Mochales-Riaño Gabriel, Barroso Frederico M, Marques Valéria, Telea Alexandra E, Sannolo Marco, Rato Catarina, Carretero Miguel A
CIBIO, Research Centre in Biodiversity and Genetic Resources, InBIO, Universidade do Porto, Vila do Conde, Portugal.
Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Barcelona, Spain.
PLoS One. 2024 Dec 26;19(12):e0316283. doi: 10.1371/journal.pone.0316283. eCollection 2024.
Thermoregulating ectotherms may resort to different external heat sources to modulate their body temperature through an array of behavioural and physiological adaptations which modulate heat exchange with the environment and its distribution across the animal's body. Even small-bodied animals are capable of fine control over such rates and the subsequent re-allocation of heat across the body. Such thermal exchanges with the environment usually happen through two non-mutually exclusive modes: heliothermy (radiant heat gain from the sun) or thigmothermy (heat gained or lost via conduction). Classically, the study of these phenomena has relied on invasive methodologies which often disregard the effect of stress, behaviour and regional heterothermy on the rates and patterns of thermal exchange across the body of the animal. This study proposes a novel experimental methodology, capitalising on thermography, to provide an alternative method to less invasively obtain reliable body temperatures of thermoregulating ectotherms, while allowing behaviour and heating mode to be considered when quantifying thermal exchange rates. This methodology was tested in the gecko Tarentola mauritanica, where twenty males were allowed to heat up and cool down under a novel experimental set-up which isolates heliothermic and thigmothermic processes, while being recorded with a thermal camera. The study revealed differences in the heating and cooling rates of several body parts per treatment suggesting that thermal exchanges are complex even in small ectotherms. Ultimately, the described set-up provides the opportunity to revisit classical questions with a less invasive and more flexible experimental approach, enabling heliothermic and thigmothermic processes to be disentangled. The described methodology also better integrates behaviour and physiology while obtaining higher temporal and spatial resolution of body temperatures in a thermoregulating ectotherm.
体温调节的变温动物可能会借助不同的外部热源，通过一系列行为和生理适应来调节体温，这些适应会调节与环境的热交换以及热量在动物体内的分布。即使是体型较小的动物也能够精确控制这些速率以及随后热量在全身的重新分配。与环境的这种热交换通常通过两种并非相互排斥的方式发生：日射热调节（从太阳获得辐射热）或接触热调节（通过传导获得或失去热量）。传统上，对这些现象的研究依赖于侵入性方法，这些方法往往忽视了应激、行为和局部异温性对动物全身热交换速率和模式的影响。本研究提出了一种利用热成像技术的新型实验方法，以提供一种侵入性较小的替代方法来可靠地获取体温调节变温动物的体温，同时在量化热交换速率时能够考虑行为和加热模式。这种方法在毛里塔尼亚沙虎壁虎身上进行了测试，让20只雄性壁虎在一个新的实验装置下升温降温，该装置将日射热调节和接触热调节过程隔离开来，同时用热成像相机进行记录。研究揭示了每种处理下几个身体部位的加热和冷却速率存在差异，这表明即使在小型变温动物中热交换也是复杂的。最终，所描述的装置提供了一个机会，以侵入性较小且更灵活的实验方法重新审视经典问题，从而能够区分日射热调节和接触热调节过程。所描述的方法在获取体温调节变温动物体温的更高时间和空间分辨率的同时，还能更好地整合行为和生理。
