饥饿对捕食者鱼和猎物鱼快速启动游泳能力及捕食-逃逸行为的影响

Effects of food deprivation on fast-start swimming and predator-prey interaction between a predator and prey fish species

快速启动游泳是鱼类的游泳方式之一,与捕食和逃避敌害行为密切相关。为了考察饥饿对捕食者乌鳢(Channa argus)和猎物麦穗鱼(Pseudorasbora parva)快速启动游泳能力的影响及其与捕食-逃逸行为的关联,在水温(25±1)℃条件下,测定不同饥饿程度乌鳢[0、7、14、28、63(饥饿半致死)d]和麦穗鱼[0、7、14(饥饿半致死)d]的快速启动游泳能力并观测二者组成的捕食对的捕食-逃逸行为。结果表明:乌鳢快速启动的最大线速度(Vmax)、120 ms移动距离(S120ms)和最大线加速度(Amax)均显著大于麦穗鱼(P<0.05),而二者的反应时滞(R)无显著差异;两种鱼的各快速启动参数均较保守,仅在半致死组(14 d或63 d)表现出Vmax、S120ms的下降和R的延长(P<0.05),其中捕食者反应时滞的变化更为明显而猎物速度变化更为明显;14 d饥饿导致乌鳢捕食麦穗鱼的追击活动增加和成功捕食历时缩短;由于食物可获得性和觅食方式的差异,猎物鱼快速启动能力对饥饿的响应更为敏感,且二者在对策上存在差异;从捕食-逃逸的结果评判,同等程度的饥饿对捕食者可能更为有利。

Fast-start is one of the important swimming modes, which is closely related to predation and escape behaviors in fish species. The aims of the present study were to compare the effects of food deprivation on fast-start swimming performance between a predator Channa argus and a prey Pseudorasbora parva and the consequent outcome of predatorprey interaction. To achieveour goals, variables related to faststart swimming were measured in C. argus after 0, 7, 14, 28, 63 （semilethal starvation time） days of starvation and P. parvaafter 0, 7, 14 （semilethal starvation time） days of starvation under water temperature of （25±1） ℃. The predationprey interaction course was also documented after 0, 7 and 14 days of starvation. The results showed thatC. argus showed significantly higher maximum linear velocity （Vmax）, moving distance during first 120 ms （S120ms） and maximum linear acceleration （Amax） than P. parva（P〈0.05）, whereas their reaction latency （R） showed no significant difference. All measured variables of fast-start swimming in both fish species were quite conservative as only the semilethal group （14 or 63 days） showed significantly lower Vmax, shorter S120msand slower R （P〈0.05）, with the predator showing relatively profound change in R and the prey showing relatively profound change inVmax. Fourteen days of starvation resulted in more hunting activities of the predator and shorter duration while hunting successfully. The present study suggested that the faststart swimming of the prey was more sensitive to starvation than that of the predator and the two species showed different response strategies possibly due to differences in availability of food resources and foraging modes. In general, starvation with the same degree would be more beneficial to the predator according to the outcome of predatorprey interaction.