Runcina
Runcina is a genus of sacoglossan sea slugs, commonly known as “sap-sucking slugs” or “solar-powered slugs.” These fascinating creatures are marine gastropods belonging to the family Runcinidae. They are characterized by their unique feeding habits and their ability to photosynthesize, a trait uncommon among animals.
Characteristics
Runcina species are typically small, with an elongated, cylindrical body and a prominent head. Their bodies are often translucent or semi-transparent, revealing their internal organs. They possess a pair of prominent cephalic tentacles used for sensing their environment and a pair of smaller, lateral tentacles called rhinophores that aid in detecting chemical cues. Runcina lack a shell, but instead have a hardened, chitinous "shield" that covers their dorsal surface.
Environment and Distribution
Runcina species are found in a variety of marine environments, primarily in shallow, coastal waters. They are typically found on algae, seagrass, and other marine plants. They are distributed worldwide, with species found in the Atlantic, Pacific, and Indian Oceans.
Feeding Habits
Runcina are herbivorous and specialize in feeding on various species of algae. They possess a unique feeding apparatus known as a "radula," which is a ribbon-like structure studded with rows of teeth. They use their radula to puncture the cell walls of algae and suck out their contents, including chloroplasts.
Photosynthesis
One of the most remarkable characteristics of Runcina is their ability to photosynthesize. After consuming chloroplasts from algae, they retain these organelles within their own cells. These "kleptoplastids" continue to photosynthesize, providing the slug with supplementary energy. This remarkable adaptation allows Runcina to survive for extended periods without feeding on algae, making them effectively "solar-powered."