The locomotor performance of reptiles is profoundly influenced by temperature, but little is known about how the time of day when the animal is usually active may influence performance. Time of day may be particularly relevant for studies on nocturnal reptiles that thermoregulate by day, but are active at night when ambient temperatures are cooler. If selection favours individuals that match their performance to activity times, then nocturnal species should perform better during the night, when they are normally active, than during the day. To test this hypothesis, we investigated how the time of day and body temperature affected the locomotor performance of adult females of the velvet gecko (Amalosia lesueurii). We measured the sprint speeds, running speeds and number of stops of 43 adult females at four different body temperatures (20, 25, 30 and 35 °C) during the day and at night. At night, sprint speeds were higher at 20 and 35 °C but sprint speeds were similar at 25 and 30 °C. By day, sprint speed increased with body temperature, peaking at 30 °C, before declining at 35 °C. However, gecko speeds over 1 m was higher at night at all four test temperatures than by day. Number of stops showed broadly similar patterns and females stopped almost twice as often on the racetrack during the day than they did at night. Furthermore, the thermal breadth of performance differed depending on when geckos were tested. Our results demonstrate that both body temperature and the time of day affects the behaviour and locomotor performance of female velvet geckos, with geckos running faster at night, the time of day when they are usually active. This study adds to evidence that both body temperature and the time of day are crucial for estimating the performance of ectotherms and evaluations and predictions of their vulnerability to climate warming should consider the context of laboratory experimental design.

中文翻译：

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体温和一天中的时间都会影响夜间蜥蜴的表现：一项实验研究

爬行动物的运动表现受温度的影响很大，但人们对动物通常活跃的一天中的时间如何影响表现知之甚少。一天中的时间可能与对白天调节体温但在夜间环境温度较低时活动的夜间爬行动物的研究特别相关。如果选择偏向于将他们的表现与活动时间相匹配的个体，那么夜间活动的物种应该在夜间表现更好，因为它们通常是活跃的，而不是在白天。为了验证这一假设，我们调查了一天中的时间和体温如何影响天鹅绒壁虎 (Amalosia lesueurii) 成年雌性的运动性能。我们测量了 43 名成年女性在四种不同体温（20、25、30 和 35 °C）白天和晚上。在夜间，冲刺速度在 20 和 35 °C 时更高，但冲刺速度在 25 和 30 °C 时相似。白天，冲刺速度随着体温的升高而增加，在 30 °C 时达到峰值，然后在 35 °C 时下降。然而，在所有四个测试温度下，夜间超过 1 m 的壁虎速度都高于白天。停止次数显示出大致相似的模式，女性在白天在赛道上停下来的频率几乎是晚上的两倍。此外，性能的热广度因测试壁虎的时间而异。我们的研究结果表明，体温和一天中的时间都会影响雌性天鹅绒壁虎的行为和运动表现，壁虎在夜间跑得更快，这是它们通常活跃的时间。