Disco clams! The secret behind the mollusk's flashy light show finally revealed
Unlike fireflies and plankton, this dazzling display is not due to bioluminescence.
Thu, Jun 26, 2014 at 11:51 AM
When University of California Berkeley graduate student Lindsey Dougherty came across a cluster of clams flashing like Studio 54 while scuba diving off the coast of Indonesia, she did what any young scientist would do. She started disco dancing underwater; and then she made a plan.
"I've dived with humpback whales and great white sharks. But when I saw the disco clam, I was enamored. I said then, 'I'm going to do a Ph.D. on the disco clam,'" Dougherty said.
Disco clams (Ctenoides ales) – also known as electric clams – live in depths of 10 to 150 feet beneath the surface of the sea in tropical Pacific locations. At only 2 inches long, the creatures have 40 eyes; but that’s not what makes them so special. It’s their unique pulsating light that inspires thoughts of John Travolta — and what makes them to be so utterly alluring.
But what’s even more fascinating is that the source of their glitzy spectacle is not bioluminescence, the chemical process that gives fireflies their glow and makes oceans glow at night. Instead, the disco clam owes its flash to a mechanical process, as Dougherty discovered during her research of the blinking bivalve.
Dougherty worked with scientists using high-speed photography, X-ray spectroscopy and computer simulations to figure out how the magic – which you can see for yourself in the video below – was happening.
What they found were small, mirror-like spheres packed along the clams’ lips that cause light to reflect off the surface. Basically, teeny disco balls. The wee clam’s tongue furls and unfurls two times a second, quickly blocking and exposing the reflective surface, which results in flashes of reflected light. The back of the area is dark blue, creating the perfect contrast to heighten the effect.
Dougherty thinks the behavior may be a way for the clams to communicate with other clams from their species; other possibilities include attracting prey or as a defense against predators.
The research team is raising disco clams in tanks to further understand this dazzling creature; so far, Dougherty says there is no evidence of any other species having a similar system. But as long as there are disco clams, that might just be enough for us. Party on, little guys.
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