Table_1_Do Incubation Temperatures Affect the Preferred Body Temperatures of Hatchling Velvet Geckos?.DOCX

In many lizards, a mother’s choice of nest site can influence the thermal and hydric regimes experienced by developing embryos, which in turn can influence key traits putatively linked to fitness, such as body size, learning ability, and locomotor performance. Future increases in nest temperatures predicted under climate warming could potentially influence hatchling traits in many reptiles. In this study, we investigated whether future nest temperatures affected the thermal preferences of hatchling velvet geckos, Amalosia lesueurii. We incubated eggs under two fluctuating temperature treatments; the warm treatment mimicked temperatures of currently used communal nests (mean = 24.3°C, range 18.4–31.1°C), while the hot treatment (mean = 28.9°C, range 20.7–38.1°C) mimicked potential temperatures likely to occur during hot summers. We placed hatchlings inside a thermal gradient and measured their preferred body temperatures (Tbs) after they had access to food, and after they had fasted for 5 days. We found that hatchling feeding status significantly affected their preferred Tbs. Hatchlings maintained higher Tbs after feeding (mean = 30.6°C, interquartile range = 29.6–32.0°C) than when they had fasted for 5 d (mean = 25.8°C, interquartile range = 24.7–26.9°C). Surprisingly, we found that incubation temperatures did not influence the thermal preferences of hatchling velvet geckos. Hence, predicting how future changes in nest temperatures will affect reptiles will require a better understanding of how incubation and post-hatchling environments shape hatchling phenotypes.

在诸多蜥蜴类群中，母体选择的巢址可影响发育胚胎所经历的热湿环境（thermal and hydric regimes），而这一环境反过来又会作用于被认为与适合度相关的关键性状，例如体型大小、学习能力与运动表现。气候变暖背景下预测的未来巢温升高，可能对诸多爬行动物的幼体性状产生影响。本研究以天鹅绒守宫（velvet gecko）Amalosia lesueurii为研究对象，探究未来巢温是否会影响其幼体的热偏好。我们将卵置于两种波动温度处理下进行孵化：常温处理模拟当前常见的集群巢温度（平均温度24.3℃，波动范围18.4–31.1℃），高温处理（平均温度28.9℃，波动范围20.7–38.1℃）则模拟炎热夏季可能出现的潜在巢温。我们将幼体放置于温度梯度环境（thermal gradient）中，分别在幼体摄食后以及禁食5天后，测量其偏好体温（preferred body temperatures, Tbs）。研究结果显示，幼体的摄食状态会显著影响其偏好体温：摄食完成后，幼体维持的偏好体温平均为30.6℃，四分位距为29.6–32.0℃，显著高于禁食5天后的幼体（平均体温25.8℃，四分位距24.7–26.9℃）。令人意外的是，我们发现孵化温度并未对该物种幼体的热偏好产生显著影响。因此，若要准确预测未来巢温变化将如何影响爬行动物，我们需要更深入地理解孵化环境以及幼体孵化后的环境如何塑造爬行动物幼体的表型（phenotypes）。