Effect of Winter High Temperatures on Reproduction and Circannual Rhythms in Hibernating Ground Squirrels

Barnes, Brian M.; York, Alison

doi:10.1177/074873049000500204

Cited by 25 publications

(25 citation statements)

References 28 publications

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“…For example, transferring hibernating male golden-mantled ground squirrels from 48C to 308C in mid-winter terminated torpor and advanced reproductive maturation. However, in the subsequent year, timing was not advanced in warmed compared with control animals, suggesting that the underlying circannual pacemaker was not affected [57]. Field and captivity studies that compared timing between locations and years showed that high spring temperatures advanced the end of hibernation and the onset of reproduction in ground squirrels [58][59][60].…”

Section: (D) Temperature and Other Factorsmentioning

confidence: 99%

Annual rhythms that underlie phenology: biological time-keeping meets environmental change

et al. 2013

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Seasonal recurrence of biological processes (phenology) and its relationship to environmental change is recognized as being of key scientific and public concern, but its current study largely overlooks the extent to which phenology is based on biological time-keeping mechanisms. We highlight the relevance of physiological and neurobiological regulation for organisms' responsiveness to environmental conditions. Focusing on avian and mammalian examples, we describe circannual rhythmicity of reproduction, migration and hibernation, and address responses of animals to photic and thermal conditions. Climate change and urbanization are used as urgent examples of anthropogenic influences that put biological timing systems under pressure. We furthermore propose that consideration of Homo sapiens as principally a 'seasonal animal' can inspire new perspectives for understanding medical and psychological problems.

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Section: (D) Temperature and Other Factorsmentioning

confidence: 99%

Annual rhythms that underlie phenology: biological time-keeping meets environmental change

et al. 2013

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“…Male sciurids usually emerge from hibernation earlier than females, and there is some evidence that they are more sensitive to the ambient temperature as an emergence cue (Barnes and York, 1990). However, there do not appear to be other significant differences in the timing and pattern of the IBAs between the sexes.…”

Section: Discussionmentioning

confidence: 99%

A simple molecular mathematical model of mammalian hibernation

Hampton

Andrews

2007

Journal of Theoretical Biology

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A simple model of the dynamics of the body temperature of a hibernating mammal is presented. Our model provides a good match to experimental data, showing the interruption of lowtemperature torpor bouts with periodic interbout arousals (IBAs). In this paper we present a mathematical model of the molecules that participate in the initiation, regulation and maintenance of the hibernating state. This model can be used to describe the role of regulatory molecules, signal transducers, downstream target enzymes, structural proteins or metabolites. Because many of the biochemical mechanisms are unknown, this is a preliminary and largely phenomenological model that we hope will inspire further investigation.

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“…If male AGS have the same developmental time-course, Atigun males would be infertile when they emerge only after 15 days of euthermy. In addition, because male gonads begin regression after 30 days of beginning euthermy [39], a mismatch between males and females would also occur if females delay their breeding as opposed to advancing it.…”

Section: Discussion (A) Phenologymentioning

confidence: 99%

Changing seasonality and phenological responses of free-living male arctic ground squirrels: the importance of sex

Sheriff

Richter

Buck

et al. 2013

Phil. Trans. R. Soc. B

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Many studies have addressed the effects of climate change on species as a whole; however, few have examined the possibility of sex-specific differences. To understand better the impact that changing patterns of snow-cover have on an important resident Arctic mammal, we investigated the long-term (13 years) phenology of hibernating male arctic ground squirrels living at two nearby sites in northern Alaska that experience significantly different snow-cover regimes. Previously, we demonstrated that snow-cover influences the timing of phenological events in females. Our results here suggest that the end of heterothermy in males is influenced by soil temperature and an endogenous circannual clock, but timing of male emergence from hibernation is influenced by the timing of female emergence. Males at both sites, Atigun and Toolik, end heterothermy on the same date in spring, but remain in their burrows while undergoing reproductive maturation. However, at Atigun, where snowmelt and female emergence occur relatively early, males emerge 8 days earlier than those at Toolik, maintaining a 12-day period between male and female emergence found at each site, but reducing the pre-emergence euthermic period that is critical for reproductive maturation. This sensitivity in timing of male emergence to female emergence will need to be matched by phase shifts in the circannual clock and responsiveness to environmental factors that time the end of heterothermy, if synchrony in reproductive readiness between the sexes is to be preserved in a rapidly changing climate.

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Effect of Winter High Temperatures on Reproduction and Circannual Rhythms in Hibernating Ground Squirrels

Cited by 25 publications

References 28 publications

Annual rhythms that underlie phenology: biological time-keeping meets environmental change

Annual rhythms that underlie phenology: biological time-keeping meets environmental change

A simple molecular mathematical model of mammalian hibernation

Changing seasonality and phenological responses of free-living male arctic ground squirrels: the importance of sex

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