Fig. 9.

Distributions of additional sensitivity peaks.A, Additional sensitivity peaks are plotted according to the frequencies at which they occur. The origins of ARF populations contributing the additional sensitivity peaks are illustrated with different fill patterns. Peaks are clustered at the frequency of intraspecific signals (4–6 kHz) and its higher harmonics.B, Additional sensitivity peaks are plotted as multiples of the CF of the ARF in which they occur. For this analysis, ARFs with CFs ≤3 or ≥40 kHz were excluded. Peaks are clustered at harmonics of the CF ( $\frac{1}{6}$, $\frac{1}{3}$, ½, and 2 times the CF). See Results for further explanation.