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:

In copulo

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 ScienceI 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:


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


  1. John Scanlon, FCD
    Posted April 19, 2014 at 8:08 am | Permalink

    These are mites in the order Psocodea.

    That would be ‘lice’, not ‘mites’, then?

    • Frank
      Posted April 19, 2014 at 11:07 am | Permalink

      Yes, and probably bark lice would be best, since many people are much more familiar with the “true” lice that infest humans. These are now in the same order as the true lice, but quite distinctive.

    • Posted April 19, 2014 at 11:30 am | Permalink

      Yes. Mites are a kind of chelicerate, related to ticks and more distantly related to arthropods like spiders and scorpions.

  2. Posted April 19, 2014 at 8:32 am | Permalink

    It’d depressing that feminism has gotten so caught up in PoMo and PC. Isn’t it enough to strive to end gender-based discrimination without having to drag along so much useless baggage along with it?


    • gbjames
      Posted April 19, 2014 at 9:05 am | Permalink

      I, too, am depressed by this sort of thing. It is a completely pointless distraction.

      • gbjames
        Posted April 19, 2014 at 9:05 am | Permalink

        Doh… and check the “Notify” box, dummy!

    • Diana MacPherson
      Posted April 19, 2014 at 9:22 am | Permalink

      Sometimes I think people look for things to offend them.

      • gbjames
        Posted April 19, 2014 at 9:29 am | Permalink

        There’s an entire cottage industry of offense-taking. It must be profitable.

        • Torbjörn Larsson, OM
          Posted April 19, 2014 at 9:44 am | Permalink

          It must be, it’s right next to the cheesy factory.

          • Posted April 19, 2014 at 9:50 am | Permalink

            It’s a blessing!


          • gbjames
            Posted April 19, 2014 at 12:02 pm | Permalink

            I think it is a cottage cheese factory, no?

        • Achrachno
          Posted April 19, 2014 at 9:45 am | Permalink

          I find your obvious disrespect for cottage industry offensive.

        • darrelle
          Posted April 20, 2014 at 10:53 am | Permalink

          I have heard from several sources in the past the idea that being offended, the brain state of feeling indignant, can be addictive. My memory is not clear on this, but I seem to remember sometime coming across some evidence, a study, that supported that idea.

    • Latverian Diplomat
      Posted April 19, 2014 at 1:49 pm | Permalink

      Asking someone to use the correct and precise term instead of sloppy euphemism with cultural baggage is sort of the opposite of PoMo.

      Even Ed Jong admits the complaint has some legitimacy.

  3. chrissimonite
    Posted April 19, 2014 at 8:35 am | Permalink

    A minor point, but since penises exist throughout the animal kingdom, it’s a bit ridiculous to call this “anthropomorphizing.” Maybe the authors were actually thinking about cat penises and not human ones, especially considering the spines! So is that ‘catopomorphizing?” 🙂

    • Mark Joseph
      Posted April 19, 2014 at 8:38 am | Permalink

      Ailuromorphizing. It looks more impressive with Greek roots…

      • chrissimonite
        Posted April 19, 2014 at 12:34 pm | Permalink

        Bingo! That’s the one!

  4. bric
    Posted April 19, 2014 at 8:42 am | Permalink

    It’s Ed Yong; luckily he isn’t hypersensitive about these matters of nomenclature

    • JoeyM
      Posted April 19, 2014 at 3:02 pm | Permalink

      Thank you, I was going to point out the typo in his family name. I’m glad to see that someone else spotted it.

  5. Posted April 19, 2014 at 9:05 am | Permalink

    “a penis is a reproductive structure that transfers gametes from one member of a mating pair to another”

    I’m Ok with penis being used in this instance. Just because it’s working backwards in this example (taking in, instead of depositing) doesn’t seem like that big of a deal breaker to me.

    Anyways, expecting ideologues to be rational about this sort of thing is naive. Some of these people go as far as saying that biological sex is “socially constructed”, so…

    • John Scanlon, FCD
      Posted April 19, 2014 at 11:55 pm | Permalink

      I’d agree with you, except that any argument involving the phrase “these people” is an automatic loser. If the individual you’re criticizing really is a stereotype, it’s up to you to prove it, not make lazy assumptions.

      • Posted April 20, 2014 at 4:06 am | Permalink

        If you’d like to know about the type of crazies being talked about, you should just ask.

