The Auditory Behaviour of Flying Locusts

1989 ◽  
Vol 147 (1) ◽  
pp. 279-301 ◽  
Author(s):  
DANIEL ROBERT
Keyword(s):  
Avoidance Response ◽  
Locusta Migratoria ◽  
Biological Significance ◽  
Sound Field ◽  
Warning System ◽  
Frequency Component ◽  
Avoidance Behaviour ◽  
Directional Hearing ◽  
Wingbeat Frequency ◽  
Auditory Physiology

The auditory behaviour of tethered locusts flying in a wind tunnel was investigated under controlled acoustic conditions. 1. Reflection, attenuation and diffraction of ultrasound evoked by the locust's physical presence caused pronounced distortions of the acoustic field. Interaural pressure variations were observed that account for directional hearing at high frequencies. 2. Sound field measurements indicated only a minor influence of flight posture or wing position on the interaural pressure gradient. 3. The locusts steered away from pulsed ultrasounds that simulated bat echolocation signals. The phonotactic response was measured as ruddering by the abdomen and hind legs, resulting in a yaw torque directed away from the sound source. Wingbeat frequency increased by 15% in response to ultrasonic stimulation. This behaviour is considered to be analogous to the bat avoidance behaviour of flying crickets. 4. The avoidance response was observed for carrier frequencies higher than 10 kHz and for sound pressure levels (on average) higher than 45 dB SPL. Lowfrequency stimuli (<10kHz) failed to elicit any phonotactic steering at any intensity used (up to 100dB SPL). Because of its relatively low threshold of reaction, this steering behaviour is thought to be part of an early-warning system adapted to the acoustic detection of echolocating predators. 5. The avoidance response was suppressed when a 30 kHz (normally effective) tone was combined with a 5 kHz tone (which is ineffective alone). Two-tone suppression only occurred when the low-frequency component was 10–15 dB SPL higher than the high-frequency tone. The biological significance of two-tone suppression is discussed. 6. The intensity-response characteristics, the frequency sensitivity and the twotone suppression of the avoidance behaviour are discussed with respect to the auditory physiology of Locusta migratoria. The involvement of some identified auditory ascending interneurones in the avoidance behaviour is considered.

Directional hearing of a grasshopper in the field

2000 ◽  
Vol 203 (6) ◽  
pp. 983-993 ◽  
Author(s):  
F. Gilbert ◽  
N. Elsner
Keyword(s):  
Sound Field ◽  
Contralateral Side ◽  
Directional Hearing ◽  
Natural Habitats ◽  
Nerve Activity ◽  
Sparse Vegetation ◽  
Dense Vegetation ◽  
Field Situation ◽  
Chorthippus Biguttulus ◽  
Similar Accuracy

An electrophysiological method for making long-term recordings from the tympanal nerve was developed in Chorthippus biguttulus (Gomphocerinae) to gain insight into the ecophysiological constraints of sound localization in acridid grasshoppers. Using this ‘biological microphone’, the directional dependence of auditory nerve activity was monitored both in the laboratory and in various natural habitats of this species. On gravel and in sparse vegetation, the overall patterns of directionality were found to be very similar to those in the free sound field in the laboratory, regardless of whether the animal was positioned horizontally or vertically. However, the differences between the ipsi- and contralateral sides were smaller in these habitats than in the laboratory. In dense vegetation, the directional patterns were greatly affected by the environment. Moreover, a minimum in nerve activity was not always reached on the contralateral side, as is typical for the free sound field situation. On the basis of these data, predictions can be made about the ability of the animals to determine the correct side of a sound source. In the free sound field of the laboratory, correct lateralizations are expected at all angles of sound incidence between 20 and 160 degrees, a prediction corresponding to the results of behavioural studies. In sparse vegetation, a similar accuracy can be anticipated, whereas on gravel and in dense vegetation directional hearing is expected to be severely degraded, especially if the animal is oriented horizontally. The predictions from our present electrophysiological investigations must now be confirmed by behavioural studies in the field.

ADAPTIVE MODIFICATIONS IN THE FLIGHT SYSTEM OF THE LOCUST AFTER THE REMOVAL OF WING PROPRIOCEPTORS

1991 ◽  
Vol 157 (1) ◽  
pp. 313-333 ◽  
Author(s):  
ANSGAR BÜSCHGES ◽  
KEIR G. PEARSON
Keyword(s):  
Normal Values ◽  
Locusta Migratoria ◽  
Motor Pattern ◽  
Afferent Input ◽  
Excitatory Input ◽  
Time Dependent ◽  
Intracellular Recordings ◽  
Wingbeat Frequency ◽  
Flight System ◽  
Flight Motor

