We initiated the use of a replicated, remote-video, artificial stream system to determine the effects of conspecific cue, refuge availability, and day/night conditions on movement, aggression, dominance, downstream preference, and refuge use by the crayfish Procambarus clarkii. In line with previous research, we found that walking on the gravel substrate was greatly increased and refuge use decreased in the dark. Conspecific cue (macerated crayfish filtrate) increased walking, contrary to our prediction but consistent with cue as a signal of food availability or of risk either from cannibalism or from visual predators. Exposure to conspecific cue in the streams resulted in a reduced degree of dominance in subsequent pairwise dominance trials. We developed and implemented a new and broadly applicable way of determining the extent of linearity (consistency of dominance ranks) for incomplete dominance; for our data, this method found a lack of evidence for linear hierarchies in these stream systems. Our results suggest that streams may tend to feature weaker dominance and reduced linearity of social hierarchies, relative to standing-water systems, a hypothesis that requires further testing.

中文翻译：

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在实验性溪流中社交：接触线索、避难所和昼夜条件的小龙虾群体

我们开始使用复制的远程视频人工流系统来确定同种线索、避难所可用性和昼/夜条件对小龙虾 Procambarus clarkii 的运动、侵略、优势、下游偏好和避难所使用的影响。与之前的研究一致，我们发现在砾石基质上行走大大增加，而在黑暗中避难所的使用减少。同种线索（浸渍小龙虾滤液）增加了步行，与我们的预测相反，但与作为食物供应或来自同类相食或视觉捕食者的风险信号的线索一致。暴露于流中的同种线索导致随后成对优势试验中的优势程度降低。我们开发并实施了一种新的、广泛适用的方法来确定不完全优势的线性程度（优势等级的一致性）；对于我们的数据，该方法发现在这些流系统中缺乏线性层次结构的证据。我们的结果表明，相对于静水系统，河流可能倾向于具有较弱的优势和较低的社会等级线性，这一假设需要进一步检验。