Insert Penile Stylet between the Eyes

by Jason Tougaw

This fall, biologists Rolanda Lange (Tubingen University, Germany), Johanna Weringhausen (Monash University, Australia), and Nils Anthes (Monash University, Australia) published an article about the “traumatic mating” practices of a colorful little hermaprhodite sea slug called Siphopteron in the Proceedings of the Royal Society B (for Biology). The study got some press, because the mating practices of this gorgeous slug are so peculiar. The hermaphrodites, usually in pairs though threesomes have been observed, bite each other a little, then insert their penises into each other’s genital openings. “So far, so normal,” observes Guardian science blogger Henry Nicholls. By normal, of course, he means: like mammals, like humans. But then the slugs surprise the biologists (and the journalists), by inserting their “penile stylets” into each other’s foreheads, right between the eyes.

Lange and colleagues speculate that the slugs may be injecting fluids from their prostates into each other’s nervous systems. In Nicholls’s words they’re hoping to find out if we’re talking about a literal mind-fuck here. It’s hard not to fantasize that Isabella Rosellin’s brilliant Green Porno series is spurring this research into the sexual peculiarities nature’s creatures get up to.

Fantasy aside, “traumatic mating” has been observed and studied in a number of species. These studies inspired Rosellini, not the other way around. But I have some questions about “traumatic mating.” Trauma has at least two meanings. It can mean the violation of flesh, as in injury or surgery; it can also mean the extreme disturbance of the mind, as in torture or witnessing atrocity or catastrophe. Some of these practices are characterized as “sexual conflict” in the literature–a term that seems to encompass both meanings of trauma. It would almost certainly be sexual conflict if two humans behaved this way. Luckily, the human penis isn’t sharp enough to penetrate our durable skulls. But of course, trauma is contextual. It depends on the experiences, desires, and responses of those involved. It’s hard to know what’s traumatic for another human, let alone a member of another species.

Before we get into the pleasures, problems–and, I’d argue, inevitability–of anthropomorphizing other creatures, you probably want to see what these slugs are getting up to. The languorous motion of their colorful, gelatinous sex looks a lot like art. Fortunately, the biologists have logged a lot of video of these fornicators in the act. As in Rosellini’s videos, art, porn, and science collide.

Lange and her colleagues observe that these slugs, unlike close relatives, have very long and flexible penises. They could insert them anywhere in each other’s bodies. But they don’t. They stab each other between the eyes. So why between the eyes? Most species who engage in traumatic mating, do so with a purpose–to make the other partner more willing to mate, or stimulate the partner’s reproductive systems, or eliminate a partner who may be a threat to the offspring. What is the purpose of these slugs stabbing each other between the eyes with their “penile stylets?” The question leads to a fascinating speculation and proposal for future research:

. . . we propose that the consistent site selection for penile stylet placement in Siphopteron sp. 1 is adaptive and directed towards the neural ganglia. Assuming that future studies indeed confirm ganglia as the target of traumatic injection, cephalotraumatic secretion transfer makes us speculate about the central nervous system as a target for sophisticated neurophysiological manipulation (perhaps similar to that found in plethodontid salamanders). First, in general, nervous control typically allows faster physiological responses than endocrine control, even though this needs confirmation in the context of reproductive manipulation. Second, direct manipulation of the central nervous system may be hard to counter-adapt to, because small changes here will probably affect many other essential systemic processes.

Translation: These slugs may be injecting their prostate fluids into each other’s nervous systems in order to change each other’s brains. This is fascinating. No question. It also makes me think we could learn something by spending more time reverse-anthropomorphizing. After all, don’t humans change each other’s brains and minds when we engage in genital contact? We all know this, but we don’t understand it very well. The brilliance of Green Porno is Rosellini’s ironic anthropomorphizing–which has the side effect of defamiliarizing sex in general, including human sex. The behavior and biology of any species is strange and fascinating if you examine it with fresh eyes.

To call something abnormal really means it defies or confounds expectations. These slugs’ layered sexual rituals are their norm, after all. In some of the literature, the slugs’ genital openings are described as “female.” Surely that’s not quite right. These slugs should show us that the natural world is not neatly divided into the categories male and female. And that’s just for starters. I don’t mean to moralize, but norms are built on expectations–and it seems to me that a meaningful and just way of living requires a capacity to revise our expectations. When they’re comfounded, it’s bound to elicit a response, whether its titillation, perplexity, or outrage. If Rosellini’s Green Porno project has a thesis, it’s that it’s that we shouldn’t be too smug about our norms. We’ll never be rid of norms or expectations, but we don’t have to let them rule us. We’ll notice when brain-stabbing slug sex, but think about what we might learn from them.

Birds do it, bees do it, even educated fleas.  



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