Rock, paper, scissors, lizard

Male side-blotched lizards (Uta stansburiana) have three heritable throat colors, associated with three divergent mating strategies. In the 19 December Proceedings of the National Academy of Sciences, Zamudio and Sinervo find that these alternative mating strategies can stably coexist because, as in a game of rock, paper, scissors, each strategy has strengths over one other, and weaknesses in the face of the third (Proc Natl Acad Sci USA 2000, published online ahead of print). The strategy of blue-throated males is to guard their mates faithfully, whereas orange-throated males rely on aggression, and yellow-throated males try to sneak in on females that already have a partner. Zamudio and Sinervo define the success of these strategies by tracking paternity in the lizards using nine microsatellite loci. They find that the faithful blue-throated males sire the most offspring in singly sired clutches, successfully excluding most sneaker yellow-throated males. The blue throaters often succumb, however, to the aggression of the orange throaters. These incursions into blue-throater territory bring the orange-throated aggressors success, but leave them open to sneaking by the yellow-throated lizards. Yellow throaters also sire by far the most offspring posthumously, suggesting that their sperm is particularly good at persisting inside the female for later fertilization.