Voluntary running in deer mice: Speed, distance, energy costs and temperature effects

Mark A. Chappell, Theodore Garland, Enrico L. Rezende, Fernando R. Gomes

Resultado de la investigación: Article

69 Citas (Scopus)

Resumen

The energetics of terrestrial locomotion are of considerable interest to ecologists and physiologists, but nearly all of our current knowledge comes from animals undergoing forced exercise. To explore patterns of energy use and behavior during voluntary exercise, we developed methods allowing nearly continuous measurements of metabolic rates in freely behaving small mammals, with high temporal resolution over periods of several days. We used this approach to examine relationships between ambient temperature (Ta), locomotor behavior and energy costs in the deer mouse, a small mammal that routinely encounters a large range of temperatures in its natural habitat. We tested for individual consistency in running behavior and metabolic traits, and determined how locomotor costs vary with speed and Ta. Because of the importance of thermoregulatory costs in small mammals, we checked for substitution of exercise heat for thermostatic heat production at Ta below the thermal neutral zone and determined the fraction of the daily energy budget comprising exercise costs. Locomotor behavior was highly variable among individuals but had high repeatability, at least over short intervals. We found few temperature-related changes in speed or distance run, but Ta strongly affected energy costs. Partial substitution of exercise heat for thermogenic heat occurred at low Ta. This reduced energy expenditure during low-temperature running by 23-37%, but running costs comprised a fairly minor fraction of the energy budget, so the daily energy savings via substitution were much smaller. Deer mice did not adjust running speed to maximize metabolic economy, as they seldom used the high speeds that provide the lowest cost of transport. The highest voluntary speeds (4-5 km h-1) were almost always below the predicted maximal aerobic speed, and were much less than the species' maximal sprint speed. Maximum voluntarily attained rates of oxygen consumption (V̇O2) were highest at low Ta, but rarely approached maximal V̇O2 during forced treadmill exercise. Mean respiratory exchange ratios coincident with maximal voluntary V̇O2 increased slightly as Ta declined, but were always below 1.0 (another indication that metabolic rate was less than the aerobic maximum). Individuals with high running performance (cumulative distance and running time) had high resting metabolism, which suggests a cost of having high capacity or propensity for activity.

Idioma originalEnglish
Páginas (desde-hasta)3839-3854
Número de páginas16
PublicaciónJournal of Experimental Biology
Volumen207
N.º22
DOI
EstadoPublished - oct 2004

Huella dactilar

Peromyscus
energy costs
temperature effect
Running
deer
Costs and Cost Analysis
Temperature
exercise
cost
energy
temperature
small mammal
small mammals
Hot Temperature
substitution
heat
Mammals
energy budget
Budgets
heat production

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)
  • Animal Science and Zoology
  • Aquatic Science
  • Molecular Biology
  • Insect Science
  • Ecology, Evolution, Behavior and Systematics
  • Physiology

Citar esto

Chappell, Mark A. ; Garland, Theodore ; Rezende, Enrico L. ; Gomes, Fernando R. / Voluntary running in deer mice : Speed, distance, energy costs and temperature effects. En: Journal of Experimental Biology. 2004 ; Vol. 207, N.º 22. pp. 3839-3854.
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abstract = "The energetics of terrestrial locomotion are of considerable interest to ecologists and physiologists, but nearly all of our current knowledge comes from animals undergoing forced exercise. To explore patterns of energy use and behavior during voluntary exercise, we developed methods allowing nearly continuous measurements of metabolic rates in freely behaving small mammals, with high temporal resolution over periods of several days. We used this approach to examine relationships between ambient temperature (Ta), locomotor behavior and energy costs in the deer mouse, a small mammal that routinely encounters a large range of temperatures in its natural habitat. We tested for individual consistency in running behavior and metabolic traits, and determined how locomotor costs vary with speed and Ta. Because of the importance of thermoregulatory costs in small mammals, we checked for substitution of exercise heat for thermostatic heat production at Ta below the thermal neutral zone and determined the fraction of the daily energy budget comprising exercise costs. Locomotor behavior was highly variable among individuals but had high repeatability, at least over short intervals. We found few temperature-related changes in speed or distance run, but Ta strongly affected energy costs. Partial substitution of exercise heat for thermogenic heat occurred at low Ta. This reduced energy expenditure during low-temperature running by 23-37{\%}, but running costs comprised a fairly minor fraction of the energy budget, so the daily energy savings via substitution were much smaller. Deer mice did not adjust running speed to maximize metabolic economy, as they seldom used the high speeds that provide the lowest cost of transport. The highest voluntary speeds (4-5 km h-1) were almost always below the predicted maximal aerobic speed, and were much less than the species' maximal sprint speed. Maximum voluntarily attained rates of oxygen consumption (V̇O2) were highest at low Ta, but rarely approached maximal V̇O2 during forced treadmill exercise. Mean respiratory exchange ratios coincident with maximal voluntary V̇O2 increased slightly as Ta declined, but were always below 1.0 (another indication that metabolic rate was less than the aerobic maximum). Individuals with high running performance (cumulative distance and running time) had high resting metabolism, which suggests a cost of having high capacity or propensity for activity.",
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Voluntary running in deer mice : Speed, distance, energy costs and temperature effects. / Chappell, Mark A.; Garland, Theodore; Rezende, Enrico L.; Gomes, Fernando R.

