Meeting Abstract
8.2 Sunday, Jan. 4 Implications of egg-brooding induced hypoxia on the development and quality of offspring in Children’s pythons (Antaresia childreni) STAHLSCHMIDT, ZR*; DENARDO, DF; Arizona State Univ. – Tempe; Arizona State Univ. – Tempe zs@asu.edu
Python egg-brooding typifies parental care in that it consists of multiple behaviors that provide for multiple developmental needs. For example, tightly coiling around the eggs benefits embryonic water balance but females periodically adjust their posture to improve embryonic gas exchange. Regardless of these postural adjustments, egg-brooding creates a hypoxic intra-clutch environment which constrains embryonic metabolism. We further examined the impact(s) of brooding-induced hypoxia to determine 1) any fitness-related costs to offspring, and 2) whether any long-term costs are alleviated by periodic postural adjustments. We artificially incubated clutches of Childrens pythons (Antaresia childreni) at optimal temperature (i.e., 31.5C) and humidity (i.e., near saturation), but modulated oxygen partial pressure (PO2) to create three treatments: normoxic (i.e., 20.3 kPa O2), brooding (i.e., PO2 profile typical of clutch PO2 (PO2clutch) in maternally brooded clutches), and low (i.e., predicted PO2 profile of maternally brooded PO2clutch if females did not make postural adjustments). We made serial morphometric and performance measurements during incubation (X = 47 d), at hatching, and at 14 d post-hatching. From incubation day 35 to 14 d post-hatching, normoxic offspring were larger, faster, and stronger than those incubated in either hypoxic condition demonstrating that brooding-induced hypoxia confers significant fitness-related costs to offspring. Since we detected no differences between the two hypoxic conditions, postural adjustments may not alleviate hypoxia-related costs to embryos. Our results demonstrate that even a parental behavior critical to offspring survival may represent a compromise between competing developmental needs and thus entails obligate costs.
