Animal Behaviour, Department of Evolutionary Biology and Environmental Science, University of Zurich, Winterthurerstrasse 190, 8051, Zurich, Switzerland.
Behavioural Ecology Research Group, Anglia Ruskin University, East Road, Cambridge, CB1 1PT, UK; Biological Anthropology, Department of Archaeology, University of Cambridge, Fitzwilliam St, Cambridge, CB2 1QH, UK.
Curr Biol. 2019 Aug 5;29(15):R732-R733. doi: 10.1016/j.cub.2019.06.022.
Acoustic allometry consists of looking at how an organism's body size scales with the characteristics of its vocalizations. A typical finding based on this framework is that across mammals body size is reflected in the fundamental frequency (f) of vocalizations, whereby lower f indicates larger body size [1]. This relationship holds owing to the fact that vocal fold length generally scales with body size [2]. Cross-species comparisons allow for the identification of interesting outliers from the body size-f regression [3]. Such cases are of particular relevance as they can provide insight into the selective forces potentially driving deviations from standard allometric principles [2]. In a recent study in Current Biology, Grawunder et al.[4] argue that selective pressure for higher f has led to the evolution of shorter vocal folds in bonobos than in chimpanzees. Thus, they claim, vocal fold length has evolved independently of body size in bonobos for the purposes of signal diminution (i.e., reducing the impression of body size that they advertise through their calls). However, considering both the existing literature and their own data, this conclusion does not appear to be supported for several reasons.
声学度量衡学包括研究生物体的体型大小与其发声特征之间的关系。基于这一框架的一个典型发现是，在哺乳动物中，体型大小反映在发声的基频 (f) 上，较低的 f 表示体型较大[1]。这种关系的产生是因为声带长度通常与体型大小成比例[2]。跨物种比较可以识别出与体型-f 回归[3]不一致的有趣异常值。这种情况特别重要，因为它们可以深入了解潜在的选择压力，这些压力可能导致偏离标准度量衡原理[2]。在《当代生物学》最近的一项研究中，Grawunder 等人[4]认为，较高的 f 的选择压力导致了倭黑猩猩的声带比黑猩猩短。因此，他们声称，为了降低信号（即减少他们通过叫声传达的体型印象），在倭黑猩猩中，声带长度已经独立于体型大小进化。然而，考虑到现有文献和他们自己的数据，由于几个原因，这一结论似乎没有得到支持。
