Water restriction in viviparous lizards causes transgenerational effects on behavioral anxiety and immediate effects on exploration behavior

Dupoué

Lourdais

et al. 2019

Ecology and Evolution

Self Cite

108

102

The regulation of body temperature (thermoregulation) and of water balance (defined here as hydroregulation) are key processes underlying ecological and evolutionary responses to climate fluctuations in wild animal populations. In terrestrial (or semiterrestrial) ectotherms, thermoregulation and hydroregulation closely interact and combined temperature and water constraints should directly influence individual performances. Although comparative physiologists traditionally investigate jointly water and temperature regulation, the ecological and evolutionary implications of these coupled processes have so far mostly been studied independently. Here, we revisit the concept of thermo‐hydroregulation to address the functional integration of body temperature and water balance regulation in terrestrial ectotherms. We demonstrate how thermo‐hydroregulation provides a framework to investigate functional adaptations to joint environmental variation in temperature and water availability, and potential physiological and/or behavioral conflicts between thermoregulation and hydroregulation. We extend the classical cost–benefit model of thermoregulation in ectotherms to highlight the adaptive evolution of optimal thermo‐hydroregulation strategies. Critical gaps in the parameterization of this conceptual optimality model and guidelines for future empirical research are discussed. We show that studies of thermo‐hydroregulation refine our mechanistic understanding of physiological and behavioral plasticity, and of the fundamental niche of the species. This is illustrated with relevant and recent examples of space use and dispersal, resource‐based trade‐offs, and life‐history tactics in insects, amphibians, and nonavian reptiles.

Section: G U Ideline S For Future S Tud Ie Smentioning

confidence: 99%

Section: G U Ideline S For Future S Tud Ie Smentioning

confidence: 99%

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When water interacts with temperature: Ecological and evolutionary implications of thermo‐hydroregulation in terrestrial ectotherms

Dupoué

Lourdais

et al. 2019

Ecology and Evolution

Self Cite

108

102

“…This cold-adapted species inhabits mesic environment and is tightly dependent on humid conditions in the wild (Lorenzon et al 1999, Massot et al 2002, Dupoué et al 2017. In previous studies, we have shown that common lizards exposed to dry soil conditions invest more in exploration behaviors (Rozen-Rechels et al 2018), and juvenile lizards living in dry habitats disperse more from their natal home range (Massot et al 2002), whereas sub-adults reduce their locomotor activity during a chronic water restriction (Lorenzon et al 1999). Here, we repeatedly measured daily patterns of individual activity and microhabitat selection as well as body temperature and thermoregulation accuracy during one week in adult individuals, gravid females and males, exposed to a chronic water restriction (Dupoué et al 2018) compared to individuals having access to water ad libitum.…”

Section: Introductionmentioning

confidence: 98%

Water restriction induces behavioral fight but impairs thermoregulation in a dry‐skinned ectotherm

Badiane

Agostini

et al. 2020

Oikos

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Behavioral fight responses to desiccation risk are important to predict the vulnerability of terrestrial animals to climate change and yet, they have received little attention so far. In terrestrial ectotherms, behavioral regulation of the water balance (i.e. hydroregulation) is likely to be plastic and may tradeoff with thermoregulation behavior because water loss rates are generally higher in warmer environments and body temperatures. When low water availability and heat stress cause physiological dehydration, we expect to highlight a shift to behavioral water‐conservation strategies including changes in activity patterns, micro‐habitat selection and thermoregulation strategies. Here, we compared the behavior of adult common lizards Zootoca vivipara in indoor arenas that either had a permanent access to water or underwent a one‐week long experimental water restriction. Water‐restricted lizards reduced their behavioral activity, selected more often cooler and wetter refuges during daytime, and performed less accurate thermoregulation than control lizards. The activity of water‐restricted gravid females shifted towards the cooler and wetter early hours of the day. In addition, they had lower body temperatures and preferred lower body temperatures at the end of the experiment (i.e. thermal depression). Water‐restricted lizards suffered from a mild physiological dehydration and had a lower mass change. Heat stress was simulated every second day, which led to a range of heat avoidance and water conservation strategies independent from water restriction. Altogether, these results confirm that chronic water restriction and dehydration induce responses towards water conservation that conflict with thermoregulation accuracy.

“…Short-term changes in water availability may influence activity patterns in terrestrial ectotherms when these decision rules depend on the perceived risks of dehydration and/or on the hydration state of individuals (Davis & DeNardo, 2009;Lorenzon, Clobert, Oppliger, & John-Alder, 1999;Rozen-Rechels et al, 2018). On the one hand, high body and environmental temperatures both increase water loss rates from evaporation and respiration in terrestrial ectotherms (Davis & DeNardo, 2009;Lourdais et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Short‐term change in water availability influences thermoregulation behaviours in a dry‐skinned ectotherm

Journal of Animal Ecology

Farigoule

Agostini

et al. 2020

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Mechanistic models of terrestrial ectotherms predict that climate warming will induce activity restriction due to heat stress and loss of shade, leading to the extinction of numerous populations. Such models rely on the assumption that activity patterns are dictated by simple temperature thresholds independent of changes in water availability. However, changes in water availability may further influence thermoregulation behaviour of ectotherms through dehydration risk perception, changes in water balance or changes in microclimatic conditions. Here, we experimentally assess the interactive effects of thermal conditions and water availability on activity patterns, shade selection and thermoregulation efficiency in a model ectothermic species. Thermoregulation behaviour of adult common lizards Zootoca vivipara was monitored in outdoor mesocosms as we manipulated water availability, providing water as mist in the morning and free‐standing water during the daytime. We recorded operative temperatures and micro‐meteorological conditions to infer thermal constraints and dehydration risk. Activity and shade selection were better predicted by continuous changes in thermal conditions and dehydration risk, respectively, than by threshold functions. In addition, water supplementation increased activity in males and reduced shade selection in both sexes, most probably as a behavioural response to the perception of a stronger dehydration risk. Water supplementation also influenced the thermal quality of the environment, which in turn altered daily activity patterns and thermoregulation statistics. This demonstrates that dual effects of heat and water stress on activity patterns may lead to stronger activity restriction as a result of climate change than currently predicted.