School of Biological and Marine Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK.
Biol Lett. 2023 Jul;19(7):20230224. doi: 10.1098/rsbl.2023.0224. Epub 2023 Jul 26.
Boldness, the way an individual reacts to risk, is a commonly studied personality trait in animals. Consistent among-individual differences in startle response durations (latency to recover from a startling stimulus) are frequently assumed to reflect variation in boldness. An alternative explanation is that these latencies are not directly driven by variation in responses to information on risk, but by underlying differences in dynamic performance capacities. Here we investigate this possibility by analysing relationships between locomotory speed, a measure of whole-body dynamic performance capacity in hermit crabs, and startle response duration, a repeatable latency measure used as an index of boldness. Individuals differed in mean startle response duration, in the consistency of their startle responses, in their reaction norms across repeated observations, and mean startle responses increased with crab mass. However, there were no relationships between startle responses and locomotory speed. This indicates that startle responses do not reflect underlying performance capacities and suggests that they provide insight into differences in how individuals respond to risky situations. Since similar latencies are used as measures of boldness in other animals, we suggest that potential relationships between apparent boldness and performance capacity should be tested.
大胆，即个体对风险的反应方式，是动物中一个常见的研究人格特质。在惊吓反应持续时间（从惊吓刺激中恢复的潜伏期）方面存在个体间的一致性差异，通常被认为反映了大胆程度的变化。另一种解释是，这些潜伏期并不是直接受到对风险信息的反应变化的驱动，而是受到潜在的动态表现能力差异的驱动。在这里，我们通过分析寄居蟹的运动速度（全身动态表现能力的衡量标准）与惊吓反应持续时间（作为大胆指标的可重复潜伏期衡量标准）之间的关系来研究这种可能性。个体在平均惊吓反应持续时间、惊吓反应的一致性、在重复观察中反应规范以及平均惊吓反应方面存在差异，且螃蟹质量越大，平均惊吓反应越高。然而，惊吓反应与运动速度之间没有关系。这表明惊吓反应并不反映潜在的表现能力，这表明它们提供了对个体如何应对危险情况的差异的深入了解。由于在其他动物中也使用类似的潜伏期作为大胆程度的衡量标准，因此我们建议应测试明显的大胆程度和表现能力之间的潜在关系。
