Panacanthus gibbosus

Calling by this species is known from the analysis of twelve males. One specimen was recorded indoors at La Planada (Colombia Narin ' o) at 18.5 '' C, the others were also recorded under laboratory conditions at 23 '' 0.5 '' C. The shortest time-amplitude song element of this species, resolvable by the human ear, is a zip: brief, noisy and with perceptible infrastructure (Fig. 11E, F). Zips are typically produced in groups of two to eight and each is a pulse train of approximately fifty transient pulses; each pulse is a waveform involving three to four cycles, separated from the next pulse by 0.1-0.15 ms. A zip lasts on average 0.076 s (n 1/4 5, range 0.060-0.087 s); each pulse lasts <0.5 ms. Teg- minal movement is slow enough to determine, by inspection, that each zip coincides with a single tegminal closure.
The spectrum of P. gibbosus is a noisy low-Q band. Measured 20 dB below its highest peak, it extends from 5 to 35 kHz. The most intense frequency varies: sometimes it is an audio peak at 6.4 kHz (n 1/4 6) and sometimes it is ultrasonic at 27.4 kHz (n 1/4 4). Less intense peaks occur consistently at 12.5 and 19.2 kHz (n 1/4 9). All these very broad peaks may be harmonically related with a funda- mental near 6kHz. Based upon single-note spectra, the most intense ultrasonic peak occurred at 30.2kHz (n1/49, standard deviation 1/4 1.6, range 26.6-31.9 kHz, Fig. 12C). The most intense audio peak averaged 5.9 kHz (n 1/4 9, stan- dard deviation 1/4 0.1, range 5.7-6.0 kHz). The call is loud to human ears and, for one male, registered ''90-95 dB with the microphone 10 cm dorsal. [1]

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