The War of the Sexes

Michele Pridmore-Brown in the Times Literary Supplement:

Darwinian sexual selection has not, in general, selected for particularly cosy relations between the sexes. The praying mantis female often cannibalizes her mate; she bites his head just as he is delivering his sperm and then completes her meal when he’s done. Aside from a hard-to-interpret wiggle, he seems not to protest the terms of the sexual bargain because he is solitary and unlikely to score again. By contrast, the male bedbug is a brutal bully; he has evolved a dagger-like projection with which to slash the female’s abdomen. The more graceful water strider has two precision antennae that serve no other purpose than to hold females down. As for the toxin-loaded scorpion, he has evolved a special toxin-lite to subdue the female of his species.

And so it goes. Sex on six legs, or eight, can be a decidedly sordid affair. As Darwin himself observed, one should not look for moral uplift in nature. For the economist and Darwinist Paul Seabright, insect sex nonetheless neatly illustrates the dialectical nature of sexual evolution. Male strategies for “scoring” escalate over time. In dialectic tandem, so do female counterstrategies for evading undesirables and exerting some choice – overt or covert – in their affairs. This is the “war” of his title.

Game theory enables evolutionary biologists and economists such as Seabright to think of the so-called war of the sexes as a strategic game. In general, the male evolves to “want” to score at all costs – whether that means being a bully, a martyr or something else entirely. The female, however, “knows” the real stakes are viable offspring. Of course, neither sex “knows” or “wants”, which would imply sentience or introspection; rather, they are unconscious vehicles for such behaviours. Insects and humans alike, we are the descendants of those who happened to play the game exceptionally well.

More here.