Creepy Parasite Stories; or, Bedtime for Daniel

I mentioned that parasite biology was one of my interests. It didn’t used to be.

When the children were smaller, we had bedtime rituals. The two oldest shared a room, so they would both get something at bedtime. Perhaps it would be a chapter from a book (Charlotte’s Web was a big hit, as was From The Mixed-Up Files Of Mrs. Basil E. Frankweiler). Or it might be a story. Stories could be about anything, but history and science were particularly popular.

So one night, they asked for a science story. About… bugs!  *Creepy* bugs. Yeah!

Well. After a moment’s thought, I decided to tell them a little bit about wasps. I paused a moment, because wasps can get quite creepy… quite creepy indeed. But okay, they did ask, and I could avoid the most disturbing bits.

So I told them about how some sorts of wasps lay their eggs inside living hosts — most typically caterpillars and grubs, but potentially any sort of small creature. There are wasps that do this to ladybugs, cockroaches, spiders, ticks, you name it. There’s a wasp that goes after tarantulas. There are wasps that go after other wasps.  The mother wasp usually stings the host with a venom that paralyzes it (though there are countless variations). And when the egg hatches, the wasp larva devours the helpless host from within.

I gave a few details: the larva eats its host selectively. It goes after fat deposits first, then muscle tissue. It saves the vital organs for last, because it wants the host to stay alive as long as possible, providing a steady flow of nutrients and oxygen. If the host is not paralyzed, the larva may manipulate the dying host to stop eating and seek shelter.  When the unfortunate host does finally die, the larva goes on a final feeding frenzy, devouring most of the corpse from within before it can decompose. Then it pupates. Some days or weeks later, the adult wasp bursts out of the pupa and the corpse of the host, and flies off to complete the cycle.

(A bit macabre? Wasps do stuff that is much worse than this. Much creepier, and much stranger. Wasps get downright baroque.)

Anyway! When I was done, older child was mildly interested. But second child — son Daniel, six years old — looked at me with shining eyes and said, “Daddy… that was the best story /ever/!”

And then, “Do you have any more?”

And so was born the tradition of the Creepy Parasite Story. Daniel liked stories about nature and science generally.  But he *loved* stories about parasites — the weirder and more creepy, the better.

So I had to learn about parasites. Over the next decade, I probably read several thousand pages about parasites, including at least a hundred scientific papers. I learned about leeches and mosquitoes, vampire bats and oxpeckers, mistletoe and athlete’s foot. I learned about the cordyceps fungus and the Sacculina barnacle. I discovered the mysterious superpower of ticks and the baffling ability of parasitic jellyfish to live without oxygen. I learned about nest parasites like the cuckoo and bully parasites like the skua.  I read about the gross but harmless pinworms that cause millions of toddlers to scratch their bottoms every year, and the horrific Guinea Worm that is mercifully close to extinction. I learned about viruses… so many viruses. And I learned about wasps and all the amazing things they do.

Daniel loved them all. But if he had a favorite, it was the malaria parasite. The malaria parasite is so complicated that it requires three or four separate bedtime stories to get through the cycle. It does stuff that we’re still figuring out. It does stuff that we still simply don’t understand. Creepy Parasite Stories were a special treat for Daniel.  He was a child unusually resistant to bribes and wheedling. But parasite stories were on the very short list of things that could motivate him — and malaria parasite stories were the very best of all.

Anyway: ten years later, Daniel was in his final year in Gymnasium, which is German high school for kids who are university-bound. And as part of his final grade, he had to research and present a 30 minute PowerPoint presentation on “a scientific topic of public interest”. He chose the malaria parasite.

Just as he was about to begin his presentation, the projector broke. After some minutes of fiddling, it became clear that it was not going to work today. Oh dear, said the teacher, what a pity; shall we re-schedule your presentation?

Oh no, said Daniel. I don’t need slides. Let me just tell you. Let me tell you about the malaria parasite.

And he spoke for 30 minutes without slides, and then took questions. And he got a perfect grade. And nobody ever knew that he was simply repeating his most favorite every bed-time story, that he’d been listening to eagerly since he was a small child.

(Should I blog about this sort of thing? I don’t think this is exactly the venue for parasite stories. Maybe a short post about wasps sometime. We’ll see.)