Adaptive frequency shifts of echolocation sounds in Miniopterus fuliginosus according to the frequency-modulated pattern of jamming sounds
Adaptive frequency shifts of echolocation sounds in Miniopterus fuliginosus according to the frequency-modulated pattern of jamming sounds
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DOI：
10.1242/jeb.188565
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发表时间：
2018-12
影响因子：
2.8
通讯作者：
Yosuke Maitani;Kazuma Hase;Kohta I. Kobayasi;S. Hiryu
中科院分区：
文献类型：
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作者：
Yosuke Maitani;Kazuma Hase;Kohta I. Kobayasi;S. Hiryu
摘要：当成群飞行时，回声定位蝙蝠必须将自己的回声与属于其他个体的脉冲和回声分开，以仅提取自身导航所需的信息。先前的研究表明，调频（FM）蝙蝠在声学干扰下会改变下行调频脉冲的终端频率（TF）。然而，目前尚不清楚干扰信号的哪些声学特性会根据声学干扰的程度引起TF偏移。在这项研究中，我们研究了小翅蝠发出的脉冲声学特征的变化，同时向单独飞行的蝙蝠提供不同调频模式的干扰刺激。当蝙蝠对向下 (dExp) 和向上 (uExp) 指数 FM 声音以及恒定频率 (CF) 刺激作出反应时，其 TF 显着改变，变化约 1-2 kHz（dExp：2.1±0.9 kHz；uExp：1.7±0.3 kHz；CF：1.3±0.4 kHz），但对线性 FM 声音则不然。这三种干扰刺激的频谱的共同特征是 TF 频率附近的频谱峰值，这表明蝙蝠会移动 TF 以避免掩盖 TF 频率范围内的干扰声音。这些结果表明，在 TF 频率范围附近的直接频率掩蔽会引起 TF 偏移，同时降低其自身回声定位声音与干扰信号之间的相似性。摘要：Miniopterus fuliginosus 根据干扰声音的频谱模式调整其回声定位声音。
ABSTRACT When flying in a group, echolocating bats have to separate their own echoes from pulses and echoes belonging to other individuals to extract only the information necessary for their own navigation. Previous studies have demonstrated that frequency-modulated (FM) bats change the terminal frequencies (TFs) of downward FM pulses under acoustic interference. However, it is not yet clear which acoustic characteristics of the jamming signals induce the TF shift according to the degree of acoustic interference. In this study, we examined changes in the acoustic characteristics of pulses emitted by Miniopterus fuliginosus while presenting jamming stimuli with different FM patterns to the bat flying alone. Bats significantly altered their TFs when responding to downward (dExp) and upward (uExp) exponential FM sounds as well as to a constant-frequency (CF) stimulus, by approximately 1–2 kHz (dExp: 2.1±0.9 kHz; uExp: 1.7±0.3 kHz; CF: 1.3±0.4 kHz) but not for linear FM sounds. The feature common to the spectra of these three jamming stimuli is a spectrum peak near the TF frequency, demonstrating that the bats shift the TF to avoid masking of jamming sounds on the TF frequency range. These results suggest that direct frequency masking near the TF frequency range induces the TF shift, which simultaneously decreases the similarity between their own echolocation sounds and jamming signals. Summary: Miniopterus fuliginosus adapt their echolocation sounds according to the spectrum pattern of the jamming sounds.