The venom blocks a chemical substance called octopamine in the cockroach's brain that controls its motivation to walk, the study found.
Unable to fight back, the "zombie" cockroach can be pulled into the wasp's underground lair, where an egg is laid in its abdomen. The larva later hatches and eats the still living but incapacitated cockroach from the inside out.
"The whole thing takes about seven to eight days, during which the meat has to be fresh," said study co-author and neurobiologist Frederic Libersat of Ben-Gurion University of the Negev in Be'ér Sheva, Israel.
"If you kill a cockroach, it rots within a day."
The mature wasp emerges from the bug victim's body after about a month.
Saturday, December 08, 2007
Zombie roaches and their wasp masters
Zombie roaches at National Geographic: