Well, cockroach brain, but the reference had to be made.
Ampulex compressa is a name that (literally) strikes fear (and a stinger) into the minds of cockroaches everywhere. Well, just in South Asia, Africa, and the Pacific Islands.
This wasp is what is known as an entomophagous parasite (there’s a five dollar word), as in it’s an insect that is parasitic on other insects. Now, when I say that this wasp lays an egg on a paralyzed cockroach and then has its young eat the cockroach alive, you’d probably think that this thing looks like some sort of freaky monstrosity. I mean, that pose in the first photo makes it hard to tell where wasp begins and cockroach ends. Well…
Don’t let her iridescent figure fool you. Millions of years of evolution have lead to a fairly elaborate and interesting reproductive mechanism, one which is simultaneously impressive (from our perspective) and really shitty (from a cockroach’s perspective).
Let’s walk through the process.
A female wasp seeks out a cockroach host and ambushes it. She inserts her stinger into its thorax and delivers a paralyzing shot of venom that immobilizes the insect for a few minutes. She pulls her stinger out and then delivers a second injection. This one goes into the cockroach’s head, delivering more chemicals to two sites in the brain of the host.
The result is a cockroach zombie. The neurosurgically altered victim recovers from its paralysis but now lacks the will to flee or fight. The wasp pulls on an antenna and leads the roach, like a dog on a leash, into a burrow. There she glues an egg to the underside of the roach. She leaves the burrow and seals it shut. In the darkness, the roach stands motionless as the wasp larva hatches from its egg and chews a hole into its side. The wasp feeds through the hole for a while, and then slithers inside. Later, it pops out as a full-grown adult.
But what the really interesting thing is the mechanics of those injections. Why do those matter?
To appreciate just how tricky this can be, consider what it takes for doctors to deliver drugs to a human brain. They scan the patient’s brain to map its anatomy in three dimensions. Then they put their patient’s head in a cage, drill a hole in the skull, and then slowly push a tube into the brain. A wasp does much the same thing in about a minute, without ever glancing at a brain scan of its victim.
Yea, it’s impressive, even though roach brains are much simpler.
How is this done? Here’s a quick excerpt-I really recommend reading the rest of the article though, it’s not too long and not super-jargon filled (plus, a video explanation is located at the end, and it’s a TED talk!)
They pull off this feat with their extraordinary stinger. It measures 2 millimeters long, enabling the wasp to insert it into the roach’s neck and snake it up to the brain. The tip of the stinger has two sets of valves. One set hold the equipment for laying eggs, and the other set hold the equipment for delivering venom. The valves interlock in a tongue-and-groove arrangement so that they can slide over each other, allowing the wasp to lay an egg or deliver a sting with the same organ….the wasp uses its stinger to feel its way through the roach’s brain.
If you didn’t want to read all that because the thought of a wasp stabbing a needle into a roach’s head in order to deliver zombie drugs into it so that the wasp larva can eat the roach alive is too disturbing, here’s a quick summary of how the process works.
To finish things off, I’ll leave you with a charming picture that shows the miracle of life.