Sea Hares Save Selves with Smell-Stopping Secretion

Imagine a bloodhound trying to hunt wearing nose plugs. That’s how the spiny lobster feels after being squirted by a substance called opaline by the sea hare, its natural prey. Georgia State researchers have discovered that opaline gunks up a lobster’s antennules, reducing its sense of smell and allowing the sea hare to escape unharmed.

Sea hares also squirt ink, which contains chemical that are noxious to lobsters. Charles Derby, the Regents’ Professor of Neurology and Biology, along with graduate students Tiffany Love-Chezem and Juan Aggio, was the first to figure out exactly how opaline works.

The researchers began their experiments by painting lobsters’ antennules with opaline extract. Then, the researchers presented the lobsters with shrimp juice, and measured the electrical activity in the lobsters’ chemosensory and motor neurons.

Both sets of neurons showed only a muted response, showing that the smell of the shrimp juice simply wasn’t getting through. The team tried the experiment again, painting the antennules with some of the non-sticky components of opaline. This time, the lobsters and their neurons responded strongly to the shrimp juice, showing that stickiness was the key to opaline’s powers