02014nas a2200157   4500008004100000022001300041245013500054210006900189260001600258300001400274490000700288520145300295100002401748700001801772856006601790       1984                        eng d  a0003347200aAuditory acuity in the orientation behaviour of the bushcricket Pachysagella australis walker (Orthoptera, Tettigoniidae, Saginae)0 aAuditory acuity in the orientation behaviour of the bushcricket   cJan-08-1984  a816 - 8290 v323 a<p>The female tettigoniid Pachysagella australis (Saginae) orients to the call of the conspecific with an angular acuity of &plusmn;5&deg;. This acuity is mediated by sound entering to the tympanic receptors through the auditory trachea and the slits exterior to the tympanic membranes. The phonokinetic response of females was filmed in an arena. The slit system was blocked on both anterior and posterior ports with the effect that the female spiralled towards the sound source; blocking the posterior slit alone reduced the auditory acuity as did the partial occlusion of the fore slit, but in both cases the female located the male. Complete blocking of the auditory spiracle caused the insect to spiral towards the unoperated side, whereas reducing the sound input to one side by some 8&ndash;12 dB, by plugging the auditory bulla with compacted cotton wool, did not substantially affect the orientation pattern of the insect. Ablation of the tympanic organ on one side caused the female to move in a circular pattern to the unoperated side. A hypothesis is formulated whereby the female, when actively orienting to the calling male, may use the slit port system to gain a high degree of auditory acuity to sound in front of her body axis. When off target she may use the less accurate spiracular input system. This system, with its greater sensitivity to high frequency sounds, may function as an effective anti-predator warning system.</p>
1 aBailey, Winston, J.1 aStephen, R.O.  uhttp://linkinghub.elsevier.com/retrieve/pii/S000334728480158X