Data from: Wind- and rain-induced vibrations impose different selection pressures on multimodal signaling

The world is a noisy place and animals have evolved a myriad of strategies to communicate in it. Animal communication signals are however often multimodal; their components can be processed by multiple sensory systems, and noise can thus affect signal components across different modalities. We studied the effect of environmental noise on multimodal communication in the túngara frog (Physalaemus pustulosus). Males communicate with rivals using airborne sounds combined with call-induced water ripples. We tested males under control, as well as noisy conditions in which we mimicked rain- and wind-induced vibrations on the water surface. Males responded more strongly to a multimodal playback in which sound and ripples were combined compared to a unimodal sound-only playback but only in the absence of rain and wind. Under windy conditions males decreased their response to the multimodal playback suggesting that wind noise interferes with the detection of rival ripples. Under rainy conditions, males increased their response, irrespective of signal playback, suggesting that different noise sources can have different impact on communication. Our findings show that noise in an additional sensory channel can affect multimodal signal perception and thereby drive signal evolution, but not always in the expected direction.

自然界始终存在环境噪声，动物已演化出多种通讯策略以适应这一背景。然而动物的通讯信号往往具有多模态（multimodal）特征，其组成部分可通过多套感官系统进行处理，因此噪声可对不同模态下的信号组分产生影响。
我们以泡蟾（Physalaemus pustulosus）为研究对象，探究环境噪声对其多模态通讯的影响。雄性泡蟾会借助空气传播的鸣声与鸣声诱发的水面水波，与同类雄性竞争者进行通讯。我们在对照组以及模拟降雨与风力诱发水面振动的噪声环境中，对雄性泡蟾进行了测试。
相较于仅播放鸣声的单模态（unimodal）信号回放实验，雄性泡蟾对“鸣声+水波”的多模态信号回放的响应更为强烈，但这一现象仅在无降雨与风力的环境中出现。在有风的噪声环境下，雄性泡蟾对多模态信号回放的响应显著下降，这表明风力噪声会干扰其对竞争者所产生水波的感知。而在降雨的噪声环境下，无论播放何种信号，雄性泡蟾的响应均有所提升，这说明不同来源的噪声对动物通讯的影响存在差异。
本研究结果表明，额外感官通道中的噪声可影响多模态信号的感知过程，进而推动信号演化，但这一影响并不总是符合预期方向。