Journal article
The evolution of the syrinx: An acoustic theory
PLoS biology, Vol.17(2), pp.e2006507-e2006507
02/07/2019
DOI: 10.1371/journal.pbio.2006507
PMCID: PMC6366696
PMID: 30730882
Abstract
The unique avian vocal organ, the syrinx, is located at the caudal end of the trachea. Although a larynx is also present at the opposite end, birds phonate only with the syrinx. Why only birds evolved a novel sound source at this location remains unknown, and hypotheses about its origin are largely untested. Here, we test the hypothesis that the syrinx constitutes a biomechanical advantage for sound production over the larynx with combined theoretical and experimental approaches. We investigated whether the position of a sound source within the respiratory tract affects acoustic features of the vocal output, including fundamental frequency and efficiency of conversion from aerodynamic energy to sound. Theoretical data and measurements in three bird species suggest that sound frequency is influenced by the interaction between sound source and vocal tract. A physical model and a computational simulation also indicate that a sound source in a syringeal position produces sound with greater efficiency. Interestingly, the interactions between sound source and vocal tract differed between species, suggesting that the syringeal sound source is optimized for its position in the respiratory tract. These results provide compelling evidence that strong selective pressures for high vocal efficiency may have been a major driving force in the evolution of the syrinx. The longer trachea of birds compared to other tetrapods made them likely predisposed for the evolution of a syrinx. A long vocal tract downstream from the sound source improves efficiency by facilitating the tuning between fundamental frequency and the first vocal tract resonance.
Details
- Title: Subtitle
- The evolution of the syrinx: An acoustic theory
- Creators
- Tobias Riede - Midwestern UniversityScott L Thomson - Brigham Young UniversityIngo R Titze - University of UtahFranz Goller - University of Münster
- Resource Type
- Journal article
- Publication Details
- PLoS biology, Vol.17(2), pp.e2006507-e2006507
- DOI
- 10.1371/journal.pbio.2006507
- PMID
- 30730882
- PMCID
- PMC6366696
- NLM abbreviation
- PLoS Biol
- ISSN
- 1544-9173
- eISSN
- 1545-7885
- Language
- English
- Date published
- 02/07/2019
- Academic Unit
- School of Music; Communication Sciences and Disorders
- Record Identifier
- 9984719565702771
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