measuring rattle duration, mean frequency, and entropy. We found evidence that rattles do indeed exhibit a “stress signature.” When squirrels were trapped and handled, they produced rattles that were longer in duration with a higher frequency and increased entropy. However, squirrels that were administered exogenous GCs had similar rattle duration, frequency, and entropy as squirrels that were fed control treatments and unfed squirrels. Our results indicate that short-term stress does affect the acoustic structure of vocalizations, but elevated circulating GC levels do not mediate such changes.
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Affiliation(s)
- Matt Sehrsweeney
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - David R Wilson
- Department of Psychology, Memorial University of Newfoundland, John’s, NL, Canada
| | - Maggie Bain
- Department of Integrative Biology, University of Guelph, Guelph, ON Canada
| | - Stan Boutin
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Jeffrey E Lane
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Andrew G McAdam
- Department of Integrative Biology, University of Guelph, Guelph, ON Canada
| | - Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
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Robertson JG, Boutin S, Humphries MM, Dantzer B, Lane JE, McAdam AG. Individual variation in the dear enemy phenomenon via territorial vocalizations in red squirrels. BEHAVIOUR 2018. [DOI: 10.1163/1568539x-00003524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Territoriality arises when the benefits of resources exceed the costs of defending them. The dear enemy phenomenon, where familiar territorial neighbours refrain from intruding on one another and mutually reduce their defensive efforts, allows for reduction of these costs but requires discrimination between conspecifics. We hypothesized that territorial vocalizations in red squirrels (Tamiasciurus hudsonicus) are used for this discrimination. We performed a speaker replacement experiment where red squirrels () were temporarily removed from their territories and replaced with a speaker broadcasting their own call, an unfamiliar call, or silence. Contrary to our prediction, there were no differences in overall intrusion risk among our three playbacks, but the identity of intruders did vary. Existing variation in familiarity within territorial neighbourhoods should be considered, rather than the binary classification of familiar or stranger, when studying dear enemy effects. We also discuss the variable importance of silence in acoustic territorial populations.
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Affiliation(s)
- Jack G. Robertson
- aDepartment of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - Stan Boutin
- bDepartment of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Murray M. Humphries
- cDepartment of Natural Resource Sciences, Macdonald Campus, McGill University, Ste-Anne-de-Bellevue, QC, Canada
| | - Ben Dantzer
- dDepartment of Psychology, University of Michigan, Ann Arbor, MI, USA
- eDepartment of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jeffrey E. Lane
- fDepartment of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Andrew G. McAdam
- aDepartment of Integrative Biology, University of Guelph, Guelph, ON, Canada
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Siracusa E, Morandini M, Boutin S, Humphries M, Dantzer B, Lane J, McAdam A. Red squirrel territorial vocalizations deter intrusions by conspecific rivals. BEHAVIOUR 2017. [DOI: 10.1163/1568539x-00003467] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
In many species, territory advertisement is thought to be one of the primary functions of acoustic communication. North American red squirrels are a territorial species in which ‘rattles’ have long been thought to be the principal signal communicating territory ownership. These vocalizations have been assumed to deter intruders, thus reducing energetic costs and the risk of injury associated with direct aggressive interactions. However, this hypothesis has not been directly tested. Here we used a speaker occupation experiment to test whether red squirrel rattles function to deter conspecific rivals. We studied 29 male squirrels and removed each individual from his territory twice in a paired design. During the experimental treatment, we simulated the owner’s presence after its removal by broadcasting the owner’s rattle from a loudspeaker at the centre of the territory once every 7 min. During the control treatment, the territory was left in silence following the temporary removal of the owner. We found that the presence of a speaker replacement reduced the probability of intrusion by 34% and increased the latency to first intrusion by 7%, providing support for the hypothesis that rattles play an active role in reducing intrusion risk. However, intrusions were not completely averted by the speaker replacement, indicating that for some individuals vocalizations alone are not a sufficient deterrent without other cues of the territory owner.
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Affiliation(s)
- Erin Siracusa
- aDepartment of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - Marina Morandini
- bSchool of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA
| | - Stan Boutin
- cDepartment of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Murray M. Humphries
- dDepartment of Natural Resource Sciences, Macdonald Campus, McGill University, Ste-Anne-de-Bellevue, QC, Canada
| | - Ben Dantzer
- eDepartment of Psychology, University of Michigan, Ann Arbor, MI, USA
- fDepartment of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jeffrey E. Lane
- gDepartment of Biology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Andrew G. McAdam
- aDepartment of Integrative Biology, University of Guelph, Guelph, ON, Canada
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