Constraints on First Reproduction in North American Red Squirrels

Oikos ◽  
1998 ◽  
Vol 81 (1) ◽  
pp. 81 ◽  
Author(s):  
C. Dustin Becker ◽  
Stan Boutin ◽  
Karl W. Larsen
Keyword(s):  
North American ◽  
Red Squirrels ◽  
First Reproduction ◽  
North American Red Squirrels

North American red squirrels mitigate costs of territory defence through social plasticity

2019 ◽  
Vol 151 ◽  
pp. 29-42 ◽  
Author(s):  
Erin R. Siracusa ◽  
David R. Wilson ◽  
Emily K. Studd ◽  
Stan Boutin ◽  
Murray M. Humphries ◽  
...  
Keyword(s):  
North American ◽  
Red Squirrels ◽  
Territory Defence ◽  
Social Plasticity ◽  
North American Red Squirrels

scholarly journals The effects of stress and glucocorticoids on vocalizations: a test in North American red squirrels

2019 ◽  
Vol 30 (4) ◽  
pp. 1030-1040 ◽  
Author(s):  
Matt Sehrsweeney ◽  
David R Wilson ◽  
Maggie Bain ◽  
Stan Boutin ◽  
Jeffrey E Lane ◽  
...  
Keyword(s):  
Stress State ◽  
North American ◽  
Physiological Stress ◽  
Physiological State ◽  
Public Information ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Acoustic Structure ◽  
North American Red Squirrels ◽  
Important Means

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.

scholarly journals Indirect effects on fitness between individuals that have never met via an extended phenotype

2018 ◽  
Author(s):  
David N. Fisher ◽  
Jessica A. Haines ◽  
Stan Boutin ◽  
Ben Dantzer ◽  
Jeffrey E. Lane ◽  
...  
Keyword(s):  
Population Dynamics ◽  
North American ◽  
Indirect Effects ◽  
Tamiasciurus Hudsonicus ◽  
Extended Phenotype ◽  
Red Squirrels ◽  
Lifetime Fitness ◽  
The Past ◽  
North American Red Squirrels ◽  
The Individual

AbstractInteractions between organisms are ubiquitous and have important consequences for phenotypes and fitness. Individuals can even influence those they never meet, if they have extended phenotypes which mean the environments others experience are altered. North American red squirrels (Tamiasciurus hudsonicus) guard food hoards, an extended phenotype that typically outlives the individual and is almost always inherited by non relatives. Hoarding by previous owners can therefore influence subsequent owners. We found that red squirrels bred earlier and had higher lifetime fitness if the previous owner was a male. This was driven by hoarding behaviour, as males and mid-aged squirrels had the largest hoards, and these effects persisted across owners, such that if the previous owner was male or died in mid-age subsequent occupants had larger hoards. Individuals can, therefore, influence each other’s resource dependent traits and fitness without meeting via extended phenotypes, and so the past can influence contemporary population dynamics.

scholarly journals Glucocorticoids coordinate changes in gut microbiome composition in wild North American red squirrels

2021 ◽  
Author(s):  
Lauren Petrullo ◽  
Tiantian Ren ◽  
Martin Wu ◽  
Rudy Boonstra ◽  
Rupert Palme ◽  
...  
Keyword(s):  
Microbial Diversity ◽  
North American ◽  
Gut Microbiome ◽  
Pathogenic Bacteria ◽  
Experimental Studies ◽  
Ecological Framework ◽  
Ecological Change ◽  
Red Squirrels ◽  
Microbiome Diversity ◽  
North American Red Squirrels

Gut microbiome diversity plays an important role in host health and fitness, in part through the diversification of gut metabolic function and pathogen protection. Elevations in glucocorticoids (GCs) appear to reduce gut microbiome diversity in experimental studies, suggesting that a loss of microbial diversity may be a negative consequence of increased GCs. However, given that ecological factors like food availability and population density may independently influence both GCs and microbial diversity, understanding how these factors structure the GC-microbiome relationship is crucial to interpreting its significance in wild populations. Here, we used an ecological framework to investigate the relationship between GCs and gut microbiome diversity in wild North American red squirrels (Tamiasciurus hudsonicus). We found that higher GCs predicted lower gut microbiome diversity and an increase in metabolic taxa. In addition, we identified a loss of potentially pathogenic bacteria with increasing GCs. Both dietary heterogeneity and an upcoming masting event exhibited direct effects on gut microbiome diversity, whereas conspecific density and host reproductive activity impacted diversity indirectly via changes in GCs. Together, our results suggest that GCs coordinate the effects of ecological change and host biology on gut microbiome diversity, and highlight the importance of situating the GC-microbiome relationship within an ecological framework.

