Glow In the Dark Snail Uses Light To Ward Off Predators

The clusterwink snail H. brasiliana emitting biolumuniescent light (right) and without light. Credit: Scripps Institution of Oceanography, UC San Diego
A species of “clusterwink” snails has a built-in home security system. The bottom-dwelling, opaque-shelled creatures clump together on Australia’s rocky shorelines, blending into the background until a crab or some other potential predator comes near. Then, similar to motion-detector security lights, the snails set off a brilliant green bioluminescent glow.
At least, that’s what researchers found while studying the snails, Hinea brasiliana, in Scripps' Experimental Aquarium, leading them to believe that the luminous displays are intended to ward off predators.
Clusterwink snails' opaque shells would seem to blunt light transmission. Credit: Scripps Institution of Oceanography, UC San Diego
The fact that the entire shell glows is remarkable, given that the creature produces the light from discrete areas on its body. The shell isn’t clear—it’s opaque and pigmented, but selectively diffuses the blue-green wavelength of the bioluminescence, emitting an eerie glow. It works out well for the snail, which can stay safely inside its shell.
"It's rare for any bottom-dwelling snails to produce bioluminescence," Nerida Wilson, who coauthored the study published in the Proceedings of the Royal Society B with Dimitri Deheyn, said in a press release. "So its even more amazing that this snail has a shell that maximizes the signal so efficiently."

The unusual green bioluminescent light emitted from the marine clusterwink snail H brasiliana. Credit: Scripps Institution of Oceanography, UC San Diego
Deheyn believes the findings could be applied to optics or bioengineering research. "Our next focus is to understand what makes the shell have this capacity and that could be important for building materials with better optical performance."
A variety of animals, from fish and microorganisms to insects and plants, glow in the dark. Click here to read more about bioluminescence. 
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