About this Research Topic
Global changes and increasing frequency of unpredictable events appear as major threat for the vast majority of animal kingdom. There is growing interest in how well behavioral and physiological flexibility can buffer organisms from environmental hazards. Key metabolic constraints imposed by environmental fluctuations include reduction in food availability, changes in food quality, periods of coldness or of dryness.
Organisms have adapted to environmental variability over the course of evolution. This occurs notably through an optimization of the mechanisms regulating energy balance involving morphological, physiological and behavioral adaptations. Energy conservation allows organisms to optimize their energy allocation to fitness components, i.e. survival, reproduction and growth, according to environmental conditions.
The ability to save energy through behavioral and physiological responses, such as altering habitat selection, reducing physical activities, lowering active metabolic rate, or entering a state of hypometabolism possibly associated with hypothermia, and to allocate it into the different fitness components, has great ecological relevance for animal species, and also implies important evolutionary aspects.
To date, underlying regulatory mechanisms of such strategies are far from being entirely understood, and many aspects still remain to be investigated. So far, the vast majority of research in this area has been done with a focus on small, endothermic animals, that have to maintain a high core body temperature but can also enter an hypometabolic state under certain environmental circumstances. More rarely these mechanisms are studied in large endotherms or in ectotherms, from which ambient temperature governs body temperature and metabolism. This also includes tolerance to high and low temperatures.
Behavioral and hypometabolic responses, however, seem to be present in a large variety of animal species from endotherms to ectotherms, and appear as a continuum of mechanisms for living at low pace. Mechanisms of energy saving imply some important evolutionary aspects leading to contrasted strategies of energy management and allocation to different fitness components. In the context of global environmental changes, understanding how the physiological flexibility, enabling organisms to cope with fluctuating environments during their lifetime, can be continued through the populations, via some inherited mechanisms, constitutes to be a great avenue of research.
This Research Topic will aim to compile the recent knowledge and advances concerning mechanisms of energy saving in the context of a constantly changing environment, as well as the ecological and evolutionary implications of such strategies for individual’s life and animal’s populations. The focus is on behavioral and hypometabolic responses, and thermal tolerance that enable animal species, from endotherms to ectotherms, to regulate their energy balance, and to optimize energy allocation to fitness components. The different approaches describing these mechanisms may range from the whole organism or even a group of organisms to cellular or molecular levels.
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