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

为了理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。动物交流研究中很大一部分是关于声音信号的，鸟类的歌声是最有用的模型之一。鸟类的鸣叫特别有趣，因为除了自然选择作用于声音的传递之外，它还受到雌性选择和雄性与雄性竞争的性选择的影响。然而，人们常常忘记，鸟鸣是一种多方面的行为，而信号的音量是传播的最重要参数之一，尽管它在编码信息方面可能具有重要作用，但却被忽视了。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曲的频率特性以减少背景噪声的干扰，以及这种适应是否与歌曲学习有关，以及（2）确定歌曲幅度是否是当前和/或过去的信号雄性状况的诚实指标。为了研究如何适应背景噪音，我们将在一个歌曲学习实验中使用大山雀，他们将暴露在不同的噪音配置文件。在信号幅度中编码的信息的主题将在繁殖斑胸草雀的实验中得到解决。该项目的结果将增加我们对环境如何影响性选择信号的演变以及这如何受到个人学习过程的影响的知识。这也将有助于阐明哪些信息可以编码在性选择信号的振幅中。除了对理论的影响外，这项研究还具有应用潜力：许多栖息地受到人为噪音的影响，由于城市化的发展以及当地和全球交通的增加，世界变得越来越嘈杂。因此，了解动物的沟通系统的适应性以及发声动物能在多大程度上科普噪音干扰，对保护工作至关重要。

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.