DISCRIMINATION BETWEEN FLUTTERING AND NON-FLUTTERING MOTHS BY BROWN LONG-EARED BATS, PLECOTUS-AURITUS

The ability of brown long-eared bats to discriminate between fluttering and non-fluttering moths in a flight cage was tested in order to determine the sensory cues used to detect prey movement. Bats chose the fluttering moth in 88 of 95 trials when all potential sensory cues were available. The fluttering moth was chosen in 91 of 106 trials when visual and ultrasonic cues were eliminated. Simultaneous video and tape recordings showed that while hovering close to potential prey, bats were more likely to remain silent than to produce echolocation pulses. The sound produced by fluttering moths contained frequencies in the 600 Hz-23 kHz range. It is suggested that the bats are able to differentiate between motile and non-motile moths by passive listening. © 1993 The Association for the Study of Animal Behaviour.