I’ve always had a fondness for Toxoplasma, to the point of featuring it prominently in one of my novels. It’s a protozoan after my metaphorical heart and my literal brain (specifically the part that synthesizes dopamine), and many of yours as well; in past installments (scroll down to May 6 on the right-hand side) I’ve eagerly reported on its potential role in the national characteristics of certain European cultures, on its tendency to increase scruffiness in males and sluttiness in females, even on its association with a marine mammal of my acquaintance from back in grad school — but most importantly, on its definitive host, the domestic LOLcat.
It’s long been known that Toxo trades up: slumming halfway through life in the brains of rats, it needs to get inside a cat to complete its life cycle. The mechanism by which it does this is also well-known in broad and correlative strokes; somehow it takes a rat’s normal aversive response to the smell of cat pee and flips it one-eighty, turns the smell of urine into an attractant. Rat detects a predator that would normally make it head for the hills, seeks out said predator, chomp. Mission accomplished.
Sex. Toxoplasma makes its host horny at the scent of feline showers. It gets right down into the amygdala and rewires pathways of sexual attraction so they respond to flight stimuli instead. It’s almost a pity the cat generally eats the infectee before the rat has the chance to ask her out; one has to wonder what kind of kinkiness might ensue if not for the whole buzz-kill of getting eaten alive. (With luck, that will be the subject of some future study.)
The thing to note here is that the fear response is not erased; in fact, when infected rats were exposed to the scent of cat urine their neural activity — normalized against uninfected controls — spiked in both the reproductive and aversive circuits. So it’s not as though these guys were fearless. For all we know they were still scared shitless. It’s just that whatever fear they experienced was overwhelmed by sheer hot interspecies horniness.
I find that interesting because I also find it familiar. Take all those family-values Republicans who get busted in public washrooms with their dicks in some other guys’ mouth. Take the endless “Bimbo Alerts” that Bill Clinton left in his wake from Arkansas all the way to the Oval Office. I for one do not believe these guys didn’t believe they were at risk. Child-rapers in frocks and residential schools, maybe; the church has traditionally wielded such unquestioned authority that I can see those guys honestly thinking they were untouchable. But did Bill Clinton really think that all those hordes of bloodthirsty Republicans wouldn’t pick up the scent? Did Mark Sanford really think there was no chance of being discovered on that ol’ Appalachian Trail? Did Bob Allen really think it was safe to buy blow jobs in a public men’s room?
I can’t believe anyone could be that stupid. There must have been an edge of fear to every dalliance, some inner voice warning of sudden death around the corner. Maybe that even added to the thrill. But the fact is, fear is only one driver; and here in Darwin’s universe, the brazen frequently leave more genes to the next generation than the overly cautious. A long life gets you nowhere if it is chaste; a short life’s no disadvantage if you leave a thousand sprogs behind.
Sex trumps survival. We see it in rats. We see it in politicians. That makes it ubiquitous at least throughout the Rodentia. Toxoplasma didn’t invent that inequality, but it sure knows how to make the most of it.
If I ever decide to run for office, remind me to get my amygdala checked for cysts.
1We also now know that you culture Toxoplasma on fibroblast monolayers grown from human foreskins, although I didn’t really need to.