PDF(Pubmed)
Abstract：
Marine planktonic predator-prey interactions occur in microscale seascapes, where diffusing chemicals may act either as chemotactic cues that enhance or arrest predation, or as elemental resources that are complementary to prey ingestion. The phytoplankton osmolyte dimethylsulfoniopropionate (DMSP) and its degradation products dimethylsulfide (DMS) and acrylate are pervasive compounds with high chemotactic potential, but there is a longstanding controversy over whether they act as grazing enhancers or deterrents. Here, we investigated the chemotactic responses of three herbivorous dinoflagellates to point-sourced, microscale gradients of dissolved DMSP, DMS, and acrylate. We found no evidence for acrylate being a chemotactic repellent and observed a weak attractor role of DMS. DMSP behaved as a strong chemoattractor whose potential for grazing facilitation through effects on swimming patterns and aggregation depends on the grazer\'s feeding mode and ability to incorporate DMSP. Our study reveals that predation models will fail to predict grazing impacts unless they incorporate chemotaxis-driven searching and finding of prey.
摘要：
海洋浮游捕食者-猎物的相互作用发生在微尺度的海景中，扩散的化学物质可以作为增强或阻止捕食的趋化线索，或者作为补充猎物摄取的基本资源。浮游植物渗透物二甲基磺丙酸酯（DMSP）及其降解产物二甲基硫醚（DMS）和丙烯酸酯是普遍存在的具有高趋化潜力的化合物，但是，关于它们是否充当放牧增强剂或威慑剂的争议由来已久。这里,我们研究了三种草食性鞭毛藻对点源的趋化反应，溶解的DMSP的微观梯度，DMS,和丙烯酸酯。我们没有发现丙烯酸酯是趋化性驱避剂的证据，并且观察到DMS的吸引子作用较弱。DMSP表现为一种强大的化学引诱物，其通过影响游泳方式和聚集而促进放牧的潜力取决于放牧者的摄食方式和掺入DMSP的能力。我们的研究表明，除非捕食模型纳入趋化性驱动的搜索和猎物的发现，否则捕食模型将无法预测放牧的影响。
