The cercarial emergence patterns of three species of Diplostomum (Diplostomum ‘mergi’, Diplostomum spathaceum and Diplostomum parviventosum) parasitizing freshwater first intermediate host Radix lagotis sampled in Most Lake, Czech Republic, were studied under various experimental conditions, i.e. field, laboratory and incubator, and seasons, i.e. spring, summer and autumn. We discovered unexpected daily periodicity-dependent species-specific emergence patterns among the three Diplostomum spp. depending on experimental conditions. At the same time, the intraspecific variation of D. spathaceum cercarial release in response to seasonal conditions was observed. We found that a complex array of mechanisms can affect Diplostomum species-specific patterns in cercarial emergence, of which behavioural characteristics of fish related to reproduction and feeding processes are considered the most important factors. This might represent a specific adaptive evolutionary mechanism to maximise transmission success while avoiding competition for host resources. Our results contribute to a better understanding of ecological and epidemiological aspects with respect to specific adaptive strategies compartmentalised among species of Diplostomum and consequences for infection risk in fish hosts.

三个品种的尾蚴出现图案Diplostomum（Diplostomum “ mergi ”，Diplostomum spathaceum和Diplostomum parviventosum）淡水寄生第一中间宿主板蓝根兔儿中的大多数湖，捷克共和国，抽查时发现，各种实验条件，即场，实验室和孵化下，研究，和季节，即春季、夏季和秋季。我们在三种Diplostomum spp 中发现了意外的每日周期性依赖性物种特异性出现模式。取决于实验条件。同时，D的种内变异。金盏花观察到响应季节性条件的尾蚴释放。我们发现一系列复杂的机制可以影响尾蚴出现的双鱼物种特异性模式，其中与繁殖和摄食过程相关的鱼类行为特征被认为是最重要的因素。这可能代表了一种特定的自适应进化机制，可以最大限度地提高传输成功率，同时避免对宿主资源的竞争。我们的研究结果有助于更好地了解生态和流行病学方面，这些方面涉及在Diplostomum物种之间划分的特定适应性策略以及鱼类宿主感染风险的后果。