jukkanmukkir: Sea hares use sticky weapon to cripple predators

শুক্রবার, ২৯ মার্চ, ২০১৩

Sea hares use sticky weapon to cripple predators

Sandrine Ceurstemont, editor, New Scientist TV

Lobsters have to be really hungry to prey on sea hares. When provoked, the animals unleash an unusual weapon, squirting predators with purple ink and sticky goo that knocks out their sense of smell (see video above).

Releasing ink is a common deterrent, thought to cloak prey so they can escape from an attacker, but how the additional sticky secretion works has been a mystery. Now Charles Derby from Georgia State University in Atlanta and colleagues have conducted the first experiments that reveal how it incapacitates predators, making them unable to sniff out prey.

To test whether the goo physically blocks a predator's sense of smell or uses chemicals to affect it, the team extracted the sticky component and painted it onto the tips of lobster antennae, which contain smell sensors. When the treated crustaceans were tempted with shrimp juice, the team found that the electrical activity in their sensory and motor neurons was greatly reduced. But when their antennae were gunk-free, or coated with the chemical attractants in the goo, their neurons fired when presented with prawn snacks.

The experiments prove that the stickiness of the goo is key to the defensive effect, physically plugging smell receptors. It's the first time a demo has uncovered a defence mechanism that knocks out one of a predator's senses.

If you enjoyed this post, see how frog embryos listen out for bad vibrations to avoid snakes or watch how slime secretions make hagfish hard to bite.