Researchers- Scorpions produce two venom types

WASHINGTON -- Scorpions don't bother to waste venom killing a victim if they don't have to. Instead they use a prevenom that causes extreme pain, resorting to the deadlier version only when necessary, researchers have discovered.

A team led by entomologist Bruce D. Hammock of the University of California, Davis, was researching the possibility of an anti-venom for scorpions when they discovered that the stinging creatures produced two kinds of venom.

When first confronted by a threat the scorpion produces a clear liquid on its stinger, Hammock said. The more deadly venom, a thick liquid, "like a milkshake," is produced later, if the threat continues.

It's a clever strategy, Hammock explained, because the deadly true venom uses a lot of proteins and peptides that are costly for the scorpion to make. So instead it tries to get by with a faster acting and more painful toxin that doesn't kill, but is easier to make.

The findings are reported in this week's online edition of Proceedings of the National Academy of Sciences.

The first scorpion weapon, what Hammock calls a pretoxin, gets its kick largely from potassium salts that block receptors in animal cells, rapidly causing severe pain.

He said he has never seen a scorpion skip the prevenom and go directly to the more deadly attack.