Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0321, Japan.
J Acoust Soc Am. 2011 Feb;129(2):1081-8. doi: 10.1121/1.3523300.
Using only a microphone array system, echolocation pulses and three-dimensional flight paths in the frequency-modulated bat, Pipistrellus abramus, during natural foraging, were simultaneously examined. During the search phase, the inter-pulse interval, pulse duration, and moving distance of the bat between successive emissions were relatively constant at around 89.5 ± 18.7 ms, 6.90 ± 1.31 ms, and 0.50 ± 0.20 m, respectively. The bats started to decrease these acoustical parameters within 2-3 m of the prey capture point. For every emission along a flight path, the distance between a bat and its prey capture point was calculated as both direct distance to capture (DDC), which corresponded to the target distance, and flight distance to capture (FDC) along the flight path. The DDC matched the FDC after the start of the approach phase, indicating that foraging bats followed a straight-ahead path to the target. In addition, the duration of the quasi-constant frequency component of emitted pulses was slightly extended just before the convergence of the DDC with the FDC. These findings suggest that the bats confirm the presence of target prey by extending the duration of the pulse and then select a straight-ahead approach by forecasting the movement of the prey.
仅使用麦克风阵列系统，同时检查了在自然觅食过程中调频蝙蝠（Pipistrellus abramus）中的声呐脉冲和三维飞行路径。在搜索阶段，蝙蝠在连续发射之间的脉冲间隔、脉冲持续时间和移动距离相对稳定，分别约为 89.5 ± 18.7 ms、6.90 ± 1.31 ms 和 0.50 ± 0.20 m。蝙蝠在距离猎物捕获点 2-3 米的范围内开始减少这些声学参数。对于飞行路径上的每一次发射，蝙蝠与其猎物捕获点之间的距离被计算为直接捕获距离（DDC），它对应于目标距离，以及沿着飞行路径的飞行捕获距离（FDC）。在接近阶段开始后，DDC 与 FDC 匹配，这表明觅食蝙蝠沿着直线飞向目标。此外，在 DDC 与 FDC 收敛之前，发出的脉冲的准恒定频率分量的持续时间略有延长。这些发现表明，蝙蝠通过延长脉冲的持续时间来确认目标猎物的存在，然后通过预测猎物的运动来选择直线前进的方法。
