寄生蝇声源定位机制分析

Analysis on Sound Source Orientation Mechanism of Parasitoid Fly

奥米亚棕蝇尺寸微小,其两耳间距与寄主声音信号的波长极不匹配,却能在极短的时间内利用双耳接收的声音信号对其寄主声源实现精确定位,针对奥米亚棕蝇的惊人定位能力展开研究,分析其定位机制。在奥米亚棕蝇听觉系统力学模型的基础上,建立其数学模型,求解其频域响应,并利用模态分解方法求解两侧鼓膜的时域瞬时响应。通过理论计算和仿真分析了两鼓膜的振动特性,仿真结果表明,奥米亚棕蝇的定位能力要归功于其独特的耦合听觉结构,该结构能放大双耳接收声音信号的强度差和时间差、且随着入射角的变化而变化,从而实现了极短基线的高精度定位。

Though ormia ochracea has very tiny size,and its interaural distance and the wavelength of sound signal are severely unmatched,it can locate its specific host for the parasite（ cricket） in a remarkably short period of time by the sound signals arriving at its two ears. According to the surprising ability of ormia ochracea,its orientation mechanism is studied and analyzed. Based on the mechanical model of ormia ochracea＇s auditory structure,its mathematical model is established,its responses in frequency domain are concluded,and the time transient responses of two eardrums are computed by mode decomposition. The vibrating characteristics of both ends are analyzed by theoretical computing and simulation. The experimental results show that the orientation ability of ormia ochracea owes to its unique coupled auditory structure,which can amplify the interaural intensity difference（ IID） and interaural time difference（ ITD） that change with the incident angle of sound source,so the high-accuracy localization with short baseline can be achieved.