Data presented in the paper "Non-linear effects of non-host diversity on the removal of free-living infective stages of parasites"

Research objective:Among the ecological functions and services of biodiversity is the potential buffering of diseases through dilution effects where increased biodiversity results in a reduction in disease risk for humans and wildlife hosts. Whether such effects are a universal phenomenon is still under intense debate and diversity effects are little studied in cases when non-host organisms remove free-living parasite stages during their transmission from one host to the next by consumption or physical obstruction. Here, we investigated non-host diversity effects on the removal of cercarial stages of trematodes, ubiquitous parasites in aquatic ecosystems. <br>Type of research, method &amp; collection of data:In laboratory experiments using response surface designs, varying both diversity and density at same time, we compared three combinations of two non-hosts at four density levels: predatory crabs that actively remove cercariae from the water column via their mouth parts and gills, filter feeding oysters that passively filter cercariae from the water column while not becoming infected themselves, and seaweed which physically obstructs cercariae.

研究目标：生物多样性的生态功能与服务中，存在通过稀释效应（dilution effect）实现疾病缓冲的潜力——即生物多样性提升可降低人类与野生宿主的疾病感染风险。目前这类效应是否为普遍现象仍存在激烈学术争议；而当非宿主生物通过摄食或物理阻隔作用，在寄生虫从宿主向其他宿主传播的过程中移除自由生活的寄生虫阶段时，相关多样性效应的研究仍较为匮乏。本研究聚焦水生生态系统中广泛分布的吸虫（trematode）尾蚴（cercaria）阶段的移除过程，探究非宿主多样性对此的影响。<br>研究类型、方法与数据采集：本研究采用响应面设计（response surface design）开展室内受控实验，同步调控物种多样性与种群密度，设置4个密度梯度，对2种非宿主的3种组合方案进行对比：一是通过口器与鳃主动从水体中移除尾蚴的掠食性螃蟹；二是虽不会自身感染寄生虫，但可被动滤除水体中尾蚴的滤食性牡蛎；三是可物理阻隔尾蚴的海藻。