ABSTRACT

Vocal communication is fundamental to the fabric of social life. Animals produce a wide variety of sounds to mediate critical interactions, including advertisement to potential mates and competitors. But why and how do distinct species sound different and what factors contribute to such differences? The widespread importance of acoustic signals in mate recognition and speciation requires a deeper understanding of the causes and consequences of signal divergence. In this project, the physiological mechanisms underlying sound production across an ecologically diverse group of vocal rodents will be studied. The researchers will test the hypothesis that changes in sound production mechanisms are mediated by variation in social organization and spacing. These studies promise to provide important insights into the evolutionary interplay between the physiology of senders, receivers, and their socio-spatial ecologies. The proposal provides training opportunities for a postdoctoral scholar, research technician, and student participants who are underrepresented in science, technology, engineering, and mathematical sciences. In addition, the work develops inquiry-based learning modules that equip middle school classrooms with animals, microphones, and sound analysis software to foster critical thinking skills. The research will be supplemented with outreach at regional events and virtual live streaming of experiments in an indoor animal-tracking arena to allow the public to engage in scientific discovery. Digital audio, video, and morphological specimens will be permanently archived for open access in public repositories.

A central challenge in the study of behavior is connecting functional and mechanistic explanations for the evolution of complex phenotypes. Advertisement vocalizations used in reproductive contexts are among the most diverse and elaborate displays in the animal kingdom, yet understanding of the physiological mechanisms driving acoustic divergence is lacking. The goal of the proposed research is to integrate functional and mechanistic perspectives in senders, receivers, and the environment to understand the evolution of acoustic signals in relation to variation in social organization. Rodents represent over 40% of mammalian diversity and exhibit extreme variation in social structure and space use, even among closely related species. Investigators will leverage the exceptional divergence in social organization and acoustic behavior found in one clade to dissect the sound production mechanisms underlying signal diversification. The work integrates approaches from the field, laboratory, and mesocosm, including high-resolution acoustic recordings and laryngeal morphometrics, auditory electrophysiology, sound propagation experiments, and animal tracking studies to evaluate the socio-spatial context of vocal production. The findings will provide a rich dataset to investigate the evolution of communication systems in relation to variation in social organization, with broad implications for other taxa across all signaling modalities.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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