Heat and water loss vs shelter: a dilemma in thermoregulatory decision-making for a retreat-dwelling nocturnal gecko

Understanding the interaction between upper voluntary thermal limit (VTmax) and water loss may aid in predicting responses of ectotherms to increasing temperatures within microhabitats. However, the temperature (VTmax) at which climate heating will force cool-climate, nocturnal lizards to abandon daytime retreats remains poorly known. Here, we developed a new laboratory protocol for determining VTmax in the retreat-dwelling, viviparous Woodworthia Otago/Southland gecko, based on escape behaviour (abandonment of heated retreat). We compared the body temperature (Tb) at VTmax, and duration of heating, between two source groups with different thermal histories, and among three reproductive groups. We also examined continuous changes in Tb (via an attached biologger) and total evaporative water loss (EWL) during heating. In the field, we measured Tb and microhabitat thermal profiles to establish whether geckos reach VTmax in nature. We found that VTmax and duration of heating varied between...明晰自愿性最高热限值（upper voluntary thermal limit, VTmax）与水分散失间的相互作用，或有助于预测外温动物（ectotherms）对微生境内温度升高的响应。然而，目前学界对气候变暖将迫使冷气候夜行性蜥蜴放弃日间隐蔽所的临界温度（VTmax）仍知之甚少。本研究基于逃逸行为（即壁虎离开加热后的隐蔽所），建立了一套用于测定栖息于隐蔽所的胎生伍氏奥塔哥/南地壁虎（Woodworthia Otago/Southland gecko）VTmax的全新实验室方案。我们对比了两组具有不同热历史的源种群以及三个繁殖组间的VTmax对应体温（body temperature, Tb）与加热时长；同时，通过附着式生物记录仪，我们监测了加热过程中Tb的连续变化，并测定了总蒸发失水量（total evaporative water loss, EWL）。在野外实验中，我们测定了Tb与微生境热特征，以明确野生壁虎是否会在自然环境中达到VTmax。我们发现，VTmax与加热时长在...