Data for: Individual differences in song plasticity in response to social stimuli and singing position

Individual animals can react to the changes in their environment by exhibiting behaviours in an individual-specific way leading to individual differences in phenotypic plasticity. However, the effect of multiple environmental factors on multiple traits is rarely tested. Such a complex approach is necessary to assess the generality of plasticity and to understand how among-individual differences in the ability to adapt to changing environments evolve. This study examined whether individuals adjust different song traits to varying environmental conditions in the collared flycatcher (Ficedula albicollis), a passerine with complex song. We also aimed to reveal among-individual differences in behavioural responses by testing whether individual differences in plasticity were repeatable. The presence of general plasticity across traits and/or contexts was also tested. To assess plasticity, we documented 1) short-scale temporal changes in song traits in different social contexts (after exposition to male stimulus, female stimulus or without stimuli), and 2) changes concerning the height from where the bird sang (singing position), used as a proxy of predation risk and acoustic transmission conditions. We found population-level relationships between singing position and both song length and complexity, as well as social context-dependent temporal changes in song length and maximum frequency. We found among-individual differences in plasticity of song length and maximum frequency along both the temporal and positional gradients. These among-individual differences in plasticity were repeatable. Some of the plastic responses correlated across different song traits and environmental gradients. Overall, our results show that the plasticity of bird song 1) depends on the social context, 2) exists along different environmental gradients and 3) there is evidence for trade-offs between the responses of different traits to different environmental variables. Our results highlight the need to consider individual differences and to investigate multiple traits along multiple environmental axes when studying behavioural plasticity.

个体动物可通过展现个体特异性的行为模式，对环境变化作出响应，由此产生表型可塑性（phenotypic plasticity）的个体间差异。然而，目前鲜有研究同时检验多种环境因子对多个性状的影响效应。这类复杂的研究范式，对于评估可塑性的普遍性，以及解析生物适应多变环境的能力所存在的个体差异如何演化，均不可或缺。本研究以鸣唱结构复杂的雀形目鸟类领姬鹟（Ficedula albicollis）为研究对象，旨在探究其个体是否会针对不同环境条件，调整多项鸣唱性状。同时，本研究通过检验可塑性的个体差异是否具有重复性，以揭示行为响应的个体间异质性。此外，本研究还验证了跨性状与跨情境的通用可塑性是否存在。为评估可塑性，我们记录了两类数据：1）不同社会情境下鸣唱性状的短时时间变化（分别为暴露于雄性同种刺激、雌性同种刺激，以及无刺激的对照情境）；2）鸟类鸣唱时所处高度的变化——该高度可作为捕食风险与声学传播条件的替代指标。研究结果显示，鸣唱位置与鸣唱时长、鸣唱复杂度均存在种群水平的关联；同时，鸣唱时长与最大频率还存在社会情境依赖的时间变化模式。我们还观察到，在时间梯度与位置梯度上，鸣唱时长与最大频率的可塑性均存在个体间差异，且这类可塑性的个体差异具有重复性。部分可塑性响应在不同鸣唱性状与环境梯度间存在关联。总体而言，本研究结果表明，鸟类鸣唱的可塑性具备三大特征：1）依赖于社会情境；2）存在于不同环境梯度之中；3）不同性状对不同环境变量的响应间存在权衡关系。本研究结果亦强调，在开展行为可塑性相关研究时，需兼顾个体差异，并沿多环境轴对多性状进行系统性调查。