Data from: Anxiety-like behaviour increases safety from fish predation in an amphipod crustacea

Anxiety is an emotional state generally expressed as sustained apprehension of the environment and elevated vigilance. It has been widely reported in vertebrates, and, more recently, in a few invertebrate species. However, its fitness value remains elusive. We investigated anxiety-like behaviour and its consequences in an amphipod crustacean, using electric-shock as an aversive stimuli, and pharmacological assays. Anxiety-like state induced by electric shocks in Gammarus fossarum was expressed through increased sheltering behaviour in absence of predation risk, thereby showing the pervasive nature of such behavioural response. Increasing the number of electric shocks both increased refuge use and delayed behavioural recovery. The behavioural effect of electric shock was mitigated by pre-treatment with LY354740, a metabotropic glutamate receptor group II/III agonist. Importantly, we found that this modulation of decision making under anxiety-like state resulted in an increased survival to predation in microcosm experiments. This study confirms the interest in taking an evolutionary view to the study of anxiety, and calls for further investigation on the costs counterbalancing the survival benefit of an elevated anxiety level evidenced here.焦虑是一种情绪状态，通常表现为对环境的持续性警觉不安与警戒水平提升。该情绪状态已在脊椎动物中被广泛报道，近年来亦在少数无脊椎动物物种中被发现。然而其适应价值仍有待阐明。本研究以端足类甲壳动物为研究对象，采用电击作为厌恶性刺激，结合药理学实验手段，探究了类焦虑行为及其相关后果。研究发现，湖沼钩虾（Gammarus fossarum）经电击诱导产生的类焦虑状态，可通过无捕食风险条件下隐蔽行为的增加得以体现，表明该行为反应具有普遍性。电击次数的增加不仅提升了个体对隐蔽场所的使用频次，还延缓了其行为恢复进程。预先施用代谢型谷氨酸受体II/III型激动剂LY354740，可有效缓解电击所引发的行为效应。值得注意的是，本研究证实，在类焦虑状态下对决策过程的这种调控，可在微宇宙实验中提升被捕食个体的存活率。本研究印证了从进化视角开展焦虑研究的重要意义，并呼吁后续研究进一步探究本研究中所揭示的、与提升焦虑水平带来的生存益处相制衡的相关代价。