Posted tagged ‘Reproduction’

Sneaky F*ckers and a momentary break from politics.

September 15, 2008

Update: One word, but it’s a crucial one, changed below.  For “Keynes,” read “Smith.”  My thanks to commenter Bob Bleakney for the sharp eyes that caught what this addled brain did not.  Apologies for the unfortunate mental images…; )

I don’t know about you, but I need ever more breaks from the continuous experience of staring into the abyss of the worst of American politics, so I read with pleasure this short post on Andrew Sullivan’s blog that marked a momentary digression from Sullivan’s near-total (and entirely laudable) focus on defeating the McCain-Palin freak show.  In it he reports on Jesse Bering’s retelling of John Maynard Keynes Smith sneaky fucker theory as applied to human reproduction.

It brought back happy memories of the time in the late 1980s I spent researching a potential NOVA documentary on the distinction in practice and in evolutionary history between sexual reproduction and sexuality.  That project took me to the University of Texas laboratory of Professor David Crews.

Crews is best known for his study of the so-called “lesbian lizards,” Cnemidophorus uniparens, which is an all female species of lizards who reproduce parthenogenetically — ie, through the development of unfertilized eggs that have full complement of chromosomes.  The twist in the tale is that C. uniparens is descended from a sexually reproducing species in which both of the usual genders take their customary part in the reproductive cycle.  When the mutation occured that enabled parthenogenetic reproduction (aka virgin births) the now all female, all sister lizards retained at least some of the behavior of their ancestral species.  So the lizards still perform what look like gender-specific practices, including mounting, even though there is, strictly speaking, no reproductive purpose for such behavior.  Cool movie here.

That was fascinating enough — but Crews didn’t stop the tour of his lab with his lizards.  Next up were  the cages of garter snakes.

It seems that among red-sided garter snakes, a few males have managed not only to achieve a physical mimicry of females, but physiological imitation as well, excreting a female sex hormone.  This has two effects observed in behavior:

1.  The garter snakes attract (distract) male snakes — Crews’ lab observed mating attempts involving 5-17 males at a time.
2.  With the competition thus distracted, these nellie (if you’ll forgive the anthropomorphization) snakes did very well for themselves in the mating game.  Crews and his colleagues reported that  “she-males mated with females significantly more often than did normal males, demonstrating not only reproductive competence but also a possible selective advantage to males with this female-like pheromone.”

You can find the abstract of a 1985 Nature paper reporting on the snakes here.  Fun movie of these wily characters here.

As Crews and I talked in his lab that day, he called his female-imitating garter snakes sneaky fuckers — with affection, or at least admiration for some clever evolutionary gamestering.  That was the first time I had heard the term, and it still brings a smile to my face, remembering Crews’ image of a wily femme snake deceiving his macho brothers to reach his desired goal.

I’m not sure how far I’d go to making the analogy between snakes and people — not very far in fact.  But the underlying idea is probably useful:  sexual behavior evolved for reasons and under selection pressure that was at least partly distinct from that which produced the physiology of sexual reproduction.  It is therefore unsurprising that a wide range of possible behavior remains part of our sexual landscape.

Image:  Michelangelo, “Forbidden Fruit and the Expulsion from Eden,” fresco from the Sistine Chapel Ceiling, 1509.  Source:  Wikimedia Commons.

And of course, gin remains a great leveler.