scholarly journals Persistent maternal effects on juvenile survival in North American red squirrels

2007 ◽  
Vol 3 (3) ◽  
pp. 289-291 ◽  
Author(s):  
Tricia D Kerr ◽  
Stan Boutin ◽  
Jalene M LaMontagne ◽  
Andrew G McAdam ◽  
Murray M Humphries
Keyword(s):  
Maternal Effects ◽  
North American ◽  
Maternal Nutrition ◽  
Dispersal Distance ◽  
Tamiasciurus Hudsonicus ◽  
Territory Quality ◽  
Red Squirrels ◽  
Juvenile Dispersal ◽  
Supplemental Food ◽  
North American Red Squirrels

Maternal effects can have lasting fitness consequences for offspring, but these effects are often difficult to disentangle from associated responses in offspring traits. We studied persistent maternal effects on offspring survival in North American red squirrels ( Tamiasciurus hudsonicus ) by manipulating maternal nutrition without altering the post-emergent nutritional environment experienced by offspring. This was accomplished by providing supplemental food to reproductive females over winter and during reproduction, but removing the supplemental food from the system prior to juvenile emergence. We then monitored juvenile dispersal, settlement and survival from birth to 1 year of age. Juveniles from supplemented mothers experienced persistent and magnifying survival advantages over juveniles from control mothers long after supplemental food was removed. These maternal effects on survival persisted, despite no observable effect on traits normally associated with high offspring quality, such as body size, dispersal distance or territory quality. However, supplemented mothers did provide their juveniles an early start by breeding an average of 18 days earlier than control mothers, which may explain the persistent survival advantages their juveniles experienced.

Are the alarm calls of North American red squirrels (Tamiasciurus hudsonicus) functionally referential?

Behaviour ◽  
2010 ◽  
Vol 147 (9) ◽  
pp. 1201-1218
Author(s):  
Shannon Digweed ◽  
Drew Rendall
Keyword(s):  
North American ◽  
Alarm Call ◽  
Alarm Calls ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Call Production ◽  
Solitary Living ◽  
North American Red Squirrels ◽  
Functionally Referential ◽  
Necessary And Sufficient

AbstractNorth American red squirrels are a small-bodied and solitary-living species that faces a diversity of predators and produces two different variants of alarm calls in response to them. Recent studies have yielded conflicting interpretations of the predator-specific and functionally referential nature of these alarm call variants. We undertook a systematic set of playback experiments to quantify the responses of red squirrels to alarm calls produced by other squirrels during encounters with different predators. The experiment was designed to test a core requirement of functionally referential alarm calls, namely that different alarm call types induce distinct and functionally appropriate escape responses in listeners. Results indicated that squirrels registered and responded to alarm calls produced by others; however, their responses were not differentiated according to the type of alarm call they heard and, thus, did not provide evidence that the different alarm call variants hold any predator-specific, referential value. These outcomes are discussed in light of complementary work on alarm call production in red squirrels and broader aspects of this species' life history in an effort to better understand the necessary and sufficient pressures promoting the evolution of referential call systems in animals.

scholarly journals Is physiological stress state reflected in acoustic structure of vocalizations? An experimental test in wild North American red squirrels

2018 ◽  
Author(s):  
Matt Sehrsweeney ◽  
David R. Wilson ◽  
Maggie Bain ◽  
Stan Boutin ◽  
Jeffrey E. Lane ◽  
...  
Keyword(s):  
Stress State ◽  
North American ◽  
Physiological Stress ◽  
Physiological State ◽  
Public Information ◽  
Tamiasciurus Hudsonicus ◽  
Short Term ◽  
Red Squirrels ◽  
Acoustic Structure ◽  
North American Red Squirrels

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, very few studies have experimentally examined the acoustic expression of short-term stress state. The transmission of such information about physiological state could have broad implications, potentially allowing other individuals to modify their behavior or life history traits in response to this public information. 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. Our results provide mixed evidence that rattles show 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 received control treatments and unmanipulated (unfed) squirrels. Our results indicate that short-term stress does affect the acoustic structure of vocalizations, but elevated circulating GC levels are not solely responsible for such changes.

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