孵化水热环境对渔异色蛇孵化卵和孵出幼体的影响

渔异色蛇卵孵化时能从环境中吸收水分导致质量增加，卵质量的增加与初始卵质量和孵化基质湿度有关。较大幅度的孵化基质湿度变化对孵化期、孵化成功率、胚胎动用孵内物质和能量、孵出幼体的性比、大小和质量无显著影响。孵化期随温度升高而缩短，并显示极强的窝间差异。温度对孵出幼体的性别无影响，但显著影响孵化成功率、胚胎对卵内物质和能量的动用、幼体的大小和质量、躯干和剩余卵黄的质量。孵出幼体总长的两性差异不显著，但雌体体长大于雄体而尾长小于雄体。３２℃不适于孵化渔异色蛇卵，该温度下孵出的幼体躯干发育不良，剩余孵黄较多，尾部均呈畸形，孵化过程中能量转化率较低。２４℃和２６℃中孵出的幼体躯干发育良好，孵化过程中能量转化率较高，各项被测定的幼体特征指标均极相似。

INFLUENCES OF THERMAL AND HYDRIC ENVIRONMENTS ON INCUBATING EGGS AND RESULTANT HATCHLINGS IN A COLUBRID SNAKE (XENOCHROPHIS PISCATOR)

Influence of thermal and hydric environments on incubating eggs, embryonic use of energy and hatchling characteristics were studied in a colubrid snake, Xenochrophis piscator. All viable eggs increased in mass over the course of incubation because these eggs absorbed water from surroundings, and mass gain during incubation was dependent on initial egg mass and substrate water potential. Duration of incubation, hatching success, embryonic use of nutrients and energy and sex ratio, size and mass of hatchlings were unaffected over a wide range of substrate moisture. Duration of incubation decreased as incubation temperature increased. There was a strong family effect on incubation length. Incubation temperature did not determine sex of hatchlings, but profoundly affected hatching success, embryonic use of nutrients and energy, size and mass of hatchlings, carcass mass and post-hatching yolk mass. There was no significant difference in total length (SVL plus TL) between female and male hatchlings, but the newborns did exhibit sexual dimorphism in snout-vent length and tail length, with females having longer SVL and shorter TL than did males. 32℃ was not a suitable temperature for incubating X. piscator eggs for two reasons: (1) eggs at 32℃ produced hatchlings with less developed carcass, greater amount of unutilized yolk and abnormal tail; (2) embryos expended more energy at 32℃ than at lower temperatures to complete development. Given that eggs at 24℃ and 26℃ both produced well-developed hatchlings of which the measured variables were nearly the same for the newborns from the two temperatures, we conclude that 26℃ is the best incubation temperature for X. piscator in this study.