Muséum National d'Histoire Naturelle, Département Systématique et Évolution, UMR 7205 CNRS (OSEB), CP 50 (Entomologie), 57 Rue Cuvier, 75231 Paris Cedex 05, France.
J Insect Physiol. 2011 Jun;57(6):694-703. doi: 10.1016/j.jinsphys.2011.02.005. Epub 2011 Feb 18.
Crickets produce stridulated sounds by rubbing their forewings together. The calling song of the cricket species Eneoptera guyanensis Chopard, 1931 alternates two song sections, at low and high dominant frequencies, corresponding to two distinct sections of the stridulatory file. In the present study we address the complex acoustic behavior of E. guyanensis by integrating information on the peculiar morphology of the stridulatory file, the acoustic analysis of its calling song and the forewing movements during sound production. The results show that even if E. guyanensis matches the normal cricket functioning for syllable production, the stridulation involves two different closing movements, corresponding to two types of syllables, allowing the plectrum to hit alternately each differentiated section of the file. Transition syllables combine high and low frequencies and are emitted by a complete forewing closure over the whole file. The double-teeth section of the stridulatory file may be used as a multiplier for the song frequency because of the morphological multiplication due to the double teeth, but also because of an increase of wing velocity when this file section is used. According to available phylogenetic and acoustic data, this complex stridulation may have evolved in a two-step process.
蟋蟀通过摩擦前翅来产生摩擦声。蟋蟀物种 Eneoptera guyanensis Chopard, 1931 的叫声会交替出现两个具有不同主频的叫声段，分别对应于摩擦结构的两个不同区域。在本研究中，我们通过整合关于摩擦结构的特殊形态、叫声的声学分析以及产生声音时的前翅运动的信息，来研究 E. guyanensis 的复杂声学行为。结果表明，即使 E. guyanensis 符合蟋蟀产生音节的正常功能，摩擦过程也涉及两个不同的闭合运动，对应于两种类型的音节，允许弹拨物交替击打摩擦结构的不同区域。过渡音节结合了高频和低频，并且通过整个摩擦结构上的前翅完全闭合来发出。由于双齿引起的形态放大以及当使用该摩擦结构区域时翼速度的增加，摩擦结构的双齿部分可能被用作歌曲频率的倍增器。根据现有的系统发育和声学数据，这种复杂的摩擦可能是通过两步进化过程演化而来的。
