Visual communication and aggressive behaviour in a giant mute torrent-frog, Megaelosia apuana (Anura; Hylodidae): Supplementary Material

Advertisement call is the most common signal used by anurans for intraspecific communication. However, some species have lost the ability to emit these vocalizations and are denoted as mute. Alternatively, these species may communicate by visual, tactile and chemical signals. The lack of advertisement call could be explained by the high background noise of breeding microhabitats. A model group to study alternative communication tactics is the genus Megaelosia, which is composed by seven mute species that inhabit noisy streams, and for which no information on intraspecific communication is available. We monitored a population of M. apuana and described its visual signalling during aggressive interactions between males. This interaction included visual signalling, physical combat, and the retreat of the smaller individual. No audible sound was detected during the whole aggressive interaction, reinforcing the genus muteness. This is the first report of any communication behaviour for the genus Megaelosia.

招引鸣唱（advertisement call）是无尾两栖类（anurans）种内通讯最常用的信号。部分物种已丧失发出此类鸣唱的能力，被归类为无声物种。这类物种转而可通过视觉、触觉及化学信号完成种内通讯。繁殖微生境的高背景噪音，或可解释这类鸣唱能力缺失的现象。
用于研究替代通讯策略的模式类群为大齿蛙属（Megaelosia），该属包含7种栖息于嘈杂溪流的无声物种，目前尚无该属种内通讯的相关研究资料。
我们对阿普阿纳大齿蛙（Megaelosia apuana，简称M. apuana）的种群开展了监测，并描述了其雄性间争斗行为中的视觉信号展示。此类争斗涵盖视觉信号展示、肢体冲突以及体型较小个体的撤退行为。整个争斗全程未检测到任何可听声响，进一步证实了该属的无声特性。本研究为大齿蛙属通讯行为的首次正式报道。