Acoustic stimuli presented to frogs. Sonograms (top graphs) and waveforms (bottom graphs) of treatment stimuli (top to bottom): conspecific P. pustulosus whine (whine), conspecific whine plus three chucks (whine-chuck), three chucks (chuck), and heterospecific whine (P. enesefae). Peak-to-peak amplitudes of stimuli were matched. Total call energy relative to P. pustulosus whine: whine chuck 1.36 dB, P. enesefae 7.82 dB, and chuck, -15.4 dB.