En: Journal of Experimental Biology, Vol. 207, N.º 22, 10.2004, p. 3839-3854.

Resultado de la investigación: Article

TY - JOUR

T1 - Voluntary running in deer mice

T2 - Speed, distance, energy costs and temperature effects

AU - Chappell, Mark A.

AU - Garland, Theodore

AU - Rezende, Enrico L.

AU - Gomes, Fernando R.

PY - 2004/10

Y1 - 2004/10

N2 - The energetics of terrestrial locomotion are of considerable interest to ecologists and physiologists, but nearly all of our current knowledge comes from animals undergoing forced exercise. To explore patterns of energy use and behavior during voluntary exercise, we developed methods allowing nearly continuous measurements of metabolic rates in freely behaving small mammals, with high temporal resolution over periods of several days. We used this approach to examine relationships between ambient temperature (Ta), locomotor behavior and energy costs in the deer mouse, a small mammal that routinely encounters a large range of temperatures in its natural habitat. We tested for individual consistency in running behavior and metabolic traits, and determined how locomotor costs vary with speed and Ta. Because of the importance of thermoregulatory costs in small mammals, we checked for substitution of exercise heat for thermostatic heat production at Ta below the thermal neutral zone and determined the fraction of the daily energy budget comprising exercise costs. Locomotor behavior was highly variable among individuals but had high repeatability, at least over short intervals. We found few temperature-related changes in speed or distance run, but Ta strongly affected energy costs. Partial substitution of exercise heat for thermogenic heat occurred at low Ta. This reduced energy expenditure during low-temperature running by 23-37%, but running costs comprised a fairly minor fraction of the energy budget, so the daily energy savings via substitution were much smaller. Deer mice did not adjust running speed to maximize metabolic economy, as they seldom used the high speeds that provide the lowest cost of transport. The highest voluntary speeds (4-5 km h-1) were almost always below the predicted maximal aerobic speed, and were much less than the species' maximal sprint speed. Maximum voluntarily attained rates of oxygen consumption (V̇O2) were highest at low Ta, but rarely approached maximal V̇O2 during forced treadmill exercise. Mean respiratory exchange ratios coincident with maximal voluntary V̇O2 increased slightly as Ta declined, but were always below 1.0 (another indication that metabolic rate was less than the aerobic maximum). Individuals with high running performance (cumulative distance and running time) had high resting metabolism, which suggests a cost of having high capacity or propensity for activity.

AB - The energetics of terrestrial locomotion are of considerable interest to ecologists and physiologists, but nearly all of our current knowledge comes from animals undergoing forced exercise. To explore patterns of energy use and behavior during voluntary exercise, we developed methods allowing nearly continuous measurements of metabolic rates in freely behaving small mammals, with high temporal resolution over periods of several days. We used this approach to examine relationships between ambient temperature (Ta), locomotor behavior and energy costs in the deer mouse, a small mammal that routinely encounters a large range of temperatures in its natural habitat. We tested for individual consistency in running behavior and metabolic traits, and determined how locomotor costs vary with speed and Ta. Because of the importance of thermoregulatory costs in small mammals, we checked for substitution of exercise heat for thermostatic heat production at Ta below the thermal neutral zone and determined the fraction of the daily energy budget comprising exercise costs. Locomotor behavior was highly variable among individuals but had high repeatability, at least over short intervals. We found few temperature-related changes in speed or distance run, but Ta strongly affected energy costs. Partial substitution of exercise heat for thermogenic heat occurred at low Ta. This reduced energy expenditure during low-temperature running by 23-37%, but running costs comprised a fairly minor fraction of the energy budget, so the daily energy savings via substitution were much smaller. Deer mice did not adjust running speed to maximize metabolic economy, as they seldom used the high speeds that provide the lowest cost of transport. The highest voluntary speeds (4-5 km h-1) were almost always below the predicted maximal aerobic speed, and were much less than the species' maximal sprint speed. Maximum voluntarily attained rates of oxygen consumption (V̇O2) were highest at low Ta, but rarely approached maximal V̇O2 during forced treadmill exercise. Mean respiratory exchange ratios coincident with maximal voluntary V̇O2 increased slightly as Ta declined, but were always below 1.0 (another indication that metabolic rate was less than the aerobic maximum). Individuals with high running performance (cumulative distance and running time) had high resting metabolism, which suggests a cost of having high capacity or propensity for activity.

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KW - Metabolism

KW - Peromyscus maniculatus

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