Thermal Ecology of an Endemic Sri Lankan Kangaroo Lizard (Otocryptis wiegmanni) tinder Wild and Captive Conditions
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Date
2018
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Uva Wellassa University of Sri Lanka
Abstract
Thermal ecology of Sri Lankan endemic agamid lizard species is poorly known, but vital for their conservation. This study examined the thermal ecology of Otocryptis wiegmanni both under wild and captive conditions. External body temperature (Tb), corresponding environmental temperature (Te), sex and behaviour of 121 lizards were recorded. In captivity Tb and Te were recorded at one hour time intervals within 24 hours for 10 days. For the wild condition, Tb and Te were randomly collected both in day and night time. In the wild, Tb was significantly lower than Te (p > 0.05) and mean difference was -1.59 °C. There is a positive correlation between Tb and Te (r = 0.816, p < 0.05). The best fit regression line is Tb = 5.86 + 0.695Te (R2 = 66.6%). Regression coefficient (0.695) is significant (p < 0.05). Although in captivity, Tb was significantly lower than Te (p > 0.05) and mean difference was 0.91 °C. Tb and Te shows strong positive correlation (r = 0.914, p < 0.05). Best fit regression line is Tb = 1.95 + 0.886Te (R2= 83.6%). Regression coefficient (0.886) is significant (p < 0.05). Moreover in both wild and captive conditions, Tb of males and females were not significantly different. Regression coefficients of both wild and captivity differ from the theoretical value of zero required for thermoregulation verify that O. wiegmanni is a thermoconformii)) species. The Tb for this population ranged between 20 - 26.5 °C. We never observed O. wiegmanni showing obvious basking behaviour, may be a reason for having a lower Tb than Te. Activities such as territorial and courtship display, mating, egg laying, and feeding occurred during daytime while they are dormant at night and mostly perch above ground. Moreover, O. wiegmanni is adept at tracking environmental temperature by selecting appropriate thermal microhabitats to maintain their body temperature within the optimal level. This study provides a basis and emphasizes the necessity of in-depth thermal ecological studies on Sri Lankan agamids.
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Keywords
Environmental Science, Environmental Engineering, Geochemistry, Ecology, Green Technology