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Previous issue date: 2017-03-27 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Acoustical signals are the main form in which birds communicate, and they are used to attract mates, defend territories, alarm others from predators and recognize each other, being than an important feature on speciation process. Then, song is extremely important, especially in Oscines, a group of birds that have a widely types of songs, singular for each species. Many studies have been shown that the vocal tract act as a constrict factor on song structure, besides body size. Beak gape, size and bite force are known as a limiting factors of note rate, frequency bandwidth and maximum/minimum frequencies, in which larger beaks produces narrow sounds with lower note rates. Our study had two objectives related of Oscine birds (of the genus Sporophila): the first one (chapter I) was to analyze the evolution of beak volume and song structure and verify the existence of song constriction and coevolution between them. The other objective (discussed in chapter II) was to test the relation between beak volumes and bite force with the song structure of three sympatric species of Sporophila, and try to infer how they organize their songs to avoid the acoustic overlap due their coexistence. In the chapter I we analyze territorial songs of 47 males from 11 species of Sporophila, representatives of Neotropical Oscines (Thraupidae). We found that frequency bandwidth and maximum frequency had a negative relation with beak volume, besides that, minimum frequency showed a trend for the same pattern. Beak volume, note rate and minimum frequency demonstrated to have a phylogenetic signal, which suggest that closely related species had beak morphology aand song structure more similar then lesser related species. Our results corroborate literature, in which beak volume acts as a limiter for song structure and also that this character can coevolve with birdsong. However, other variables did not present a constriction by the beak volume, what suggest that there is much to discover about this relation in songbirds yet. It is interesting to test the phylogenetic influence besides morphological characters, since this feature can be influencing song structure more than song constrainers. In chapter II, we selected S. beltoni, S. caerulescens and S. hypoxantha as a model of large, medium and small species respectively. These three species used to occur in the same habitat where they breed in northern of Rio Grande do Sul, Brazil. Adult that were observed and recorded were captured, had they beak measured and pass though bite force test. We found that S. beltoni and S. hypoxantha had more differences among song parameters, in which the first one presents the larger beak among the three species evaluated, and the second the smallest beak. The highest relation between strength/beak size and song was observed in S. caerulescens in which frequency bandwidth and minimum/maximum frequencies presented a positive relationship with bite force and beak size, showing that this feature do not limit song on this taxa against that other studies have shown. Concerning to the use of acoustical space, the greatest differences found were related with note rate and song duration. These factors should be some features used to avoid the song overlap on nature. In general terms our study shows that the limitation of sound per characters of the beak it is not a rule in Oscines, although there is a negative relationship between song variation and beak size when more species are add to the model. With these results we belive that it is important to know how changes in morphology of all vocal tract can affect song structure and how morphologic and acoustic features had evolved through their phylogenetic history, because understand this is essential to better comprise the speciation process among these groups. / A principal forma de comunica??o das aves ? por meio de sinais ac?sticos, ? atrav?s deles que elas atraem parceiros, defendem territ?rios e se reconhecem. Com isso, o canto ? extremamente importante no processo de especia??o, em particular nas aves Oscines, um grupo que tem amplos tipos de canto, singulares a cada esp?cie. Sabe-se que o trato vocal atua como modulador na estrutura do som; caracter?sticas do bico podem atuar como fatores limitantes influenciando a taxa de notas, largura de banda e frequ?ncias, no qual bicos maiores produzem sons com menor taxa de notas e com frequ?ncias mais restritas. O nosso trabalho teve dois objetivos relacionados a um grupo de aves Oscines (Sporophila), o primeiro (cap?tulo I) foi analisar a evolu??o do volume do bico e da estrutura do canto para verificar a exist?ncia de limita??es e coevolu??o entre os mesmos. No segundo (cap?tulo II) testamos a rela??o entre volume do bico e a capacidade de mordida com a estrutura do canto de tr?s esp?cies simp?tricas de Sporophila spp., al?m de verificar como estas aves organizam seus cantos para evitar a sobreposi??o deles no ambiente. No cap?tulo I analisamos cantos territoriais representando 11 esp?cies de Sporophila. Encontramos que a largura de banda e m?xima frequ?ncia tiveram rela??o negativa com o volume do bico; al?m disso, a frequ?ncia m?nima apresentou uma tend?ncia para o mesmo padr?o. O volume do bico, taxa de notas e frequ?ncia m?nima demonstraram ter sinal filogen?tico, sugerindo que esp?cies proximamente relacionadas apresentem essas vari?veis mais similares. Nossos resultados mostram que o volume do bico atua como limitador na estrutura do canto al?m de indicar que esse fator pode coevoluir com o canto destas aves, corroborando a literatura. Entretanto, a frequ?ncia dominante, taxa de notas e dura??o do canto n?o apresentaram limita??o pelo volume do bico, o que sugere que ainda existem muitas informa??es sobre o tema para serem descobertas. Assim ? interessante que se teste a influ?ncia filogen?tica, al?m dos caracteres morfol?gicos sobre as caracter?sticas do canto em aves Oscines. No segundo cap?tulo n?s selecionamos S. beltoni, S. caerulescens e S. hypoxantha como modelos de esp?cie grande, m?dia e pequena respectivamente. Estes tr?s t?xons costumam coexistir e se reproduzir nas mesmas ?reas no sul do Brasil e foram amostrados concomitantemente no nordeste do Rio Grande do Sul. Machos adultos foram observados e gravados e ap?s foram capturados, tiveram seus bicos medidos e passaram pelo teste de press?o de mordida em campo. N?s encontramos que S. beltoni e S. hypoxantha s?o as esp?cies que mais divergem em par?metros ac?sticos, sendo que a primeira apresenta bico mais volumoso dentre as tr?s esp?cies. A maior rela??o entre for?a/tamanho do bico e o canto foi observada em Sporophila caerulescens na qual a largura de banda e frequ?ncia m?xima/m?nima do canto apresentaram rela??o positiva com a for?a e o tamanho do bico, evidenciando que este car?ter n?o limita o som deste t?xon ao contr?rio do que outros estudos t?m mostrado. Referente ? ocupa??o do espa?o ac?stico, as maiores diferen?as encontradas foram relacionadas ?s vari?veis de tempo do canto e taxa de notas. Cogita-se que estes podem ser alguns dos fatores usados para evitar a sobreposi??o dos cantos na natureza. Em termos gerais nosso estudo mostra que a limita??o do canto por caracteres do bico n?o ? uma regra geral em Oscines embora exista uma rela??o negativa entre varia??es no canto e tamanho do bico quando mais esp?cies s?ao adicionadas ao modelo. Com esses resultados n?s acreditamos que ? interessante seguir pesquisando sobre os fatores ?limitadores do canto? j? que n?o existe um padr?o generalizado para aves canoras. ? importante conhecer como as mudan?as na morfologia de todo o trato vocal podem alterar a estrutura do som das aves e como caracteres morfol?gicos e ac?sticos evolu?ram atrav?s da sua hist?ria filogen?tica, j? que este entendimento ? essencial para melhor compreender o processo de especia??o destes grupos.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/7721 |
| Date | 27 March 2017 |
| Creators | Porzio, Nat?lia Simoni |
| Contributors | Fontana, Carla Suertegaray |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Zoologia, PUCRS, Brasil, Faculdade de Bioci?ncias |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 2008925231902741151, 600, 600, 600, 600, 36528317262667714, -6482652380601267558, -2555911436985713659 |
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