Intensity responses of the single auditory receptor of notodontid moths: Atest of the peripheral interaction hypothesis in moth ears

It has been proposed that the most sensitive auditory receptor cell (Al) in the two-celled ears of certain noctuoid moths is inhibited by its partner, the A2 cell, at high stimulus intensities, We used the single-celled ears of notodontid moths, also noctuoids, to test this hypothesis. The Al cells of all but one of the moths tested exhibited non-monotonic firing rates, wi th reduced firing rates at high stimulus intensities and showing no relatio nship to the firing rate of the only other receptor, the non-auditory B cel l. These results challenge the peripheral interaction hypothesis for Al fir ing patterns in two-celled moth ears. An examination of notodontid Al adapt ation rates and laser vibrometry results suggests that receptor adaptation and tympanal motion non-linearity are more likely explanations for the non- monotonic receptor observed in both single- and multi-celled moth ears.