Zombie Cockroaches Revived by Brain Shot
30 November 2007
NewScientist.com
Nora Schultz
There is a cure for zombies after all – if you are a cockroach. A new study has shown that cockroaches that turned into "zombies" after being stung by a parasitic wasp can be revived with an antidote.
Cockroaches can lose their ability to walk when stung by jewel wasps (Ampulex compressa) – the females of which use the cockroaches to feed their young.
The wasp, being much smaller than the cockroach, has evolved a fine sting that can deliver a venom cocktail directly into the cockroach’s brain. The poisons effectively turn the cockroach into a zombie.
The cockroach is not entirely paralysed, but loses its ability to escape. The wasp then grabs it by the antennae and pulls it into its burrow and lays an egg on its abdomen. The cockroach sits still while the wasp's larva hatches, chews a hole into its belly, and slowly eats its living host from the inside over a period of eight days.
Brain Injection
To find out if he could revive the cockroaches, Frederic Libersat from Ben-Gurion University in Be'er Sheva, Israel, injected stung zombie cockroaches with candidate chemicals that resembled various neurotransmitters in the brain.
Libersat found that one of the drugs, a mimic of the neurotransmitter octopamine, succeeded in bringing the roaches back to life.
"The cockroach begins to walk spontaneously again, especially when injected directly into the brain," says Libersat.
He had previously discovered that octopamine-producing neurons elsewhere in the cockroach’s body show reduced activity when stung by the wasps. Libersat thinks that the same thing may happen in the brain.
Zombie Humans
"I think the most likely explanation is that a component of the toxin affects the expression of genes that regulate the activity of these neurons", he says.
So could octopamine become a possible antidote for future humans turned into zombies by, say, invading aliens? Not quite, says neuroscientist Hans-Joachim Pflüger at the Freie Universität Berlin, Germany.
"Our brain is of course much more complex, and we use different neurotransmitters,” he says. “But new research shows tiny quantities of octopamine exist in the vertebrate spinal cord and do affect leg movement, so it will be interesting to see what exactly octopamine does in humans."
