The role and the nature of the metabolic rate-temperature curves in lizards from different climatic regions : a comparative study between Chalcides ocellatus (desert species) and Lacerta vivipara (cool-temperature species)

Al-Sadoon, Mohamed Khalid (1983) The role and the nature of the metabolic rate-temperature curves in lizards from different climatic regions : a comparative study between Chalcides ocellatus (desert species) and Lacerta vivipara (cool-temperature species). University of Southampton, Doctoral Thesis.

Abstract

The metabolic rate-temperature curves of various lizards species different climatic regions were investigated using a double chamber volumetric closed system. Acute oxygen consumption determinations were made, i.e. the animals were not allowed to acclimate to the test temperature. A series of acute M-T curves were obtained. Same species had a low temperature dependence within their M-T curves. These were near the preferred body temperatures. The metabolic rates of cool-temperate species were higher than that of the wane-temperate and desert species of comparable size. The metabolic rate-temperature curves of Chalcides ocellatus and Lacerta vivipara were investigated with respect to body-weight, thermal acclimation effect, total metabolic scope, winter dormancy, photoperiod, effect of feeding and starvation. The weight-specific resting metabolic rate relationship at different temperatures were established for both species. Juveniles and sub-adults of both species were found to have higher rates of oxygen consumption than adults. Partial compensation to cold was observed in L. vivipara and was associated with an upward translation of the metabolic rate-temperature curve in respect to the wanmr acclimated lizards. However, C. ocellatus showed a response to cold acclimation by decreasing its metabolism only at 1CPC. The aerobic and anaerobic scopes were found to be maximal at or near the preferred body temperature (PBT) of both species. The total metabolic scope of both species was found to be maximal at the PBT. However, anaerobic metabolism contributes more to the total scope compared to that of aerobic metabolism, in contrast to L. vivipara, which relies mainly on aerobic metabolism as a major source for Energy.During winter dormancy both adults and sub-adults of L. vivipara were found to have a lower metabolic rate over the temperature range compared to that of summer season. Rates of oxygen consumption in L. vivipara and C. ocellatus initially increased after feeding and then decreased following several weeks of starvation. The effect of photoperiod on the N-T curve of L. vivipara was studied. In most instances the results ficam this research indicated that the metabolic rate-temperature curves of different lizards species were specifically modified and adjusted to the respective climatic regions. Inspecies examined there was found to be a close relationship between the characteristics of the metabolic rate-temperature curves and the ecology of the lizard species.

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