Relationships between Respiratory Quotient and Metabolic Rate during Entry to and Arousal from Daily Torpor in Deer Mice (Peromyscus maniculatus)

1990 ◽  
Vol 63 (3) ◽  
pp. 504-515 ◽  
Author(s):  
James R. Nestler
1996 ◽  
Vol 74 (7) ◽  
pp. 1179-1186 ◽  
Author(s):  
Brandon A. Sheafor ◽  
Gregory K. Snyder

We examined metabolic rates in 25 deer mice, Peromyscus maniculatus nebrascensis, held at an ambient temperature of 10 °C and found that all of them had the ability to enter torpor. However, we found a gradation between the most torpor-sensitive and the most torpor-resistant animals, suggesting that the expression of torpor is more than a simple all-or-nothing phenomenon. On a daily basis, the most torpor-sensitive and torpor-resistant mice partition energy similarly when food is not restricted. On restricted food, both groups of mice decrease the amount of time spent active and increase the amount of time spent at rest and in torpor. In addition, both groups of mice decrease oxygen-consumption rates and body temperatures during rest and the most torpor-sensitive mice further decrease energy costs by entering longer and deeper bouts of torpor. However, the overall energy saving due to torpor is only about 6%. Thus, the widely held view that the adaptive advantage of daily torpor is a large energy saving may be open to question. Alternatively, daily torpor may be important for reducing the rate of energy turnover when these small rodents must rely on body fat reserves.


2010 ◽  
Vol 88 (1) ◽  
pp. 36-42 ◽  
Author(s):  
J. J. Smith ◽  
J. S. Millar ◽  
F. J. Longstaffe ◽  
R. Boonstra

The stable isotopic compositions of nitrogen and carbon in animal tissues reflect diet. However, factors other than diet can also affect these stable isotope ratios, leading to misinterpretations of diet composition. To test the hypothesis that variation in metabolic rate alters the isotopic compositions of tissues, deer mice ( Peromyscus maniculatus (Wagner, 1845)) were kept at three temperatures (thermoneutral (23 °C), cool (5 °C), and cold (–10 °C)) and fed ad libitum. The changes in carbon and nitrogen isotope compositions of liver associated with the thermoneutral versus cool and cold conditions were very small in comparison with those arising from differences in diet. We conclude that temperature-induced variations in metabolic rate are insufficient to produce differences in the stable carbon or nitrogen isotope compositions that could be mistaken for changes in diet.


1997 ◽  
Vol 70 (1) ◽  
pp. 61-67 ◽  
Author(s):  
James R. Nestler ◽  
Stacy J. Peterson ◽  
B. David Smith ◽  
R. Brian Heathcock ◽  
Christina R. Johanson ◽  
...  

2000 ◽  
pp. 347-353 ◽  
Author(s):  
James Nestler ◽  
Tiffany Lingenfelter ◽  
Gary Gonthier ◽  
Jenee Gifford ◽  
Stacy Peterson

1996 ◽  
Vol 77 (1) ◽  
pp. 147-154 ◽  
Author(s):  
J. R. Nestler ◽  
G. R. Dieter ◽  
B. G. Klokeid

1990 ◽  
Vol 68 (2) ◽  
pp. 381-388 ◽  
Author(s):  
Michael Earle ◽  
D. M. Lavigne

Deer mice (Peromyscus maniculatus) from three populations were used to examine patterns of covariation among body size, metabolic rate, and selected reproductive and developmental traits. Mass at birth and at 21 days, growth rates of individual neonates and whole litters, litter size, interlitter interval, and metabolic rates of adult females were used as dependent variables against maternal mass in allometric equations. Litter mass was positively correlated with maternal mass within each of the three populations. Conversely, litter size, litter mass at 21 days, litter growth rate, interlitter interval, and maternal metabolic rate were correlated with maternal mass in only one or two of the populations. Neonatal traits (mean mass of individuals at birth and at weaning and their growth rates) were consistently independent of maternal mass. There was no significant relationship between any of the reproductive parameters measured and metabolic rate of individual females. These results support the view that patterns of covariation in life history traits, metabolic rate, and maternal mass, which are generally evident in interspecific comparisons, are not necessarily apparent at the level of individuals within a single population.


1989 ◽  
Vol 264 (10) ◽  
pp. 5593-5597
Author(s):  
C Norsten ◽  
T Cronholm ◽  
G Ekström ◽  
J A Handler ◽  
R G Thurman ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document