Related Experiment Video
Updated: Jun 5, 2026

Assessing Differences in Sperm Competitive Ability in Drosophila
Published on: August 22, 2013
The dynamics of operational sex ratios and competition for mates
1Charlotta Kvarnemo is at the Dept of Zoology, University of Western Australia, Nedlands, WA 6009, Australia.
Abstract:
In sexually reproducing animals, individuals of one sex may have to compete for access to mating partners of the opposite sex. The operational sex ratio (OSR) is central in predicting the intensity of mating competition and which sex is competing for which. Thanks to recent theoretical and empirical advances, particularly by exploring the concept of OSR, sexual selection studies today are becoming more fine-tuned and dynamic. The original role of parental investment in predicting sexual selection has recently been complemented by the use of sexual differences in potential reproductive rates (PRR).
Related Concept Videos
Mate Choice
Natural Selection and Mating Preferences
Females, due to their biological roles in conception, pregnancy, and nursing, inherently...
Competition
Types of Selection
Criticisms of the Evolutionary Perspective
Evolutionary psychology provides one explanation for these findings, suggesting...
The Ratio of X Chromosome to Autosomes
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...

