An experimental test of frequency-dependent selection on male mating strategy in the field.
We provide field-based experimental evidence for the frequency-dependent nature of the fitness of alternative mating strategies. We manipulated the frequency of genetically determined phenotypic strategies in six wild populations of the side-blotched lizard, Uta stansburiana. The within-population pattern of mating was assessed using nine microsatellite loci to assign paternity. Within populations of the side-blotched lizard exist three colour morphs (orange, blue and yellow) associated with male mating strategy. The frequency of these morphs has previously been found to oscillate over a 4- to 5-year period. We found, as predicted, that the common phenotype lost fitness to its antagonist. The mating patterns of all six populations adhered to a priori predictions that were derived from previous empirical and theoretical observations on this system. We found that the frequency-dependent nature of male fitness could be accounted for by the composition of their competitors at a small local population level, driven by associations within a focal female's social neighbourhood.
Bleay
C
C
School of Biological sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK. colin.bleay@bristol.ac.uk
Comendant
T
T
Sinervo
B
B
D000818:Animals; D003116:Color; D005260:Female; D008116:Lizards / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D008297:Male; D018895:Microsatellite Repeats; D010641:Phenotype; D011156:Population Density; D012641:Selection, Genetic; D012726:Sexual Behavior, Animal