The results of the present study indicate that bioluminescence functions as a burglar
alarm in bright emitting dinoflagellates throughout a range of cell concentrations,
but only above a certain threshold in dim emitters. The question our study
raises is whether or not dim emitters like L. polyedrum have any effect on grazers
at low cell concentrations—and if so, by what mechanism. Since so many of the dim
light emitters among the dinoflagellates, including L. polyedrum, are toxic, the possibility
arises that bioluminescence in these species functions as an aposematic signal.
These different functions for bioluminescence are further supported when one
considers the variations in molecular biology and cell physiology between dim and
bright emitters. Multiple Alexandrium spp, L. polyedrum, and Protoceratium reticulatum
(Claparède & Lachmann) Butschli, 1885, which can be considered dim emitters,
are all toxic and possess the luciferin binding protein (LBP), which through its