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Updated: Aug 3, 2026
06:16
Electrophysiological Measurements from a Moth Olfactory System
Published on: March 29, 2011
Hearing and bat defence in geometrid winter moths
J Rydell1, N Skals, A Surlykke
1Department of Zoology, University of Göteborg, Sweden.
Proceedings. Biological Sciences
|January 22, 1997
Summary
Male winter moths possess ultrasonic hearing to detect bats, exhibiting evasive flight maneuvers. This adaptation is crucial for survival, despite reduced bat activity during their flight seasons.
Area of Science:
- Ecology
- Bioacoustics
- Animal Behavior
Background:
- Many insects, including moths, are preyed upon by bats.
- Bat echolocation relies on ultrasonic frequencies for navigation and hunting.
- Understanding insect hearing adaptations provides insight into predator-prey dynamics.
Purpose of the Study:
- To investigate the ultrasonic hearing capabilities of male geometrid winter moths.
- To determine the behavioral responses of these moths to bat-like ultrasonic pulses.
- To explore the role of sexual dimorphism in hearing and its evolutionary implications.
Main Methods:
- Audiograms were used to assess moth hearing sensitivity and best frequencies.
- Behavioral responses to controlled ultrasonic pulses were observed in laboratory and field settings.
- Tympanic organ morphology was examined in relation to hearing ability.
Main Results:
- Male winter moths exhibit broadly tuned ultrasonic hearing (25-40 kHz), matching sympatric bat frequencies.
- Moths reacted to ultrasound with evasive flight patterns (diving, changing course) depending on distance.
- Females, being flightless, have reduced hearing organs and are virtually deaf.
Conclusions:
- Sexual dimorphism in hearing is driven by differential selection pressures from bat predation.
- Moth hearing adaptations are crucial for survival against aerial predators.
- The evolution of hearing in male moths persists despite reduced bat activity in certain seasons.
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