Seasonal and between-population variation in heat tolerance and cooling efficiency in a Mediterranean songbird.

Autor: Cabello-Vergel J; Conservation Biology Research Group, Faculty of Sciences, Universidad de Extremadura, Badajoz, Spain. Electronic address: jucabellov@unex.es., Gutiérrez JS; Conservation Biology Research Group, Faculty of Sciences, Universidad de Extremadura, Badajoz, Spain; Ecology in the Anthropocene, Associated Unit CSIC-UEx, Faculty of Sciences, Universidad de Extremadura, Badajoz, Spain., González-Medina E; Conservation Biology Research Group, Faculty of Sciences, Universidad de Extremadura, Badajoz, Spain., Sánchez-Guzmán JM; Conservation Biology Research Group, Faculty of Sciences, Universidad de Extremadura, Badajoz, Spain; Ecology in the Anthropocene, Associated Unit CSIC-UEx, Faculty of Sciences, Universidad de Extremadura, Badajoz, Spain., Masero JA; Ecology in the Anthropocene, Associated Unit CSIC-UEx, Faculty of Sciences, Universidad de Extremadura, Badajoz, Spain., Villegas A; Conservation Biology Research Group, Faculty of Sciences, Universidad de Extremadura, Badajoz, Spain; Ecology in the Anthropocene, Associated Unit CSIC-UEx, Faculty of Sciences, Universidad de Extremadura, Badajoz, Spain.
Jazyk: angličtina
Zdroj: Journal of thermal biology [J Therm Biol] 2024 Oct; Vol. 125, pp. 103977. Date of Electronic Publication: 2024 Sep 20.
DOI: 10.1016/j.jtherbio.2024.103977
Abstrakt: Discrete populations of widely distributed species may inhabit areas with marked differences in climatic conditions across geographic and seasonal scales, which could result in intraspecific variation in thermal physiology reflecting genetic adaptation, phenotypic plasticity, or both. However, few studies have evaluated inter-population variation in physiological responses to heat. We evaluated within- and inter-population seasonal variation in heat tolerance, cooling efficiency and other key thermoregulatory traits in two Mediterranean populations of Great tit Parus major experiencing contrasting thermal environments: a lowland population subject to hotter summers and a higher annual thermal amplitude than a montane population. Specifically, we measured heat tolerance limits (HTL), body temperature, resting metabolic rate, evaporative water loss, and evaporative cooling efficiency (the ratio between evaporative heat loss to metabolic heat production) within and above the thermoneutral zone during winter and summer. Heat tolerance during summer was greater in lowland than in montane birds; indeed, lowland birds seasonally increased this trait to a significant level, while montane ones did to a lesser extent. Besides, lowland birds showed greater evaporative cooling efficiency during summer (possibly due in part to reductions in total endogenous heat load), while surprisingly montane ones showed the opposite trend. Thus, lowland birds displayed greater seasonal flexibility in HTL, body temperature and resting metabolic rate above thermoneutrality, thus giving some support to the climatic variability hypothesis - that flexibility in thermoregulatory traits should increase with climatic variability. Our results partially support the idea that songbirds' adaptive thermoregulation in the heat is flexible, highlighting the importance of considering intraspecific variation in thermoregulatory traits when modelling the future distribution and persistence of species under different climate change scenarios.
Competing Interests: Declaration of competing interest The authors declared no competing or financial interests.
(Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: