Usage and plasticity of sexually selected signals: the role of background noise individual learning and signal amplitude

为了了解动物如何交流以及它们的信号是如何进化的，我们需要知道它们的信号传达了什么信息，以及塑造它们的选择性力量。很高比例的动物交流研究都是关于声音信号的，鸟鸣是最有用的模型之一。鸟鸣之所以特别有趣，是因为除了自然选择作用于声音传递之外，它还受到雌性选择和雄性竞争的性别选择的影响。然而，人们经常忘记，鸟鸣是一种多方面的行为，传输的最重要参数之一--信号的响度--被忽视了，尽管它可能在编码信息方面发挥重要作用。为了填补我们知识中的这一关键空白，我们建议(1)调查鸟类是否能够调整其歌声的频率特征以减少来自背景噪音的干扰，以及这种适应是否与歌声学习有关，以及(2)确定歌声幅度是否是发出信号的雄鸟当前和/或过去状况的真实指示器。为了研究大山雀是如何适应背景噪音的，我们将在一个歌曲学习实验中使用大山雀，在这个实验中，它们将暴露在不同的噪音中。以信号幅度编码的信息的主题将在繁殖斑马雀的实验中解决。该项目的结果将增加我们对环境如何影响性选择信号的进化以及个人学习过程如何影响这一点的了解。这也将有助于阐明哪些信息可以以性选择信号的幅度进行编码。除了对理论的影响，这项拟议的研究还具有应用潜力：许多栖息地受到人为噪音的影响，由于城市化进程和当地和全球交通的增加，世界变得越来越嘈杂。因此，找出动物的交流系统的适应性以及发声的动物能在多大程度上应对噪音的干扰，对于保护动物来说是非常重要的。

To understand how animals communicate and how their signals evolved, we need to know what information their signals convey and the selective forces that have shaped them. A high proportion of animal communication research has been on vocal signals, with bird song one of the most useful models. Bird song is particularly interesting because, in addition to natural selection acting on sound transmission, it is also subject to sexual selection by female choice and male-male competition. However, it is often forgotten that bird song is a multifaceted behaviour, and one of the most important parameters for transmission, how loud the signal is, has been neglected, although it may have an important role in encoding information. To fill this crucial gap in our knowledge, we propose (1) to investigate whether birds are able to adjust the frequency characteristics of their songs to reduce interference from background noise, and whether such an adaptation is related to song learning, and (2) to determine whether song amplitude is an honest indicator of the current and/or past condition of signalling males. To investigate how adaptation to background noise is achieved, we will use great tits in a song learning experiment in which they will be exposed to different noise profiles. The topic of the information coded in signal amplitude will be addressed in experiments with breeding zebra finches. The results of the project will increase our knowledge of how the environment influences the evolution of sexually selected signals and how this is affected by individual learning processes. It will also help to shed light on which messages can be encoded in the amplitude of a sexually selected signal. In addition to this impact on theory, the proposed research also has applied potential: many habitats are affected by man-made noise and the world is becoming more and more noisy because of progressing urbanisation and increasing local and global traffic. It is therefore of great importance for conservation to find out how adaptable the communication systems of animals are and the extent to which a vocalising animal can cope with interference from noise.