Wind- and Rain-Induced Vibrations Impose Different Selection Pressures on Multimodal Signaling

Area of Science:

• Animal behavior
• Bioacoustics
• Sensory ecology

Background:

• Animals communicate using multimodal signals processed by multiple sensory systems.
• Environmental noise can interfere with signal components across different sensory modalities.
• The túngara frog (Physalaemus pustulosus) uses both airborne sounds and water ripples for communication.

Purpose of the Study:

• To investigate the impact of environmental noise on multimodal communication in túngara frogs.
• To determine how rain and wind noise affect the perception of combined auditory and visual signals.
• To understand the consequences of noise on signal evolution.

Main Methods:

• Túngara frogs were exposed to multimodal (sound and water ripples) and unimodal (sound only) playbacks.
• Experiments were conducted under control (no added noise) and noisy conditions (simulated rain and wind).
• Male frog responses to playbacks were measured under different noise conditions.

Main Results:

• Males responded more strongly to multimodal signals than sound-only signals in the absence of noise.
• Wind noise reduced male responses to multimodal signals, indicating interference with ripple detection.
• Rain noise increased male responses regardless of signal type, suggesting complex noise impacts.

Conclusions:

• Environmental noise, particularly in an additional sensory channel, can significantly affect multimodal signal perception.
• Noise impacts on communication are not always predictable and can vary depending on the noise source.
• These findings highlight how noise can drive the evolution of animal communication signals.