VISUAL PIGMENTS AND OIL DROPLETS IN GENETICALLY MANIPULATED AND CAROTENOID DEPRIVED QUAIL - A MICROSPECTROPHOTOMETRIC STUDY

The spectral absorbances of visual pigments and retinal oil droplets w ere studied in three groups of Japanese quail (Coturnix coturnix japon ica): an unselected control population and two artificially selected s trains that exhibited different early approach preferences between blu e and red stimuli. The oil droplets were examined with and without pri or carotenoid deprivation. Four cone pigments and five oil droplet typ es were identified, resembling those in other avian species. Carotenoi d deprivation eliminated all pigmentation detectable in oil droplets b y microspectrophotometry. Placement of chicks on normal diet gradually reintroduced normal pigmentation within the span of about a week. No statistically significant differences were found between normal and ge netically selected birds in either visual pigments or oil droplet type s, or in their relative proportions. It is concluded that differences in the early colour preferences of quail are unlikely to be a result o f variation in the spectral properties of their photoreceptors.