Fig. 4: Waveforms and spectrograms of the six treatment stimuli for phonotaxis experiments.

A represents the original advertisement call (OC), B illustrates the rising intonation version of OC, where the pitch of the sixth note was increased by 15% (OCP), C shows the modified version of OC, where the sixth note was replaced by the sixth note of an advertisement call from a sympatric anuran species, Quasipaa boulengeri (OQ), D presents a modified version of OC with the last note was reversed in situ (OR), E shows a modified version of OC with the last note replaced by silence (OS), F demonstrates the altered version of OC, with the last note replaced by white noise (OW). It is worth noting that the rising intonation in the last note (OCP) results in measurable alterations in the frequency spectrum profiles of the last components compared to the original version (OCP vs. OC).