Predator community and resource use jointly modulate the inducible defense response in body height of crucian carp

Phenotypic plasticity can be expressed as changes in body shape in response to environmental variability. Crucian carp (Carassius carassius), a widespread cyprinid, displays remarkable plasticity in body morphology and increases body depth when exposed to cues from predators, suggesting the triggering of an anti-predator defense mechanism. However, these morphological changes could also be related to resource use and foraging behavior, as an indirect effect of predator presence. In order to determine whether phenotypic plasticity in crucian carp is driven by a direct or indirect response to predation threat, we compared twelve fish communities inhabiting small lakes in southeast Norway grouped by four categories of predation regimes: no predator fish, or brown trout (Salmo trutta), perch (Perca fluviatilis) or pike (Esox lucius) as main piscivores. We predicted the body shape of crucian carp to be associated with the species composition of predator communities, and that the presence of ...

表型可塑性（Phenotypic plasticity）可表现为生物体形随环境变化而发生的改变。鲫（Carassius carassius）作为广泛分布的鲤科鱼类，其体形具有显著的可塑性：当暴露于捕食者的化学信号时，体高会显著增加，提示其触发了反捕食防御机制。然而，这些形态变化也可能与资源利用及觅食行为相关，该关联是捕食者存在所带来的间接效应。为明确鲫的表型可塑性是对捕食威胁的直接响应还是间接响应，我们对挪威东南部小型湖泊中的12个鱼类群落开展了对比分析：这些群落按捕食者类型划分为4类，即无捕食性鱼类、以褐鳟（Salmo trutta）为主要捕食者、以河鲈（Perca fluviatilis）为主要捕食者，或以白斑狗鱼（Esox lucius）为主要捕食者。我们推测，鲫的体形将与捕食者群落的物种组成相关，且捕食者的存在……