Effects Of Reproductive Status And Body Posture On Thermoregulation In Scaly Reptiles

Since temperature affects many life activities,maintaining a stable body temperature range in the ambient temperature is often critical for reptiles that are ectotherms.To this end,Squamates that accounted for more than 90%of reptiles are used as experimental subjects.Reproductive status(gender,and pregnancy or not)and body posture are chosen as variables to explore their effect on the body temperature of reptiles.Leiolepis reevesii and Phrynocephalus vlangalii,two species of Agamidae,were selected as experimentai materials.The body temperatures of the two species were measured by radio telemetry.The effect on thermoregulation of gender and pregnancy status were studied.The results showed that during the daytime,in L.reevesii,the body temperatures of the pregnant females were significantly lower than the air temperature and that of non-pregnant females and males.The body temperatures of non-pregnant females and males were similar to the air temperature,but there were still some difference.In P.vlangalii,the body temperatures of the pregnant females is higher than that of non-pregnant females and male individuals.The body temperatures of nonpregnant females and males are relatively close,and all these are significantly higher than the air temperature.The probable reason is that for L.reevesii,the optimum temperature for embryonic development is much lower than the air temperature,so the pregnant females must regulate their body temperatures much lower than the air temperature;non-pregnant females and males have the demand for food and courtship.They require higher body temperatures,so they compliant to the air temperature.For P.vlangalii,embryonic development requires much higher temperature than the air temperature,so pregnant females adopt positive thermoregulation behaviors,which make their body temperatures much higher than the air temperature;other adult individuals may not do this because of high costs.Elaphe carinata and Naja atra,two species of Serpentes,were selected as experimental materials to research the effect of body posture on thermoregulation.The results showed that both species of snakes were good at regulating their body temperatures in a curled position.In the straightened position,their ability of thermoregulation is very poor.This is because the straight snake exposes more body surface than the curled snake.N.atra have better thermoregulation capacity than E.carinata.This may because of the fact that N.atra has a smaller surface area than E.carinata,and it may also be related to the difference in behavior between the two species.