The Physiology of Heat Tolerance in Small Endotherms

McKechnie, Andrew E.; Wolf, Blair O.

doi:10.1152/physiol.00011.2019

Cited by 124 publications

(114 citation statements)

References 138 publications

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“…in doves) and panting (e.g. in passerines) 12 , 13 . The efficiency of panting is substantially lower than those of gular flutter or cutaneous evaporative water loss 14 – 16 .…”

Section: Introductionmentioning

confidence: 99%

Vocal panting: a novel thermoregulatory mechanism for enhancing heat tolerance in a desert-adapted bird

Pessato

McKechnie

Buchanan

et al. 2020

Sci Rep

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Animals thriving in hot deserts rely on extraordinary adaptations and thermoregulatory capacities to cope with heat. Uncovering such adaptations, and how they may be favoured by selection, is essential for predicting climate change impacts. Recently, the arid-adapted zebra finch was discovered to program their offspring’s development for heat, by producing ‘heat-calls’ during incubation in hot conditions. Intriguingly, heat-calls always occur during panting; and, strikingly, avian evaporative cooling mechanisms typically involve vibrating an element of the respiratory tract, which could conceivably produce sound. Therefore, we tested whether heat-call emission results from a particular thermoregulatory mechanism increasing the parent’s heat tolerance. We repeatedly measured resting metabolic rate, evaporative water loss (EWL) and heat tolerance in adult wild-derived captive zebra finches (n = 44) at increasing air temperatures up to 44 °C. We found high within-individual repeatability in thermoregulatory patterns, with heat-calling triggered at an individual-specific stage of panting. As expected for thermoregulatory mechanisms, both silent panting and heat-calling significantly increased EWL. However, only heat-calling resulted in greater heat tolerance, demonstrating that “vocal panting” brings a thermoregulatory benefit to the emitter. Our findings therefore not only improve our understanding of the evolution of passerine thermal adaptations, but also highlight a novel evolutionary precursor for acoustic signals.

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“…in doves) and panting (e.g. in passerines) 12 , 13 . The efficiency of panting is substantially lower than those of gular flutter or cutaneous evaporative water loss 14 – 16 .…”

Section: Introductionmentioning

confidence: 99%

Vocal panting: a novel thermoregulatory mechanism for enhancing heat tolerance in a desert-adapted bird

Pessato

McKechnie

Buchanan

et al. 2020

Sci Rep

Self Cite

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“…In contrast to the risk of hypothermia presented by highaltitude environments, the energetic cost of flight at sea level may lead to hyperthermia, which may limit flight duration (Bevan et al, 1997;Butler et al, 1977). There are a number of physiological maladjustments that excessive heat gain might cause, including damage to enzymes, increased oxidative stress and dehydration (Dawson, 1982;McKechnie and Wolf, 2019). Sufficient heat can be generated during flight to reduce flight duration to 15 min in migrating eider ducks (Somateria mollissima), a predominantly diving species (Guillemette et al, 2016), and necessitate periods of cooling following these flights (Guillemette et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Tackling the Tibetan Plateau in a down suit: insights into thermoregulation by bar-headed geese during migration

Parr

Bishop

Batbayar

et al. 2019

Journal of Experimental Biology

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The authors discovered that autocorrelation was not properly accounted for in their analyses of body temperature. They reanalysed the data using a CorARMA correlation term and found that the overall results and conclusions were unaltered. This was confirmed by a reviewer of the original paper, who was asked to review the corrected version and specifically state whether or not, in their opinion, the conclusions were unchanged.

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“…This shows that ringtail possums are perhaps particularly susceptible to water stress and the ability to replenish lost body water will be the primary factor limiting their survival during heatwaves. Theoretically, if animals are able to remain hydrated, they can persist for extended periods at high T a without injury (McKechnie and Wolf, 2019;Mitchell et al, 2018). However, possums must contend with dietary plant secondary metabolitesnaturally occurring toxins that limit the type and amount of food folivores can consumeand the ability of animals to The horizontal dotted line where ECC=1 indicates the point where metabolic heat production equals evaporative heat loss (i.e.…”

Section: Resultsmentioning

confidence: 99%

Facultative hyperthermia during a heatwave delays injurious dehydration of an arboreal marsupial

Turner

2020

Journal of Experimental Biology

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Heatwaves negatively impact wildlife populations and their effects are predicted to worsen with ongoing global warming. Animal mass mortality at extremely high ambient temperature (T a) is evidence for physiological dysfunction and, to aid conservation efforts, improving our understanding of animal responses to environmental heat is crucial. To address this, I measured the water loss, body temperature and metabolism of an Australian marsupial during a simulated heatwave. The body temperature of the common ringtail possum Pseudocheirus peregrinus increased passively by ∼3°C over a T a of 29-39°C, conveying water savings of 9.6 ml h −1. When T a crossed a threshold of 35-36°C, possums began actively cooling by increasing evaporative water loss and thermal conductance. It is clear that facultative hyperthermia is effective up to a point, but once this point is surpassedthe frequency and duration of which are increasing with climate changebody water would rapidly deplete, placing possums in danger of injury or death from dehydration.

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The Physiology of Heat Tolerance in Small Endotherms

Cited by 124 publications

References 138 publications

Vocal panting: a novel thermoregulatory mechanism for enhancing heat tolerance in a desert-adapted bird

Vocal panting: a novel thermoregulatory mechanism for enhancing heat tolerance in a desert-adapted bird

Tackling the Tibetan Plateau in a down suit: insights into thermoregulation by bar-headed geese during migration

Facultative hyperthermia during a heatwave delays injurious dehydration of an arboreal marsupial

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