|Tamieka Armstrong -
University of New England, Biddeford ME
DINOFLAGELLATE PREDATOR, PARASITE, AND PREY:
WORKABLE TROPHIC TRIANGLE?
The predatory dinoflagellate Polykrikos kofoidii and parasitic dinoflagellate Amoebophrya sp. both feed on the red-tide dinoflagellate Akashiwo sanguinea in the Chesapeake Bay. P. kofoidi may also prey upon A. sanguinea infected with Amoebophrya sp. and thereby limit parasite success. To further explore this trophic triangle, we conducted lab experiments to test the hypothesis that P. kofoidii feeds preferentially on infected A. sanguinea and grows better when given a diet of infected vs. uninfected prey. Results showed that P.kofoidiioffered infected A. sanguinea as prey grew at the same rate as those offered uninfected prey. However, in a mixture of infected and uninfected prey, P. kofoidii preferential grazed uninfected A. sanguinea. Thus, P. kofoidii and Amoebophrya sp. are in direct competition for uninfected A. sanguinea. Together, they may exert strong top-down control on A. sanguinea populations in the Chesapeake Bay.
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