Ocean life
Mantis shrimp visual pigments act as reversible switches
A study reveals that marine crustaceans possess self-resetting pigments capable of detecting far-red light under shifting underwater conditions.
Reported by Phys.org · · 2 min read
Mantis shrimp are celebrated for having one of the most intricate visual systems in the animal kingdom, relying on roughly 30 visual pigments compared to just three cones in human eyes. In a study published in the journal Science Advances, researchers discovered that several of these pigments detect deep red wavelengths and operate as reversible light switches.
Working across institutions including the University of Liège and Humboldt University in Berlin, scientists analyzed the light absorption and signaling behavior of 17 opsin proteins located in the crustacean eye's central band. They determined that 12 are standard green pigments, while the remainder include three infrared-sensitive opsins and two that respond to blue and orange light. Coupled with specialized eye filters, these proteins enable the animal to perceive wavelengths reaching 687 nanometers using the same vitamin A-derived retinal molecule found in people.
Crucially, four of these proteins are bistable, meaning they switch between two stable configurations upon capturing light without needing separate cellular machinery to regenerate. In human eyes, retinal detaches following light absorption and must be rebuilt, temporarily leaving afterimages in bright conditions. By contrast, two of the shrimp's bistable pigments activate under red light and shut off under blue light, while another pair does the opposite. An incoming photon directly resets the molecule, keeping the visual pathway continuously active.
Researchers liken the crustacean's visual strategy to using tinted glasses during the day and carrying a light source at twilight. When intense sunlight overwhelms blue, green, and ultraviolet sensors, red opsins continue gathering information. At dawn or dusk, the animals can switch their reliance to the green and bistable blue pigments.
Beyond confirming how these pigments operate biochemically, researchers note that behavioral trials will be needed to show how the animals use this vision to target prey, guard territory, or escape danger. The discovery may also aid optogenetics, where light-triggered switches from the G-protein receptor family could offer new ways to control cellular signaling in medical research.
