How the Clusterwink Snail Produces Light

Nature abounds with a wide, and weird, variety of creatures.  Some of the most interesting ones are those that can create light with their bodies –  glow worms, fireflies, angler fish, comb jellyfish, even certain earthworms.  And also, a tiny thumbnail-sized snail found in the area off Australia’s eastern coast that can flash a bright green light from its shell, called the Clusterwing Snail.  These snails are the only mollusks known to have this incredible ability.

The Clusterwink Snail was actually discovered decades ago, but no one ever knew how the snail managed to create pulsing light from its shell.   Now, two scientists from the Scripps Institute of Oceanography at the University of California, San Diego, have provided the first insight into how this marine snail pulls off this feat.  Researchers Dimitri Deheyn and Nerida Wilson discovered that the Clusterwink Snail uses its shell to diffuse (or spread) its bioluminescent light in all directions at once.  This gives the appearance that the snail’s shell is what’s doing the blinking.

When the snail is observed under normal conditions, its shell appears to be opaque and yellowish in color.  This baffled scientists because it seemed that the shell should stifle light transmission, not intensify light like it does.  But researchers have found that when the snail emits its bioluminescence, it comes from the body of the snail.  What the shell does is disperse only the particular color emitted by the snail, amplifying the snail’s glow and emitting it in all directions.

When the Clusterwink Snail feels threatened, it creates lightning-fast pulses of light from a single spot on its body.  The flashes can be so quick that they only last 1/50th of a second – truly a winking cluster of lights.  And thus, the snail’s name.  The light then diffuses out through the entire surface of the snail’s shell.  The flashes seem to scare off predators, either because the light is unexpected, or because it gives the temporary illusion of greater size.

The study was funded in part by the United States Airforce Office of Scientific Research, possibly with an eye toward using the secrets of the Clusterwink Snail in the biotech industry.  Researchers feel that if they can understand how the Clusterwink Snail’s shell is able to so effectively amplify the snail’s natural bioluminescence, that it may be possible to copy it into practical uses for humans, such as improved optical materials or light transmittal devices.  Can you imagine a flashlight that shines light through a hard, shell-like surface?

Sources:  UC San Diego, Scripps Institute of Oceanography