Muscles Serve as a Water Source for Egg Development in Children's Pythons (Antaresia childreni)

Water-balance is a critical but understudied consideration for animals reproducing in dry environments, as females invest a significant amount of water into their offspring. What makes water especially challenging, is that few animals are known to have true water storage, whereas energy as fat storage is well-documented. Recent studies have suggested the possibility that, when drinking water is scarce, animals can catabolize their muscles, thereby extracting cellular water. In this study, the aim was to show this as a potential method used by animals reproducing in dry environments to cope with dehydration and still produce a clutch. Children's pythons (Antaresia childreni) were used to investigate this phenomenon due to the fact that they experience two, distinctive, reproductive phases- vitellogenesis (when protein and energy are mobilized and invested into the yolk) and gravidity (when the major water investment into the egg occurs, as well as egg shelling). Other factors that make them excellent candidates are that they are pure capital breeders (don't eat during the reproductive season) and can withstand periods of water deprivation that far outlast their reproductive gravid phase. Reproductive and non-reproductive females were deprived of water for the duration of gravidity, and their mass decrease, epaxial muscle shrinkage, blood osmolality, total protein, uric acid, triglycerides and ketones were measured at the onset of each reproductive stage; these values were compared to their water-provided counterparts. Water-deprived females experienced greater mass loss, epaxial muscle loss, blood plasma osmolality, and uric acid than water-provided females. These findings suggest that muscle catabolism is used as a method of dealing with water-deprivation during gravidity.