66.6 Jan. 7 Implications of brooding python postural changes on embryonic gas exchange and water loss STAHLSCHMIDT, Z.R.**; DENARDO, D.F.; HOFFMAN, T.C.M.; Arizona State University; Arizona State University; Arizona State University firstname.lastname@example.org
Female pythons typically coil tightly around their eggs throughout the incubation period (40-80 days). While this behavior has been shown to provide thermal and hydric benefits to the clutch, it may also restrict embryonic gas exchange. To address this possible trade-off, we hypothesized that brooding female pythons occasionally relax their posture to expose some of the clutch and thus promote embryonic gas exchange at a short-term cost to water conservation. Brooding Children’s python (Antaresia childreni) underwent 24-hour trials during which we continually measured gas exchange and water loss while monitoring changes in brooding posture via an infrared digital camera. Trials were conducted during both early (mean = 16% of post-oviposition development) and late (mean = 73%) periods of incubation to elucidate the effect of embryonic metabolic rate on postural adjustments. After each trial, eggs were separated from the brooding female, and clutch and female gas exchange and water loss were measured independently. Results demonstrated that brooding reduced water loss from the clutch by 99%. Analysis of behavioral data indicates that a slight adjustments in posture, and thus minor exposures of the apex of the clutch, lead to significant bursts of CO2 release, O2 consumption, and H2O loss. Additionally, embryonic gas exchange increased nearly threefold between early and late measurements, while brooded clutch evaporative water loss was maintained at a relatively constant rate. Together, these findings imply that brooding pythons provide an adjustable diffusive barrier that leads to discontinuous gas exchange which minimizes clutch water loss.