Waters D A, Jones G
School of Biological Sciences, University of Bristol, UK.
J Exp Biol. 1995 Feb;198(Pt 2):475-89. doi: 10.1242/jeb.198.2.475.
Echolocation call intensity was measured in the laboratory for five species of British insectivorous bats in free flight and in the hand. All species showed similar call intensities of between 80 and 90 dB peSPL (peak equivalent SPL) at 1 m during flight except Plecotus auritus, whose call intensity was between 68 and 77 dB peSPL at 1 m. Calls from stationary bats were about 13 dB less intense than calls during flight. A method is proposed to measure the root mean square (rms) amplitude of echolocation calls and, hence, to calculate the energy flux density of the call. The constant-frequency calls of Rhinolophus hipposideros have energy flux densities approximately ten times higher than those of bats using frequency-modulated calls as a result of their longer durations and lower crest factors. It is argued that the low-intensity calls of P. auritus allow it to approach tympanate moths more closely before triggering their escape response.
在实验室中，对五种英国食虫蝙蝠在自由飞行和抓在手中的情况下的回声定位叫声强度进行了测量。所有物种在飞行时，在距离1米处的叫声强度相似，峰值等效声压级（peSPL）在80至90分贝之间，但毛腿鼠耳蝠除外，其在1米处的叫声强度在68至77分贝peSPL之间。静止蝙蝠发出的叫声强度比飞行时的叫声低约13分贝。本文提出了一种测量回声定位叫声均方根（rms）振幅的方法，从而计算叫声的能量通量密度。由于菊头蝠的恒频叫声持续时间更长且波峰因数更低，其能量通量密度比使用调频叫声的蝙蝠高出约十倍。有人认为，毛腿鼠耳蝠的低强度叫声使其能够在触发鼓膜蛾的逃逸反应之前更接近它们。
