Climate-mediated energetic constraints on the distribution of hibernating mammals

Nature ◽  
2002 ◽  
Vol 418 (6895) ◽  
pp. 313-316 ◽  
Author(s):  
Murray M. Humphries ◽  
Donald W. Thomas ◽  
John R. Speakman
Keyword(s):  
Energetic Constraints

scholarly journals Is behavioural plasticity consistent across different environmental gradients and through time?

2017 ◽  
Vol 284 (1860) ◽  
pp. 20170893 ◽  
Author(s):  
David J. Mitchell ◽  
Peter A. Biro
Keyword(s):  
Food Deprivation ◽  
Environmental Gradients ◽  
Reaction Norm ◽  
Environmental Variable ◽  
Behavioural Plasticity ◽  
Thermally Responsive ◽  
State Dependent ◽  
Energetic Constraints ◽  
High Consistency ◽  
Outstanding Question

Despite accumulating evidence for individual variation in behavioural plasticity, there is currently little understanding of the causes and consequences of this variation. An outstanding question is whether individual reaction norm (RN) slopes are consistent across different environmental variables—that is, whether an individual that is highly responsive to one environmental variable will be equally responsive to a second variable. Another important and related question is whether RNs are themselves consistently expressed through time or whether they are simply state dependent. Here, we quantified individual activity rates of zebrafish in response to independent manipulations of temperature and food availability that were repeated in discrete ‘bursts’ of sampling through time. Individuals that were thermally responsive were not more responsive to food deprivation, but they did exhibit greater unexplained variation. Individual RN slopes were consistent (repeatable) over time for both temperature (Rslope= 0.92) and food deprivation responses (Rslope= 0.4), as were mean activity rates in the standard environment (Rintercept= 0.83). Despite the high potential lability of behaviour, we have demonstrated consistency of behavioural RN components and identified potential energetic constraints leading to high consistency of thermal RNs and low consistency of food deprivation RNs.

scholarly journals The metabolic response of the Bradypus sloth to temperature

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5600 ◽  
Author(s):  
Rebecca Naomi Cliffe ◽  
David Michael Scantlebury ◽  
Sarah Jane Kennedy ◽  
Judy Avey-Arroyo ◽  
Daniel Mindich ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Energy Expenditure ◽  
High Power ◽  
Metabolic Response ◽  
Metabolic Responses ◽  
Metabolic Depression ◽  
Wide Range ◽  
Energetic Constraints ◽  
Power Costs

Poikilotherms and homeotherms have different, well-defined metabolic responses to ambient temperature (Ta), but both groups have high power costs at high temperatures. Sloths (Bradypus) are critically limited by rates of energy acquisition and it has previously been suggested that their unusual departure from homeothermy mitigates the associated costs. No studies, however, have examined how sloth body temperature and metabolic rate vary with Ta. Here we measured the oxygen consumption (VO2) of eight brown-throated sloths (B. variegatus) at variable Ta’s and found that VO2 indeed varied in an unusual manner with what appeared to be a reversal of the standard homeotherm pattern. Sloth VO2 increased with Ta, peaking in a metabolic plateau (nominal ‘thermally-active zone’ (TAZ)) before decreasing again at higher Ta values. We suggest that this pattern enables sloths to minimise energy expenditure over a wide range of conditions, which is likely to be crucial for survival in an animal that operates under severe energetic constraints. To our knowledge, this is the first evidence of a mammal provisionally invoking metabolic depression in response to increasing Ta’s, without entering into a state of torpor, aestivation or hibernation.

Energetic constraints on the diet of terrestrial carnivores

Nature ◽  
10.1038/46266 ◽  
1999 ◽  
Vol 402 (6759) ◽  
pp. 286-288 ◽  
Author(s):  
Chris Carbone ◽  
Georgina M. Mace ◽  
S. Craig Roberts ◽  
David W. Macdonald
Keyword(s):  
Energetic Constraints

Iterative Reverse Monte Carlo and Molecular Statics for Improved Atomic Structure Modeling: A Case Study of Zinc Oxide Grown by Atomic Layer Deposition

2021 ◽  
Author(s):  
Ryan C Gettler ◽  
Henry D Koenig ◽  
Matthias J Young
Keyword(s):  
Monte Carlo ◽  
Zinc Oxide ◽  
Diffraction Data ◽  
Atomic Structure ◽  
Atomic Layer ◽  
Structure Modeling ◽  
Reverse Monte Carlo ◽  
Layer Deposition ◽  
Energetic Constraints

Reverse Monte Carlo (RMC) modeling is a common method to derive atomic structure models of materials from experimental diffraction data. However, RMC modeling does not impose energetic constraints and can...

Egg Characteristics in Relation to Skipped Days of Laying in the Grey Partridge

2017 ◽  
Vol 10 (4) ◽  
pp. 231-240 ◽  
Author(s):  
Marco Cucco ◽  
Marco Grenna ◽  
Irene Pellegrino
Keyword(s):  
Literature Review ◽  
Physiological Stress ◽  
Beta Carotene ◽  
Egg Laying ◽  
Hatching Rate ◽  
Short Term ◽  
Grey Partridge ◽  
Short Term Adaptation ◽  
Energetic Constraints ◽  
Egg Components

Birds sometimes skip a day along the sequence of egg laying, which may vary the mass or the composition of delayed eggs compared with those that were laid consecutively. Our literature review shows that this has been interpreted as a short-term adaptation that enables females to overcome energetic constraints during the laying period, but other hypotheses implying the influence of weather, pollution, or hormonal cycles have also been proposed. We collected freshly laid Grey Partridge Perdix perdix eggs to determine the effects of laying gaps on egg characteristics. Egg shape, as well as egg components (beta-carotene, avidin and lysozyme concentrations) did not vary in relation to skipped days. Eggs were slightly heavier when one or two days were skipped (0.72% and 0.45%, respectively). However, when examining the hatching rate, we found a significant decrease in relation to skipped days, hence eggs following laying gaps showed a lower hatching rate than other eggs. The pattern observed could indicate the presence of some physiological stress that caused females to skip one or two days and to lay eggs that hatched less.

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