Brittlestar Color‐Change and Phototaxis (Echinodermata: Ophiuroidea: Ophiocomidae).

Publisher Website
Google Scholar
Abstract
In the first decisive study of color‐change in brittlestars, four Caribbean species,Ophiocoma echinata, 0. paucigranulata, O. pumila,andO. wendtiare reported to change color from day to night. Color‐change is most striking inO. wendti,which is dark brown during the day, and is banded gray and black from dusk to dawn. The transformation occurs over a 3 to 4 hour period and is effected by chromatorphores which appear to respond to illumination, independently of the central nervous system. Color‐change may also be mediated by an endogenous rhythm.Ophiocoma wendtiis more responsive to light than the other 3 species tested. It reacts to lower levels of illumination at night than during the day, exhibiting negative phototaxis in moonlight as well as in sunlight. I suggest that color‐change may expose (or shield) photosensitive tissues that control the brittlestar's detection of shaded fissures in the reef. Thereby, chromatophore activity may be connected with the brittlestar's chief defense from predators, the ability to detect shadow and escape into darkened crevices. Although experiments to date with predacious fish are equivocal. the color patterns ofOphiocomaspecies mav provide protective camouflage.

This publication has 21 references indexed in Scilit: