THE DYNAMICS OF OPERATIONAL SEX-RATIOS AND COMPETITION FOR MATES

In sexually reproducing animals, individuals of one sex may have to co mpete for access to mating partners of the opposite sex. The operation al sex ratio (OSR) is central in predicting the intensity of mating co mpetition and which sex is competing for which. Thanks to recent theor etical and empirical advances, particularly by exploring the concept o f OSR, sexual selection studies today are becoming more fine-tuned and dynamic. The original role of parental investment in predicting sexua l selection has recently been complemented by the use of sexual differ ences in potential reproductive rates (PRR).