        I’m wasn’t making an “argument”. It would only seem so to those not in the known…

  6. Posted April 19, 2014 at 9:14 am | Permalink

    I tend to fall on the side of not wanting to call this thing a penis for all the concrete reasons given – mainly that it’s more of a siphon or vacuum, and its possessor is getting pregnant. I don’t think the implied argument that “penis” = “semen passageway” – no matter whether it’s pulling or pushing, or who has it, is really sufficient. Part of my reaction comes from hearing about this over breakfast when my boyfriend shared some of a not-terribly-detailed news article and having sort of a brain lock while I tried to understand what was happening (eg, if the nutrients come with a male gamete, why isn’t THAT an egg – I had to poke around before I realized what was going on and why the sexes are labeled as they are). If I were hearing ‘gynosome’ or some new term, this process would have been faster and not confused by not tremendously relevant associated info.

    My argument isn’t a feminist one but rather one of clarity. If you’re so close to this material that you suffer no lack of clarity in hearing about this, that is awesome, but I am pretty sure you are in a small minority. I have been a medical editor for 20 years, and if I had read the first draft of this paper, I’d have asked the authors “Are you sure you want to use this somewhat loaded term that already has strong connections with basically the opposite function? This is a neat, new thing – let’s describe it in a way that doesn’t divert attention to something it’s quite different from.”

    I hear Yong’s “I’m a lumper” argument, but I think it goes too far here – the language is unnecessarily lumping a rare and interesting structure in with a common structure that actually functions quite differently. On top of which, it is obviously widely hindering non-expert understanding of this phenomenon with a detour into “HAW HAW THIS WEIRD BUG’S GIRLS HAVE PEENS.”

    • Marta
      Posted April 19, 2014 at 10:21 am | Permalink

      “This is a neat, new thing – let’s describe it in a way that doesn’t divert attention to something it’s quite different from.”


      I appreciate your entire comment.

    • Latverian Diplomat
      Posted April 19, 2014 at 1:30 pm | Permalink


    • Luis
      Posted April 19, 2014 at 5:03 pm | Permalink

      Fantastic comment! As a biologist I completely agree with you. I think the use of the word penis is wrong, although nor for the reasons stated by Newitz, but for the reasons you mention. I suspect the authors, (and who knows, maybe even the editors) intentionally used the term “penis” to be able to sensationalize the paper and get it into the news.

    • jesse
      Posted April 19, 2014 at 5:34 pm | Permalink

      You know, I thought about your comment for a while and would like to thank you for taking the time to write it. I think it makes a lot of sense.

      The word penis didn’t sit well with me when I first read JAC’s treatment, and I went over and read Ed Yong’s article as well, but it still does not sit right with me. Granted I am not a professional scientist, not in a position to make decisions about use of the term, and not even close to being an expert. All I can go with is my first impression as a person with a bachelor’s in biology, and my first impression is that using the word is not necessary when another word already exists. No need to call it by two names.

    • Diane G.
      Posted April 20, 2014 at 7:33 pm | Permalink

      Well said, Caitlin, I completely agree .

  7. Pliny the in Between
    Posted April 19, 2014 at 9:17 am | Permalink

    What a wonderful example of adaption as opposed to design. Species evolving gender characteristics in the context of their niche rather than to some arbitrary standard. Thanks for sharing.

  8. Diana MacPherson
    Posted April 19, 2014 at 9:24 am | Permalink

    I’m envious of the women who studies penises because she gets to say that when people ask her upon first meeting her. I bet she gets a lot of, “excuse me?”

  9. Posted April 19, 2014 at 9:47 am | Permalink

    Usually I want to see precise terms and accurate definitions. But in this case, the P word is analogous even if not completely accurate, and it’s a “hook” that might encourage people to read the article and learn something. Call it a gyn-HUH? in the headline, and most readers will say “oh, an article about hmm-hmm, yuck!” and flip to the comics section.

    Too much PC worry about semantics, like arguing about whether we should replace “woman” with “womon”.

    On the creature’s spines…might they also function to add strength and protection to otherwise fragile body parts?

  10. Torbjörn Larsson, OM
    Posted April 19, 2014 at 9:50 am | Permalink

    I think it is a clarifying terminology if evolution with resource competition produces a cave insect penis, or a seahorse brood puch, in the analogous circumstances.

    But as far as terminology goes, I’m a “slumper”.

  11. Achrachno
    Posted April 19, 2014 at 9:54 am | Permalink

    This seems related to the several cases where the male is consumed by the female following mating in order to nourish the developing eggs. Different in detail, but the underlying evolutionary logic seems similar. Here the male might be able to mate again, though that probability appears to be diminished — still not zero though?

