Related Experiment Video
Updated: May 28, 2026

Assessing Differences in Sperm Competitive Ability in Drosophila
Published on: August 22, 2013
Understanding dimorphism as a function of changes in male and female traits
1University of Arkansas, Fayetteville, AR, USA. mplavcan@uark.edu
Abstract:
I once received a review of a manuscript that took exception to the analysis of sexual dimorphism because the phenomenon is reified from independent changes in male and female characters. The reviewer was both right and wrong. Sexual dimorphism, a difference between males and females of a species in any anatomical, physiological, or behavioral character, is real in the sense that it reflects some underlying difference between the sexes. The fact that the magnitude of these differences varies among species in a measurable and constant way suggests that the phenomenon has a biological basis. But it is also true that dimorphism is a product of independent changes in male and female traits. It is becoming more and more apparent that a complete understanding of the phenomenon of sexual dimorphism can be achieved only by understanding variation in the factors that affect both male and female traits, and the potentially different responses to those factors in each sex.
Related Concept Videos
Mate Choice
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...
X-linked Traits
X-linked Traits
Background and Environment Affect Phenotype
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
Dosage Compensation
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...

