Dynamics of the echolocation beam during prey pursuit in aerial hawking bats
Dynamics of the echolocation beam during prey pursuit in aerial hawking bats
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DOI：
10.1073/pnas.1419943112
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发表时间：
2015-06-30
影响因子：
11.1
通讯作者：
Surlykke, Annemarie
中科院分区：
文献类型：
--
作者：
Jakobsen, Lasse;Olsen, Mads Nedergaard;Surlykke, Annemarie
在猎物和捕食者之间的进化军备竞赛中，措施和对策不断演变，以提高双方的生存率。蝙蝠和飞蛾就是最好的例子。当暴露在强烈的超声波下时，有耳蛾会表现出戏剧性的逃跑行为。 Vespertilionid 和 rhinolophid 蝙蝠在追击的最后阶段会扩大它们的回声定位光束，大概是为了在它们的“声学视野”内躲避飞蛾。在这项研究中，我们研究了动态波束展宽是否是捕捉移动猎物时回声定位的一般特性。我们记录了三种 emballonurid 蝙蝠（Saccopteryx bilineata、Saccopteryx leptura 和 Rhynchonycteris naso）在田间捕捉空中昆虫的情况。研究表明，S. bilineata 和 S. leptura 在整个猎物追踪过程中保持恒定的波束形状，而 R. naso 通过将峰值呼叫频率从搜索期间的 100 kHz 降低到嗡嗡声中的 67 kHz 来拓宽波束。令人惊讶的是，两种蝙蝠在整个追击过程中发出的叫声都具有非常高的能量，比鼻蝠和道本托鼠耳蝠（类似大小的vespertilionid）高出60倍，为它们提供了与vespertilionid一样多甚至更多的周边“视觉”，但对远处物体的感知表明更混乱。因此，波束展宽并不是回声定位系统的基本特性。然而，根据结果，我们假设增加外围检测对于所有空中捕食蝙蝠在猎物追击的最后阶段至关重要，并推测波束展宽是更先进的回声定位的特征。
In the evolutionary arms race between prey and predator, measures and countermeasures continuously evolve to increase survival on both sides. Bats and moths are prime examples. When exposed to intense ultrasound, eared moths perform dramatic escape behaviors. Vespertilionid and rhinolophid bats broaden their echolocation beam in the final stage of pursuit, presumably as a countermeasure to keep evading moths within their "acoustic field of view." In this study, we investigated if dynamic beam broadening is a general property of echolocation when catching moving prey. We recorded three species of emballonurid bats, Saccopteryx bilineata, Saccopteryx leptura, and Rhynchonycteris naso, catching airborne insects in the field. The study shows that S. bilineata and S. leptura maintain a constant beam shape during the entire prey pursuit, whereas R. naso broadens the beam by lowering the peak call frequency from 100 kHz during search and approach to 67 kHz in the buzz. Surprisingly, both Saccopteryx bats emit calls with very high energy throughout the pursuit, up to 60 times more than R. naso and Myotis daubentonii (a similar sized vespertilionid), providing them with as much, or more, peripheral "vision" than the vespertilionids, but ensonifying objects far ahead suggesting more clutter. Thus, beam broadening is not a fundamental property of the echolocation system. However, based on the results, we hypothesize that increased peripheral detection is crucial to all aerial hawking bats in the final stages of prey pursuit and speculate that beam broadening is a feature characterizing more advanced echolocation.