Sea Slugs Steal Body Parts from Prey to Acquire New Abilities
Scientists have discovered that lettuce sea slugs (Elysia crispata) possess a remarkable ability to steal body parts from their prey and utilize them for their own benefit.
Unlike typical feeding methods, these slugs harvest chloroplasts—the photosynthesizing organelles—from algae and incorporate them into their own cells. This unique process allows them to perform photosynthesis, effectively generating energy from sunlight. When they consume algae, the slugs divert the chloroplasts into small membrane-bound sacs called 'kleptosomes' within their intestines, keeping them alive and functional. These chloroplasts are then transported to the slugs' backs, where they act like solar panels, extending the slugs' energy reserves.
Chemical analyses reveal that the chloroplasts continue to produce proteins consistent with their original function, and the host slugs actively work to maintain them, evidenced by the presence of slug proteins within the chloroplasts. The slugs' coloration varies depending on their health and food intake, with well-fed individuals appearing green and those deprived of food turning orange. Researchers suggest that these stolen organelles may serve multiple purposes beyond photosynthesis, such as camouflage, food storage, or deterrents to predators.
This extraordinary form of symbiosis may shed light on how organisms acquire new functions through absorbing external biological components—a concept potentially linked to the evolutionary origin of mitochondria within our own cells. The study was published in the journal Cell.
