P1.220 Wednesday, Jan. 4 Energy use in terrestrially hibernating hatchling turtles (Chrysemys picta) is extremely sensitive to overwintering temperature MUIR, T.J.*; DISHONG, B.D.; COSTANZO, J.P.; LEE, R.E.; Augustana College; Miami University; Miami University; Miami University firstname.lastname@example.org
Many animals across diverse taxa endure extended bouts of dormancy during which they are aphagic and thus, must rely on endogenous energy stores to survive long-term dormancy and, when food is not immediately available, fuel post-arousal activities. Because temperature directly influences metabolic rate in ectothermic animals, the thermal environment during dormancy may have profound effects on energy use and conservation for dormant ectotherms. To better understand those effects, we quantified energy storage and use by hatchling painted turtles (Chrysemys picta) during a 5-mo simulated hibernation at 4, 10, or 15°C (n=8 for each group). All turtles survived hibernation and those held at 4°C appeared healthy, whereas those held at 10 and 15°C appeared debilitated. Dry yolk mass at the end of hibernation did not vary among groups, but dry carcass and dry liver mass each varied (P<0.05) inversely with hibernation temperature. Likewise, total remaining energy, determined by bomb calorimetry, was inversely related (P<0.05) to hibernation temperature. Rates of oxygen consumption (VO2) measured during hibernation showed an extreme temperature effect with an overall Q10=9.0. Predicted energy use, which was calculated based on our VO2 data, matches well with our calorimetric data suggesting that the large differences in VO2 we measured among groups were sustained throughout hibernation. Low winter temperature enhances energy conservation by hatchling turtles, and the high Q10 implies that even a modest increase in overwintering temperature, which may occur over the next several decades of climate change, could cause a large increase in energy use leaving turtles with less energy reserved to fuel emergence and post-emergence activities.