Hermaphrodite ‘disco clams’ produce underwater light show

By David Ferguson
Wednesday, January 16, 2013 12:41 EDT
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Disco clams via screencap
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A species of glowing clam, which scientists call a “disco clam,” flashes on and off underwater, creating a strobe-light like effect. According to a Jan. 16 New Scientist article, it is the only bivalve organism known to create a controlled light show, and scientists are only gradually finding out how and why the little mollusks make the light.

Marine biologist Dr. Lindsey Dougherty and her colleagues at the University of California, Berkeley are studying Ctenoides ales, the “disco clams,” to understand what evolutionary pressures would produce the flashing phenomenon, what bio-mechanical mechanism controls it and what “inter- or intra-species benefit” is gained by it.

The team has found that the clams produce the flashing effect by furling and unfurling a reflective lip at the edge of its mantle, the soft inner shell that protects a mollusk’s body. The flashing is visible when the clams are in brightly lit water, but they continue to make the furling motion with the lip even when light is not present.

The clams reflect mostly blue light, which is an advantage since blue light is visible for the greatest distance underwater.

Scientists theorize that, while the clams are filter feeders, the flashing may lure more prey to the mouth area. The light could also be a way of warding off predators. Yet another theory holds that female clams use the light to attract male juveniles, which settle around them prior to spawning.

Dougherty says she believes that the clams are hermaphroditic.

“We think the clams might be hermaphrodites, starting out as small males and maturing into large females, but we have yet to confirm this,” she said.

Watch the video, embedded via New Scientist, below:

David Ferguson
David Ferguson
David Ferguson is an editor at Raw Story. He was previously writer and radio producer in Athens, Georgia, hosting two shows for Georgia Public Broadcasting and blogging at Firedoglake.com and elsewhere. He is currently working on a book.
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