鸣鸣蝉(Oncotympana maculaticollisMotsch)调音肌的功能特性

FUNCTIONAL PROPERTY OF TONING MUSCLE IN Mingming CICADA (Oncotympana maculaticollis Motsch)

本文给出了鸣鸣蝉调音肌(TMc)的结构及其与发声膜(SM)的连接关系,揭示了TMc的调音功能。 TMc的前、后支分别与SM前缘底面的外、内侧连接,有助于牵拉SM,其纵轴与SM的膜面约成120°角。理论上估计,TMc对SM的向下垂直拉力和沿膜面的向前水平拉力可能分别约为总拉力的87％和50％。 TMc具有重要的调音功能。不仅影响每侧SM产生的2个脉冲列(PT)的脉冲幅值,每个PT中第1和2脉冲幅值平均约下降3—10dB;而且影响SM发声过程的均一性。同时,对鸣声谱中第二陪音的峰值频率的幅值有明显的影响,其13600—13900Hz、15015—15100Hz和16756—17090Hz的幅值分别平均下降约5.9、8.4和16.3dB。

In the Mingming cicada, the structure of toning muscle (TMc) and its connection with sounding membrane (SM) are given, and the toning function of TMc is also revealed in this paper.The front and back branch es of TMc are respectively connected with the bottom outside and inside of the anterior plate of SM and it is conducive to pulling SM. An angle between the lon-gitudinal axis of TMc and membrane surface of SM is about 120°. The downward vertical-pulling force to SM and forward horizontal-pulling force along the membrane surface may be about 87% arid 50% of the total pulling force respectively in a theoretical appraisal.The TMc possesses the significant toning function. It has an effect not only on pulse amplitudes of the two pulse trains (PT) produced by SM on each side, i.e. the amplitudes of the first and second pulse in each PT decrease by about 3-10 dB on an average, but also on the uniformity of sounding process in SM. Moreover, it has a s-gnificat effect on amplitudes of peak frequencies o the second upper partial in song spectra, ex. the amplitudes of 16756-17090 Hz decrease by about 16.3 dB on an average.