“It’s not brain surgery you know”. That phrase (along with “it’s not rocket science”) is often used to denote a simple act, as compared to the recognised difficulty of surgery on the human brain, one of the most complex objects known. Neurosurgery is one of those things that shows how humans are very different from other living things, with our knowledge of the various functions of different parts of the brain, and our extremely advanced ‘tool use’ when performing surgery on it.
So much so that we are often surprised when we hear about early attempts at neurosurgery in ancient times – “wow, they were more advanced than we thought”. The only trouble with this type of thinking is that humans are not the only animal to perform ‘brain surgery’.
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 part called an ovipositor—at the middle of the body, the thorax, in between the first pair of legs. The quick jab takes only a few seconds, and venom compounds work fast, paralyzing the cockroach temporarily so the wasp can aim her next sting with more accuracy. With her long stinger, she targets her mind-altering venom into two areas of the ganglia, the insect equivalent of a brain.
The wasp’s stinger is so well tuned to its victim that it can sense where it is inside the cockroach’s dome to inject venom directly into subsections of its brain. The stinger is capable of feeling around in the roach’s head, relying on mechanical and chemical cues to find its way past the ganglionic sheath (the insect’s version of a blood-brain barrier) and inject venom exactly where it needs to go. The two areas of the roach brain that she targets are very important to her; scientists have artificially clipped them from cockroaches to see how the wasp reacts, and when they are removed, the wasp tries to find them, taking a long time with her stinger embedded in search of the missing brain regions.
Then the mind control begins…
Oh, not nightmarish enough for you yet? Read on…
With her prey calm and quiescent, the wasp can replenish her energy by breaking the roach’s antennae and drinking some sweet, nutritious insect blood. Then she leads her victim to its final resting place, using what remains of an antenna as an equestrian uses the reins on a bridle. Once inside her burrow, she attaches one egg to the cockroach’s leg, then seals her offspring and the roach in.
As if the mind manipulation wasn’t bad enough, the wasp’s venom has one final trick. While the roach awaits its inevitable doom, the venom slows down the roach’s metabolism to ensure it lives long enough to be devoured still fresh.
For the morbidly fascinated, here’s video of the jewel wasp doing its thing:
What does this mean for our understanding of intelligence, and/or ‘blind’ evolution? I’m not sure, but it does seem to tip a lot of our assumptions upside down.