Calling males of this species often display limb movements in order to defend against blood-sucking parasites such as frog-biting midges that eavesdrop on their acoustic signal.
Here, we assess whether the physical movements of parasite defense behavior increase the complexity and attractiveness of an acoustic sexual signal in the little torrent frog ( Amolops torrentis). Despite being taxonomically widespread, we often lack insight into how multimodal signals evolve from unimodal signals and in particular what roles unintended eavesdroppers play. These multimodal displays can however also attract unintended receivers, which can be an important driver of signal complexity. Many animals rely on complex signals that target multiple senses to attract mates and repel rivals.
