UTILIZATION OF ENERGY AND NUTRIENTS IN INCUBATING EGGS AND POSTHATCHING YOLK IN A COLUBRID SNAKE, ELAPHE CARINATA

This paper reports data on the mobilization of some yolk and eggshell nutrients and their incorporation into hatchlings and post-hatching yo lk in an oviparous colubrid snake, Elaphe carinata. The incubation tim e at 30 +/- 0.3 degrees C averaged 50.5 days. During incubation, pliab le-shelled E. carinata eggs increased in wet mass. Dried shells from f reshly laid eggs averaged 8.1% of the entire egg dry mass. Freshly lai d eggs had significantly heavier shells than did hatched eggs with the same wet mass at oviposition. Dry mass conversion from egg contents o f the freshly laid egg to hatchling averaged 81.1%. During incubation, approximately 63.7% of non-polar lipids and 72.1% of energy in egg co ntents of the freshly laid egg were transferred to the hatchling, with 36.3% of non-polar lipids and 27.9% of energy used for embryogenesis. Shells from freshly laid eggs had a higher level of calcium but a low er level of magnesium than did shells from hatched eggs. Fully develop ed embryos could obtain all magnesium from yolk but withdrew approxima tely 30.5% of their total calcium requirements from sources other than yolk. A few days after hatching, a decrease in post-hatching yolk dry mass was accompanied by an increase in carcass dry mass. This confirm s that post-hatching yolk could be used to support early growth of hat chlings.