Researchers report female cave insect with grasping penis, leads to accusations of sexist science

The interesting stuff in this post is the biology, and the subsequent controversy about whether these female cave insects really have “penises,” is an ancillary and unpredictable result of politically correct policing of internet science. But first let me tell you about the science.

In a new paper in Current Biology by Kazunori Yoshizawa et al. (abstract and reference below), four authors from Japan and Brazil report observations of several species of cave insects in the genus Neotragla. These are mites in the order Psocodea. And the researchers found something pretty amazing, at least to a biologist. In species studied in this genus, the females have a penis-like structure called the gynosome, which is normally retracted inside the body. (The researchers call this a “penis” from time to time in their paper.) When the insects copulate, though, the female gynosome is inserted into the body of the male, and sucks up spermatophores (packets of sperm that contain other substances) from the male’s sperm ducts.

The males do have a penis, but it’s small and inconspicuous. The female’s is large, conspicuous (1/7 the length of their bodies), and covered with spines. When inside the male, the gynosome (I’ll use “penis” and “gynosome” alternatively, setting me up for accusations of sexism!), inflates—and that, along with the spines, keeps the insects firmly coupled together. So firmly, in fact, that they can’t be separated manually during copulation without ripping off the abdomen of the male.

The species studied intensively in this paper was N. curvata in Brazil, from which the pictures come.  The photo below shows them having at it, with male and female labeled:

The amazing thing about this copulation, besides the females intromittent penis, is that the average copulation lasts 52.5 hours, with a standard deviation of 11.2 hours. As far as I know, that’s a record.

Why does it last so long? Probably because this whole system, including the gynosome with its adaptations for anchoring the female to the male, is driven by a special consideration in this system: males transfer, along with their sperm, lots of nutritious substances in the spermatophore. The authors posit that the adaptations on the female penis to hold it fast, as well as the long copulation, enable her to remove as much sperm and nutrition from the male as possible.  Females have, in fact, been observed to consume some of the contents of the male spermatophore before allowing her egg to be fertilized. (In other insect species males give females nutritious spermatophores as “nuptial gifts” that they often consume.)

The cave environment is poor in nutrition, and males are carrying around a valuable source of food. In such a case, females are competing for males—the reverse of the usual situation in animals, in which males compete for females because sperm is cheap and eggs, for the female, are expensive. In this case, the sperm is expensive because it contains a food source.

Below is an amazing photograph of the male and female in copulo (they were killed with hot water during the act: an awful fate!). You can see the female’s gynosome (the big curvy blue thing at the bootom) stuck into the male and inflated. You can also see its spines, anchoring it securely inside the male. The males also have genital pouches into which the spines fit, so there’s been some kind of coevolution of male and female (different species in the genus have different shaped spines and pouches, and the fit is species-specific, like a lock and key).

Male to the left, female to the right:

You see, above, the female penis sucking the sperm out of the male’s “seminal duct”, drawing the spermatophores along her “spermathecal duct” to the spermathecae, or sperm storage organs.

This is a schematic showing the parts as well, though it doesn’t add a lot for me.

Why the spines? We’re not sure, but it may be the result of antagonistic sexual selection: the female’s reproductive interests may diverge from those of the male. She wants every bit of sperm he has for nutrition, and he, presumably, wants to fertilize as many females as possible to have the maximum number of offspring. The female seems to have “won” here: she has spines that prevent the male from getting away, which may account for the long copulations. The spines may also stimulate the male to release sperm. Lots of animals, including cats, have spiny penises, and stimulation may be a common function. In this case, though, anchoring is clearly of primary importance.

The male penis, or “phallosome,” is shown below. It’s inconspicuous and hidden within his abdomen. (You can also see it in the diagram above).

You’d think that this case of females winning an antagonistic race involving sexual selection would at least not put off female readers. (Males often win, as in the case of bedbugs in which males inseminate the females hypodermically, bypassing her genitals to inject sperm directly into the body cavity. This practice, also called “traumatic insemination,” causes harm to the female, but males who do it inseminate the females faster. In such a case of sexual antagonism, the males have won in an evolutionary sense, for their reproductive interests take precedence.) In insects, sex isn’t always the earth-moving experience it is in humans.

Sadly,  Annalee Newitz has taken severe exception to how this work was described in her piece at io9 called: “Your penis is getting in the way of my science“. Her beef: that journalists (and of course the researchers in the article) call the gynosome a “penis”. And, to her, that smacks of sexism and anthropomorphism:

When we deprive Neotrogla of her gynosome by calling it a penis, of course Neotrogladoesn’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.

. . . By anthropomorphizing Neotrogla‘s sex life, we teach people the wrong lesson about nature. Even if it’s meant in fun, calling every organ that gets erect a “penis” makes it appear that all animals are just like us. Not only is that almost sinister in its dishonesty, but it erases one of the most beautiful things about life, which is its awe-inspiring diversity.

So as funny as some people might find a dick joke, I’m afraid those fit better in articles about porn or on FOX television than they do in ones about biological sex. Science can be funny, but it’s not a joke. And the more we make it into a joke, the more we undermine the power science has to unveil real truths about the universe.

