The dynamic nature of antipredator behavior: prey fish integrate threat-sensitive antipredator responses within background levels of predation risk
The dynamic nature of antipredator behavior: prey fish integrate threat-sensitive antipredator responses within background levels of predation risk
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DOI：
10.1007/s00265-006-0232-y
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发表时间：
2006-11-01
影响因子：
2.3
通讯作者：
Chivers, Douglas P.
中科院分区：
文献类型：
--
作者：
Brown, Grant E.;Rive, Alix C.;Chivers, Douglas P.
被捕食动物经常不得不在反捕食行为的代价和其他与健康相关的活动（如觅食和繁殖）的好处之间进行动态权衡。根据威胁敏感的捕食者回避假说，被捕食动物的反捕食行为的强度应与捕食者构成的直接威胁程度相匹配。此外，捕食风险的长期时间变化（几天到几周）可以塑造反捕食者行为的强度。根据风险分配假说，改变几天的背景风险水平往往足以改变猎物对给定刺激的反应强度。随着背景风险水平的增加，猎物的反应强度降低。在这项研究中，我们测试了对当前感知风险的不同水平的即时威胁敏感反应与过去3天内经历的背景风险的时间变异性之间可能的相互作用。将幼年罪犯稚鱼预先暴露在低频率或高频率的捕食风险中（使用相同的化学警报提示）3天，然后测试对五种浓度（100,50,25,12.5%或蒸馏水对照）之一的反应。根据威胁敏感的捕食者回避假说，我们发现对更集中的警报提示的反应强度更大。此外，根据风险分配假设，我们发现先前暴露于高背景风险水平的慈鲷对每个警报提示浓度的总体强度反应低于暴露于低背景风险水平的慈鲷。值得注意的是，我们发现过去3天的背景风险水平影响了对不同浓度警报提示的反应阈值水平。事实上，在高背景捕食水平的鱼中，引起行为反应的最低刺激浓度比低背景捕食水平的鱼要低。这些结果表明，在形成反捕食者反应的强度方面，直接（当前）风险和背景风险之间存在显著的相互作用。
Prey animals often have to face a dynamic tradeoff between the costs of antipredator behavior and the benefits of other fitness-related activities such as foraging and reproduction. According to the threat-sensitive predator avoidance hypothesis, prey animals should match the intensity of their antipredator behavior to the degree of immediate threat posed by the predator. Moreover, longer-term temporal variability in predation risk (over days to weeks) can shape the intensity of antipredator behavior. According to the risk allocation hypothesis, changing the background level of risk for several days is often enough to change the response intensity of the prey to a given stimulus. As the background level of risk increases, the response intensity of the prey decreases. In this study, we tested for possible interactions between immediate threat-sensitive responses to varying levels of current perceived risk and temporal variability in background risk experienced over the past 3 days. Juvenile convict cichlids were preexposed to either low or high frequencies of predation risk (using conspecific chemical alarm cues) for 3 days and were then tested for a response to one of five concentrations (100, 50, 25, 12.5%, or a distilled water control). According to the threat-sensitive predator avoidance hypothesis, we found greater intensity responses to greater concentrations of alarm cues. Moreover, in accordance with the risk allocation hypothesis, we found that cichlids previously exposed to the high background level of risk exhibited a lower overall intensity response to each alarm cue concentration than those exposed to the low background level of risk. It is interesting to note that we found that the background level of risk over the past 3 days influenced the threshold level of response to varying concentrations of alarm cues. Indeed, the minimum stimulus concentration that evoked a behavioral response was lower for fish exposed to high background levels of predation than those exposed to low background levels of predation. These results illustrate a remarkable interplay between immediate (current) risk and background risk in shaping the intensity of antipredator responses.