Competition between Color Morphs of the Polychromatic Midas Cichlid Cichlasoma citrinellum.

Competition Between Color Morphs of the Midas Cichlid, Cichlasoma citrinellum, in Lake Jiloá, Nicaragua

Cost of morphological specialization: feeding performance of the two morphs in the trophically polymorphic cichlid fish, <Emphasis Type="Italic">Cichlasoma citrinellum</Emphasis>

The feeding performance on soft and hard prey of two morphs of the trophically polymorphic Neotropical cichlid fish, Cichlasoma citrinellum, was investigated in the laboratory. The molariform morphs, specialized to feed on hard prey, are able to crack snail shells that are twice as hard as those cracked by the papilliform morphs. During ecological bottlenecks in food resources this ability shou...

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 ...

Two Modal Action Patterns with a Continuous Temporal Distribution

and Summary Most methods of quantitative analysis of animal behavior assume that action patterns can be unambiguously classified into discrete, exclusive categories. This is not invariably the case. The digging behavior of the Midas cichlid (Cichlasoma citrinellum), for example, exhibits two functionally distinct modalities, scoop and pi&, that intergrade continuously in form but are separable ...

Social control of primary sex differentiation in the Midas cichlid.

Sexual differentiation in teleost fishes is characteristically labile. The most dramatic form of sexual lability is postmaturational sex change, which is common among teleosts although rare or absent in other vertebrate taxa. In many cases this process is regulated by social cues, particularly dominance interactions. Here we show that in the Midas cichlid, Cichlasoma citrinellum, these same sor...