| Abstract: | The non-photosynthetic, phagotrophic dinoflagellate, Gymnodinium fungiforme Anissimova is attracted to a variety of amino acids and other organic compounds. Glycine, taurine and serine attracted the dinoflagellates at a threshold detection level of 10?8 M fallowed by dextrose (10?7 M) and alanine, proline and threonine (10?6 M). Glycine, taurine and alanine are three of the most abundant free amino acids found in invertebrates and protozoa which are major food sources of this dinoflagellate. Three additional species of cultured heterotrophic dinoflagellates were exposed to the water soluble fraction of a shrimp extract known to attract G. fungiforme. All three species responded to the extract, but one species, Oxyrrhis marina, did so only after changing its food source. It is suggested that chemosensory behavior may be suppressed or expressed depending on culture conditions. |
