Koprivnikar J, Thieltges D W, Johnson P T J
Department of Chemistry and Biology, Toronto Metropolitan University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3.
Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands.
J Helminthol. 2023 Mar 27;97:e33. doi: 10.1017/S0022149X23000111.
Given their sheer cumulative biomass and ubiquitous presence, parasites are increasingly recognized as essential components of most food webs. Beyond their influence as consumers of host tissue, many parasites also have free-living infectious stages that may be ingested by non-host organisms, with implications for energy and nutrient transfer, as well as for pathogen transmission and infectious disease dynamics. This has been particularly well-documented for the cercaria free-living stage of digenean trematode parasites within the Phylum Platyhelminthes. Here, we aim to synthesize the current state of knowledge regarding cercariae consumption by examining: (a) approaches for studying cercariae consumption; (b) the range of consumers and trematode prey documented thus far; (c) factors influencing the likelihood of cercariae consumption; (d) consequences of cercariae consumption for individual predators (e.g. their viability as a food source); and (e) implications of cercariae consumption for entire communities and ecosystems (e.g. transmission, nutrient cycling and influences on other prey). We detected 121 unique consumer-by-cercaria combinations that spanned 60 species of consumer and 35 trematode species. Meaningful reductions in transmission were seen for 31 of 36 combinations that considered this; however, separate studies with the same cercaria and consumer sometimes showed different results. Along with addressing knowledge gaps and suggesting future research directions, we highlight how the conceptual and empirical approaches discussed here for consumption of cercariae are relevant for the infectious stages of other parasites and pathogens, illustrating the use of cercariae as a model system to help advance our knowledge regarding the general importance of parasite consumption.
鉴于寄生虫庞大的累积生物量及其无处不在的特性，它们日益被视为大多数食物网的重要组成部分。除了作为宿主组织消费者的影响外，许多寄生虫还具有自由生活的感染阶段，这些阶段可能被非宿主生物摄取，这对能量和营养转移以及病原体传播和传染病动态产生影响。对于扁形动物门内复殖吸虫寄生虫的尾蚴自由生活阶段，这一点已有充分记录。在这里，我们旨在通过研究以下方面来综合当前关于尾蚴被摄食情况的知识状态：（a）研究尾蚴被摄食的方法；（b）迄今为止记录的消费者和吸虫猎物的范围；（c）影响尾蚴被摄食可能性的因素；（d）尾蚴被摄食对个体捕食者的后果（例如它们作为食物来源的生存能力）；以及（e）尾蚴被摄食对整个群落和生态系统的影响（例如传播、营养循环以及对其他猎物的影响）。我们检测到121种独特的消费者 - 尾蚴组合，涉及60种消费者和35种吸虫物种。在考虑到这一点的36种组合中，有31种出现了有意义的传播减少；然而，对相同尾蚴和消费者的单独研究有时会显示出不同的结果。在解决知识空白并提出未来研究方向的同时，我们强调这里讨论的关于尾蚴被摄食的概念和实证方法如何与其他寄生虫和病原体的感染阶段相关，说明了将尾蚴用作模型系统以帮助推进我们对寄生虫被摄食普遍重要性的认识。
