Abstract：
Pathogen spores have been recognized as prey with implications for resource dynamics, energy transfer and disease transmission. In aquatic ecosystems, filter-feeders are able to consume such motile forms of pathogens that can cause severe disease in susceptible hosts. The interactions between European crayfish and the crayfish plague pathogen Aphanomyces astaci are of particular conservation interest. In this study, we aim to evaluate the ecological interactions between Ap. astaci, its host Astacus astacus and individuals of the genus Daphnia, filter-feeding planktonic crustaceans. Our focus was on the consumption of the motile zoospores by Daphnia individuals, but we also considered the potential of Daphnia as non-target hosts. We conducted a series of infection and life-history experiments with Ap. astaci, three Daphnia species (D. magna, D. galeata, and D. pulex) and the noble crayfish As. astacus. We did not observe any lethal effects in the infection experiments involving Ap. astaci and Daphnia. Only D. pulex showed differences in some life-history traits. The feeding experiment using the motile zoospores of Ap. astaci as alternative food source or as supplement to different amounts of algal food revealed their nutritional value: D. magna individuals survived, grew, and reproduced on a zoospore diet alone. When zoospores were supplemented to the regular algal diet, all life-history parameters have been significantly improved. However, this successful consumption of zoospores did not result in a reduced mortality of the susceptible crayfish As. astacus during the infection experiment. Nevertheless, the pathogen load of Ap. astaci in the tissues of As. astacus was significantly reduced as a consequence of the feeding activity of Daphnia. Our results indicate that an abundant filter-feeding community can reduce the amount of infective zoospores in the water body and thus be beneficial to susceptible crayfish hosts, potentially acting as a general buffer against zoospore-transmitted diseases in lentic waters.
摘要：
病原体孢子已被认为是对资源动态有影响的猎物，能量传递和疾病传播。在水生生态系统中，滤食动物能够消耗这种活动形式的病原体，这些病原体可能在易感宿主中引起严重的疾病。欧洲小龙虾与小龙虾鼠疫病原体阿phanomycesastaci之间的相互作用具有特殊的保护意义。在这项研究中,我们的目标是评估Ap之间的生态相互作用。astaci,它的寄主AstacusAstacusAstacus和Daphnia属的个体，滤食浮游甲壳类动物。我们的重点是水蚤个体对活动游动孢子的消耗，但我们也考虑了水蚤作为非目标宿主的潜力。我们用Ap进行了一系列感染和生活史实验。astaci,三种水蚤(D.麦格纳,D.Galeata,和D.pulex）和高贵的小龙虾As。astacus.在涉及Ap的感染实验中，我们没有观察到任何致死作用。astaci和Daphnia.只有D.pulex在某些生活史特征上表现出差异。使用活动的Ap游动孢子进行饲养实验。作为替代食物来源或作为不同量的藻类食物的补充显示了它们的营养价值：D.magna个体存活，长大了，仅靠游动孢子饮食繁殖。当游动孢子补充到常规藻类饮食中时，所有生活史参数都有显著改善.然而,这种对游动孢子的成功消费并未降低易感小龙虾As的死亡率。在感染实验期间的虾。然而，Ap的病原体负荷。As组织中的astaci。由于水蚤的摄食活动，水星鱼显着减少。我们的结果表明，丰富的滤食群落可以减少水体中感染性游动孢子的数量，从而有利于易感小龙虾宿主，潜在的作用是一般的缓冲区，以防止动物园传播的疾病。
