page_title: Symsagittifera roscoffensis
section_title: Life cycle
hierarchical_section_title: Symsagittifera roscoffensis / The photosynthetic partner and the modus vivendi between the animal and the micro-algae / Life cycle
caption_attribution_description: Français&#160;: Cycle de vie de S. roscoffensis
context_page_description: Symsagittifera roscoffensis, also called the Roscoff worm, the mint-sauce worm, or the shilly-shally worm, is a marine flatworm belonging to the phylum of Xenacoelomorpha. The origin and nature of the green color of this worm stimulated the curiosity of zoologists early on. It is due to the partnership between the animal and a green micro-algae, the species Tetraselmis convolutae, hosted under its epidermis. It is the photosynthetic activity of the micro-algae in hospite that provides the essential nutrients for the worm. This partnership is called photosymbiosis, from "photo", "light", and symbiosis "who lives with". These photosynthetic marine animals live in colonies on the tidal zone.
caption: The captive life cycle is completed (from the adult to the gravid adult) in about 2.5 to 3 months.
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