How Does The Disco Clam Light Up?

By John Virata

How many of you are old enough to remember what a disco ball looks like and what it does? Were you aware that there is a little mollusk called the disco clam (Ctenoides ales) that gives off a spectacular light show? Scientists weren’t exactly sure how the disco clam lit up the waters around it until now.

A University of California at Berkeley graduate student and scientist has finally figured out how the strobing clam puts on a light show with its mirrored lips. Lindsey Dougherty was diving in Indonesia with her mother and sister when they came across the little mollusk with the built-in strobe light. According to a press release put out by UC Berkeley, Dougherty, her sister and her mother even danced to the strobe of the clam during their dive in Wakatobi. At that point, Dougherty told herself that she was going to do a Ph.D on the disco clam and find out how it lights up.

In just a few short years she found out that the flashing lights were not based on bioluminescence as most had thought, but rather, the little clam’s mantle lip is reflective on one side and when the clam opens its lip up, the reflective side captures ambient light, which makes it strobe like a disco ball.

Dougherty’s work was recently featured on the cover of the British Journal of the Royal Society Interface

According to Dougherty, the inside of the clam’s lip is built with spheres of silica that are 340 nanometers in diameter. These spheres act as the reflectors, especially when blue light bounces off the spheres. The outer lip doesn’t have this feature so it does not reflect light. When the clam opens and closes its lips is when the lights appear like that of light striking the mirrors of a disco ball.

Dougherty then used a variety of high tech scientific tools, including high speed video, transmission electron microscopy, spectrometry, energy dispersive x-ray spectroscopy and computer modeling to get a better look at the internal structure of the clam’s lips. More research determined that no other animal uses silica nanospheres as flashing reflectors. She did find that the white color of certain insects reflect light.

Ctenoides ales can be found in tropical regions of the Pacific Ocean living on reefs. They are found in clusters of two or more and can be found in waters ranging from 3 to 50 meters deep. Dougherty told FishChannel that Ctenoides ales is often mislabeled in the trade as Lima sp., the electric flame scallop. She said that Ctenoides ales is the only known bivalve that flashes.

Dougherty is unsure why the disco clam reflects light in the way it does but has her theories. Is it lighting up to attract prey, ward off predators or signal potential partners? She hopes to answer those questions in her next research project.

This article originally appeared on, which was incorporated into

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