page_title: Kleptoplasty
section_title: Sacoglossan sea slugs
hierarchical_section_title: Kleptoplasty / Sacoglossan sea slugs
caption_attribution_description: Costasiella Kuroshimae
context_page_description: Kleptoplasty or kleptoplastidy is a symbiotic phenomenon whereby plastids, notably chloroplasts from algae, are sequestered by host organisms. The word is derived from Kleptes which is Greek for thief. The alga is eaten normally and partially digested, leaving the plastid intact. The plastids are maintained within the host, temporarily continuing photosynthesis and benefiting the predator. The term was coined in 1990 to describe chloroplast symbiosis.
context_section_description: One of the only known animals that practice kleptoplasty are sea slugs in the clade Sacoglossa. Several species of Sacoglossan sea slugs capture intact, functional chloroplasts from algal food sources, retaining them within specialized cells lining the mollusc's digestive diverticula. The longest known kleptoplastic association, which can last up to ten months, is found in Elysia chlorotica, which acquires chloroplasts by eating the alga Vaucheria litorea, storing the chloroplasts in the cells that line its gut. Juvenile sea slugs establish the kleptoplastic endosymbiosis when feeding on algal cells, sucking out the cell contents, and discarding everything except the chloroplasts. The chloroplasts are phagocytosed by digestive cells, filling extensively branched digestive tubules, providing their host with the products of photosynthesis. It is not resolved, however, whether the stolen plastids actively secrete photosynthate or whether the slugs profit indirectly from slowly degrading kleptoplasts.
  Due to this unusual ability, the sacoglossans are sometimes referred to a "solar-powered sea slugs," though the actual benefit from photosynthesis on the survival of some of the species that have been analyzed seems to be marginal at best. In fact, some species may even die in the presence of the carbon dioxide-fixing kleptoplasts as a result of elevated levels of reactive oxygen species.
  Changes in temperature have been shown to negatively effect kleptoplastic abilities in sacoglossans. Rates of photosynthetic efficiency as well as kleptoplast abundance have been shown to decrease in correlation to a decrease in temperature. The patterns and rate of these changes, however, varies between different species of sea slug.
caption: Costasiella kuroshimae, a  Sacoglossan sea slug which uses kleptoplasty to create complex patterns on its body
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