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Echolocation by the barbastelle bat, Barbastella barbastellus
A Denzinger1, B M Siemers, A Schaub
1Lehrstuhl Tierphysiologie, Universität Tübingen, Germany. annette.denzinger@uni-tuebingen.de
Journal of Comparative Physiology. A, Sensory, Neural, and Behavioral Physiology
|December 4, 2001
Summary
Barbastella barbastellus bats use two distinct echolocation signal types for insect detection. These signals, differing in duration, frequency modulation, and amplitude, may offer independent control for emission and localization.
Area of Science:
- Bioacoustics
- Echolocation in bats
- Animal communication
Background:
- Bats use echolocation for navigation and foraging.
- Barbastella barbastellus, a European bat species, exhibits complex echolocation behaviors.
- Understanding bat echolocation signal variations is crucial for ecological studies.
Purpose of the Study:
- To analyze the characteristics of two distinct echolocation signal types used by Barbastella barbastellus.
- To hypothesize the functional significance of these signal types in insect detection and localization.
- To compare the observed signal structures with those of other vespertilionid bats.
Main Methods:
- Recording and acoustic analysis of echolocation signals from Barbastella barbastellus during foraging.
- Characterization of signal parameters including duration, frequency modulation, bandwidth, and amplitude.
- Comparative analysis of signal structures and their potential functions.
Main Results:
- Two signal types, Type-1 and Type-2, were identified with distinct temporal and spectral features.
- Type-2 signals (approx. 6 ms) showed a downward frequency modulation, while Type-1 signals (approx. 2.5 ms) were stereotyped with a short rise time.
- Type-1 signals generally had higher amplitudes than Type-2 signals, potentially due to head movements.
Conclusions:
- The two signal types likely serve complementary roles in insect detection and localization.
- Type-2 signals may share adaptive value with broadband/narrowband signals in other bats, but in a reversed arrangement.
- Type-1 signals are hypothesized to aid in localizing background targets, with localization components distributed across both signal types for independent control.