Posted BySimon on December 05, 2000 at 19:35:54:
CBC Radio aired an interesting segment tonight.
A research team had been studying a group of wild lizards. These lizards come in three varieties, each distinguishible by differently coloured necks. These lizards are also distinguishible by their mating practices.
One of the lizards copulates with a female, then protects her from other males. Another variety holds a large territory with many females, and tries to protect the territory, rather than the individual females within it. The final variety does not have territory or mates, but sneaks around to copulate with ungarded females.
The odd part of this is that these three varieties of lizards have been coexisting for a very long time, and none is dominant. Typically, when such dramatically varying behaviour exists in a community, the most succesful wins out, and the other types go extinct. This is not the case for the lizards.
The team determined that the behaviours work just like RPS. Each strategy is effective against one of the others, but unsuccesful against the third. The sneaky lizards compete well against the territorial lizards, but badly against the protectors. Since there is a three way RPS balance, no one technique is any more succesful than another, and the three coexist.
I wonder if there are more cases of RPS symmetry in nature, leading to three way stabilities. I am sure that there are...
Simon