Previous investigations on the flight system of the locust have found that removal of the wing tegulae in mature locusts (Locusta migratoria) results in an immediate change in the flight motor pattern: the wingbeat frequency (WBF) decreases, the interval between the activity of the depressor and the elevator muscles (the D-E interval) increases, and the phase of the elevator activity in the depressor cycle increases. Here we report the results of a detailed quantitative analysis of these changes. We also examined the flight motor pattern for up to 14 days after removal of the tegulae and found that the changes caused by this operation were not permanent. Beginning on the first day after the operation there was a time-dependent recovery of the WBF, the D-E interval and the phase towards their normal values. In about 80% of the experimental animals the flight motor pattern recovered almost completely. Intracellular recordings from elevator motoneurones showed that this recovery was associated with changes in the pattern of excitatory input to these motoneurones. The modification of activity in elevator motoneurones was dependent on afferent input since complete deafferentation of recovered animals resulted in a motor pattern similar to that following deafferentation of normal animals.

CALCIUM CHANNEL CURRENTS IN CULTURED PARS INTERCEREBRALIS NEUROSECRETORY CELLS OF ADULT LOCUSTA MIGRATORIA

1994 ◽  
Vol 197 (1) ◽  
pp. 393-398
Author(s):  
U Bickmeyer ◽  
W RÖssler ◽  
H Wiegand
Keyword(s):  
Calcium Channel ◽  
Calcium Influx ◽  
Locusta Migratoria ◽  
Biological Significance ◽  
Ionic Currents ◽  
Neurosecretory Cells ◽  
Calcium Currents ◽  
Pars Intercerebralis ◽  
Channel Currents

The medial neurosecretory cells (MNSCs) of the pars intercerebralis in the brain of insects release various hormonal factors that control essential physiological and developmental functions such as moulting, reproduction and metabolism (Wigglesworth, 1940; Girardie, 1966; Goldsworthy, 1969), and these cells are therefore of considerable biological significance. A culture system for locust embryonic pars intercerebralis neurosecretory cells has recently been developed (Vanhems et al. 1993), and Rossler and Bickmeyer (1993) have established an in vitro system for growing larval and adult medial neurosecretory cells. Calcium plays an important role in neural physiology: neurosecretion depends on calcium influx into the cells and calcium currents carry the rising phase of action potentials in different types of insect neurones (Orchard, 1976; Pitman, 1979); calcium also mediates other ionic currents (Thomas, 1984). It is therefore of considerable interest to characterize the types of calcium channel currents found in locust neurosecretory neurones.

scholarly journals Keeping Safe: Intra-individual Consistency in Obstacle Avoidance Behaviour Across Grasping and Locomotion Tasks

i-Perception ◽  
2017 ◽  
Vol 8 (1) ◽  
pp. 204166951769041 ◽  
Author(s):  
Karina Kangur ◽  
Jutta Billino ◽  
Constanze Hesse
Keyword(s):  
Avoidance Response ◽  
Obstacle Avoidance ◽  
Visual Information ◽  
Hand Movement ◽  
Avoidance Behaviour ◽  
Motor Behaviour ◽  
Motor Systems ◽  
Gaze Behaviour ◽  
Individual Consistency

Successful obstacle avoidance requires a close coordination of the visual and the motor systems. Visual information is essential for adjusting movements in order to avoid unwanted collisions. Yet, established obstacle avoidance paradigms have typically either focused on gaze strategies or on motor adjustments. Here we were interested in whether humans show similar visuomotor sensitivity to obstacles when gaze and motor behaviour are measured across different obstacle avoidance tasks. To this end, we measured participants’ hand movement paths when grasping targets in the presence of obstacles as well as their gaze behaviour when walking through a cluttered hallway. We found that participants who showed more pronounced motor adjustments during grasping also spent more time looking at obstacles during locomotion. Furthermore, movement durations correlated positively in both tasks. Results suggest considerable intra-individual consistency in the strength of the avoidance response across different visuomotor measures potentially indicating an individual’s tendency to perform safe actions.

Postembryonic development of an insect sensory system: ingrowth of axons from hindwing sense organs in Locusta migratoria

1978 ◽  
Vol 202 (1149) ◽  
pp. 497-516 ◽  
Keyword(s):  
Locusta Migratoria ◽  
Sensory System ◽  
Postembryonic Development ◽  
Stretch Receptor ◽  
Sensory Nerves ◽  
Chordotonal Organ ◽  
Wingbeat Frequency ◽  
Adult Locust ◽  
Wing Bud ◽  
To Come

