Peripheral interaction in the tympanic organ of a moth

Coro, F.; Pérez, Mairiannys Quianella León

doi:10.1007/bf00365515

Cited by 27 publications

(12 citation statements)

References 5 publications

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“…It is difficult to link a particular behaviour to the activity of the A2 cell since there has been no clear demonstration of when the moth begins its near-bat flight. In addition, in previous studies the responses of the A2 cell have been evoked to pulsed sounds that do not simulate the full suite of call characteristics emitted by attacking bats (Suga, 1961;Roeder, 1964Roeder, , 1974Coro and Pérez, 1983). Our results reveal that while the A2 cell exhibits a rigorous response in the noctuid L. pseudargyria, its significance is less apparent for the two arctiids tested, moths whose ears also possess A2 cells.…”

Section: A2 Cellmentioning

confidence: 58%

Auditory encoding during the last moment of a moth's life

Fullard

Dawson

Jacobs

2003

Journal of Experimental Biology

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Many insects hear the ultrasonic echolocation calls of hunting insectivorous bats in time to allow them to escape predation (Hoy and Robert, 1996;Miller and Surlykke, 2001) and the ears of moths are amongst the most neurologically simple, containing up to four auditory receptors. The most intensively studied of these are the two-celled ears of owlet moths (Noctuidae) (for reviews, see Roeder, 1967Roeder, , 1974Spangler, 1988;Hoy and Robert, 1996;Fullard, 1998) and in a series of classic papers, Roeder and his colleagues described the physiological responses of the noctuid A1 and A2 auditory cells as well as the apparently non-auditory B-cell. They proposed that noctuids respond to the approach of bats with a bimodal defensive flight behaviour determined by the closeness of the bat as perceived by the moth (Roeder, 1962(Roeder, , 1964(Roeder, , 1974. Aerially foraging bats emit intense echolocation calls as they hunt and use a series of acoustic stages leading to prey capture (Griffin, 1958): (1) search, (2) approach, (3) tracking (Kick and Simmons, 1984), (4) terminal buzz (I) and (5) terminal buzz (II) (Surlykke and Moss, 2000). According to Roeder's (1974) model, the first stage (far-bat) of a flying moth's anti-bat response occurs when it directionally detects a distant bat in its search mode (i.e. emitting relatively faint and slowly repeated echolocation calls) with the most sensitive receptor, the A1 cell. Theoretically, the responses of the A1 cell then evoke controlled, directional flight that takes the moth away from the bat before the bat has detected the echo of the moth. The moth's second defensive mode (near-bat) occurs when it detects a close bat (i.e. emitting relatively intense and rapidly repeated echolocation calls). These sounds activate both the A1 cell and the less sensitive receptor, A2 cell, evoking erratic, non-directional flight as a 'last-ditch', anti-bat flight maneuver. In addition to the A2 cell, Lechtenberg (1971) suggested that the third noctuid receptor, the B cell, considered by earlier authors to be non-auditory (Roeder and Treat, 1957;Treat and Roeder, 1959), might identify the characteristic calls of the terminal stage of the bat's attack to evoke a sustained near-bat response in an escaping moth. The A2 cell has also been implicated in the activation of another near-bat defence, sound-production in the dogbane tiger moth, Cycnia tenera (Fullard, 1992;Dawson and Fullard, 1995). As a way of testing the bimodal theory, Roeder (1974) suggested observing the anti-bat behaviour of prominent moths (Notodontidae) whose ears each contain only the A1 receptor cell, and the subsequent study by Surlykke (1984) challenged the theory that near-bat The simple auditory system of noctuoid moths has long been a model for anti-predator studies in neuroethology, although these ears have rarely been experimentally stimulated by the sounds they would encounter from naturally attacking bats. We exposed the ears of five noctuoid moth species to the pre-recorded echolocation calls of an attacking bat...

