ITHACA, N.Y. -- If the objective of the genetic game of life is to distribute one's genes among the greatest number of offspring, an aggressive male with lots of females in a big territory would seem a likely winner.
Or would the loyal male who guards a single mate in a small territory come out ahead in the game? How about the landless loner who sneaks into other males' territories and mates with their females?
Thinking about the traditional children's game rock-paper-scissors (also known as paper- scissors-stone or roshambo), evolutionary biologists at Cornell University and the University of California at Santa Cruz have learned why nature allows all three genetic strategies to continue: Just as in the rock-paper-scissors game, each sexual strategy has advantages over one competitor and a vulnerability to another, so that all strategies have a reasonable chance of prevailing.
At least, they do for side-blotched lizards (Uta stansburiana ) on the rocky bluffs of coastal California, Kelly R. Zamudio and Barry Sinervo report in the Dec. 5, 2000 issue of Proceedings of the National Academy of Sciences (PNAS). The researchers show that each mating strategy allows its adherents enough reproductive success to perpetuate a contentious system.
"Some animals have been playing the rock-paper-scissors game long before our kids caught on," said Zamudio, a Cornell assistant professor of ecology and evolutionary biology. The rules, she recalls, are: Sharp scissors cut the soft paper; hard rock dulls scissors; but paper, although softer, covers rock. Thus, success in the game depends on each player's strengths and weaknesses.
Zamudio and Sinervo brought an appreciation for game theory as well as the observational skills of field biologists and the gene-screening techniques of molecular biologists to a lizard lair where almost anything goes: o For months during the lizard mating season, the biologists watched orange "bullies
Contact: Roger Segelken
Cornell University News Service