  12. alnitak
    Posted April 19, 2014 at 9:59 am | Permalink

    For simplicity’s sake, why not just use “outie” to describe the female parts?

    • Diane G.
      Posted April 20, 2014 at 7:34 pm | Permalink

      I like the scientific ring to that…

  13. jesse
    Posted April 19, 2014 at 10:03 am | Permalink

    I don’t know if I would get all militant about it either way, but I do tend to agree with comment #5 on this thread.

    It almost seems like using the word penis in this case is not necessary and in fact distracting, especially among non-science, non-entomology types. Maybe it is just a grab for headlines.

  14. Ken Kukec
    Posted April 19, 2014 at 11:33 am | Permalink

    Newitz’s column is the type of weirdness encountered when someone strains to find political incorrectness where none ostensibly exists. The coverage she criticizes seems markedly restrained, with nary a dick joke to be found.

    Contrary to Newitz’s claim, it isn’t self-evident that the clinical phraseology “females with penises” was meant as “a funny play on the offensive phrase ‘chicks with dicks'” — and how does she know what “they [journalist and headline writers] thought” when writing it anyway?

    Lastly, while Fox television runs a steady stream of repugnant reporting, it’s hardly home (pace Newitz) of the dick joke.

    • Ken Kukec
      Posted April 19, 2014 at 1:03 pm | Permalink

      Would that Fox tv were to break the tedium of its soi-disant “reporting” with a bit of bawdy humor. When Fox ventures into double entendre or sexual innuendo, it’s invariably of the leering-at-scantily-clad-young-women variety (which seems of a piece with its inexhaustible supply of expensively coiffed, heavily made-up, well-under-40 blonde co-hostesses). Ailes and his gang at Fox aren’t known for finding humor in matters pertaining to the male member — save for japing allusions to liberal limpness.

  15. Stephen P
    Posted April 19, 2014 at 11:51 am | Permalink

    I’m inclined to sit on the fence here, but I think Caitlin Burke (comment 6) at least makes the case better than Annalee Newitz does.

    Perhaps we could call it a sinep.

  16. Posted April 19, 2014 at 11:51 am | Permalink

    It might be helpful to remind people that this is not the only example of a female ‘penis’. The female spotted hyena, squirrel monkey, and the females of a couple other species have an enlarged clitoris and is called a ‘pseudopenis’. In the case of the spotted hyena, this appendage is used for copulation and urination, and is well, pretty big. Calling this insect organ a penis is a novel use of the term, and is not really accurate as it is more like the various genital ‘claspers’ that insects employ, but there is no harm in it.

  17. Latverian Diplomat
    Posted April 19, 2014 at 2:10 pm | Permalink

    I’m not sure I follow this bit:

    “In such a case of sexual antagonism, the males have won in an evolutionary sense, for their reproductive interests take precedence.”

    Since every offspring has one male and one female parent, I don’t see how males and females can compete in an evolutionary sense.

    It’s true that actions like this force females to invest more resources in the offspring. This just makes females less likely to breed as often, and thereby more sought after.

    Forcing one sex is to invest more and breed with fewer or only one partner(s) increases competition between members of the other sex, many more of whom may never find a mate as a result. I don’t see how females as a group or males as a group win or lose.

    Male and female, whatever the particulars, are complementary roles, reproductively. To suggest they compete is perhaps to overemphasize the fates of individuals over the realities of population genetics. In terms of evolution, there can be no competition between them as I see it. Whatever the breeding mechanism, males and females contribute the same number of alleles to the next generation, and from an evolutionary perspective that is all that matters.

    • Posted April 19, 2014 at 3:11 pm | Permalink

      It’s simple; the males do something to the females to make them produce fewer offspring than they would have had the males not done that. For example, hypodermic insemination injures the female, and can sometimes kill her. Drosophila sperm contains substances that shorten the life of the female. Yes, every offspring must have one mother and one father, but a given female can have fewer offspring than she would otherwise, while the male, if he inseminates a full brood before the female dies, could care less from a genetic point of view if she can’t have future broods fathered by other males.

      • Latverian Diplomat
        Posted April 22, 2014 at 3:33 pm | Permalink

        Let’s focus on the Drosophila case.

        What’s being selected for? Males that poison their partners deny access to the same female by other males.

        What’s being selected against? Males that don’t poison their partners. Because the same female may go on to mate with a poisoning male, another win for the other side, as it were.

        In the absence of female traits that counteract this male strategy, are any females selected against? No, even in a mixed population of males that do and don’t poison, which females breed once vs. multiple times is random, there is not a difference between females that is being selected for.

