Seasonal Metabolic Acclimatization in a Northern Population of Free-Ranging Snowshoe Hares,<i>Lepus americanus</i>

Sheriff, Michael J.; Kuchel, Louise; Boutin, Stan; Humphries, Murray M.

doi:10.1644/08-mamm-a-247r.1

Cited by 32 publications

(34 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The increase in glucose mobilization in response to increased predation risk must be extremely costly to hares during the food-scarce winter. Although hares have reduced energy expenditure in winter (SheriV et al 2009c), they have minimal winter body reserves (Whittaker and Thomas 1983) and would need to increase foraging (in an already food-reduced winter environment) to compensate for the increased glucose mobilization, further exposing them to predators. Free fatty acids (FFA) are one of the substrates delivered to the liver during gluconeogenesis.…”

Section: Energy Expenditurementioning

confidence: 99%

From process to pattern: how fluctuating predation risk impacts the stress axis of snowshoe hares during the 10-year cycle

2011

Self Cite

View full text Add to dashboard Cite

Predation is a central organizing process affecting populations and communities. Traditionally, ecologists have focused on the direct effects of predation--the killing of prey. However, predators also have significant sublethal effects on prey populations. We investigated how fluctuating predation risk affected the stress physiology of a cyclic population of snowshoe hares (Lepus americanus) in the Yukon, finding that they are extremely sensitive to the fluctuating risk of predation. In years of high predator numbers, hares had greater plasma cortisol levels at capture, greater fecal cortisol metabolite levels, a greater plasma cortisol response to a hormone challenge, a greater ability to mobilize energy and poorer body condition. These indices of stress had the same pattern within years, during the winter and over the breeding season when the hare:lynx ratio was lowest and the food availability the worst. Previously we have shown that predator-induced maternal stress lowers reproduction and compromises offspring's stress axis. We propose that predator-induced changes in hare stress physiology affect their demography through negative impacts on reproduction and that the low phase of cyclic populations may be the result of predator-induced maternal stress reducing the fitness of progeny. The hare population cycle has far reaching ramifications on predators, alternate prey, and vegetation. Thus, predation is the predominant organizing process for much of the North American boreal forest community, with its indirect signature--stress in hares--producing a pattern of hormonal changes that provides a sensitive reflection of fluctuating predator pressure that may have long-term demographic consequences.

show abstract

Section: Energy Expenditurementioning

confidence: 99%

From process to pattern: how fluctuating predation risk impacts the stress axis of snowshoe hares during the 10-year cycle

2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…At the population level, seasonal changes of BM and RMR have been shown in numerous mammalian species (Gębczyń ski et al 1972;Wunder et al 1977;Merritt andZegers 1991, 2002;Aalto et al 1993;McDevitt and Andrews 1995;Corp et al 1997;Voltura 1997;Zhang and Wang 2007;Sheriff et al 2009; Boratyń ski and Koteja 2009). The cross species analysis showed that the small mammals below 500 g decrease in BM even as much as 50% during winter (Lovegrove 2005).…”

Section: Discussionmentioning

confidence: 99%

“…Studies focusing on individual variation were almost exclusively carried out in laboratory or seminatural settings. Increase in BM was observed mainly in larger mammals and was caused primarily by fat storage (e.g., snowshoe hares [Sheriff et al 2009], Mongolian gerbils [Zhang and Wang 2007], arctic foxes [Fuglei and Ørtisland 1999], gray seals [Sparling et al 2006], badgers [Harlow 1981]). …”

Section: Discussionmentioning

confidence: 99%

“…Several studies have demonstrated a reduction of body mass (BM) in overwintering mammals (Iverson and Turner 1974;Aars and Ims 2002), as well as in BM-corrected metabolic rates (Harrington et al 2003;Arnold et al 2004Arnold et al , 2006Fuglesteg et al 2006;Kumagai et al 2006); mainly basal (resting) metabolic rate (BMR or RMR, the lowest measured metabolic rate of a resting animal in its thermoneutral zone). On the other hand, numerous authors have reported winter increases in BM and RMR (Sparling et al 2006;Zhang and Wang 2007;Sheriff et al 2009) or a lack of appreciable seasonal variation (Mauget et al 1996;Harrington et al 2003;Wang et al 2006).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Seasonal Variation of Resting Metabolic Rate and Body Mass in Free-Living WeaselsMustela nivalis

Szafrańska

Zub

Konarzewski³

2013

Physiological and Biochemical Zoology

View full text Add to dashboard Cite

Metabolic rates and body mass of mammals vary seasonally along with ambient temperatures and food availability. At the population level, seasonal changes in metabolic rate and mass can be due to selective mortality or emigration of individuals whose metabolic rate or mass differs from the average for the population. Alternatively, the metabolic rates of individuals can change seasonally, such that the population average increases or decreases due to shifts in the physiology of the overall population. The latter implies that individuals respond in a similar manner to changing seasonal conditions. We studied seasonal changes in body mass (BM) and resting metabolic rate (RMR) in free-ranging male weasels (Mustela nivalis) to test the consistency of these traits in individuals caught in different seasons of the year. At the population level, BM was remarkably stable across the seasons (F(3, 124)=0.25, P=0.9). In contrast, BM- corrected RMR varied significantly between seasons and was the lowest in winter (F(3, 135)=9.13, P<0.0001). We demonstrated that individual weasels were consistent in how their BM and RMR deviated from the seasonal means for the population (intraclass correlation, τ=0.78 and 0.33, respectively). This variation among individuals explained ~76% and 27% of the total variation of BM and basal metabolic rate, respectively. Hence, the relatively constant BM at the population level across seasons is due to a relative constancy of BM in individuals. Our study is one of relatively few research projects that demonstrate that seasonal changes in RMR observed in the wild population are in part due to a consistency in individual responses to changing environmental conditions.

show abstract

“…Snowshoe hares (Lepus americanus Erxleben) are the primary herbivore and they undergo a regular 10-to 12-year population cycle. In 2006 the snowshoe hares were at the peak of this population cycle in the Kluane region (Sheriff et al, 2009). Other small mammals in this system, including the northern red backed vole (Clethrionomys rutilus) and the meadow vole (Microtus pennsylvanicus), include understory vegetation in their diet but these are not excluded with the mesh size used, and were not examined in this experiment.…”

Section: Site Descriptionmentioning

confidence: 99%

The Effects of Fertilization and Herbivory on the Phenology of the Understory Vegetation of the Boreal Forest in Northwestern Canada

Fremlin

McLaren

DeSandoli

et al. 2011

Arctic, Antarctic, and Alpine Research

View full text Add to dashboard Cite

Seasonal Metabolic Acclimatization in a Northern Population of Free-Ranging Snowshoe Hares,Lepus americanus

Cited by 32 publications

References 49 publications

From process to pattern: how fluctuating predation risk impacts the stress axis of snowshoe hares during the 10-year cycle

From process to pattern: how fluctuating predation risk impacts the stress axis of snowshoe hares during the 10-year cycle

Seasonal Variation of Resting Metabolic Rate and Body Mass in Free-Living WeaselsMustela nivalis

The Effects of Fertilization and Herbivory on the Phenology of the Understory Vegetation of the Boreal Forest in Northwestern Canada

Contact Info

Product

Resources

About