Echolocation and flight strategies of aerial-feeding bats during natural foraging

Abstract

Aerial-feeding bats actively emit sonar sounds and capture large amounts of airborne insects a night. Microphone-array system allows us to know not only the positions where the bat emits sonar sounds (i.e., 3-D flight path) but how the bats dynamically control the acoustical field of view during searching and approaching target-prey. Here, we show echolocation strategy of bats during natural foraging revealed by the large-scale microphone-array system which covered the horizontal area of approximately 20 m × 20 m. Pipistrellus abramus was found to expand the width of their sonar beams in both horizontal and vertical planes just before the prey-capture. Since the bats emit echolocation pulses at a high rate (i.e., feeding buzz) just before capturing, the capture positions can additionally be measured. Recently, we have investigated the relationship between flight patterns, capture positions, and foraging efficiency of Myotis macrodactylus during natural foraging above the pond. Further investigation from the viewpoint of the optimal foraging would reveal echolocation and flight strategies of the bats to efficiently search and approach prey items. [This research was supported by a Grant-in-Aid for Young Scientists (B) and Scientific Research on Innovative Areas of JSPS, and the JST PRESTO program.]