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 impacts 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.

自然界充满噪声，动物已演化出多种多样的通讯策略以适应这一环境。然而，动物的通讯信号往往为多模态（multimodal）信号：其组成部分可被多类感知系统处理，噪声可因此影响不同模态下的信号组分。本研究以通古拉泡蟾（túngara frog, Physalaemus pustulosus）为研究对象，探究环境噪声对其多模态通讯的影响。雄性个体通过结合空气传播的鸣声与鸣声诱发的水面波纹，与同类雄性展开交流。我们设置了对照组与模拟降雨、风力诱发水面振动的噪声组，对雄性个体开展测试。相较于仅单模态（unimodal）鸣声回放刺激，雄性个体对结合鸣声与波纹的多模态回放刺激的响应更为强烈，但该现象仅在无降雨与无风的条件下出现。在有风的条件下，雄性个体对多模态回放刺激的响应会减弱，这表明风力噪声会干扰其对同类竞争者所产生波纹的感知。在降雨条件下，无论信号回放类型如何，雄性个体的响应均会增强，这提示不同类型的噪声源会对动物通讯产生差异化的影响。本研究结果表明，额外感知通道中的噪声可影响多模态信号的感知，进而推动信号演化，但该影响并非总与预期方向一致。