Influence of Thermal and Hydric Environments on Egg Incubation，Hatching Success,and Hatchling Traits in a Lacertid Lizard,Eremias brenchleyi

Influence of thermal and hydric environments on incubation eggs,embryonic use of energy and hatchling traits were studied in the lacertid lizards,Eremias brenchleyi,which were collected in Qianshan,Suzhou,Anhui,Eastern China.The eggs were incubated at temperatures of 27,30,and 33 ℃ on substrates with water potentials of 0 and -220 kPa using a 3×2 factorial design. Laid eggs were collected in one hour.Eggs were weighed at five-days intervals till hatchlings from eggs incubated.Each hatchling was thawed and separated into carcass,residual yolks,and fat bodies after measured and weighed.The components were preserved frozen for later determination of composition.All viable eggs increased in mass throughout the course of incubation due to absorption of water,and both thermal and hydric environments affected water exchanges between eggs and their surroundings.Final eggs incubated in wetter substrates (0 kPa) gained more mass than did eggs in drier substrates (-220 kPa) but at the same temperature;final eggs incubated at 27 and 30 ℃ gained more mass than did eggs at 33 ℃ but at the same substrate water potential.Incubation temperature significantly affected duration of incubation,and which decreased as incubation temperature increased,but substrate moisture and its interaction with temperature did not.Both incubation and substrate moisture did not affected hatching success.Substrate moisture and its interaction with temperature were unaffected almost all hatchling traits examined except residual yolk.However,Incubation temperature profoundly affected embryonic use of nutrients and size，mass,and residual yolk mass of hatchlings.33 ℃ was not a suitable incubation temperature for E.brenchleyi eggs,because eggs incubated at 33 ℃ produced smaller hatchlings that contained larger residual yolks than did eggs incubated at 27 ℃ and 30 ℃.Given that eggs incubated at 27 ℃ and 30 ℃ both produced well-developed hatchlings of which all measured variables were nearly the same,we conclude that 30 ℃ is better than 27 ℃ for incubation of E.brenchleyi eggs because of the shortened duration of incubation at 30 ℃.