Melanophores and their role in color change and the ecology of the marine Isopod, Sphaeroma quadridentatum Say.

On the Texas coast Sphaeroma quadridentatum is found along the beachfront and bays. Beachfront populations near Galveston, Texas are restricted to man-made rock groins and jetties, and on these structures they are usually associated with oysters and barnacles in the surf zone. In these microhabitats substrate coloration ranges for nearly white shell surfaces to the grey coloration of the granite substrate. The objectives of this investigation were to define the relationships between melanophore pigment migrations and incident light, substrate reflectance, and change response. S. quadridentatum offers an especially valuable opportunity to examine the adaptive significance of melanophore responses, because its natural environment consists of a finely patterned mosaic in shades of grey that correspond well with the range of animal color observed in field collections.