Seasonal changes in gut capacity in the white-footed mouse (Peromyscus leucopus) and meadow vole (Microtus pennsylvanicus)

1995 ◽  
Vol 73 (2) ◽  
pp. 243-252 ◽  
Author(s):  
Terry L. Derting ◽  
Edward B. Noakes III
Keyword(s):  
Energy Conservation ◽  
Body Mass ◽  
Seasonal Changes ◽  
Peromyscus Leucopus ◽  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Surface Areas ◽  
Seasonal Environment ◽  
Different Types ◽  
White Footed Mouse

Changes in gut capacity may be important for a species adapting to increased energy requirements or decreased food quality in a seasonal environment. We conducted a comparative study of seasonal changes in gut capacity in two rodent species with diets of different types. Although the lengths and masses of gut organs differed between species within a season, the species did not differ in the types of gut changes that occurred from summer to winter. All organs except the colon had significantly heavier wet and dry masses in winter than in summer. No significant differences in organ lengths, volumes, or surface areas occurred with season. Increased mass of the small intestine was due to large increases in the mass of the mucosa and smaller increases in the mass of the serosa. In winter, Microtus pennsylvanicus had significantly lower body mass than in summer. Peromyscus leucopus had no change in body mass in winter but may have used torpor as an energy-conservation mechanism. Energy-conservation adaptations in each species may have minimized the need for large changes in the gut organs.

scholarly journals Effects of physical impairments on fitness correlates of the white-footed mouse, Peromyscus leucopus

2021 ◽  
Vol 288 (1962) ◽  
Author(s):  
Francesca I. Rubino ◽  
Kelly Oggenfuss ◽  
Richard S. Ostfeld
Keyword(s):  
Body Mass ◽  
Evolutionary Biology ◽  
Ixodes Scapularis ◽  
Peromyscus Leucopus ◽  
Mass Movement ◽  
Natural Populations ◽  
Home Ranges ◽  
Wild Populations ◽  
Physical Impairments ◽  
White Footed Mouse

Physical impairments are widely assumed to reduce the viability of individual animals, but their impacts on individuals within natural populations of vertebrates are rarely quantified. By monitoring wild populations of white-footed mice over 26 years, we assessed whether missing or deformed limbs, tail or eyes influenced the survival, body mass, movement and ectoparasite burden of their bearers. Of the 27 244 individuals monitored, 543 (2%) had visible physical impairments. Persistence times (survival) were similar between mice with and without impairments. Mice with eye and tail impairments had 5% and 6% greater mass, respectively, than unimpaired mice. Mice with tail impairments had larger home ranges than did unimpaired mice. Burdens of black-legged ticks ( Ixodes scapularis ) were higher among mice with tail and limb impairments while burdens of bot fly larvae ( Cuterebra ) were higher among mice with cataracts compared to mice without impairments. Our findings do not support the presupposition that physical impairments reduce viability in their bearers and are inconsistent with the devaluation of impaired individuals that pervaded early thinking in evolutionary biology.

Body mass and attractivity of female offspring are negatively affected by food restriction of meadow vole (Microtus pennsylvanicus) dams during lactation

Behaviour ◽  
2014 ◽  
Vol 151 (12-13) ◽  
pp. 1847-1868 ◽  
Author(s):  
Ramona M. Sabau ◽  
Lyndsey Pierson ◽  
Michael H. Ferkin
Keyword(s):  
Body Mass ◽  
Sexual Behaviour ◽  
Food Restriction ◽  
Female Offspring ◽  
Microtus Pennsylvanicus ◽  
The Body ◽  
Male Offspring ◽  
Meadow Vole ◽  
Body Weights ◽  
And Control

