What’s sexier than sex and warfare? Taking the “arms race” one turn too far.

Talk about sexy science. How could any science be any sexier than sexual selection?

Then combine sexual selection with “nature’s arms race,” and what do you get?  Science so titillating that even a seasoned science journalist might get a little…carried away.

This was the only explanation I could contrive yesterday morning after I read Nicholas Wade’s latest contribution to the New York Times Tuesday Science section. Only last week I posted about the importance of the arms race analogy to my dissertation research on the history of coevolutionary research. So I was very excited to see Wade’s piece, “Extravagant Results of Nature’s Arms Race,” gracing the cover of the Science Times.

Sexual selection is not really my bag—the evolutionary “arms races” that I write about are between hungry herbivores and unpalatable plants, not males of the same species. But the general concept is the same: offense and defense is heightened over many generations as a result of natural selection for the best-fed herbivore, or the least palatable plant, or, in the case of the sexual selection, the most successful (read: sexiest) male.

Sexual selection is a special case of natural selection where the most successful features do not always seem obviously adaptive. Take the classic example, the peacock’s plumage. Its lavishness makes no sense when you imagine the peacock trying to outrun a tiger. What can be more evolutionarily important than avoiding being eaten? Being sexy, of course. At some point in evolutionary history, females developed a preference for gaudy tails, and since the males with the gaudiest tails were the ones getting the action, more pretty boys in the next generation had gaudy tails. And so on– you get the picture.

This “female choice” type of sexual selection does involve an “arms race” of sorts: Peahens’ preference for gaudy tails escalates even as the gaudiness of male tails escalates—female preference and male success mutually reinforce and drive each other to greater extremes.

But invoking the “arms race” seems a lot more convincing when you are talking about out-and-out evolutionary combat. The second type of sexual selection, “male-male competition” is all about the escalating evolution of better and better weapons. In some species, males actually fight for sex, as with these male elephant seals battling for control of a harem of females. But in other species, it’s enough to look big and scary, to intimidate the other guy before he even tries to fight you. If your antlers are large, you might fight other males and win. But if your antlers are humongous?  You could be king of the lek without ever having to tangle. Possible bonus: Your “armament” may also serve as an “ornament” if females find your big antlers sexy. These University of Minnesota researchers found that lion’s manes did double duty, attracting females AND intimidating other males.

Wade’s Science Times article profiled a recent review paper on the diversification of male animal “weaponry” by Douglas Emlen at the University of Montana.

Dung beetles -- from a nice Discover Mag blog posting about the evolution of female dung beetle horns.

 

For your viewing pleasure, the piece focuses especially on the dramatically beautiful “horns” of dung beetles. And, as in most profiles of sexy science, Wade could not resist taking the next step, pushing toward that ultimate climax of sexy science.

What’s sexier than sex and warfare?

Sex and warfare and humans, of course:
“People have pathetically puny teeth and claws compared with the armaments of other dominant species. This is a sign not of pacific intent but of the fact that they manufacture their weapons.”

In other words, the “arms race” is more than just a metaphor that allows us to comprehend the evolution of elaborate organic weaponry on our own terms, those of technological weaponry. It’s an analogy between human and nonhuman evolved features.

If you read what I wrote about analogies last week, you’ll know that when evolutionary biologists posit such an analogy, they are claiming that evolved tusks and manufactured guns were generated in response to the same selective pressures. They have different evolutionary histories–in this case, the difference is even more extreme, since one has a biological evolutionary history and the other has a cultural evolutionary history.  But they are analogous because they share an adaptive function.

I am most fascinated by analogies like these, which effectively blur the boundary between biological evolution and cultural evolution. But it’s not just the boundary between biology and culture that becomes a bit blurry here. Wade interviewed a primatologist who claimed that it’s “very reasonable to assume that, as humans evolved and our culture became more complex, skills in tool making or other cultural behaviors took over from anatomical traits as ‘markers’ of a male’s competitive skill.”  In other words, the proposed mechanism for such a shift is also kind of hazy.  Claiming that cultural evolution just “took over” from biological evolution is not exactly a substitute for a testable hypothesis.

In any case, whether or not you think this is a reasonable assumption, you have to admit that it’s very compelling. Analogies are compelling—that’s why they are so useful.  They motivate us to make analytical leaps that, in the best of scientific circumstances, may also be empirically verified.

Sometimes those gravity-defying leaps also defy logic, however. Even a seasoned science journalist like Nicholas Wade may be seduced by sexy analogies into making such a logic-defying leap.

Wade analogizes between the organic “weaponry” featured in Dr. Emlen’s paper and a samurai helmet or a crossbow. So far, so good—these could make sense within the context of sexual selection.

Then, suddenly, Wade leaps into the geopolitical domain of the “menacing tanks and rockets that paraded through Red Square in Moscow in the days of the Soviet Union.” This is where the allure of the arms-race analogy becomes dangerous. Was the Cold War a result of sexual competition? Is the “the advent of chemical, biological and nuclear arsenals” really relevant to a piece on male-male competition?

The arms-race analogy has been scientifically productive, helping biologists imagine a series of evolutionary interactions that mimic the military escalation of the Cold War.  But when it leads us to relate sexual selection to global politics, it has probably overreached the limits of its utility. And when this overreaching happens on the cover of the Science Times, we must take pause.

Evocative analogies are powerful tools and—just like that nuclear arsenal—they should be used only with the greatest of caution.

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7 Responses to “What’s sexier than sex and warfare? Taking the “arms race” one turn too far.”

  1. Lisa says:

    re: “Is the “the advent of chemical, biological and nuclear arsenals” really relevant to a piece on male-male competition?”