        Also in the case of a female who only breeds once due to poisoning, her genes may still come out ahead. Because her sons and grandsons are more likely to have the advantageous poisoning trait and propagate her share of their genes better.

        From a selfish gene perspective, I don’t see how the term “males have won in an evolutionary sense” can be applied correctly here. Aside from the poisoning gene which is under selection from male/male competition, a gene residing in a female is just as likely to be passed to the next generation as the gene of a male.

    • Thanny
      Posted April 19, 2014 at 7:43 pm | Permalink

      Your confusion seems to stem from the fact that you’re taking a species-centric point of view, which is wrong. Species don’t reproduce. Individuals reproduce. Those individuals can always compete with other individuals, and intraspecific competition is almost universally the most serious kind.

      If it helps you to understand, consider spiders, where females have absolutely won the competition – males are much smaller, and tend to end up as meals following mating (often before). All else being equal, a male spider would much rather find another female spider to mate with than be eaten. That’s better for that male individual’s reproductive success. A female prefers having a nice injection of protein to support egg production. That increases her reproductive success. Interestingly enough, there are species of spider where it’s evidently more advantageous for the male to be eaten, rather than trying to find another mate (which can happen if females are especially hard to find) – the male will tumble himself into position near her fangs after mating, donating his body to his future offspring. But more often, the male wants to get away to mate again, and tries to, often unsuccessfully.

      In summary, while it’s a simple arithmetic necessity that half of genes of a new generation come from females, and half from males (assuming sex and a lack of haplodiploidy), that says nothing about which females and which males. It’s actually quite astonishing to imagine that there wouldn’t be competition between males and females.

      • Latverian Diplomat
        Posted April 22, 2014 at 5:17 pm | Permalink

        “Species don’t reproduce. Individuals reproduce. ” But we’re talking about evolution here. Populations evolve individuals don’t.

        “If it helps you to understand,” off topic, but I humbly suggest sticking with a polite “For example,” in the future.

        As to the example itself, assuming the nutrition provided by the male is just a tasty treat and not crucial to the female’s reproductive success, my case made just above to Jerry about his Drosophila example applies just as well, sexes reversed of course.

        As you noted, in some cases at least, that nutrition seems to be crucial, and males donate themselves. That actually supports my point, the males do this because males who donate are advantaged over males who don’t donate. This trait became fixed by male/male competition.

        “while it’s a simple arithmetic necessity that half of genes of a new generation come from females,” Here’s one place where we differ, since I see that as a fundamental and important fact about sexual reproduction, and you see it as trivia to hand wave away. From a population genetics perspective, I don’t see how one can talk about reproductive strategies without bearing it in mind.

        “that says nothing about which females”
        true and I said this.

        “and which males.” Yes, I said this too.

        “It’s actually quite astonishing to imagine that there wouldn’t be competition between males and females.” Well if it contradicts that simple arithmetic we both agreed was true, then it must be false, no matter how astonishing one may find it.

        Given two disjoint subsets A and B of a population, they can only “compete” in the evolutionary sense if A can contribute more genes to the next generation than B, and vice versa. Male and female are disjoint subsets, but they simply cannot compete in this manner.

        I understand that antagonistic sexual selection is a thing, and I don’t disagree that it’s truly antagonistic on the individual, but thinking in terms of one sex winning the competition over the other is a misleading description of it. Traits that force ones sex to devote more resources to offspring or not mate with additional partners can and do arise and become fixed. That doesn’t make the opposite sex the loser in any meaningful evolutionary sense. It makes that trait, and its gene(s), a winner over other alternative genes for the same allele.

        • Diane G.
          Posted April 26, 2014 at 10:31 am | Permalink

          That doesn’t make the opposite sex the loser in any meaningful evolutionary sense.

          Emphasis added to, uh, emphasize that there are plenty of other senses for which the premise holds true.

          /sore loser

  18. marksolock
    Posted April 19, 2014 at 3:37 pm | Permalink

    Reblogged this on Mark Solock Blog.

  19. uglicoyote
    Posted April 19, 2014 at 4:25 pm | Permalink

    Reblogged this on The Road.

  20. Kurt Lewis Helf
    Posted April 19, 2014 at 4:46 pm | Permalink

    Female cave crickets of the genus Hadenoecus are always on top, too.

    • John Scanlon, FCD
      Posted April 20, 2014 at 12:05 am | Permalink

      Anything special about their genitalia? There might be a nice theory/review paper in the wind…

    • Dominic
      Posted April 24, 2014 at 2:44 am | Permalink

      Also troglohiles – is that the connection? Resource poor environments?

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