ยป Rock-Paper-Sex
Alex has mentioned a few times how rock-paper-scissors mechanics1 are key in game design. In a case of life following art, it turns out that side-blotched lizards follow a RPS evolutionary strategy in their mating:
- Orange-throated males
- Practice serial monogamy; Beat up blue-throated males to take their females; Don’t notice yellow-throated “best friends”
- Blue-throated males
- Practice long-term monogamy; Can’t beat blue-throated males in a fight but do notice inappropriate attention from yellow-throated males
- Yellow-throated males
- Coloration and size mimics females so they can mate with the partners of orange-throated males while they’re busy fighting
The genes which determine what kind of mating strategy a lizard will play shift in dominance over time.2
It strikes me that this evolutionary strategy got noticed (and not till 2001) because the lizards conveniently colour themselves according to which strategy they’re born to play. There could be many more cases of this in biology that are more subtle. How much human behaviour has an RPS mechanism?
1 More formally: a win relation with a functional graph forming an intransitive cycle
2 More formally: an unstable, mixed-strategy Nash equilibrium
Does serial monogamy mean they only practice monogamy for short periods of time than switch partners and the long term monogamy lizard stays with the same lizard forever?
karen
23 Mar 09 at 6:10 pm
Yes.
Jared
23 Mar 09 at 6:52 pm
Some sort of RPS behaviour is fairly common: in fish the yellow-throated-male behaviour is practiced by “jacks” and “sneaker males”, in evolutionary biology they’ve found it among sex ratios (complete with mitochondrial male-killer genes that try to tip it), and many species (possibly including humans) influence the sex of their offspring based on which one will give them a leg up in the current circumstances.
Unless I’m not understanding what you mean by RPS. If you mean there has to be three balanced strategies, then yeah, that’s unusual.
Kyla
23 Mar 09 at 10:34 pm
Yeah, I’m interested particularly in evolutionary strategies where strategy A beats strategy B beats strategy C beats strategy A. When there’s only two strategies, they will eventually fall into an equilibrium, but three (or more) strategies should be unstable forever.
Jared
23 Mar 09 at 10:38 pm