The memorably-named Disco Clam is back in the news, and biologists may have figured out why this unique (and until-now mysterious) coral reef dweller emits flashes of light.
As National Geographic reports, UC Berkeley grad student Lindsey Dougherty — who previously deduced that the flashes are caused not by bioluminescene, but by "reflecting light through tiny bits of silica near the edge of its shell" — has moved on from how into the why. As in: Why are we having a Saturday Night Fever club night off the coast of Indonesia?
The answer makes sense: to tell predators to bug off, or to entice prey. Surprisingly, luring a mate was not among the reasons (though they have around 40 eyes, the clams don't see well enough for that to work).
Dougherty, who presented new research on the subject at the Society of Integrative and Comparative Biology's annual meeting this week, found that placing a fake predator in a disco clam's tank made its flash rate increase; to a lesser degree, the same held true with plankton.
Questions remain; for instance, is the plankton attracted to the flashes, and if so, how? And are predators scared off by the flashes, or by the sulfur in the clam's tentacles and mantle? Fortunately, Ctenoides ales aficionados have Dougherty, who told National Geographic that "for me, the most fun place is underwater with the clams," on the case.