Just what counts as a penis? A debate over what to call the genitals of an unusual group of cave insects has broader implications, because it gets right at the heart of science and science communication: what's the relationship between the labels we use in science and the way those labels are understood by our culture?

If you missed it, I reported Thursday that an international group of researchers discovered an entirely new sort of sex organ in a set of insects called Neotrogla. They called it a "gynosome."


Above: "Phallic Rock," a formation near Carefree, Arizona (Source)

Lots of news outlets have reported it as a "female penis," which isn't entirely surprising, because the title of the Current Biology paper is "Female Penis, Male Vagina, and Their Correlated Evolution in a Cave Insect." The researchers also refer to it in the paper as a "penis-like structure." Were they wrong to do so?

Annalee Newitz argued that calling the gynosome a penis obfuscates the science:

When we deprive Neotrogla of her gynosome by calling it a penis, of course Neotrogla doesn't care. But we fail to advance the scientific project, which is above all things dedicated to expanding people's understanding of the world. Instead of learning that there are female bugs with sex organs that behave unlike anything in the human world, articles about a "female penis" reassure readers that nothing could ever exist that challenges the penis/vagina sexual system — nor the system of sexual selection that led to it.

And that makes our minds a little smaller.


In an update to his original post on the finding, Ed Yong argues that both gynosome and penis can be accurate:

The key difference is that rather than delivering sperm, it collects it—as I stated right up top. And the only reason we think of penises as sending sex cells in that direction is that we never knew any other set-up could occur. Now we do, which either forces us to introduce a new term and demand that it be used, or to expand the bounds of our old term. I prefer the latter. I'm generally a lumper, rather than a splitter.

Yong acknowledges that metaphor is used all the time in biology. The snail's foot isn't really a foot, the octopus's radula isn't really a tongue, and we refer to all manner of light-sensitive organs as eyes. But is "penis" really a metaphor, in the same sense?


On the one hand, the gynosome is sort of like a penis, since it gets erect and is used by one half of a mating pair to penetrate the other half and to transfer gametes between the two. But it's also sort of like a vagina, as Scicurious points out in a comment on Ed's post. "The gynosome does still receive sperm, like a vagina, and cause the male to release nutrient packets. The females produce eggs through it, like a vagina. The only difference is in the penetrative aspect." Indeed, the gynosome could equally be thought of as a "vagina-like structure."

Which is it? Penis-like? Vagina-like? Or superficially similar to both in different ways, yet entirely different and never-before-seen?

Pluto Before The Firing Squad

Today this debate might just be an obscure bit of anatomical nerdery, a squabble over what the most useful label might be to explain this unfamiliar bit of insect anatomy. But in science communication, labels matter. Nobody knows this better than Pluto.


It used to be a planet, and now it isn't. It's still there, of course, orbiting our sun every 247 Earth years, give or take, but that didn't matter to the hordes of people writing to Mike Brown and Neil deGrasse Tyson and others demanding that Pluto be reinstated.

Brown points out that the label "planet" usually means: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. We now know that's a terribly unscientific understanding of the concept. Poor Eris, poor Sedna. In his book How I Killed Pluto (And Why It Had It Coming), Brown writes (emphasis added):

Perhaps it is wrong for astronomers to attempt to redefine a word when people already know what it means when they say it. Perhaps the job of astronomer is, instead, to discover the definition of the word planet as people use it. After all, the word planet has been around much longer than, well, our understanding of planets… if Pluto was a planet, why were the many things just a little smaller than Pluto not considered planets? It made no scientific sense at all. Why draw such an arbitrary line right around the size of Pluto? Isn't the job of scientists to guide the public's understanding of nature rather than acquiesce to unscientific views?


And that's why Pluto had to be killed. Sort of. Pluto, along with Eris, Sedna, Haumea, Makemake, and also Ceres are now called "dwarf planets"?

Pluto, highlighted in red, among the tens of thousands of Kuiper belt objects, in green. (Source)


The reason is simple, really: They're a little bit like planets - they orbit the sun and they've got enough mass to condense into a roughly spherical shape - but they're not quite enough like the other planets to count, since they don't have enough gravity to "clear their neighborhood" of other hunks of rock. They're also a little bit like the 100,000 other Kuiper belt objects, swarming together as they slowly spin around our solar system beyond the orbit of Neptune.

Pluto and the others are more "planet-like" than the Kuiper belt objects, and more "Kuiper-like" than the other planets. In the same way, the gynosome is in some ways "penis-like" and in some ways "vagina-like." But the gynosome is no more a penis than Pluto is a planet. Pluto doesn't get to remain a planet just because it's an easier concept for people to understand.

"It's easy to sit inside the scientific bubble and make pronouncements," Brown writes, "but [the other astronomers] were forgetting how much of an impact this decision was going to have on the outside world…of course Xena [which would later be called Eris] was not a planet. And Pluto likewise. Hadn't we settled that question 150 years ago when the asteroids became asteroids?"


Cultural Inertia

In some ways, the Pluto story echoes the tale of Brontosaurus. Brian Switek, author of My Beloved Brontosaurus, points out scientists knew that Brontosaurus, as a bit of scientific nomenclature, stopped existing in 1903. "Paleontologists should have stopped using the name. Yet they didn't because Brontosaurus already had a kind of popular inertia."


At the Iceland Phallological Museum, you can see these preserved minke whale penises, among hundreds of other specimens. (Source)

If anything has a popular inertia, it's the penis. Actually, the sociocultural weight behind the penis – both the label and the concept – is orders of magnitude larger than the cultural connectedness that people feel for Pluto and Brontosaurus. "These entities are keystones that relate to how we perceive nature, past and present," Switek says. That makes it so much more important that we get this right.


Does the discovery of the gynosome challenge our notion of what qualifies as a penis, or does it change the way we've organized the different types of sex organs in the natural world? The distinction between the two is nuanced to be sure, but it is important, and the ramifications of the decision have the potential to reverberate.

As a sex columnist, AV Flox already spends a lot of time thinking about this. "You cannot and must not rely on your reader to know that when you say penis-like they'll understand it isn't a protrusion that has vascular erections and through which something spurts out," she says. "Look at the number of people who don't know a baculum exists, who don't know lymphatic erections are possible."

By calling the gynosome a penis, it robs the discovery of the fact that this is a sexual organ unlike anything we've ever seen before. Yes, it has some superficial similarities to penises (and to vaginas), just as Pluto has some superficial similarities to Mars, but to call it a penis (or vagina) is too simplistic, because that rhetoric conjures up a set of preconceived notions about just what a penis (or vagina) is.


"There are certain labels that we take for granted to grab people's interest," Switek said. "The problem is that nature - as it so often does - defies those labels." A penis isn't just the dangly bits that you use for sex and elimination of waste, just as a planet is not just any old hunk of rock circling the sun.