Miller L A
Biologisk Institut, Odense Universitet, Denmark.
J Comp Physiol A. 1991 May;168(5):571-9. doi: 10.1007/BF00215079.
Four big brown bats (Eptesicus fuscus) born and raised in captivity were trained using the Yes/No psychophysical method to report whether a virtual sonar target was at a standard distance or not. At threshold bats were able to detect a minimum range difference of 6 mm (a delta t of 36 microseconds). Following threshold determinations, a click burst 1.8 ms long containing 5 pulses from the ruby tiger moth, Phragmatobia fuliginosa (Arctiidae), was presented randomly after each phantom echo. The sound energy of the click burst was -4 dB relative to that of the phantom echo. Clicks presented for the very first time could startle naive bats to different degrees depending on the individual. The bats' performance deteriorated by as much as 4000% when the click burst started within a window of about 1.5 ms before the phantom echo. Even when one of ten phantom echoes was preceded by a click burst, the range difference discrimination worsened by 200%. Hence, clicks falling within the 1.5 ms time window seem to interfere with the bat's neural timing mechanism. The clicks of arctiid moths appear to serve 3 functions: they can startle naive bats, interfere with range difference determinations, or they can signal the moth's distastefulness, as shown in earlier studies.
对4只在圈养环境中出生并长大的大棕蝠（棕蝠属）进行训练，采用是/否心理物理学方法，让它们报告虚拟声纳目标是否处于标准距离。在阈值水平，蝙蝠能够检测到最小6毫米的距离差异（时间差为36微秒）。在确定阈值后，每次虚拟回声后随机呈现一段1.8毫秒长的脉冲串，其中包含来自红虎蛾（灯蛾科）的5个脉冲。该脉冲串的声能相对于虚拟回声的声能为-4分贝。首次出现的脉冲会使不同个体的未接触过该声音的蝙蝠受到不同程度的惊吓。当脉冲串在虚拟回声前约1.5毫秒的时间窗口内开始时，蝙蝠的表现恶化多达4000%。即使在十个虚拟回声中有一个之前有脉冲串，距离差异辨别能力也会恶化200%。因此，落在1.5毫秒时间窗口内的脉冲似乎会干扰蝙蝠的神经计时机制。灯蛾科蛾子的脉冲似乎有三个作用：它们可以惊吓未接触过该声音的蝙蝠，干扰距离差异测定，或者如早期研究所示，它们可以表明蛾子的难吃性。
