Laboratoire de Morphologie Fonctionnelle et Evolutive, Institut de chimie, Bât, B6c, Université de Liège, B-4000, Liège, Belgium.
Front Zool. 2012 Dec 6;9(1):34. doi: 10.1186/1742-9994-9-34.
Many Ophidiidae are active in dark environments and display complex sonic apparatus morphologies. However, sound recordings are scarce and little is known about acoustic communication in this family. This paper focuses on Ophidion rochei which is known to display an important sexual dimorphism in swimbladder and anterior skeleton. The aims of this study were to compare the sound producing morphology, and the resulting sounds in juveniles, females and males of O. rochei.
Males, females, and juveniles possessed different morphotypes. Females and juveniles contrasted with males because they possessed dramatic differences in morphology of their sonic muscles, swimbladder, supraoccipital crest, and first vertebrae and associated ribs. Further, they lacked the 'rocker bone' typically found in males. Sounds from each morphotype were highly divergent. Males generally produced non harmonic, multiple-pulsed sounds that lasted for several seconds (3.5 ± 1.3 s) with a pulse period of ca. 100 ms. Juvenile and female sounds were recorded for the first time in ophidiids. Female sounds were harmonic, had shorter pulse period (±3.7 ms), and never exceeded a few dozen milliseconds (18 ± 11 ms). Moreover, unlike male sounds, female sounds did not have alternating long and short pulse periods. Juvenile sounds were weaker but appear to be similar to female sounds.
Although it is not possible to distinguish externally male from female in O. rochei, they show a sonic apparatus and sounds that are dramatically different. This difference is likely due to their nocturnal habits that may have favored the evolution of internal secondary sexual characters that help to distinguish males from females and that could facilitate mate choice by females. Moreover, the comparison of different morphotypes in this study shows that these morphological differences result from a peramorphosis that takes place during the development of the gonads.
许多蛇鳝科鱼类在黑暗环境中活动，并具有复杂的发声器官形态。然而，有关该科鱼类的声音记录却很少，对其声学通讯也知之甚少。本文以 Ophidion rochei 为研究对象，该种鱼类的鳔和前骨骼存在显著的两性异形。本研究的目的是比较 O. rochei 幼鱼、雌鱼和雄鱼的发声形态及其产生的声音。
雄鱼、雌鱼和幼鱼具有不同的形态类型。雌鱼和幼鱼与雄鱼形成对比，因为它们在发声肌肉、鳔、上枕骨嵴、第一椎骨和相关肋骨的形态上存在显著差异。此外，它们缺乏雄鱼通常具有的“摇骨”。每个形态类型的声音都有很大的差异。雄鱼通常产生非谐波、多脉冲声音，持续数秒（3.5±1.3 s），脉冲周期约为 100 ms。幼鱼和雌鱼的声音是首次在蛇鳝科鱼类中记录到的。雌鱼的声音是谐波的，脉冲周期更短（±3.7 ms），且从不超过几十毫秒（18±11 ms）。此外，与雄鱼的声音不同，雌鱼的声音没有长短脉冲周期交替出现。幼鱼的声音较弱，但似乎与雌鱼的声音相似。
虽然无法从外部区分 O. rochei 的雌雄，但它们的发声器官和声音存在显著差异。这种差异可能是由于它们的夜行习性，这有利于内部第二性征的进化，有助于区分雌雄，并可能促进雌鱼的择偶。此外，本研究中不同形态类型的比较表明，这些形态差异是在性腺发育过程中发生的变态现象的结果。
