Risky ripples allow bats and frogs to eavesdrop on a multisensory sexual display

Animal displays are often perceived by intended and non-intended receivers in more than one sensory system. In addition, cues that are an incidental consequence of signal production can also be perceived by different receivers, even when the receivers employ different sensory systems to perceive them. Here, we show that vocal responses of male túngara frogs (Physalaemus pustulosus) increase two-fold when call-induced water ripples are added to the acoustic component of a rival’s call. Hunting bats (Trachops cirrhosus) can echolocate this signal byproduct and prefer to attack model frogs when ripples are added to the acoustic component of the call. This study illustrates how the perception of a signal byproduct by intended and non-intended receivers through different sensory systems generate both costs and benefits for the signaler.