The environment experienced by pups during lactation (nutrition and maternal behaviour) can contribute not only to sexual development, but also to individual differences in offspring sexual behaviour. We tested the hypothesis that female offspring of meadow vole dams (Microtus pennsylvanicus) that were 30% food restricted (FR) during days 1–7 of lactation (FR 1–7), days 8–14 of lactation (FR 8–14), or days 15–21 of lactation (FR 15–21) show negative effects on their food intake, growth, and the three components of sexual behaviour (attractivity, proceptivity and receptivity) as compared with female offspring of control dams. With the exception of age 29 days or age 34 days, the body weights of female offspring of FR 1–7 dams and FR 8–14 dams between days 21 and 48 were lower than the body weights of female offspring of FR 15–21 dams and those of control dams. Female offspring of FR 1–7 dams maintained a lower body weight than the other female offspring throughout the study. Female offspring of FR 8–14 and FR 15–21 dams produced odours that were less attractive to males than odours produced by those of FR 1–7 and control dams. Female offspring of FR dams and control dams did not differ in their measures of proceptivity and receptivity. However, the total amount of time allocated for copulation by males was shorter for those males that were paired with female offspring of FR 1–7 dams than it was for those that were paired with the female offspring of FR 8–14, FR15–21, and control dams. The results of this study, coupled with those found in a study conducted on the male offspring of FR dams, indicate that for female offspring days 1–7 and for male offspring days 8–14 of lactation are the time periods during which food restriction of dams had the greatest impact on deficits in sexual behaviour and body mass in meadow voles.

Seasonal variations in the mass and composition of brown adipose tissue in the meadow vole, Microtus pennsylvanicus

1969 ◽  
Vol 47 (4) ◽  
pp. 547-555 ◽  
Author(s):  
L. A. Didow ◽  
J. S. Hayward
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Seasonal Changes ◽  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Relative Mass ◽  
Laboratory Studies ◽  
Meadow Voles ◽  
Percentage Composition ◽  
Brown Adipose

Wild meadow voles were collected each month of the year and analyzed for the mass and composition of their brown adipose tissue. The relative mass of brown adipose tissue decreased with increasing body weight in both summer and winter.Seasonal changes in the relative mass of brown adipose tissue were inversely related to seasonal changes in ambient temperature. In mature voles, the relative mass of brown adipose tissue was lowest during summer (0.5%) and increased rapidly to a level of 1.7% in early winter. Similarly, immature voles had their lowest relative mass in summer (1.0%) and increased this to 2.3% in winter. Both groups showed some decrease in the winter amount of the tissue when the subnivean environment became established. The percentage composition of brown adipose tissue with respect to water, lipid, and protein did not change significantly through the year.The results provide corroboration for laboratory studies which show that the mass and composition of brown adipose tissue are related to the requirement for cold thermogenesis. In voles, this requirement was present throughout the year and varied only in degree.

Prediction of signs/symptoms of decompression sickness following submarine tower escape

2019 ◽  
pp. 17-33
Author(s):  
Joel Edney ◽  
Geoffrey Loveman ◽  
Fiona Seddon ◽  
Julian Thacker ◽  
Karen Jurd ◽  
...  
Keyword(s):  
Body Mass ◽  
Marked Effect ◽  
Decompression Sickness ◽  
Outcome Data ◽  
Calibration Data ◽  
Limb Pain ◽  
Pulmonary Barotrauma ◽  
Escape Depth ◽  
Different Types ◽  
Risk Curves

Crew survival in a distressed submarine (DISSUB) scenario may be enhanced by the knowledge of the risks of different types of decompression sickness (DCS) should the crew attempt tower escape. Four models were generated through calibration against DCS outcome data from 3,919 pressure exposures, each for the prediction of one of four categories of DCS: neurological, limb pain, respiratory and cutaneous. The calibration data contained details of human, goat, sheep and pig exposures to raised pressure while breathing air or oxygen/nitrogen mixtures. No exposures had substantial staged decompression or cases of suspected pulmonary barotrauma. DCS risk was scaled between species and with body mass. A parameter was introduced to account for the possibility of the occurrence of some symptom types masking others. The calibrated models were used to estimate likelihood of DCS occurrence for each symptom category following submarine tower escape. Escape depth was found to have a marked effect only on predicted rates of neurological DCS. Saturation at raised internal DISSUB pressure prior to escape was found to affect predicted rates of all symptom types. The iso-risk curves presented are offered as guidance to submarine crews and rescue forces in preparation for, or in the event of, a DISSUB scenario.

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