Whew…some content arrives!

Hey, you want some science? My latest Seed column on battling beetle balls is online.

(And I’ve just arrived in Ann Arbor after a long travel day!)


  1. Christian Burnham says

    You know what they say about large horns? Large horns, tiny testes.

    So, any progress on the foot/nose-genitalia correlation in humans?

  2. Mosasaurus rex says

    Yes indeed, welcome to Michigan! Are you holding court in a bar or coffee shop while you’re here?

  3. Kelli says

    Another one of your great SEED articles! I enjoyed the Three Stooges analogy. You really know how to make biology come alive.

  4. Fernando Magyar says

    Is there a similar correlation with regards mandible size in Stag beetles or is that a whole nuther ball of wax? BTW reading this just made me really nostalgic for my younger years when I lived in Brazil and got to play with and collect specimens of Titanus giganteus. I could always impress my friends by having one easily snap a pencil in half.

  5. Rich says

    “So, the reason beetles have large horns is compensation?”

    No. That’s why they drive candy apple red Porsches.

  6. S. Fisher says

    This would seem to be evidence that “the contingencies of developmental architectures may well be as significant a force on evolutionary histories as selection.” It seems to me that canalization and plasticity are opposite ends of a spectrum and that canalization will always occur when a “mission critical” system is under selection. I don’t see how developmental constraints can be viewed as a “force” in the same way that selection can.

  7. Carlie says

    When I saw the link text, all I could think of was “And when the tweedle beetles battle with their paddles in a bottle and the bottle’s on a poodle and the poodle’s eating noodles…”
    I need to read more Seed and less Seuss.

  8. Mike Saelim says

    Welcome to Michigan! Now it’s best to leave Ann Arbor and make tracks for East Lansing as quickly as possible. Belief in the superiority of U of M basketball is much like fundamentalist belief – flying in the face of reality and completely resistant to evidence.

  9. Paguroidea says

    Oh those quick mating sneaker males with the big testes! Quite the clever strategy.

    Wonderful article.

  10. Skeptic8 says

    Great classical induction!
    By the way, did we learn anything from the Thalidomide mess & developmental processes?

  11. wright says

    Fascinating. Another illustration of the complex trade-offs in living systems. Great article; very accessible to this layman.

  12. says

    You may have lost me a little bit towards the end, but it’s all interesting enough that I’ll definitely be going back to re-read until I get it. Thanks for expanding my world a little!

  13. djlactin says

    skeptic8: Off Topic, but…
    To my astonishment, Thalidomide has a current medical application: it cures Leprosy! Doctors just have to make sure that the patient is not pregnant.

  14. says

    Thalidomide’s original use was legitimate as well, as long as you didn’t give it to pregnant women. You could give it to men and pre-pubescent girls and crones without doing any harm.

  15. Tessa says

    PZ – Thanks for your informative and entertaining articles. After reading your columns, I found myself developing a new interest in evolutionary development. This issue’s topic on the competition between developing weapons and testes is especially intriguing. I must admit that thinking about the Three Stooges and those sneaker males makes me laugh.

  16. leophoreo says

    I remember when I first came across what you call sneaker males in a paper by Tim Clutton Brock who was studying red deer in Scotland. He used the term sneaky fuckers. The next time I read about this behaviour they were called sneaky copulators. Now they are sneaker males. I preferred the original term.

  17. rjb says

    Hey PZ, you should also know that there’s huge variation in Scarabs in their brains as well that’s correlated with their feeding behavior. Check out the following:

    Farris, SM and Roberts, NS. 2005. Coevolution of generalist feeding ecologies and gyrencephalic mushroom bodies in insects. Proc Natl Acad Sci U S A. 102(48):17394-9.

  18. says

    PZ: The opening metaphor you use for your column brings a different meaning to the concept of Intelligent Design.

    Woop woop wooop woop! Nyuk Nyuk Nyuk… Hey you, pick two fingers … Boink!

  19. says

    PZ: The opening metaphor you use for your column brings a different meaning to the concept of Intelligent Design.

    Woop woop wooop woop! Nyuk Nyuk Nyuk… Hey you, pick two fingers … Boink!

  20. says

    Sorry about that… all I ever saw was “Internal Server Error” then there were two of those posts. The Three Stooges Filter must be broken..

    But seriously, this is a very interesting scenario you write about. There is a (potentially) entirely different explanation. The secondary and primary sexual characteristics can be totally unlinked but look like they are linked. Unlinked genetically and developmentally, but still linked strategically (so this would be one of those other dimensions of evolution…)

    Testes size responds to exclusivity of access (negatively). This has been postulated and demonstrated again and again in many species. The link is actually sperm production to access, and sperm production is in turn linked to testes size. Gorillas have really tiny testex, chimps huge ones. There is no tradeoff in developmental or maintenance energy between testes and body size going on there. The testes vary by dozens of grams, the bodies vary by dozens of kilograms.

