Bat thermoregulation in the heat: seasonal variation in evaporative cooling capacities in four species of European bats.

Autor: Czenze ZJ; Centre for Behavioural and Physiological Ecology, University of New England, Armidale, NSW, 2351, Australia. Electronic address: zczenze@une.edu.au., Noakes MJ; School of Animal, Plant, and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa., Wojciechowski MS; Department of Vertebrate Zoology and Ecology, Nicolaus Copernicus University, Toruń, Poland.
Jazyk: angličtina
Zdroj: Journal of thermal biology [J Therm Biol] 2024 Jul; Vol. 123, pp. 103911. Date of Electronic Publication: 2024 Jul 05.
DOI: 10.1016/j.jtherbio.2024.103911
Abstrakt: Phenotypic flexibility is an important source of physiological variation in endotherms and plays an integral role in species' response to rapid environmental changes. Studies of phenotypic flexibility have focused on winter acclimatization and cold endurance, and there are fewer data on summer acclimatization and adjustments in heat dissipation capacity, especially in Temperate-Zone species. We used indirect calorimetry and thermometry to test if thermoregulation at high air temperatures (T a ) varies between spring and summer in four species of European vespertilionid bats: Nyctalus noctula, Pipistrellus nathusii, P. pygmaeus, and P. pipistrellus. We measured subcutaneous body temperature (T sub ), evaporative water loss, and resting metabolic rate while exposing bats to a stepped profile of increasing T a , from 28 °C-48 °C. We predicted that during summer, bats increase heat tolerance and evaporative cooling capacity, to better tolerate hotter T a s. In contrast, we found lower maximum ratios of evaporative heat loss (EHL) to metabolic heat production (MHP) during summer, but no seasonal differences in maximum T a tolerated or T sub . The main cause of this seasonal difference in maximum EHL/MHP seems to be from bats increasing EWL more gradually with increasing T a in summer than spring, particularly in the smaller Pipistrellus species. Therefore, this seasonal variation in heat-dissipation strategies may reflect enhanced water conservation during summer to avoid dehydration, as bats are confined to roosts for longer and hotter days compared to spring.
Competing Interests: Declaration of competing interest The authors declare no conflict of interest.
(Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Databáze: MEDLINE
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