Axon counts have been made from electron micrographs of the hind­wing sensory nerves 1C 1 and 1D 2 in the adult locust and during develop­ment. In the adult, nerve 1C 1 contains approximately 1000 axons. At least a quarter have diameters over 1 µm, more than forty 5-12 µm. Seventy large axons come from the tegula, the rest from the wing. Nerve 1D 2 contains 400 axons, 64 between 1 µm and 6.5 µm in diameter. Large axons are assumed to come from the wing base chordotonal organ and stretch receptor, the remainder from thoracic hair fields. During development, axon numbers in nerve 1C 1 rapidly increase at the 4th instar, corresponding to the development of the wing bud. By the final moult there are over 2000 axons, half of which disappear in the two weeks after fledging. In nerve 1D 2 the stretch receptor and chor­dotonal axons are present from the first instar. Small fibres increase in number mainly in the 5th instar. In contrast to nerve 1C 1 there is no change in numbers after fledging. In both nerves, diameters and glial wrapping of axons increase in the two weeks after fledging, although the changes are more marked in nerve 1C 1 . The large input from the tegula suggests an important rôle in the phasic control of flight. The post-fledging increase in diameter and glial wrappings of tegula axons may influence the increase in wingbeat frequency with age.

scholarly journals Axial variation of deoxyhemoglobin density as a source of the low-frequency time lag structure in blood oxygenation level-dependent signals

2019 ◽  
Author(s):  
Toshihiko Aso ◽  
Shinnichi Urayama ◽  
Fukuyama Hidenao ◽  
Toshiya Murai
Keyword(s):  
Time Lag ◽  
Biological Significance ◽  
Low Frequency ◽  
Frequency Component ◽  
Real Space ◽  
Blood Oxygenation ◽  
Vascular Tree ◽  
Physiological Basis ◽  
Fmri Signal ◽  
Lag Structure

AbstractPerfusion-related information is reportedly embedded in the low-frequency component of a blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signal. The blood-propagation pattern through the cerebral vascular tree is detected as an interregional lag variation of spontaneous low-frequency oscillations (sLFOs). Mapping of this lag, or phase, has been implicitly treated as a projection of the vascular tree structure onto real space. While accumulating evidence supports the biological significance of this signal component, the physiological basis of the “perfusion lag structure,” a requirement for an integrative resting-state fMRI-signal model, is lacking. In this study, we conducted analyses furthering the hypothesis that the sLFO is not only largely of systemic origin, but also essentially intrinsic to blood, and hence behaves as a virtual tracer. By summing the small fluctuations of instantaneous phase differences between adjacent vascular regions, a velocity response to respiratory challenges was detected. Regarding the relationship to neurovascular coupling, the removal of the whole lag structure, which can be considered as an optimized global-signal regression, resulted in a reduction of inter-individual variance while preserving the fMRI response. Examination of the T2* and S0, or non-BOLD, components of the fMRI signal revealed that the lag structure is deoxyhemoglobin dependent, while paradoxically presenting a signal-magnitude reduction in the venous side of the cerebral vasculature. These findings provide insight into the origin of BOLD sLFOs, suggesting that they are highly intrinsic to the circulating blood.

scholarly journals Humming hummingbirds, insect flight tones and a model of animal flight sound

2020 ◽  
Vol 223 (19) ◽  
pp. jeb214965
Author(s):  
Christopher J. Clark ◽  
Emily A. Mistick
Keyword(s):  
Sound Pressure ◽  
Insect Flight ◽  
Aerodynamic Force ◽  
Sound Field ◽  
Far Field ◽  
Aerodynamic Forces ◽  
Wingbeat Frequency ◽  
Predator Prey ◽  
Aerodynamic Pressure ◽  
Animal Flight

ABSTRACTWhy do hummingbirds hum and insects whine when their wings flap in flight? Gutin proposed that a spinning propeller produces tonal sound because the location of the center of aerodynamic pressure on each blade oscillates relative to an external receiver. Animal wings also move, and in addition, aerodynamic force produced by animal wings fluctuates in magnitude and direction over the course of the wingbeat. Here, we modeled animal wing tone as the equal, opposite reaction to aerodynamic forces on the wing, using Lowson's equation for the sound field produced by a moving point force. Two assumptions of Lowson's equation were met: animal flight is low (<0.3) Mach and animals from albatrosses to mosquitoes are acoustically compact, meaning they have a small spatial extent relative to the wavelength of their wingbeat frequency. This model predicted the acoustic waveform of a hovering Costa's hummingbird (Calypte costae), which varies in the x, y and z directions around the animal. We modeled the wing forces of a hovering animal as a sinusoid with an amplitude equal to body weight. This model predicted wing sound pressure levels below a hovering hummingbird and mosquito to within 2 dB; and that far-field mosquito wing tone attenuates to 20 dB within about 0.2 m of the animal, while hummingbird humming attenuates to 20 dB at about 10 m. Wing tone plays a role in communication of certain insects, such as mosquitoes, and influences predator–prey interactions, because it potentially reveals the predator's presence to its intended prey.

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