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Section: A2 Cellmentioning

confidence: 58%

Auditory encoding during the last moment of a moth's life

Fullard

Dawson

Jacobs

2003

Journal of Experimental Biology

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“…5), although the input synapses may have been distant from the recording site. Input as well as output synapses have been reported on the primary afferent terminals of other wind-sensitive hairs in the locust (Watson and Pfltiger, 1984), providing an anatomical basis for the type of direct excitatory and inhibitory interactions between mechanosensory afferents described by Eckert (196 l), Baylor and Nicholls (1969) Coro and Perez (1983), and Blagbum and Sattelle (1987).…”

Section: Discussionmentioning

confidence: 99%

Presynaptic inhibition of identified wind-sensitive afferents in the cercal system of the locust

Boyan

1988

J. Neurosci.

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The paired cerci located at the tip of the locust abdomen bear a large number of wind-sensitive filiform hairs, each of which sends an axon via the cercal nerve into the terminal ganglion of the CNS. The filiform afferents fire bursts of action potentials when their hairs are displaced by wind or mechanical stimuli. Filiform axon terminals in the CNS are depolarized concomitantly with the discharge of another type of unit (a primary afferent-depolarizing, or PAD, unit) recorded in the cercal nerve. The instantaneous spike frequency of PAD unit discharges matches the evoked depolarization very closely, and during such depolarizations spike amplitudes in the filiform afferent terminals are reduced by up to 55%. Depolarizing current pulses injected into the axonal terminals of an identified filiform afferent evoke spikes that are blocked by the PAD unit, probably via an intercalated interneuron. The PAD unit makes a monosynaptic connection with only one of the 4 giant interneurons (GIN 2) on each side of the terminal ganglion, and indirect connections with 2 others. Depolarizing current pulses injected into the neuropilar segments of GINs evoke fewer spikes when the PAD unit is active, consistent with the PAD unit's mediation of conductance changes in postsynaptic cells. Iontophoretic injection of Lucifer yellow shows the PAD unit to be an afferent with axon terminals overlapping those of filiform afferents and posteriorly directed branches of interneurons such as GIN 2 in the CNS. Passive movements of a cercus, monitored with a position transducer, show that the PAD unit fires discrete bursts during cercal displacement. The PAD unit most probably has its soma and dendrites in tissue spanning the cercal base. By responding to cercal movements sufficient to also activate filiform hairs, and by mediating conductance changes in both the presynaptic terminals of filiform afferents and the postsynaptic membranes of interneurons, the PAD unit desensitizes a pathway to movement-generated afferent input, and ensures that the locust remains sensitive to external wind stimuli.

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“…Due to the higher A2 thresholds, stimulus intensities that activate A2 coincide with the decreased spike output in A1. This suggested the possibility of inhibitory interactions between the two receptors as a mechanism for the decline in A1 responses at high intensities (Coro and Perez, 1983;Perez and Coro, 1986). Similar non-monotonic intensity effects are seen in notodontid moths, however, which possess only a single auditory receptor per ear Surlykke 1984).…”

Section: Intensitymentioning

confidence: 74%

The physiology of insect auditory afferents

Mason

Faure

2004

Microscopy Res & Technique

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This review presents an overview of the physiology of primary receptors serving tympanal hearing in insects. Auditory receptor responses vary with frequency, intensity, and temporal characteristics of sound stimuli. Various insect species exploit each of these parameters to differing degrees in the neural coding of auditory information, depending on the nature of the relevant stimuli. Frequency analysis depends on selective tuning in individual auditory receptors. In those insect groups that have individually tuned receptors, differences in physiology are correlated with structural differences among receptors and with the anatomical arrangement of receptors within the ear. Intensity coding is through the rate-level characteristics of tonically active auditory receptors and through variation in the absolute sensitivities of individual receptors (range fractionation). Temporal features of acoustic stimuli may be copied directly in the timing of afferent responses. Salient signal characteristics may also be represented by variation in the timing of afferent responses on a finer temporal scale, or by the synchrony of responses across a population of receptors.

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Peripheral interaction in the tympanic organ of a moth

Cited by 27 publications

References 5 publications

Auditory encoding during the last moment of a moth's life

Auditory encoding during the last moment of a moth's life

Presynaptic inhibition of identified wind-sensitive afferents in the cercal system of the locust

The physiology of insect auditory afferents

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