Laboratory of Functional and Evolutionary Morphology (Department of Biology, Ecology & Evolution), FOCUS, AFFISH-RC, Institut de Chimie B6c, University of Liège, 4000 Liège, Belgium
Laboratory of Functional and Evolutionary Morphology (Department of Biology, Ecology & Evolution), FOCUS, AFFISH-RC, Institut de Chimie B6c, University of Liège, 4000 Liège, Belgium.
J Exp Biol. 2019 Jun 10;222(Pt 11):jeb196931. doi: 10.1242/jeb.196931.
The /Kwa/ vocalization dominates the soundscape of meadows but the identity of the species emitting this peculiar fish sound remains a mystery. Information from sounds recorded in the wild indicates that the emitting candidates should be abundant, nocturnal and benthic. spp. combine all these characteristics. This study used an interdisciplinary approach to investigate the vocal abilities of spp.; morphological, histological and electrophysiological examinations were interpreted together with visual and acoustic recordings conducted in semi-natural conditions. All observed spp. (, and ) share the same sonic apparatus at the level of the abdominal region. This apparatus, present in both males and females, consists of 3 bilaterally symmetrical muscular bundles, having 3-5 long tendons, which insert on ventral bony apophyses of the vertebral bodies. In all chordophones (stringed instruments), the frequency of the vibration is dependent on the string properties and not on the rate at which the strings are plucked. Similarly, we suggest that each of the 3-5 tendons found in the sonic mechanism of spp. acts as a frequency multiplier of the muscular bundle contractions, where the resonant properties of the tendons determine the peak frequency of the /Kwa/, its frequency spectra and pseudo-harmonic profile. The variability in the length and number of tendons found between and within species could explain the high variability of /Kwa/ acoustic features recorded in the wild. Finally, acoustic and behavioural experiments confirmed that spp. can emit the /Kwa/ sound.
/kwa/ 发声在草地的声音景观中占据主导地位，但发出这种特殊鱼类声音的物种身份仍是个谜。来自野外记录的声音信息表明，发出这种声音的候选物种应该是丰富的、夜间活动的和底栖的。 spp. 结合了所有这些特征。本研究采用跨学科的方法来研究 spp. 的发声能力；形态学、组织学和电生理学检查与在半自然条件下进行的视觉和声学记录一起进行了解释。所有观察到的 spp.（，和）在腹部区域具有相同的发声器官。该器官存在于雄性和雌性中，由 3 个双侧对称的肌肉束组成，每个肌肉束有 3-5 个长肌腱，这些肌腱插入椎体腹侧骨突上。在所有弦乐器（弦乐器）中，振动的频率取决于弦的性质，而不是弦被弹拨的速度。同样，我们建议在 spp. 的发声机制中发现的 3-5 个肌腱中的每一个都充当肌肉束收缩的频率倍增器，其中肌腱的共振特性决定了 /kwa/ 的峰值频率、其频谱和伪谐波轮廓。在物种之间和内部发现的肌腱的长度和数量的可变性可以解释在野外记录到的 /kwa/ 声学特征的高度可变性。最后，声学和行为实验证实 spp. 可以发出 /kwa/ 声音。
