Data from: Social information from immigrants: multiple immigrant based sources of information for dispersal decisions in a ciliate

Dispersal is increasingly recognized as being an informed process, based on information organisms obtain about the landscape. While local conditions are often found to drive dispersal decisions, local context is not always a reliable predictor of conditions in neighbouring patches, making the use of local information potentially useless or even maladaptive. In this case, using social information gathered by immigrants might allow adjusting dispersal decisions without paying the costs of prospecting. However, this hypothesis has been largely neglected despite its major importance for ecological and evolutionary processes. We investigated three fundamental questions about immigrant informed dispersal: do immigrants convey information that influences dispersal, do organisms use multiple cues from immigrants, and is immigrant informed dispersal genotype-dependent? Using Tetrahymena thermophila ciliates in microcosms, we manipulated the number of immigrants arriving, the density of congeners and resource quality in neighbouring patches, matrix characteristics and the level of cooperation of individuals in the neighbouring populations. We provide the first experimental evidence that immigrants convey a number of different cues about neighbouring patches and matrix (patch quality, matrix characteristics, and cooperation in neighbouring populations) in this relatively simple organism. Furthermore, we demonstrate genotype-dependent immigrant-informed dispersal decisions about patch quality and matrix characteristics. Multiple cues from immigrants and genotype-dependent use of cues have major implications for theoretical metapopulation dynamics and the potential for local adaptation.

扩散（dispersal）行为如今愈发被学界认定为一种基于生物体对栖息景观所获取信息的主动决策过程。尽管局域环境常被证实会驱动扩散决策，但局域背景往往无法可靠预测邻域生境斑块（patch）的实际状况，这使得依赖局域信息的策略不仅可能毫无效用，甚至会引发适应不良的后果。在此情形下，借助迁入个体（immigrants）采集到的社会信息，或可在无需付出探索成本的前提下调整扩散决策。然而，尽管该假说对生态学与进化过程具有关键意义，却长期被学界忽视。

本研究围绕迁入介导的主动扩散（immigrant informed dispersal）探讨了三个核心科学问题：迁入个体是否会传递影响扩散行为的信息？生物体是否会利用迁入个体释放的多重信号？迁入介导的主动扩散是否存在基因型依赖性？

本研究以纤毛虫（ciliate）类群的嗜热四膜虫（Tetrahymena thermophila）的微宇宙实验系统（microcosm）为研究对象，设置了以下操纵变量：迁入个体的数量、邻域生境斑块内的同属物种（congener）密度与资源质量、景观基质（matrix）特征，以及邻域种群内个体的合作水平。

本研究首次通过实验证实，在这类结构相对简单的生物体中，迁入个体能够传递关于邻域生境斑块与景观基质的多种信号（涵盖生境斑块质量、景观基质特征以及邻域种群的合作水平）。此外，本研究还证明，生物体针对生境斑块质量与景观基质特征的迁入介导主动扩散决策，确实存在基因型依赖性。

迁入个体释放的多重信号，以及生物体对信号的基因型依赖性利用，对理论集合种群（metapopulation）动态与局部适应（local adaptation）的潜在机制均具有重要启示。