Data from: Bearding the scorpion in his den: desert isopods take risks to validate their 'landscape of fear' assessment

Animals balance the risk of predation against other vital needs by adjusting their spatial behavior to match spatiotemporal variation in predation risk. To map this 'landscape of fear', prey use evolutionary rules of thumbs that are associated with the activity and hunting efficiency of predators. In addition, prey acquire perceptual information about the presence, identity, and state of potential predators and use these cues to focus their acute anti-predatory responses. Our goal was to explore if and how prey also use such perceptual information that decays with time to update their spatiotemporal risk assessment. We placed scorpions in freshly dug burrows and recorded the isopods' spatial activity and their defense behavior upon encountering the burrows straight after settling the scorpions and seven days later. To corroborate our understanding, we also examined the isopods' detailed reactions towards deserted scorpion burrows. The isopods reacted defensively to scorpion burrows during their first encounter. After seven days, proportionally more isopods approached the scorpion burrows on their way out for foraging and fewer isopods encountered it on their way back. No changes in the spatial activity were observed towards deserted burrows. In addition, on the eighth day, more isopods entered the risky area near the scorpion burrows when leaving their own burrow than on the first encounter. The results suggest that isopods used predator cues to readjust the 'landscape of fear'. Yet, rather than avoiding the dangerous areas altogether, the isopods implemented risky inspection behavior, validating whether the danger is actual. Our findings imply that inspection behavior toward predators can be used for future planning of prey spatial activity, offsetting possible 'information decay costs'.

动物可通过调整空间行为以匹配捕食风险的时空变化，从而在捕食风险与其他关键生存需求之间达成权衡。为绘制此类“恐惧景观（landscape of fear）”，猎物会采用与捕食者活动及狩猎效率相关的进化经验法则。此外，猎物可获取潜在捕食者的存在、种类及状态相关的感知信息，并借助这些线索激活其精准的反捕食响应。本研究旨在探究猎物是否以及如何利用此类随时间衰减的感知信息，来更新其时空风险评估。我们将蝎子置入新挖掘的洞穴中，并分别在蝎子安置完成后即刻，以及7天后，记录等足类动物（Isopoda）的空间活动及其遭遇该洞穴时的防御行为。为验证研究结论的可靠性，我们还观测了等足类动物对废弃蝎子洞穴的细致反应。等足类动物在首次遭遇蝎子洞穴时即表现出防御反应。7天后，外出觅食途中接近蝎子洞穴的等足类动物比例更高，而返程途中遭遇该洞穴的个体则更少。针对废弃蝎子洞穴，等足类动物的空间活动未出现任何变化。此外，在第8天，等足类动物离开自身洞穴时进入蝎子洞穴附近危险区域的数量，较首次遭遇时显著更多。研究结果表明，等足类动物可借助捕食者线索重新调整其恐惧景观。但等足类动物并未完全避开危险区域，而是采取了带有风险的探查行为，以验证危险是否真实存在。本研究结果还显示，针对捕食者的探查行为可用于规划猎物后续的空间活动，从而抵消可能产生的“信息衰减成本”。