Direct control of pigment aggregation and dispersion in tilapia erythrophores by light

Innervated and denervated erythrophores of the tilapia, Oreochromis nilotic us, responded directly to light of defined wavelength by pigment aggregatio n or dispersion, although similar effects did not occur in melanophores. In spectral regions between 400-440 nm and 550-600 nm, pigment aggregation to ok place, while the dispersion response was accelerated at wavelengths betw een 470-530 nm. The progress of the aggregation or dispersion response depe nded on the light intensity. These results may imply the coexistence of thr ee kinds of visual pigments in tilapia erythrophores.