The origins of acoustic communication in vertebrates

Abstract

Acoustic communication is crucial to humans and many other tetrapods, including birds, frogs, crocodilians, and mammals. However, large-scale patterns in its evolution are largely unstudied. Here, we address several fundamental questions about the origins of acoustic communication in terrestrial vertebrates (tetrapods), using phylogenetic methods. We show that origins of acoustic communication are significantly associated with nocturnal activity. We find that acoustic communication does not increase diversification rates, a surprising result given the many speciation-focused studies of frog calls and bird songs. We also demonstrate that the presence of acoustic communication is strongly conserved over time. Finally, we find that acoustic communication evolved independently in most major tetrapod groups, often with remarkably ancient origins (~100-200 million years ago). Overall, we show that the role of ecology in shaping signal evolution applies to surprisingly deep timescales, whereas the role of signal evolution in diversification may not.

Fig. 1. Summary of the evolution of acoustic communication across tetrapods.

Pie diagrams at select nodes indicate proportional likelihoods of each state, with acoustic communication present (black) or absent (white). The tree includes 1799 species and is based on the Hackett backbone tree within birds. Reconstructions were based on the ARD model (with different rates for gains and losses). Major clades are indicated by colored rings on the outside of the tree; concentric circles (and associated numbers) indicate clade ages in millions of years before present. Images of representative species are from Aijing Li, Jundong Tian, Xiaofei Zhai, Xiaowei Hong, and Yanjun Zhu. Reconstructions for all nodes and using alternative models and trees are shown as Supplementary Data 5–8 (this tree and model correspond to Supplementary Data 8). Source data are provided in Supplementary Data 3.