D.N. LAPSHIN "ECHOLOCATION SYSTEM OF NOCTURNAL MOTHS"

CONTENTS

1. Introduction

2. Story of discovery and study of echolocation in nocturnal Lepidoptera

3. Emission of acoustic signals in Noctuidae family
3.1. Properties of acoustic emission
3.1.1. Spectral characteristics of clicks
3.1.2. Directional properties of ultrasonic emission
3.1.3. Correlation of acoustic emission with wingbeats
3.1.4. Dynamics of acoustic emission in laboratory experiments
3.1.5. Natural acoustic activity of noctuid moths
3.2. Mechanisms of click generation and emission
3.2.1. Morphology of wings-thorax coupling areas
3.2.2. Experiments on ultrasonic identification of the mechanism of click generation
3.2.3. Emission of acoustic signals
3.3. Other possible mechanisms of click generation
3.4. Rustles accompanying a flight of a moth
3.5. On evolution of the mechanism of acoustic emission in noctuid moths

4. Noctuoidea auditory system
4.1. Morphological organization of Noctuoidea auditory system
4.1.1. Tympanic organ
4.1.2. Central projections of tympanic receptors
4.1.3. Thoracic auditory interneurons
4.1.4. Interconnections between auditory and motor systems
4.2. Properties of the auditory system as a perceiving part of a sonar
4.3. Frequency-threshold characteristics
4.3.1. Frequency characteristics of noctuid tympanic organ
4.3.2. Audiograms of intact moths
4.3.3. Frequency tuning of the auditory system in ultrasonically active noctuid moths
4.3.4. Electrophysiological correlations of the frequency tuning process
4.3.5. Tuning in a high-frequency ultrasonic range
4.3.6. Features of spectral response in other Noctuoidea families
4.4. Dynamic range of auditory sensilla
4.5. Temporal resolution of tympanic organ
4.5.1. Decay time of tympanic membrane free oscillations
4.5.2. Responses of A1 receptor to paired clicks
4.5.3. Responses of A1 receptor to paired clicks with a descending level
4.5.4. Responses of prothoracic auditory interneurons to paired clicks
4.6. Possible mechanisms of perception of an echo
4.7. Functions of the B-cell
4.7.1. Response of tympanic receptors to the deformation of thoracic sclerites
4.7.2. Activity of the B-cell in arctiids
4.7.3. Response of arctiid tympanic receptors to an artificially generated tymbal click
4.8. Directional sensitivity of moth's ears
4.9. Interneurons of the head ganglia
4.9.1. Auditory responses of subpharyngeal ganglion interneurons
4.9.2. Activity of protocerebral ganglion interneurons
4.10. Influence of the flight noise on the auditory system of a moth

5. Echolocation
5.1. Preliminary estimate of spatial characteristics of the echolocation system
5.1.1. Determining the spatial range
5.1.2. Depth resolution
5.1.3. The accuracy of angular localization of an echo source (Angular resolution)
5.2. Examination of ability of noctuid moths to accept an echo
5.2.1. Background acoustic activity of a noctuid moth
5.2.2. Experimentally induced modulation of emission of echolocation signals
5.2.3. Stimulation of a moth with retransmitted echoes
5.2.4. Measuring of echolocation auditory thresholds
5.2.5. Recovery of auditory sensitivity after emission of a click
5.2.6. Ability of echo perception in different noctuid subfamilies
5.2.7. Responses of noctuid moths to an echo from the real obstacle
5.3. Ability of noctuid moths to orientate in darkness
5.3.1. Orientation of noctuid moths among angled reflection shields (the first series of experiments)
5.3.2. Effect of ultrasonic emission on spatial orientation (the second series of experiments)
5.4. Moth's flight among different obstacles: examination of tracks
5.4.1. Types of moth's manoeuvres
5.4.2. Latency of the turning motor program
5.4.3. Interrelation between coordinates of approaching obstacle and manoeuvres of a moths
5.5. Analysis of the factors which affected the distribution of results in behavioural experiments
5.6. Echolocation within the system of moth's spatial orientation

6. Cooperation of visual and echolocation systems
6.1. Effect of visual information on dynamics of ultrasonic emission
6.2. Latency of moth's motor response to a visual stimulation
6.3 Mechanisms for estimation of cause-effect relation between moth's signals and external stimuli

7. Confrontation between bats and nocturnal Lepidoptera: echolocation strategies
7.1. Detection of sounds emitted by other animals
7.2. Reduction in echolocating signal levels and in overall time of ultrasonic presence in the air
7.3. Shift of frequency spectra of bat's echolocating calls to the hyposensitivity range of the victim's auditory system
7.4. Cautionary acoustic behaviour
7.5. Mimicry
7.6. Jamming acoustic signals
7.7. Imitation of false targets
7.8. Modification of echolocation signals to distort the representation of their source

8. Afterword

References