    Independently of this, secondary sexual characteristics can relate to exclusivity of access. This varies and I know squat about bettles. But the secondary characteristics that correlate to small testes cause the conditions in which small testes are optimal.

    There is a way of interpreting the models you’ve described so that they match with this hypothesis. What changes is where the “ultimate” as opposed to proximate and developmental mechanisms lie.

  21. Pierce R. Butler says

    Two different types of males in the same species is a phenomenon reported in that indispensable biology text, G. L. Simons’s Simons’ Book of World Sexual Records:

    The nineteenth-century naturalist Fritz Muller described Tanais, a remarkable species of crustacean… in which the male is represented by two distinct forms. In the one form the male carries numerous smelling threads; and in the other more powerful pincers which serve to hold the female in copulation. Thus one type of male finds many females but cannot secure them as easily; the other type finds fewer females but hangs on to a bigger proportion. The upshot is the same for each male type – they both reproduce approximately the same number of offspring.

    This rather tidily epitomizes the male dilemma – finding females, & scoring with same – and provides no little food for thought. One thought I’ve chewed on, to no useful result: why isn’t this sort of variation more common?

  22. says


    Good question. Of course, it may be a little more common than currently understood. The existence of two kinds of males in Orangutans is a fairly recent discovery, for example. In some species, it is possible that the hummels (yet another word for sneaky rutters) look enough like females that they are overlooked. Which may in some cases be the whole idea.

  23. says


    Good question. Of course, it may be a little more common than currently understood. The existence of two kinds of males in Orangutans is a fairly recent discovery, for example. In some species, it is possible that the hummels (yet another word for sneaky rutters) look enough like females that they are overlooked. Which may in some cases be the whole idea.

  24. says

    Damn, it happened again. Deja vu all over again…

    …Is it because I am pressing the “Clone the Post” button, or what?

  25. Pierce R. Butler says

    Laden: …hummels (yet another word for sneaky rutters)…

    An interesting term, though it’ll need a major blues song, or at least a C&W tune, before it catches on.

    Does this appellation tell us titillating implications about early-Romantic German piano composers, or about any of the other 9 instances of the name found in a Wikipedia search?

    How did this word (the Wiki entry on the hummel as a Swedish zither notes that, “The name is thought to come from the german word “Hummel”, meaning “bee”, referring to the droning sound created by the accompaniment strings.”) come to be applied to a “back-door man” (or orangutan)?

    For that matter, can you cite any links about this particular form of monkey business?

  26. JohnnieCanuck says

    The sneak approach also occurs in Coho salmon, Oncorhynchus kisutch. Here the small male (jack) is one that returns to spawn after two years instead of three. It must wait until a female accepts the ‘victorious’ large male and begins to lay, when it will dash in and lay down its milt as well.

    By doing so, it is exposed to one less year of potential predation in the ocean. Another notable effect is that this strategy transfers genes between what would otherwise be three separate populations, using the spawning bed in a serial timeshare arrangement.

    Pink salmon, Oncorhynchus gorbuscha, which have only a two year cycle do not exhibit ‘jacking’ and the odd and even years are genetically isolated. Often the two populations have a substantial difference in numbers.

    A study on heritability of jacking in Chinook salmon, Oncorhynchus tshawytscha appeared in the October 2002 issue of Heritability.

  27. albinosquid says


    I can think of three examples off the top of my head of species displaying two distinct male forms(there are many more than this, I’m sure):

    -Giant Pacific Cuttlefish (HEY PZ! LOOK! CEPHALOPODS!)

    -at least one species of African cichlid; I can’t remember the exact species, it may have been one of the shell-breeding ones.

    -a species of baboon, again can’t remember the specifics

    I think the first two practice the ‘sneaker male’ tactic, while the last one might have more to do with female sexual preference.

    Sorry I can’t provide citation on these…I learned all of this information through countless hours of watching nature documentaries:)

  28. says

    Pierce: For “Hummel” … the word has been used for a very long time to refer to male deer that grow only the smallest of antlers (later discovered to be sneaky rutters).

    Regarding Orangs: You can find this in any of the orang literature. The smaller males are the ones that “rape” the females (the famales prefer the larger males). The small males lack the secondary sexual characteristics of the larger males but are adults and are sexually mature.

    What is really strange about this is that now and then the smaller males grow into large size. This is rare. Its been observed in the wild and in zoos… in totally mature, decades old males.

    The most recent thing I’ve seen on this is a talk by Cheryl Knott. Cheryl reports that in one animal she has been observing for a few years, a “hummel” male grew to large size ( a few years ago) and has recently … and amazingly … reverted to small male morphology.

  29. Pierce R. Butler says

    Fascinating – I may never leave my girlfriend alone with a small, shaggy zither player again…

    Some pop ethologist is going to compile a bestseller out of all this. Maybe Dean Hamer will find a Dandy gene!

    My gut sense (well, some place in the nether regions) suggests that there’s very little reason to expect such, ah, morphological ingenuity among the females of just about any species. Or are you better-informed behavioral biologists about to shock me again?