Meeting Abstract

38.5  Friday, Jan. 4  Implications of python egg brooding behavior on clutch gaseous micro-environment and metabolic rate STAHLSCHMIDT, Z.R.*; DENARDO, D.F.; Arizona State University at Tempe; Arizona State University at Tempe zs@asu.edu

All female pythons exhibit a brooding behavior that involves tightly coiling around a clutch of eggs during an incubation period (more than 80 days in some species). This posture reduces water loss by the porous-shelled eggs but may also reduce embryonic gas exchange (O₂ and CO₂). However, python brooding behavior is a dynamic process that involves both tight coiling and loose coiling postures. Thus, it is possible that python brooding maintains adequate clutch water balance and gas exchange through postural adjustments and, therefore, serves as an adjustable diffusive barrier. We hypothesized that brooding females occasionally open their posture to allow clutch-nest gas exchange. We tested this hypothesis with the Children�s python (Antaresia childreni) and two experimental systems. The first system monitored behavior, brooding unit (e.g., mother and clutch) metabolic rate, and intraclutch oxygen concentration in real-time to correlate female postural adjustments and clutch-nest gas exchange. As A. childreni clutch metabolism increases 5-7 fold during an incubation period and we serially measured throughout incubation, we were also able to ascertain any developmental effects on the clutch gaseous micro-environment. The second system used separate artificially incubated clutches to determine the critical oxygen tension for A. childreni embryos at the same proportional increments of post-oviposition development as the first system. Overall results demonstrated that brooding creates a hypoxic clutch micro-environment that reduces the metabolic rate of A. childreni embryos during development. Also, periodic postural adjustments reduce the degree of intraclutch hypoxia. However, the effectiveness of these behaviors to reduce any longer term, fitness costs associated with hypoxia has not been explored.