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Acoustic mirror effect increases prey detection distance in trawling bats
Björn M Siemers1, Eric Baur, Hans-Ulrich Schnitzler
1Animal Physiology, Zoological Institute, Tübingen University, Auf der Morgenstelle 28, 72076, Tübingen, Germany. bjoern.siemers@uni-tuebingen.de
Die Naturwissenschaften
|May 5, 2005
Summary
Bats can detect prey on water surfaces from farther away than in mid-air. This enhanced detection, due to the acoustic mirror effect, improves foraging efficiency for echolocating bats.
Area of Science:
- Echolocation
- Bioacoustics
- Animal Behaviour
Background:
- Bats frequently hunt insects above water using 'trawling behaviour'.
- Smooth water surfaces act as acoustic mirrors, enhancing prey detection by echolocation.
- Previous studies indicated higher echo amplitudes for targets on smooth surfaces.
Purpose of the Study:
- To test if bats can detect prey at greater distances on smooth water surfaces compared to airborne prey.
- To investigate the role of the acoustic mirror effect in bat foraging efficiency.
Main Methods:
- Behavioral experiments were conducted with three pond bats (Myotis dasycneme).
- Prey detection was identified by changes in echolocation behavior.
- Detection distances were measured in 3D using infrared video and stereo-photogrammetry.
Main Results:
- Bats demonstrated significantly increased prey detection distances for targets on smooth water surfaces.
- The observed increase in detection distance supports the acoustic mirror effect hypothesis.
Conclusions:
- The acoustic mirror effect enhances bat search efficiency when foraging above water.
- These acoustic advantages may have driven the convergent evolution of trawling behavior in bats.