Data from: Sound amplification by means of a horn-like roosting structure in Spix's disc-winged bat

While sound is a signal modality widely used by many animals, it is very susceptible to attenuation, hampering effective long-distance communication. A strategy to minimize sound attenuation that has been historically used by humans is to use acoustic horns; to date, no other animal is known to use a similar structure to increase sound intensity. Here, we describe how the use of a roosting structure that resembles an acoustic horn (the tapered tubes that form when new leaves of plants such as Heliconia or Calathea species start to unfurl) increases sound amplification of the incoming and outgoing social calls used by Spix's disc-winged bat (Thyroptera tricolor) to locate roosts and group members. Our results indicate that incoming calls are significantly amplified as a result of sound waves being increasingly compressed as they move into the narrow end of the leaf. Outgoing calls were faintly amplified, probably as a result of increased sound directionality. Both types of call, however, experienced significant sound distortion, which might explain the patterns of signal recognition previously observed in behavioural experiments. Our study provides the first evidence of the potential role that a roost can play in facilitating acoustic communication in bats.尽管声音是诸多动物广泛采用的一种信号模态，但它极易发生衰减，进而阻碍高效的长距离通讯。人类历史上用于最小化声音衰减的一种策略是使用声学号角（acoustic horn）；截至目前，尚无其他动物被发现会使用类似结构来提升声音强度。本研究阐明了一种类似声学号角的栖息结构——当蝎尾蕉（Heliconia）或竹芋（Calathea）等植物的新叶开始展开时，会形成锥形管——如何提升斯氏盘翼蝠（Thyroptera tricolor）用于定位栖息点与群体成员的传入与传出社交叫声的声放大效果。研究结果显示，传入叫声因声波在进入叶片窄端时不断被压缩而得到显著放大；传出叫声则获得微弱放大，这可能源于声音指向性的提升。不过，两类叫声均出现了显著的声音畸变，这或许可以解释此前行为实验中观测到的信号识别模式。本研究首次证明了栖息点可在蝙蝠的声学通讯中发挥促进作用。