Tardigrades may be divided into the following feeding groups: herbivores, carnivores and omnivores. However, little is known about their specific feeding preferences. Here, we used a number of laboratory experiments with 18 potential food sources, representing a wide variety of organisms, to test feeding preferences, survival and fecundity of three tardigrade species, representing different feeding modes. We also tested for differences in preferences between juveniles and adults, and differences in survival between two age groups: one that started the experiment as juveniles and the other as adults. In our experiments, Milnesium inceptum is confirmed to be a carnivore, being able to reproduce only on animal prey. We also show that Hypsibius exemplaris is a herbivore, feeding on cyanobacteria, algae and fungi. Paramacrobiotus fairbanksi, on the other hand, is demonstrated to be an omnivore, feeding on cyanobacteria, algae, fungi and animals. In some cases, juveniles preferred different types of food than adults. Reproduction was strongly affected by food type. Finally, we demonstrate that tardigrades may ingest food types that they are not able to digest. Thus, gut content analysis may be misleading as a method of studying tardigrade feeding habits.

中文翻译：

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饮食偏好和饮食对节肢动物生活史特征的影响

缓坡动物可分为以下喂养组：草食动物，食肉动物和杂食动物。但是，关于它们的具体喂养偏好知之甚少。在这里，我们使用了代表18种潜在食物来源的多种实验室实验，这些食物代表了各种各样的生物，以测试代表不同喂养方式的三种tardigrade物种的喂养偏好，存活率和繁殖力。我们还测试了青少年和成年人之间在喜好方面的差异以及两个年龄组之间的生存差异：一个年龄组是少年时开始实验的，另一个是成年人时。在我们的实验中，Milnesium inceptum被确认为是食肉动物，仅能在动物的猎物上繁殖。我们还显示了Hypsibius示例是一种草食动物，以蓝细菌，藻类和真菌为食。另一方面，事实证明，Paramacrobiotus fairbanksi是杂食动物，以蓝细菌，藻类，真菌和动物为食。在某些情况下，与成人相比，青少年更喜欢不同类型的食物。繁殖受到食物类型的强烈影响。最后，我们证明了缓凝剂可能摄入了他们无法消化的食物。因此，肠道内容物分析可能是误导性的研究饮食习惯的方法。