A utilização de Herpsilochmus longirostris Pelzeln, 1868 (Passeriformes; Thamnophilidae) como modelo de adaptação acústica

Abstract

The acoustics communication is well developed in birds. According to Acoustics Adaptation Hypothesis the birds tend to maximize the transmission of the acoustic signals in accordance with the environment where they are adapted. This work had as objective to describe the vocalizations of Herpsilochmus longirostris, Pelzeln, 1868 (Passeriformes: Tamnophilidae), an endemic species of the Cerrado, and to test the Acoustics Adaptation Hypothesis, from the comparison of recorded cantos of the species in different areas urban and natural environments. The writings had been carried through in the Municipal Park of Sabiá, the Victório Siquierolli Municipal Park and the Acampamento Manancial. The songs had been recorded, digitalized and for it analyzes structural of the sound had been generated spectrograms. The following parameters had been used: frequency, maximum frequency, minimum frequency, amplitude and duration of song and notes. The description of these songs includes: the average and the error standard of the frequency, the frequencies minimum and maximum, the duration of the song of it and the duration between the song and the amplitude. In the natural area the frequency was the greats found with 1854 ±153 Hz (n=8) and the minor in 45 the Siquierolli Park was of 1059 ± Hz (n= 5). The maximum frequency in the natural areas was of 2200 ± 80 Hz (n=8), being lesser in the Park Siquierolli 1300 ± 210 Hz (n=5). The minimum frequency was of 424 ± 60 Hz (n=8) in the natural area being higher in the Park of Sabiá was of 886 ± 43 Hz (n=13). The song of H. longirostris on average 8 (± 0.1) notes for second in the natural area and the greater was in the Siquierolli Park of 9 (±0.1). The duration of the songs in the natural areas was of 2 (±0.1) and was 1.8 (±0.1) seconds in the Park of Sabiái of duration between cantos sufficiently was varied having on average a duration of: 16s (±3.0) in natural environments, 37s (±9.0) in the Park of Sabiá; 6s (±2.0) and in the Siquierolli. The maximum amplitude was 30 dB (±4.0) in the natural areas; of 20dB (±2.0) in the park of Sabiá. The song of H. longirostris shows a larger duration and lower frequency in the natural areas, when compared with the espectrogramas of the parks. There was significant difference in the minimum frequency and in the duration of the songs between the Park of Sabiá and the natural area. In the Park of Siquierolli there was difference in the frequency, maximum and minimum frequency, interval and duration when compared with the natural areas. Among the two parks there was difference in the frequency, maximum frequency. In the comparison the note of the song between the parks and the natural areas, some variations were verified in the acoustic parameters. The variations observed in the acoustic parameters of Herpsilochmus longirostris corroborate with adaptation hypothesis acoustics, a time that evidences the influence of the environment in the election of a characteristic genetically determined.