In truth, I doubt that using the shorthand “penis” will have the dire consequences Newitz predicts. Does she really think that using the name “penis” is going to “undermine the power that science has to reveal truths about the universe”? That’s pure hyperbole. And, in truth, the gynosome is like a penis in many ways: it gets erect, it has spines (like cat penises), it has adaptations to give its bearer a reproductive advantage that are similar to those of penises in males, and so on. The only thing it doesn’t do is ejaculate (but it does suck up sperm!).

Now if journalists had used this nomenclature to somehow demean females, Newitz would have a justified beef, but I haven’t seen that happening. All that’s occurred is that the organ has been called a “penis,” which somehow angers those like Newitz who tout a diversity of sex roles in animals.  But then wouldn’t calling it a “penis” actually emphasize this diversity?

Poor Ed Jong, who reported this paper and made the deadly misstep of calling the female’s organ both a gynosome and a penis, has had to defend himself over at Not Exactly Rocket Science. I find his defense calm and compelling:

But first, to clarify, I absolutely agree with Newitz that cheap dick jokes are doing the topic a disservice, which is why you won’t find any here.[JAC: I haven’t seen any “cheap dick jokes,” and Newitz doesn’t cite any.] The tone is as deadpan as I can muster—the only sniggering is reserved for the part of the study where one mating pair gets pulled apart and the male is accidentally bisected.

As to the other parts of Newitz’s critique, she repeatedly says that “female penis” is an inaccurate term that is “anthropomorphizing” Neotrogla’s anatomy—one should call the organ a “gynosome” (which I also do). I don’t agree that gynosome is accurate, while penis is not. As Diane Kelly, who studies penises points out: “As a technical term, a penis is a reproductive structure that transfers gametes from one member of a mating pair to another.” Which is exactly what is happening here.

Newitz points to differences. “When was the last time you found a penis that grew spines, absorbed nutrients, remained erect for 75 hours, or allowed its owner to get pregnant?” Actually spines are pretty common; long sexual bouts are pretty common; and the gynosome doesn’t absorb nutrients—it collects sperm packets that contain nutrients, which the animal then eats in the normal way. 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.

The gynosome is very much like a penis in both form and function. The authors highlight the differences by giving it its own specific name. But they also acknowledge its similarities to what we typically think of as penises by describing the organ as such, both in the title of their paper—“Female Penis, Male Vagina, and Their Correlated Evolution in a Cave Insect”—and throughout its text. They don’t get any special privilege because of their authorship, of course—but I’m pointing out that you can either look at this discovery through the lens of difference or similarity. And similarities are actually critical here because evolution crafts organs that are convergently similar—though different in the details—thanks to similar selection pressures.

In fact, there is a long tradition in anatomy of describing organs with almost metaphorical names. A snail’s foot is not remotely the same as a human’s foot, but they’re both muscular locomotive organs that are kinda on the bottom of the body. We call them both feet. An octopus radula is not a human tongue, but they’re both mobile things inside the mouth that perform feeding functions, so we call them both tongues. “Eye” gets used to refer to all manner of light-detecting organs regardless of huge differences in their anatomy, evolutionary history, physiology, because they all share the common theme of detecting light. And in a similar vein, a Neotrogla penis/gynosome is not the same as a human penis but they’re both used during penetrative sex for the transfer of gametes. Other penetrating sexual organs, like the aedagus (insect) and gonopodium (fish) are also colloquially known as penises.

So, do we make a special case for sex-related terms? Newitz would say yes, because of the cultural and social baggage that “female penis” carries, in a way that “snail foot” does not. This is the strongest part of the argument, and the part that gives me pause.

But Newitz also argues that the term “erases one of the most beautiful things about life, which is its awe-inspiring diversity”, and there I disagree. The post above specifically references that diversity—not just in Neotroglabut other animals like hyenas and seahorses, and goes into detail about sexual selection. It ends deliberately with a quote about how the split between males and females comes down to sex cells, and everything else is labile. If that’s not celebrating the diversity of life, I don’t know what is. I don’t think that referring to Neotrogla’s female sex organ as a penis whitewashes that diversity. If anything, it forces us to realise that one of the traits we often link to a penis–that it lives on a male–isn’t a necessary truth. The usage expands what we know, rather than erases.

Indeed. Incensed by her offended feelings, Newitz has missed the most important implication of this paper: sex roles are labile depending on evolutionary and ecological contingencies.  For years I’ve been telling students that seahorse males get “pregnant” . In seahorses, females produce eggs to deposit in the male’s pouch, the males do the brooding, and there is a shortage of empty male pouches compared to eggs produced by females. That makes the males the desired sex for which females must compete (much like the mites above). And, sure enough, in seahorses it’s the females who are brightly colored and ornamented, since, because of this role reversal, they must attract males.  Am I now to be pilloried by Newitz for calling the males “pregnant”?

Have a look at this male seahorse described as “giving birth: (don’t tell Newitz!), and see what you think:

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Yoshizawa, K., R. L. Ferreira, Y. Kamimura, and C. Lienhard. 2014. Female penis, male vagina, and their correlated evolution in a cave insect. Current Biology http://dx.doi.org/10.1016/j.cub.2014.03.022