Green Kleptomania

We all learned that plants get their energy from the sun through photosynthesis, whereas animals have to eat plants or other animals to get their energy.

Right? Well, it appears a sea slug named Elysia chlorotica, living in the western Atlantic Ocean, hasn’t been to biology class.

This colorful green slug looks like a fancy leaf, and unlike other sea slugs, it uses the sun for energy, just like a plant. How does it do this? Elysia is a thief, and its thievery is known as kleptoplasty. When it’s young, it eats algae which are loaded with chloroplasts. These chloroplasts, which perform photosynthesis, are removed intact from within the algae. The algae are digested but their chloroplasts are not! The chloroplasts are then absorbed by the slug’s gut cells and distributed to it’s surface. From then on, the slug is solar powered and can make its own energy.

This, and that’s not all. Chloroplasts should not be able to work once they are removed from algal cells because those cells contain proteins that control their operation. But they do work inside the slug. Scientists have discovered that Elysia not only steals chloroplasts, it has the genes to control their functions.