Banca de DEFESA: LUANA PINI CAVALCANTI DE SOUSA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : LUANA PINI CAVALCANTI DE SOUSA
DATA : 16/03/2018
HORA: 08:30
LOCAL: Anfiteatro das Aves
TÍTULO:

Rate of song change within a humpback whale (Megaptera novaeangliae) breeding stock

PALAVRAS-CHAVES:

Cultural evolution; horizontal cultural transmission; Levenshtein distance; passive acoustic monitoring; sexual display; cetacean.

PÁGINAS: 94
GRANDE ÁREA: Ciências Humanas
ÁREA: Psicologia
RESUMO:

Humpback whales (Megaptera novaeangliae) migrate annually from feeding to breeding grounds in tropical and subtropical areas during the winter and spring. One of these reproductive habitats is off Brazil, where the Abrolhos’ Bank (Bahia) is the principal area of the subspecies M. n. australis occurrence and concentration in the Occidental South Atlantic Ocean. Throughout the breeding season, males produce complex and long vocalizations: the song. It is comprised of repetitive patterns and it is structured hierarchically by units, phrases and themes. Even though the song’s function is not fully understood, it is associated with the species sexual selection. The hypothesis most accepted is that the song is a way to attract females and may act as inter- and intra-sexual displays. Each population in the world has its own song version that evolves along the years with varying rates of change and all males from the same population incorporate these changes. The modifications and the learning of all the males result in different or new songs, phenomenon previously described as cultural evolution. There are few qualitative studies about the song evolution of the humpback whale population that visits Brazil, but to the best of our knowledge no quantitative study in medium temporal scale has been done yet. The present study aims (1) to describe the song themes of males in Brazil from 2006 to 2017, (2) to characterize themes composition in phrase level and (3) to identify theme sequences alterations quantitatively by Levenshtein distance similarity index method from 2000 to 2017. Data were collected by passive acoustic monitoring during the breeding season in Brazil (July to November). Just static themes were considered to define the median song of each year and a song cycle was compounded by a sequence of themes without repetition of themes. The results enabled verifying song cultural evolution in small temporal scale when comparing consecutive years and medium temporal scale when assessing a longer time interval (2000 to 2017). Inter- and intra-individual variations were found in different hierarchical levels of the song: unit, phrases and themes, probably reflecting the dynamics of the species’ sexual selection process. Qualitative analyses characterized the structure of the song from Breeding Stock ‘A’ (Brazil). Additionally, quantitative analyses showed different rates of change in the song over the years, demonstrating no single pattern. These results show that song cultural evolution within the population that visits Brazil is not directed by a single force emphasizing that and further research is necessary to define what is driving this phenomenon.

MEMBROS DA BANCA:
Presidente - 1863735 - RENATA SANTORO DE SOUSA LIMA MOBLEY
Externo ao Programa - 1439088 - MAURO PICHORIM
Externo à Instituição - MARIA ISABEL CARVALHO GONÇALVES - UESC