Big slimy lips are the secret to this fish’s coral diet
Imaging study shows how tubelip wrasses slurp coral snot
SMOOCHES Scanning electron microscope images show the differences between the lips of a coral-eating wrasse species (left) and one that dines on a more mundane diet of crabs and other invertebrates (right). While teeth are thought of as a key factor in the evolution of fish feeding strategies, the new study implies that lips are important, too.
Tubelip wrasses eat dangerously, daring to dine on sharp corals lined with stinging cells. New images reveal the fish’s secret to safe eating: lubing up and planting a big one on their dinner.
“It is like sucking dew off a stinging nettle. A thick layer of grease may help,” says David Bellwood, a marine biologist at James Cook University in Townsville, Australia, who snapped the shots with his colleague Victor Huertas.
Of roughly 6,000 fish species that roam reefs, just 128 consume corals. These corallivores specialize in different menus. Well-studied butterfly fish, for example, use their long, thin snouts to nip up coral polyps, the tiny animals that build corals. Tubelip wrasses such as Labropsis australis of the South Pacific are known for nibbling coral with their luscious lips, but until now, it was unclear what part of the coral the fish were eating or how they were eating it.