Freshwater ecosystems worldwide are facing the establishment of non-native species, which, in certain cases, exhibit invasive characteristics. The impacts of invaders on native communities are often detrimental, yet, the number and spread of non-native invasive species is increasing. This is resulting in novel and often unexpected combinations of non-native and native species in natural communities. While the impact of invaders on native species is increasingly well-documented, the interactions of non-native invaders with other non-native invaders are less studied. We assessed the potential of an invasive amphipod, the killer shrimp Dikerogammarus villosus (Sowinsky, 1894), to cope with other established invaders in European waters: North American crayfish of the Astacidae family—represented by signal crayfish Pacifastacus leniusculus (Dana, 1852), and the Cambaridae family—represented by marbled crayfish Procambarus virginalis Lyko, 2017. The main goal of this study was to investigate if killer shrimp, besides their role as prey of crayfish, can significantly influence their stocks by predating upon their eggs, hatchlings and free-moving early juveniles. Our results confirmed that killer shrimp can predate on crayfish eggs and hatchlings even directly from females abdomens where they are incubated and protected. As marbled crayfish have smaller and thinner egg shells as well as smaller juveniles than signal crayfish, they were more predated upon by killer shrimp than were signal crayfish. These results confirmed that the invasive killer shrimp can feed on different developmental stages of larger freshwater crustaceans and possibly other aquatic organisms.

中文翻译：

---

盗窃者，无辜者或猎物的凶手？杀手虾（Dikerogammarus villosus）对小龙虾的潜在影响

全世界的淡水生态系统正面临着非本地物种的建立，在某些情况下，这些物种表现出入侵特征。入侵者对本土社区的影响往往是有害的，但非本土入侵物种的数量和传播正在增加。这导致了自然群落中非本地和本地物种的新颖且通常出乎意料的组合。虽然入侵者对本地物种的影响越来越有据可查，但非本地入侵者与其他非本地入侵者的相互作用研究较少。我们评估了一种侵入性片脚类动物——杀手虾 Dikerogammarus villosus (Sowinsky, 1894) 应对欧洲水域其他入侵者的潜力：北美 Astacidae 科的小龙虾——以信号小龙虾 Pacifastacus leniusculus (Dana, 1852) 为代表，和 Cambaridae 科——以大理石纹小龙虾 Procambarus virginalis Lyko 为代表，2017 年。这项研究的主要目标是调查杀手虾，除了作为小龙虾的猎物之外，是否可以通过捕食它们的卵、幼体和自由来显着影响它们的种群。 - 移动早期的少年。我们的结果证实，杀手虾甚至可以直接从雌性腹部孵化和保护小龙虾卵和幼体，捕食它们。由于大理石纹小龙虾的蛋壳更小更薄，而且幼体比信号小龙虾更小，因此它们比信号小龙虾更容易被杀手虾捕食。这些结果证实，侵入性杀手虾可以以较大的淡水甲壳类动物和可能的其他水生生物的不同发育阶段为食。