01238nas a2200121 4500008004100000245006600041210006600107520081600173100003100989700002301020700002501043856004801068 1983 eng d00aTympanal membrane motion is necessary for hearing in crickets0 aTympanal membrane motion is necessary for hearing in crickets3 a

1. Sound guided through the tracheal tube to the internal tracheal spaces in the region of the cricket ear is capable of eliciting auditory neural responses in the prothoracic ganglion if the tympanal membrane is allowed to vibrate freely. If the tympanal membrane motion is prevented mechanically neural responses are abolished (Fig. 3) whereas the sound pressure in the tracheal air spaces behind the tympanum is increased.

2. If the motion of the tympanum, as measured with laser vibrometry, is prevented by adjusting the internal and external sound pressure, then neural responses cease simultaneously (Fig. 5).

3. These findings demonstrate that motion of the large tympanum is a necessary requisite in the sound transduction process of the cricket ear.

1 aKleindienst, Hans, -Ulrich1 aWohlers, David, W.1 aLarsen, Ole, Næsbye uhttp://link.springer.com/10.1007/BF0060545502082nas a2200181 4500008004100000022001400041245012000055210006900175260002000244300001300264490000700277520137400284100002501658700002101683700002501704700002701729856014401756 2017 eng d a1742-568900aFrequency tuning and directional sensitivity of tympanal vibrations in the field cricket Gryllus bimaculatus0 aFrequency tuning and directional sensitivity of tympanal vibrati cDec-28-20172018 a201700350 v143 a

Female field crickets use phonotaxis to locate males by their calling song. Male song production and female behavioural sensitivity form a pair of matched frequency filters, which in Gryllus bimaculatus are tuned to a frequency of about 4.7 kHz. Directional sensitivity is supported by an elaborate system of acoustic tracheae, which make the ears function as pressure difference receivers. As a result, phase differences between left and right sound inputs are transformed into vibration amplitude differences. Here we critically tested the hypothesis that acoustic properties of internal transmissions play a major role in tuning directional sensitivity to the calling song frequency, by measuring tympanal vibrations as a function of sound direction and frequency. Rather than sharp frequency tuning of directional sensitivity corresponding to the calling song, we found broad frequency tuning, with optima shifted to higher frequencies. These findings agree with predictions from a vector summation model for combining external and internal sounds. We show that the model provides robust directional sensitivity that is, however, broadly tuned with an optimum well above the calling song frequency. We therefore advocate that additional filtering, e.g. at a higher (neuronal) level, significantly contributes to frequency tuning of directional sensitivity.

1 aLankheet, Martin, J.1 aCerkvenik, Uroš1 aLarsen, Ole, Næsbye1 avan Leeuwen, Johan, L. uhttp://rsif.royalsocietypublishing.org/lookup/doi/10.1098/rsif.2017.0035https://syndication.highwire.org/content/doi/10.1098/rsif.2017.0035