H. arenicola cannot divide without containing the endosymbiont. But, unlike a fully integrated organelle, the Nephroselmis alga does not divide along with the host cell. When the host cell divides, one of the daughter cells receives the Nephroselmis cell and the other daughter returns to a heterotrophic lifestyle. Hence, the mother protist gives rise to green-coloured and white-coloured daughter cells. The latter behaves like a predator until it ingests a Nephroselmis green alga. The alga then loses its flagella and cytoskeleton, while the Hatena, now a host, switches to photosynthetic nutrition, gains the ability to move towards light and loses its feeding apparatus. Thus, the protist exhibits an unusual life cycle of alternating autotrophy and heterotrophy.
