Sound production mechanism in carapid fish: first example with a slow sonic muscle.
Fish sonic swimbladder muscles are the fastest muscles in vertebrates and have fibers with numerous biochemical and structural adaptations for speed. Carapid fishes produce sounds with a complex swimbladder mechanism, including skeletal components and extrinsic sonic muscle fibers with an exceptional helical myofibrillar structure. To study this system we stimulated the sonic muscles, described their insertion and action and generated sounds by slowly pulling the sonic muscles. We find the sonic muscles contract slowly, pulling the anterior bladder and thereby stretching a thin fenestra. Sound is generated when the tension trips a release system that causes the fenestra to snap back to its resting position. The sound frequency does not correspond to the calculated resonant frequency of the bladder, and we hypothesize that it is determined by the snapping fenestra interacting with an overlying bony swimbladder plate. To our knowledge this tension release mechanism is unique in animal sound generation.
Parmentier
Eric
E
Laboratoire de Morphologie Fonctionnelle et Evolutive, Institut de chimie, Université de Liège, B-4000 Liège, Belgium. E.Parmentier@ulg.ac.be
Lagardère
Jean-Paul
JP
Braquegnier
Jean-Baptiste
JB
Vandewalle
Pierre
P
Fine
Michael L
ML
D000400:Air Sacs / Q000502:physiology*; D000819:Animal Communication; D000818:Animals; D005399:Fishes / Q000033:anatomy & histology* / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D013016:Sound