Energy Allocation by Yellow-Bellied Marmots

Melcher, Jaye C.; Armitage, Kenneth B.; Porter, Warren P.

doi:10.1086/physzool.62.2.30156178

Cited by 25 publications

(9 citation statements)

References 25 publications

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“…Michener & Locklear (1 990b) reported that mating effort in male Richardson's ground squirrels was more costly per unit time than female parental care. Melcher, Armitage & Porter (1989) suggested that male territoriality in yellow-bellied marmots (MarmotaJaviventris) may be as expensive energetically as female reproduction because food intake was similar in both sexes. The annual energy budget of male and female golden-mantled ground squirrels (Spermophilus saturatus) was also determined to be equivalent (Kenagy, 1987).…”

Section: Discussionmentioning

confidence: 99%

“…The cost of pregnancy and lactation can double or triple the energy requirement of females in rodents (Kenagy, 1987;Kenagy, Stevenson & Masman, 1989;Melcher et a]., 1989). Some small mammals meet this increased demand by increasing food consumption (Millar, 1975;Kurta et a/., 1990), while others use a combination of increased food intake and use of fat reserves (Kenagy, 1987;Millar, 1987;Oswald & McClure, 1990).…”

Section: Discussionmentioning

confidence: 99%

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Seasonal variation in body composition and morphology of adult muskrats in central Saskatchewan, Canada

Virgl

Messier

1992

Journal of Zoology

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We quantified seasonal variation in body composition and morphology of adult muskrats (Ondatra zibethicus) inhabiting freshwater marsh environments in central Saskatchewan, Canada. The study areas were characterized by long and cold winters extending over six months during which muskrats were restricted to foraging under ice. A total of 162 adult muskrats were collected during nine sampling periods across the year. The large accumulation of fat reserves (16% of body mass) during winter and the concurrent decline in protein mass suggested a reduced maintenance requirement associated with the presence of energy‐rich food resources. Dietary fibre content increased significantly during mid‐summer and was manifested by changes in gut morphology. Mobilization of fat reserves during summer months by both sexes reflected high energetic demands for reproduction. Males depleted fat reserves soon after spring break‐up, while near‐exhaustion of fat reserves in females occurred 4–6 weeks later, during lactation. Pregnant females contained significantly greater fat and protein reserves compared to non‐pregnant and lactating females. The dynamics of body reserves in muskrats should be viewed as an integral part of the sex‐specific life‐history traits of this important herbivore species of marsh environments.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Seasonal variation in body composition and morphology of adult muskrats in central Saskatchewan, Canada

Virgl

Messier

1992

Journal of Zoology

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“…The need to mobilize energy for reproduction and then prepare for hibernation in a short time period accounts for the energy conservative physiology of this species 32,33 . The critical factor determining winter survival and subsequent reproductive success is the amount of fat accumulated prior to hibernation 34,35 . Upon emergence all age classes start gaining mass at the rate of about 12 to 14 g/day.…”

Section: Methodsmentioning

confidence: 99%

Coupled dynamics of body mass and population growth in response to environmental change

Özgül

Childs

Oli

et al. 2010

Nature

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551

607

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Environmental change has altered the phenology, morphological traits and population dynamics of many species1,2. However, the links underlying these joint responses remain largely unknown due to a paucity of long-term data and the lack of an appropriate analytical framework3. Here, we investigate the link between phenotypic and demographic responses to environmental change using a novel methodology and an exceptional long-term (1976–2008) dataset from a hibernating mammal (the yellow-bellied marmot) inhabiting a dynamic subalpine habitat. We demonstrate how earlier emergence from hibernation and earlier weaning of young has led to a longer growing season and larger body masses prior to hibernation. The resulting shift in both the phenotype and the relationship between phenotype and fitness components led to a decline in adult mortality, which in turn triggered an abrupt increase in population size in recent years. Direct and trait-mediated effects of environmental change had comparable contributions to the observed dramatic increase in population growth. Our results help explain how a shift in phenology can cause simultaneous phenotypic and demographic changes, and highlight the need for a theory integrating ecological and evolutionary dynamics in stochastic environments4,5.

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“…The critical factor determining winter survival and subsequent reproductive success is the amount of fat accumulated before hibernation (Melcher et al 1989). Survival and reproduction are affected by the length of the active season, which shows substantial annual variation associated with changes in onset and termination of snow cover (Armitage and Downhower 1974;Schwartz et al 1998;Ozgul et al 2010).…”

Section: Dnmentioning

confidence: 99%

How Life History Influences Population Dynamics in Fluctuating Environments

Sæther

Coulson

Grøtan

et al. 2013

The American Naturalist

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168

186

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A major question in ecology is how age-specific variation in demographic parameters influences population dynamics. Based on long-term studies of growing populations of birds and mammals, we analyze population dynamics by using fluctuations in the total reproductive value of the population. This enables us to account for random fluctuations in age distribution. The influence of demographic and environmental stochasticity on the population dynamics of a species decreased with generation time. Variation in age-specific contributions to total reproductive value and to stochastic components of population dynamics was correlated with the position of the species along the slow-fast continuum of life-history variation. Younger age classes relative to the generation time accounted for larger contributions to the total reproductive value and to demographic stochasticity in "slow" than in "fast" species, in which many age classes contributed more equally. In contrast, fluctuations in population growth rate attributable to stochastic environmental variation involved a larger proportion of all age classes independent of life history. Thus, changes in population growth rates can be surprisingly well explained by basic species-specific life-history characteristics. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. Submitted December 17, 2012; Accepted June 19, 2013; Electronically published October 25, 2013 abstract: A major question in ecology is how age-specific variation in demographic parameters influences population dynamics. Based on long-term studies of growing populations of birds and mammals, we analyze population dynamics by using fluctuations in the total reproductive value of the population. This enables us to account for random fluctuations in age distribution. The influence of demographic and environmental stochasticity on the population dynamics of a species decreased with generation time. Variation in age-specific contributions to total reproductive value and to stochastic components of population dynamics was correlated with the position of the species along the slow-fast continuum of life-history variation. Younger age classes relative to the generation time accounted for larger contributions to the total reproductive value and to demographic stochasticity in "slow" than in "fast" species, in which many age classes contributed more equally. In contrast, fluctuations in population growth rate attributable to stochastic environmental variation involved a larger proportion of all age classes independent of * Corresponding author; e-mail: bernt.erik.sather@bio.ntnu.no.Am. Nat. 2013. Vol. 182, pp. 743-759. ᭧ 2013 by The University of Chicago. 0003-0147/2013/18206-54347$15.00. All rights reserved. DOI: 10.1086/67349...

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Energy Allocation by Yellow-Bellied Marmots

Cited by 25 publications

References 25 publications

Seasonal variation in body composition and morphology of adult muskrats in central Saskatchewan, Canada

Seasonal variation in body composition and morphology of adult muskrats in central Saskatchewan, Canada

Coupled dynamics of body mass and population growth in response to environmental change

How Life History Influences Population Dynamics in Fluctuating Environments

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