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

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journal contribution
posted on 01.12.2020, 00:00 authored by Anais Claudia Pessato, Andrew E McKechnie, Kate BuchananKate Buchanan, Mylene MarietteMylene Mariette
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.

History

Journal

Scientific Reports

Volume

10

Article number

18914

Publisher

Nature Publishing Group

Location

London, Eng.

ISSN

2045-2322

eISSN

2045-2322

Language

eng

Publication classification

C Journal article; C1 Refereed article in a scholarly journal

Copyright notice

2020, The Authors