Many-lined Sun Skinks(Mabuya multifasciata) Shift Their Thermal Preferences Downwards When Fasted

We maintained adult many-lined sun skinks(Mabuya multifasciata; 12 females and 12 males) collected from Hainan(southern China) in September 2006 in two outdoor enclosures to examine the effect of feeding condition on selected body temperature(Tsel).Skinks shifted their thermal preferences when fasted.Temporal variation in Tsel was not found within each sex feeding condition combination,and neither in fed nor in fasted skinks did the mean values for Tsel differ between sexes.Body temperatures selected by fed skinks fell within the range from 30.2 to 33.9 C,and those selected by fasted skinks within the range from 25.1 to 31.8 C.Body temperatures(31.8 0.3 C) selected by fed skinks were on average 4.0 C higher than those(27.8 0.4 C) selected by fasted skinks.Fasted skinks had no difficulty in attaining higher body temperatures,but they voluntarily shift their thermal preferences downwards to save energy.This finding suggests an adaptive mechanism adopted by many-lined sun skinks to enhance their fitness during the periods when food availability is low.

Thermal preference, thermal tolerance and the thermal dependence of digestive performance in two Phrynocephalus lizards （Agamidae）, with a review of species studied

We reported data on thermal preference, thermal tolerance and the thermal dependence of digestive performance for two Phrynocephalus lizards （P. frontalis and P. versicolor）, and compared data among lizards so far studied worldwide. Mean values for selected body temperature （Tsel） and critical thermal maximum （CTMax） were greater in P versicolor, whereas mean values for critical thermal minimum （CTMin） did not differ between the two species. The two lizards differed in food intake, but not in food passage time, apparent digestive coefficient （ADC） and assimilation efficiency （AE）, across the experimental tem- peratures. Four general conclusions can be drawn from published data. Firstly, thermal preference and thermal tolerance differ among lizards differing in distribution, temporal activity pattern and habitat use. Lizards in thermally more variable regions are better able to tolerate low and high temperatures. Diurnal lizards generally select higher body temperatures than nocturnal lizards, and lizards using habitats with direct sun exposure generally selected higher body temperatures and are better able to tolerate high temperatures. Secondly, CTMax is positively correlated with Tsel. Lizards more likely exposed to extremely high temperatures while active select higher body temperatures than those using shaded habitats. Thirdly, the effects of body temperature on food intake, food passage time, ADC and AE differ among lizards, but it seems to be common among lizards that ADC and AE are less thermally sensitive than food intake and food passage time. Lastly, ADC is dependent on the type of food ingested, with insectivorous lizards digesting food more efficiently than herbivorous lizards