The Herpetological Journal

pp. 69-76
Authors: Rock, Jennifer & Cree, Alison

Abstract: Nocturnal lizards inhabiting cool temperate environments potentially experience a wide range of body temperatures (T_b). We used radio telemetry to characterize field T_b in a nocturnal diplodactylid gecko (Hoplodactylus maculatus) from a high-latitude (45°S), sub-alpine site in southern New Zealand. Variation in T_b within days (diel), among days and among different reproductive groups of this viviparous species (pregnant females, non-pregnant females and males) was measured with temperature-sensitive transmitters. We found that surgical implantation of transmitters did not have a significant effect on selected temperature on a laboratory gradient (T_sel). Field T_b values were examined in concert with T_sel and microhabitat temperature in late summer, revealing marked fluctuations of up to 30 °C in T_b both within and between days. When weather conditions allowed, all reproductive groups exhibited some degree of thermoregulation, with T_b generally elevated at least 4 °C above microhabitat temperature and within the bounds (central 50%) of T_sel at the warmest times of day on most days. Considerable thermoregulation occurred early in the day, particularly for pregnant females, and is likely to have involved some degree of direct solar basking. Temperature telemetry revealed both extreme variability in T_b and complexity of thermoregulatory behaviour in a primarily nocturnal, thigmothermic lizard.

Keywords: MICROHABITAT TEMPERATURE, GECKO, THERMOREGULATION, REPRODUCTIVE CONDITION, DIPLODACTYLIDAE, TELEMETRY