LOURDAIS, Olivier; DENARDO, Dale F.*; HOFFMAN, Ty C.M.; Arizona State Univeristy; Arizona State University; Arizona State University: Maternal brooding in the Children’s python (Antaresia childreni) promotes egg water balance

Pythonine snakes show extended care of their clutches with maternal egg brooding. While brooding may provide the eggs thermal advantages via insulation and, in some species, shivering thermogenesis, it is also possible that it promotes water conservation in the clutch. In this study we experimentally tested the functional significance of maternal brooding relative to water balance in the Children�s python, Antaresia childreni, a small species that does not shiver during incubation. First, we found that eggs were very sensitive to dehydration when exposed to sub-saturated air. Consistently we found that evaporative water loss (EWL) from the clutch was high. Clutch EWL was positively influenced by clutch mass, reflecting the independent influences of litter size and egg mass on water loss. Mean egg EWL was inversely related to litter size, suggesting the conglomerated clutch behaves as a single unit with a decreasing surface to volume ratio with increasing clutch size. Maternal brooding had a dramatic impact, reducing and possibly eliminating clutch EWL. Indeed, EWL values of brooding females were lower than EWL of females alone. Overall, these results demonstrate that brooding behavior can be an extremely efficient posture, promoting egg water balance in pythons. Interestingly, a preliminary inter-specific comparison suggested that Children�s python eggs are more sensitive to water loss than are the eggs of colubrid snakes.