Color discrimination thresholds in a cichlid fish: Metriaclima benetos

Pigments of a color polymorphism in a cichlid fish.

i. Cichlasoma citrinellum occurs as gray or gold morphs in lakes in Nicaragua. The gold morph is variable and individuals range from yellow to dark orange. 2. The pigments responsible for the carotenoid coloration are E-carotene and canthaxanthin. The gray morph contains a carotenoid component and also heavy melanin deposits. 3. The carotenoids are dietary in origin, but their distribution and ...

Frequency-dependent social dominance in a color polymorphic cichlid fish.

A mechanism commonly suggested to explain the persistence of color polymorphisms in animals is negative frequency-dependent selection. It could result from a social dominance advantage to rare morphs. We tested for this in males of red and blue color morphs of the Lake Victoria cichlid, Pundamilia. Earlier work has shown that males preferentially attack the males of their own morph, while red m...

Color discrimination in Caspian pony

Thresholds for color discrimination in English and Korean speakers.

Categorical perception (CP) is said to occur when a continuum of equally spaced physical changes is perceived as unequally spaced as a function of category membership (Harnad, S. (Ed.) (1987). Psychophysical and cognitive aspects of categorical perception: A critical overview. Cambridge: Cambridge University Press). A common suggestion is that CP for color arises because perception is qualitati...

Male courtship preferences demonstrate discrimination against allopatric colour morphs in a cichlid fish

Whether premating isolation is achieved by male-specific, female-specific or sex-independent assortative preferences often depends on the underlying evolutionary processes. Here we test mate preferences of males presented with females of different allopatric colour variants of the cichlid fish Tropheus sp., a Lake Tanganyika endemic with rich geographical colour pattern variation, in which the ...