饥饿对中华倒刺鲃幼鱼代谢、个性和集群的影响

在自然界中,环境变化、季节更替和人为因素造成食物资源时空分布的不均一性,导致鱼类经常面临食物资源短缺的环境胁迫,对其能量代谢和行为造成一定影响。为考察食物资源短缺下暖水性鲤科鱼类能量代谢、个性与集群行为的应对策略及其可能的内在关联,选取中华倒刺鲃(Spinibarbus sinensis)幼鱼为实验对象,分别测定饥饿组(2周)和对照组(维持日粮)在处理前后实验鱼的标准代谢率(Standard metabolic rate,SMR)、个性行为(勇敢性、探索性和活跃性)以及实验处理后的集群行为(凝聚力和协调性)。研究发现:(1)饥饿组和对照组实验过程中实验鱼SMR均显著下降,但仅饥饿组实验鱼SMR具有重复性;(2)饥饿导致中华倒刺鲃幼鱼勇敢性、探索性、活跃性均显著增加;(3)饥饿导致群体成员间距离缩短,游泳速度及其同步性上升。研究表明:饥饿后的中华倒刺鲃不仅适应性降低SMR以减少能量消耗,而且呈现出更高的勇敢性、探索性和活跃性以利于获取食物资源;饥饿迫使中华倒刺鲃群体提高凝聚力和协调性,可能有助于提高群体的生存能力。

Effect of starvation on energy metabolism, fish behavior, and schooling behavior of Spinibarbus sinensis

Fishes in natural environments are often affected by food resources as a result of environmental and seasonal changes, and human activities. Feeding is a fundamental physiological function, which provides essential energy for the survival, growth, and reproduction of fishes. We selected juvenile Spinibarbus sinensis (Cyprinidae) to investigate the adaptive responses of energetic metabolism, fish behavior, and shoaling to food shortages and the possible interaction between energetic metabolism and physiology. We first measured the standard metabolic rate (SMR) and fish behavior (including boldness, exploration, and activity) of experimental fish before and after two weeks of treatment (food deprived or fed with maintenance rations). We also measured the schooling behavior (cohesion and coordination) of fish from both starvation and control groups at the end of experiment. The main results of this study are as follows:1) the SMR decreased significantly in both the starvation and control groups, whereas only the SMR of the food deprived group showed repeatability across the experiment; 2) starvation resulted in significant increases in both boldness and exploration; and 3) starvation elicited shorter individual distances among group members, but higher swimming speed and its synchronization. Therefore, the results of the present study suggested that:1) to maintain their energy balance, starved fish exhibited higher boldness and stronger exploration for more feeding opportunities, but decreased their maintenance metabolism for energy saving; and 2) starved fish shoaled with higher cohesion and coordination to improve their survival.