Body temperature and time of day both affect nocturnal lizard performance: An experimental investigation. (October 2020)

• Record Type: Journal Article
• Authors: Dayananda, Buddhi; Jeffree, Ross A.; Webb, Jonathan K.
• Is Part Of: Journal of thermal biology. Volume 93(2020)
• Publication Date: 2020-10
• Subjects: Ectotherms -- Thermoregulation -- Reptile -- Climate warming -- Thermal performance; Thermobiology -- Periodicals; Temperature -- Periodicals; Biology -- Periodicals; Thermobiologie -- Périodiques; Thermobiology; Periodicals; 571.46
• DOI: 10.1016/j.jtherbio.2020.102728
• Languages: English
• ISSNs: 0306-4565

Abstract

Abstract: 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. Highlights: Performance and physiology of reptiles is profoundly influenced by the temperature. But little is known about how time of day that the animal is usually active influences their performance. In nocturnal species time of day when they are usually active affects their performance. Both body temperature and the time of day are crucial for estimating the performance of ectotherms.