Bioluminescence control mechanisms and functions in brittle stars


Researchers: Jérôme Mallefet (principal investigator)
                      Constance Coubris (Ph.D. student)
External collaborators:
- Dr. Patrick Flammang & Dr. Jérôme Delroisse (UMons, Belgium)
- Prof. Maria Byrne (Sydney Univ., Australia)
- Dr. Tim O’Hara (Melbourne Museum, Australia)
- Dr. Keiichi Sato (Okinawa Churashima Research Center, Japan)
- Prof. Hsuan-Ching Ho (National Dong Hwa Univ., Taiwan)


Control mechanisms

The luminescence control mechanisms are studied on several species of brittle stars. Two types of biological preparations (dissociated arm segments and photocytes) are used to determine the nature of the control (nervous control, importance of the ionic movements) and to identify the second messengers involved in the control of the light reaction. The following species are currently used as models: Amphiura filiformis, Ophiopsila aranea, Ophiopsila californica, Ophionereis schayeri and Ophionereis fasciata.



Up to now, 65 species of brittle stars are known to bioluminesce, on nearly 200 species tested among 2173 known species in total. The abundance of luminous species in this class of echinoderms is already quite remarkable, and it is likely that many other luminous species will be discovered in the years to come. This abundance suggests that luminescence plays a major ecological role for these brittle stars. The research carried out in this area since 2009 at the laboratory aims at understanding and determining the functions of bioluminescence in brittle stars. They are articulated around two main aspects: determine the role(s) of luminescence in five model species of brittle stars: Amphipholis squamata, Amphiura filiformis, Ophiopsila californica, Ophiopsila aranea and Ophiocomina nigra; and define groups of species (according to ecological, physiological or morphological criteria) that share common bioluminescence functions. This is to understand why so many species of brittle stars are bright, and to understand the evolutionary mechanisms of luminescence selection in this class of benthic invertebrates.