Banca de QUALIFICAÇÃO: BRUNO DE SOUZA MAGGI

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : BRUNO DE SOUZA MAGGI
DATA : 02/12/2016
HORA: 09:00
LOCAL: Sala de Reuniões do Prédio de Ecologia
TÍTULO:

Collor, Peformance and sexual selection in Tropidurus hispidus


PALAVRAS-CHAVES:

female mate choice, male competition, bite force, sprint speed, coloration, lizards, South America

 

PÁGINAS: 50
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
RESUMO:

Within this proposal, we aim to resolve the following issues: Are there differences in coloration between males and females of Tropidurus hispidus? Do females use color traits to choose between mates? Does male coloration predicts the outcome of agonistic encounters? Is there relation between coloration and performance (sprint speed and bite force)? For that, we will use as model system T. hispidus Spix (1825), the larger species of the Torquatus group. Lizards of this genus are diurnal, extremely abundant, heliophiles, sit-and-wait foragers, and territorials, occurring predominantly in open areas. We used a spectrophotometer to measure color variables, a force transducer coupled to an amplifier to measure bite force, video camcorders and a lizard racetrack to measure sprint speed data. To access whether or not females use the color as dominance signal and a choosing criteria, we performed two controlled experiments with size-paired males. The first, a female mate-choice experiment in which we put males in a terraria enclosure with three separated parts. We assigned each male to a compartment in which they did not have mutual visual contact. We assigned females to the third compartment that enables visual contact to both the males. The second, a agonistic interaction experiment among males, in which we put a pair of males in a single terraria enclosure for 30 min. During the experiment period we recorded behavioral displays in order to determine winners of each trial. Separately, we used color variables to differentiate males from females, to access if females use color to choose for mates. To achieve the relation between color and performance we ran a correlation between color variables, bite force and sprint speed. All together, we expect to have a better understanding of the evolution of the design of signals and, also, how inter- and intra-sexual selection act in this process. Our first results show that T. hispidus has sexual dichromatism and that this difference is perceived by conspecifics. Among 11 body regions that we used to compare males against females, nine showed significant difference. In the dorsal region, red Chroma is the best discriminator variable between males and females. Whereas that for the ventral region, brightness distinguishes males from females the most. In addition to the brightness in ventral body regions, UV Chroma in tail base also distinguishes sexes. The visual model showed that other lizards perceive the color differences, confirming the spectrophotometric data.


MEMBROS DA BANCA:
Interno - 1678338 - ADRIAN ANTONIO GARDA
Externo ao Programa - 1476621 - DANIEL MARQUES DE ALMEIDA PESSOA
Presidente - 1715227 - GABRIEL CORREA COSTA
Notícia cadastrada em: 24/11/2016 15:09
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