A graduate student at the University of Berkley has discovered the secret of disco clams. If you’re not familiar, these two-inch clams have plains shells, bright red insides and put on a bit of a show underwater when it opens wide. Lindsey Dougherty first discovered them when she was diving with her family in Indonesia. After first coming into contact with the clam, Dougherty decided to dedicate her graduate studies to them. Now, four years later, she’s presented her findings.
Previously, it had been thought that the light shows that the clams create were based on a form of bioluminescence or a chemical reaction inside animals that can produce light—think glow worms, fireflies and the like.. However, thanks to Dougherty and her team’s research, we now know that the light is actually caused by the mirrors that line the lips of the clam. Dougherty found that since the clam moves its lip about twice per second, the reflections from the mirror will glint just like a disco ball.
The “mirror’ part of the lip actually contains tiny spheres of silica, which reflect the blue light that penetrates well through water. Since the surrounding areas don’t contain any reflective properties, it makes the reflections even more apparent. And since the lip is nearly in constant motion, what appears to be a light show is produced.
Now the question remains as to why these clams, or electric clams have the ability to reflect light in this way at all. Currently, she believes that the clams are either attempting to attract food, plankton or other clams for potential breeding, or if it is actually designed to scare away predators.
To study this, she’s now focusing her studies on the eyes of clams. She wants to know if, with all 40 of their eyes, if clams can even detect light and if they can, do they use these flashes to communicate.