Bioacoustics of Ariasa iporaensis

Males called from the trunk and thick branches of trees at heights of at least 3 m . Some specimens were observed singing from urban lamp posts made of wood or concrete so that feeding is not required while emitting signals. Males would call in isolation unless there was a high population density when small choruses would form. Male would sing and stay on the same perch for extended periods of time. In some observations, it appeared that a male stayed in the same place for several days. Most intense activity was from 9.00 a.m. to 12.00 p.m. when the greatest number of males were emitting signals. During the afternoon, sporadic signals were heard until around 3.00 p.m. Emission of signals was not observed at dawn or at dusk. Eighteen calling songs recorded from nine males were analyzed. The calling song of A. iporaensis n. sp. lasted 25.3 s ± 7.2 (16.1–36.9) with a dominant frequency of 5335.1 Hz ± 107.6 (5132–5531) ( Figs. 5 and 6 ). The call initiated with a buzzing (first part) lasting 13.6 s ± 6.8 (4.6–24.6). The first part was composed of groups of four distinct pulses with a repetition rate of 55.5 Hz ± 4.69 (46–62). There were up to three or four modulations in the posterior third of this phase. The second part sounded like a whistle lasting 11.3 s ± 2.3 (6.8–16.4). The pulse repetition rate was 521.3 Hz ± 32.34 (480–560) during the second part of the call. There was no significant difference between dominant frequency of the both parts ( F = 0.027; p = 0.86). Calling song can be emitted in sequence of several with a short silent interval. Mean sound pressure levels were determined to be 93.0 dB, + 2.50 dB, − 6.50 dB (range of individual measurements 87.0–97.0 dB). Four males were recorded emitting a short call ( Fig. 7 ). This has the same pattern as the calling song but it is much shorter, with a first part lasting 0.68 s ± 0.2 (0.44–1.12) and the second part lasting 1.23 s ± 0.49 (0.66–2.22). The full short call lasted 1.91 s ± 0.56 (1.1–2.88) and has a rapid increase of amplitude with an abrupt ending. The mean of dominant frequency was 5020.8 Hz ± 105.9 (4875–5156). The short calls were produced in sequences of two and three without a silent period. Once it was possible to observe that a male emitted a short call sequence in an interaction with another male that had landed a few centimeters from the emitter. There was a conflict and the invader flew. This short call was heard sometimes coming from a tree where only a single male was singing, suggesting the signal may also be used in an interaction with a female, probably as a courtship song.