Only a fraction of the species that are introduced succeed in the non-native environment, while others fail to survive, reproduce and/or disperse. Understanding the causes underlying each outcome is key to designing better early detection, prevention and management programs, and to deepen our knowledge of the invasion process. Here, we examine whether predator–prey interactions favor the invasion of a potentially neurotoxic mollusk in the South Western Atlantic (SWA). The grey side-gilled sea slug Pleurobranchaea maculata was recently detected in the SWA, where it has spread rapidly along the coast. In this work, we examine two hypotheses that may have driven the invasion success of P. maculata: (1) it has a high dietary plasticity, able to exploit resources in a variety of habitats within the invaded range and simultaneously (2) it lacks native predators that can control its abundance or spread. First, we identified the prey sources of P. maculata through experimental trials; then we compared its diet composition between different sites and seasons; and finally we experimentally assessed the effect of native potential predators. We found that diet composition is broad and varies in time and space, probably in relation to prey availability. Additionally, we observed that local predators do not recognize P. maculata as a prey. Probably, mechanisms underlying predator avoidance are related to the presence of chemical defenses that can be novel in the invaded environment. We propose that predator–prey interactions are key drivers favoring the establishment of non-native P. maculata via high levels of plasticity to exploit resources, the absence of biotic resistance and the increased availability of food associated with artificial substrates such as ports are probable mechanisms underlying the invasion success of this marine gastropod.

引入的物种中只有一小部分在非本地环境中成功，而其他物种则无法生存，繁殖和/或扩散。了解每个结果的根本原因对于设计更好的早期发现，预防和管理程序以及加深我们对入侵过程的了解至关重要。在这里，我们检查了捕食者与猎物之间的相互作用是否有利于入侵西南大西洋地区（SWA）的潜在神经毒性软体动物。最近在SWA中发现了灰色的侧面镀金海参Pleurobranchaea maculata，并在沿海迅速扩散。在这项工作中，我们研究了两个可能推动斑节对虾入侵成功的假说。：（1）它具有高的饮食可塑性，能够在入侵范围内的各种生境中开发资源，同时（2）它缺乏可以控制其丰度或传播能力的天敌。首先，我们确定的猎物来源P.斑通过实验等; 然后我们比较了不同地点和季节的饮食结构。最后，我们通过实验评估了潜在潜在掠食者的影响。我们发现饮食结构很广泛，并且在时间和空间上可能变化，这可能与猎物的可获得性有关。此外，我们观察到本地捕食者不识别斑节对虾作为猎物。避免捕食者的机制可能与入侵环境中化学防御的存在有关。我们认为，捕食者与猎物之间的相互作用是通过高水平的可塑性来利用资源，无生物抗性以及与人工底物（如港口）相关的食物供应量增加等因素，有利于建立非本地黄斑假单胞菌的主要驱动力。暗示了这种海洋腹足动物的入侵成功。