title: Variation in swim bladder drumming sounds from three doradid catfish species with similar sonic morphologies.
abstract: A variety of teleost fishes produce sounds for communication by vibrating the swim bladder with fast contracting muscles. Doradid catfishes have an elastic spring apparatus (ESA) for sound production. Contractions of the ESA protractor muscle pull the anterior transverse process of the 4th vertebra or Müllerian ramus (MR) to expand the swim bladder and elasticity of the MR returns the swim bladder to the resting state. In this study, we examined the sound characteristics and associated fine structure of the protractor drumming muscles of three doradid species: Acanthodoras cataphractus, Platydoras hancockii and Agamyxis pectinifrons. Despite large variations in size, sounds from all three species had similar mean dominant rates ranging from 91 to 131 Hz and showed frequencies related to muscle contraction speed rather than fish size. Sounds differed among species in terms of waveform shape and their rate of amplitude modulation. In addition, multiple distinguishable sound types were observed from each species: three sound types from A. cataphractus and P. hancockii, and two sound types from A. pectinifrons. Although sounds differed among species, no differences in muscle fiber fine structure were observed at the species level. Drumming muscles from each species bear features associated with fast contractions, including sarcoplasmic cores, thin radial myofibrils, abundant mitochondria and an elaborated sarcoplasmic reticulum. These results indicate that sound differences between doradids are not due to swimbladder size, muscle anatomy, muscle length or Müllerian ramus shape, but instead result from differences in neural activation of sonic muscles.
authors.affiliation: Laboratoire de Morphologie Fonctionnelle et Evolutive, AFFISH-RC, Institut de chimie, Bât. B6c, Université de Liège, Liège B-4000, Belgium kboyle@mnhn.fr.
authors.forename: Kelly S
authors.initials: KS
authors.lastname: Boyle
authors.affiliation: Laboratoire de Morphologie Fonctionnelle et Evolutive, AFFISH-RC, Institut de chimie, Bât. B6c, Université de Liège, Liège B-4000, Belgium.
authors.forename: Ségolène
authors.initials: S
authors.lastname: Riepe
authors.affiliation: Département clinique des animaux de compagnie et des équidés, Imagerie médicale, Faculté de Médecine Vétérinaire, Bât. B41, Université de Liège, Liège B-4000, Belgium.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Bolen
authors.affiliation: Laboratoire de Morphologie Fonctionnelle et Evolutive, AFFISH-RC, Institut de chimie, Bât. B6c, Université de Liège, Liège B-4000, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Parmentier
mesh_terms: D000400:Air Sacs / Q000033:anatomy & histology / Q000502:physiology*; D000819:Animal Communication; D000818:Animals; D002397:Catfishes / Q000033:anatomy & histology / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology; D013016:Sound
keywords: Acanthodoras cataphractus; Agamyxis pectinifrons; Amplitude modulation; Elastic spring apparatus; Platydoras hancockii; Sound production