How a Wasp Turns Cockroaches into Zombies

From Scientific American:

I don’t know if cockroaches dream, but i imagine that if they do, jewel wasps feature prominently in their nightmares. These small, solitary tropical wasps are of little concern to us humans; after all, they don’t manipulate our minds so that they can serve us up as willing, living meals to their newborns, as they do to unsuspecting cockroaches. It’s the stuff of horror movies, quite literally; the jewel wasp and similar species inspired the chest-bursting horrors in the Alien franchise. The story is simple, if grotesque: the female wasp controls the minds of the cockroaches she feeds to her offspring, taking away their sense of fear or will to escape their fate. But unlike what we see on the big screen, it’s not some incurable virus that turns a once healthy cockroach into a mindless zombie—it’s venom. Not just any venom, either: a specific venom that acts like a drug, targeting the cockroach’s brain.

Brains, at their core, are just neurons, whether we’re talking human brains or insect brains. There are potentially millions of venom compounds that can turn neurons on or off. So it should come as no surprise that some venoms target the carefully protected central nervous system, including our brains. Some leap their way over physiological hurdles, from remote injection locations around the body and past the blood-brain barrier, to enter their victims’ minds. Others are directly injected into the brain, as in the case of the jewel wasp and its zombie cockroach host.

Jewel wasps are a beautiful if terrifying example of how neurotoxic venoms can do much more than paralyze. The wasp, which is often just a fraction of the size of her victim, begins her attack from above, swooping down and grabbing the roach with her mouth as she aims her “stinger”—a modified egg-laying body …

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