So, what exactly does the clam do?
The disco clam (Ctenoides ales) lives in the waters of the Indo-Pacific, and it gained its name because its fleshy lips flash like a mirror ball over a dance floor. The clam is able to do this by using nanoparticles of silica to reflect light, a study published on Jan. 4 found, according to the science journal Nature.
This clam is unique because the kind of control it displays is something that hasn’t been observed before.
“We don’t know of anything that is quite like the disco clam,” Lindsey Dougherty, a biologist at the University of California Berkeley, told Nature. She led the study, which was published in the Journal of the Royal Society Interface.
Wanting to learn more about the colorful clams, Dougherty and her collaborators, Professor Roy Caldwell and Alexandria Neibergall, an undergraduate student, brought a few of the clams back to the lab to find out how and why the clams flash, Discovery News reports.
Scientists originally thought the bivalve was bioluminescent, which results when light-emitting chemical reactions — produced by creatures like fireflies and deep-sea fish — giving them their characteristic glow.
What Dougherty and her team discovered, is that the light show is due entirely to reflected light, Nature reports. Tiny spheres of silica, which are chemically similar to window glass are utilized in order to do this. The disco clam has two fleshy mantle lips that are the color of a ripe mango. It sequesters the silica on one side of these lips, in the soft fold that the clam uses to filter feed. By contrast, the other side of the lip absorbs light and is a reddish color. The flashing colors occurs when the mollusk rolls up and unfurls each side simultaneously, several times a second.
The tissues on the clam’s delicate lips are so reflective that they can even flash low levels of blue light found in the dark caves where they live, Discovery News reports. These little mollusks are the only species of bivalve to have evolved this kind of structural coloration, the researchers report.
The scientists had wondered if the clams used this flashy display to attract a mate. Using a powerful microscope, they studied the structure and proteins in the creature’s tiny eyes. What they found is that the clam’s vision is too poor to allow it to observe the displays put on by other clams. So they concluded that the clams aren’t visually attracted to each other.
So what does the disco clam do with all that bling?
The scientists decided to find out. They began by wondering what would happen if a predator dropped by.
“In this case, the false predator was just a styrofoam lid,” Dougherty said, per Discovery News. “But it turns out a styrofoam lid is indeed pretty scary to the clams, because their flash rate almost doubled from just under two Hz to just under four Hz.
Equally surprising, the researchers found high levels of sulfur in the creature’s tentacles. When it was attacked by a peacock mantis shrimp, the shrimp recoiled and became catatonic. The scientists think the feisty clam is releasing toxic and distasteful mucus that repels predators.
When the researchers added phytoplankton, a tasty edible that some clams love, to the creature’s tank, the clam really turned flashy. Phytoplankton is attracted to light, so it’s believed that the lights attract prey, per Discovery News.
Discovering these amazing creatures in the darkness of an underwater cave during a dive in Indonesia was a thrill for Dougherty.
“It was on that trip I first saw the disco clam, and immediately fell in love,” Dougherty said in a press release.
Indeed, the little clams are beautifully colored, and besides, who couldn’t love a creature that repels predators with toxic snot?
