Trajectories of groups of Rana latastei tadpoles

Predation is a strong driver for the evolution of prey behaviour. To properly assess the actual risk of predation, anuran tadpoles mostly rely on water-borne chemical cues, and their ability to evaluate environmental information is even more crucial when potential predators consist of unknown alien species. Behavioural plasticity, that is the capacity to express changes in behaviour in response to different environmental stimuli, is crucial to cope with predation risk. We explored the defensive behaviour of Italian agile frog (Rana latastei) tadpoles when exposed to the chemical cues of two predators’ species, one native (dragonfly larvae) and one alien (red swamp crayfish). Firstly, we observed if a sensible life history trait (i.e. hatching time) might be affected by native predatory cues. Secondly, we recorded a suite of behavioural responses (activity level, lateralization and sinuosity) to each cue. For assessing lateralization and sinuosity, we developed a C++ code for the automat...

捕食是驱动猎物行为演化的关键选择压力。为精准评估实际捕食风险，无尾类蝌蚪（anuran tadpoles）主要依赖水传播化学信号；当潜在捕食者为未知外来物种时，其解析环境信息的能力尤为关键。行为可塑性（behavioural plasticity），即生物针对不同环境刺激表现出行为变化的能力，是应对捕食风险的核心适应性策略。本研究以意大利敏捷蛙（Rana latastei）蝌蚪为对象，探究其在暴露于两种捕食者的化学信号时的防御行为：其中一种为本地捕食者蜻蜓幼虫（dragonfly larvae），另一种为外来捕食者红色沼泽螯虾（red swamp crayfish）。实验分为两个环节：首先，我们观测了关键生活史性状——孵化时间（hatching time）——是否会受到本地捕食者化学信号的影响；其次，我们记录了蝌蚪针对每种信号的一系列行为响应，包括活动水平、偏侧性（lateralization）与弯曲度（sinuosity）。为评估偏侧性与弯曲度，我们开发了一套用于自动化的C++代码