Influence of Incubation Temperature on Characteristics of Dinodon rufozonatum (Reptilia:Colubridae) Hatchlings,With Comments on The Function of Residual Yolk

Influences of incubation temperatures on hatchling characteristics and the function of residual yolk were studied in the colubrid snake,Dinodon rufozonatum,from a population in Zhoushan Islands.Duration of incubation was strongly dependent on incubation temperature,and decreased as temperature increased.The result that hatchlings from eggs incubated at a lower temperature (24℃) had a smaller body dimension (SVL and TL) than did those incubated at higher temperatures (28 and 32℃) was in contrast to that reported for other species of reptiles.Except for the influence on hatchling dimension,over the range from 24 to 32℃,incubation temperature did not affect embryonic use of material and energy and other hatching characteristics such as mass and major components (carcass,residual yolk,fatbodies,lipids and energy) of hatchlings.Incubation temperature did not determine sex of hatchlings.The overall sex ratio of hatchlings was biased towards males.The residual yolk could be used to support carcass growth and maintenance during the first days of a hathclings life.During incubation,approximately 81.4% dry material,70.0% lipids and 79.4% energy in egg contents of the freshly laid egg were transformed to the hatchling.