    I’m not sure, but there are plenty of people (mostly feminists) who have drawn these kinds of analogies. I kept thinking about Helen Caldicott’s book, Missile Envy, while reading this. She definitely does not display an intimate knowledge of evolutionary biology or sexual selection, but she repeatedly discusses the arms race as a competitive display of male sexual prowess. And, there are tons of examples from defense intellectuals that reinforce her conclusions – or, at least, that these men consistently relied on sexual metaphors – i.e. weapons tests are mighty orgasms, my nuke (read: dick) is bigger than your nuke, etc. – to describe the power of nuclear weapons and the rationale for American (and Soviet) nuclear defense policies.

    Stuff like Caldicott’s book are really fun to read, but I’ve always thought that she (and others) put too much emphasis on “essential” biological differences between men and women – i.e. men are aggressors, women are nurturing, etc..

    The thing that really struck me while reading this post is just how much biological research continues to draw on these essential male/female traits to describe sexual selection. Female peacocks are high fashionistas – really? But that’s totally anecdotal based on my reading of your post and the NYT article. Very interesting!

    I don’t know if you’ve ever read anything by Emily Martin (you probably have!), but she writes some fascinating stuff on the use of metaphors in science. Below is a short piece about her work from Discover Magazine.

    http://discovermagazine.com/1992/jun/theaggressiveegg55

    • Rachel Mason Dentinger says:

      Hi, Lisa!
      I’m sorry if I gave the impression that the peacock example was purely anecdotal. There has been a good deal of empirical work done on the reproductive value of the peacock’s tail, mostly in the 1990s. I did some quick searches, curious to see if any work is being done on the question today, and found that the peacock’s tail has become newly controversial, with a couple of articles in /Animal Behaviour/ in the past year (Vol 75, pp 1209-1219 and Vol 76, pp e5-e9).

      It’s exactly right that essentialist ideas of “male” and “female” shape research on sexual selection. However, the basic idea behind sexual selection actually gives a very different impression of the relative *value* of males and females, based on the relative value of sperm and egg. Anisogamy, the asymmetry between the two types of gametes (sperm and egg), is the basis for determining which sex is which and the basis for sexual selection. Biologically speaking, “females” are the organisms that produce a single large, energetically expensive gamete–always the limited resource when it comes to reproduction. “Males” produce bucketfuls of disposal, cheap gametes, essentially a genetic packet with a flagellum. In the case of internal fertilization, females are even more of a precious limited resources, because they must make such a heavy biological investment in gestation. Of course, it’s in the cases of external fertilization, like in fishes (see, especially, cichlids), that the investment becomes less asymmetrical or even be reversed–the exceptions that prove the rule. The idea of female choice, as you might imagine, was not at first a welcome one in animal behavior circles. But now it is really the gold standard of sexual selection research (which is one reason why Dr. Emlen claims that the evolution of “weaponry” is neglected).

      So, as much as evolutionary biology can sometimes reify–or naturalize– societal norms, it also often undermines them.

      I love the work that has been done on the egg and sperm—I was not familiar with Emily Martin, but the philosopher of science Evelyn Fox Keller has also looked at the idea of sperm as conquerers and the egg as a passive maiden, just waiting to be, ahem, penetrated. She does awesome stuff on metaphors on science, particularly on the concept of the “gene” as THE active causal agent in development.
      http://web.mit.edu/sts/faculty/info/Keller_Evelyn-css.html

      As far as “my nuke is bigger than your nuke,” I have to admit that on first appraisal I don’t think it as much to do with evolutionary biology. That kind of posturing seems to be so divorced from actual *reproductive success*, as it would be assessed by evolutionary biologists (see Gina’s comment below). But I will think about it more…

      • Lisa says:

        no, you didn’t give the impression that the peacock example was anecdotal. I meant to say that my assessment was anecdotal based on the anecdotes in the article and in your post.

        as for the my nuke is bigger than your nuke business, I definitely do not think it has anything to do with evolutionary biology – in reality. I just thought it was interesting how both Wade and Caldicott (and others) seem to play fast and loose with the analogies/metaphors, whatever.

        I remember reading the fox-keller piece in my undergrad and thinking that it was some kind of subversive and revolutionary revelation that I had to share with EVERYONE! I couldn’t believe I had been lied to during all those years of biology class in high school…I didn’t realize the patriarchy penetrated that deep ;)

  2. Gina says:

    I have not read the Times article, but it seems to conflate types of selection and also the value of having the weapons with the value of using them. If the one country blows the other country off the face of the earth, then I suppose the males of the country that did the bombing would be more fit, meaning they would have higher reproductive success than the dead males. But I doubt that men in the country with the bomb would have higher reproductive success without actually deploying the bomb. And, frankly, nuclear warfare is bad for all living things, including children.

    • Rachel Mason Dentinger says:

      Hey, Gina,
      Yeah, totally—you have to be completely divorced from the idea of actual reproductive success in order to argue that a nuclear arsenal is a sexually selected weapon. Warfare probably has resulted in higher reproductive success throughout history, in the raping and pillaging sense–but, again, that has nothing to do with wholesale nuclear destruction or, as you rightly point out, the *threat* of wholesale nuclear destruction.

      And, more to the point, would reproductive success in the raping and pillaging sense be *individual* reproductive success or *group* reproductive success? I am pretty sure that most evolutionary arguments about human warfare are based on group selection. I won’t try to assess the validity of those arguments here, but I will say that the idea of sexual selection and group selection somehow working in concert in the cultural evolution of nuclear weapons seems extremely outlandish.

  3. JamesD says:

    Thanks for the useful info. It’s so interesting

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