Zhang Wenyi, Niu Cuijuan, Liu Yukun, Storey Kenneth B
1Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875 China.
2State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102 People's Republic of China.
Front Zool. 2019 Feb 13;16:3. doi: 10.1186/s12983-019-0301-5. eCollection 2019.
The relationships among energy metabolic levels, behavioral and other physiological traits help to determine the trade-off of energy allocation between different traits and the evolution of life-history driven by natural selection. However, these relationships may be distinctive in selected animal taxa because of their unique traits. In the present study, the relationships among energy metabolic levels, behavioral defense strategies, and antioxidant capacity were explored in three freshwater turtle species with different shell morphologies, by assessing responses to attack, righting time, shell morphology, whole-organism metabolic rates, tissue metabolic enzyme activities and antioxidant levels.
The Chinese three-keeled pond turtles, , showed a passive defense strategy, relatively larger shells, a higher resting metabolic rate (RMR) and higher antioxidant levels compared to the snapping turtle, or the Chinese soft-shelled turtle, These latter two species both showed an active defense strategy, a higher factorial aerobic scope and better muscle anaerobic metabolic capacity but relatively smaller shells, lower RMR and antioxidant capacity
Our results indicate a negative relationship between RMR and activity levels in behavioral defense strategies along small-big shell continuum among the three turtle species. We also found a positive relationship between antioxidant capacity and energy metabolism but a negative one between antioxidant capacity and activity levels in defense strategies. The present study indicated a role of turtle shell in forming unique relationship between energy metabolic levels and behaviors in freshwater turtle taxa and a possible trade-off between the maintenance of physiological homeostasis and activity levels in energy allocation.
能量代谢水平、行为及其他生理特征之间的关系有助于确定不同特征间能量分配的权衡以及自然选择驱动的生活史进化。然而，由于其独特的特征，这些关系在特定的动物类群中可能有所不同。在本研究中，通过评估对攻击的反应、翻正时间、壳形态、整体代谢率、组织代谢酶活性和抗氧化水平，探讨了三种具有不同壳形态的淡水龟物种的能量代谢水平、行为防御策略和抗氧化能力之间的关系。
中华花龟相较于鳄龟或中华鳖，表现出被动防御策略、相对较大的壳、较高的静息代谢率（RMR）和较高的抗氧化水平。后两个物种均表现出主动防御策略、较高的有氧代谢范围和较好的肌肉无氧代谢能力，但壳相对较小、RMR和抗氧化能力较低。
我们的结果表明，在这三种龟类中，沿着小壳到 大壳的连续体，行为防御策略中的RMR与活动水平之间存在负相关关系。我们还发现抗氧化能力与能量代谢之间存在正相关关系，但在防御策略中抗氧化能力与活动水平之间存在负相关关系。本研究表明龟壳在淡水龟类群中能量代谢水平与行为之间形成独特关系中所起的作用，以及在能量分配中生理稳态维持与活动水平之间可能存在的权衡。
