@article {57975, title = {Further studies on the peripheral auditory system of {\textquoteright}CF-FM{\textquoteright} bats specialized for fine frequency analysis of Doppler-shifted echoes}, journal = {Journal of Experimental Biology}, volume = {69}, year = {1977}, pages = {207-232}, chapter = {207}, abstract = {

In the mustache bat (Pteronotus parnellii rubiginosus), the cochlear\ microphonic (CM) recorded from the round window is sharply tuned at 61 kHz and shows a prominent transient response to a tone burst at about 61 kHz (i.e. its amplitude increases exponentially at the onset of the stimulus and decreases at its cessation). In terms of the time constant (I-I + 0-3 ms) and the resonance frequency (6I*I + 0-43 kHz) of this transient response, the Q of this system, assumed to correspond to a second-order filter, is 204 + 57. Peripheral neurones sensitive to 61 kHz have a very sharp excitatory area (or tuning curve). The Q of a tuning curve markedly increases with the rise in best frequency up to 61 kHz and decreases beyond 61 kHz. The Q value of a single neurone with best frequencies between 60-76 and 61-75 kHz is 210189. If the assumption that the CM is directly related to the mechanical motion of the basilar membrane is correct, the very sharp tuning curves of single neurones at about 61 kHz could be simply due to the mechanical tuning of the basilar membrane. Since this animal predominantly uses a 61 kHz sound for echolocation and peripheral auditory neurones show a low threshold and extremely sharp tuning at about 61 kHz, its peripheral auditory system is specialized for the reception and fine-frequency analysis of the principle component of orientation sounds and echoes. Sharply tuned neurones can code a frequency modulation as small as o-oi\%, so that the wing beat of an insect would be easily coded by them. Unlike the CM, Nx is tuned at 64 kHz. This difference in best frequency is simply due to the properties of a sharply tuned resonator and Nlt and not due to a mechanism comparable to lateral inhibition.

}, author = {NOBUO SUGA and PHILIP H.-S. JEN} } @article {17204, title = {Acoustic Orientation in the Cricket Teleogryllus Oceanicus (Le Guillou)}, journal = {Journal of Experimental Biology}, volume = {67}, year = {1977}, pages = {61-75}, chapter = {61}, abstract = {

New information is presented on acoustic orientation in crickets following a comparison between as species with a discontinuous song pattern, Scapsepidus maginatus (Murphet \& Zaretsky, 1972) and one with a continuous osng pattern, Teleogrylluys oceanicus. The females acuity for side discrimination is \±10\° from the body axis whereas total phonokinetic response shows a greater degree of error. Females can scan their turn angle to target angles beneath 60\°. Error is expressed in terms of information loss through the total behavioural sequence. The cricket does not orient while moving, requires no fixed leg position during the stop for effective orientation and can establish source direction on the basis of at least two syllables. Evidence of differential anterioir and posterior tympanic membrane function is suggested.

}, author = {Winston J. Bailey and Thomson, Peter} }