Banca de DEFESA: LARISSA DA MATA OLIVEIRA PRADO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : LARISSA DA MATA OLIVEIRA PRADO
DATA : 27/09/2018
HORA: 14:00
LOCAL: Sala de Reuniões do Centro de Biociências
TÍTULO:

BACKGROUND COLOR AND BRIGHTNESS PREFERENCE BY THE SOUTH AMERICAN ELECTRIC FISH ITUÍ-CAVALO (Apteronotus albifrons) 

PALAVRAS-CHAVES:

Color vision; Background preference; Gymnotiform; Apteronotus albifrons.

PÁGINAS: 44
GRANDE ÁREA: Ciências Humanas
ÁREA: Psicologia
RESUMO:

The Gymnotiform weakly electric fishes are widely used as animal models for studies in electrocommunication. The theoretical body regarding the vision of these animals is scarce, since their eyes are less developed than their electric sense. In comparison to the physiological evidence from the Gymnotiform Eigenmannia virescens, it is believed that the South American electric fish Ituí-cavalo (Apteronotus albifrons) is a long-wave-sensitive cone monochromat. However, no experiment demonstrated the color perception in this animal by behavioral basis, nor was the influence of the brightness cue on its natural behavior investigated. In the present study, eight Ituí-cavalos in the UFRN Sensory Ecology laboratory were tested for preference of brightness and color by comparisons on backgrounds. The stimuli were designed after visual modeling for the photopic and mesopic vision of the fish under 800 and 8 lux, respectively. The brightness parameters were referenced at 40, 65, 70 and 100% to the gray color reflectance standard, while the chromaticity parameters were 100% of the reflectance pattern of the yellow and green colors. Circular backgrounds were divided into three equal parts, one for the brightness experiment, divided into gray40 (dark), gray65 (intermediate) and gray100 (light), and one for color test, divided into yellow100, green100 and gray70. The greys used in the brightness test were controlled for the same chromatic value and varied only in achromatic value, inciting discernment based solely on the brightness cue; in the color test, all colors were controlled for the same achromatic value and only varied in chromatic value, guaranteeing that the animal would only differentiate them if it had color vision. The time spent/area of the stimulus was recorded as a deterministic parameter of preference. The results showed that the Ituí-cavalo had a population preference for darker shades, avoiding the lightest one, and that the possible color preferences were individual and without any discernible pattern. The preference for dark backgrounds can be justified as a possible maneuver to reduce stress and/or risk of predation, as observed in Heterandria formosa, while color preference rests on a possible visual modeling mismatch, since the spectral sensitivity of a close species was considered in the absence of accurate physiological evidence on Ituí-cavalo. These findings demonstrate the importance of behavioral experimentation for the practical verification of physiological studies. 

MEMBROS DA BANCA:
Externo à Instituição - ANDRE CARREIRA BRUINJÉ - USP
Presidente - 1476621 - DANIEL MARQUES DE ALMEIDA PESSOA
Externo ao Programa - 350638 - MARIA DE FATIMA ARRUDA DE MIRANDA