Predicting the population dynamics in Amoebophrya parasitoids and their dinoflagellate hosts using a mathematical model

Abstract

Free-living, photosynthetic marine dino- flagellates are frequently infected by microparasites of the genus Amoebophrya. Attacks by Amoebo- phrya can contribute to the termination of dino- flagellate blooms and have been suggested to in- fluence the geographical distribution of certain host species. Because infection terminates with the killing of the host (i.e. Amoebophrya behaves like a parasitoid), the interaction can be considered, from a modeling point of view, similar to the process of predation, with the difference that it takes a longer time for the parasitoid to kill the host as compared to typical predator-prey interactions. In the present work, we explored the population dynamics in Amoebophrya and their dinoflagellate hosts using the Rosenzweig-MacArthur modification of the tra- ditional Lotka-Volterra predation model. The model was parameterized for 3 systems, Akashiwo san- guinea, Gymnodinium instriatum, and Karlodinium micrum, and their respective Amoebophrya para- sitoids, using published experimental data. Parame- ter validation was possible for parasitoid search rate and mortality. The potential for host control by Amoebophrya and the probability for host extinction were studied with respect to carrying capacity, a parameter that is influenced by e.g. eutrophication. The model may be useful to predict conditions under which Amoebophrya can control populations of its dinoflagellate hosts. . Parasitism . Marine dinoflagellates . Mathematical model .