Related Experiment Video
Updated: Jul 17, 2026
04:10
Visually Sexing Loggerhead Shrike (Lanius Ludovicianus) Using Plumage Coloration and Pattern
Published on: March 8, 2020
The evolution of condition-dependent sexual dimorphism.
1School of Biological, Earth, and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia. r.bonduriansky@unsw.edu.au
The American Naturalist
|January 9, 2007
Summary
Individual condition strongly influences sexual traits in flies, revealing a close link between sexual dimorphism and condition dependence. This suggests shared genetic and developmental pathways underlie these variations.
Area of Science:
- Evolutionary biology
- Animal behavior
- Genetics
Background:
- Sexual traits evolve under sexual selection and individual condition.
- Sexual dimorphism and condition dependence are predicted to covary.
- The link between sexual dimorphism and condition dependence is poorly understood.
Purpose of the Study:
- To investigate the effects of condition on multivariate sexual dimorphism.
- To examine the covariation between condition dependence and sexual dimorphism.
Main Methods:
- Studied the fly Telostylinus angusticollis.
- Manipulated larval diet quality to alter individual condition.
- Analyzed multivariate sexual dimorphism in body shape and size.
Main Results:
- Condition affected the direction of sexual size dimorphism and modulated sexual shape dimorphism.
- Male sexual traits showed the greatest response to condition manipulation.
- Condition dependence strongly predicted the magnitude of sexual dimorphism, explaining over 90% of variation.
Conclusions:
- Sexual dimorphism and condition dependence are tightly linked in T. angusticollis.
- Genetic mechanisms for sexual dimorphism operate in a condition-dependent manner.
- Shared genetic and developmental bases likely underlie within- and between-sex variation.
Related Concept Videos
01:20Mate Choice
Mate choice—the decision about whom to mate with—is a type of natural selection, since animals must reproduce to pass down their genes. Mate choice is also called intersexual selection because the behavior occurs between the sexes.
01:06Natural Selection and Mating Preferences
The principle of natural selection posits that organisms better adapted to their environment are more likely to survive and reproduce. This principle is closely intertwined with mating preferences, a key aspect of sexual selection, which evolutionary psychologists believe is driven by instincts to propagate one's genes. Such instincts significantly influence mating behaviors and preferences between genders.
Females, due to their biological roles in conception, pregnancy, and nursing, inherently...
Females, due to their biological roles in conception, pregnancy, and nursing, inherently...
01:46Types of Selection
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
01:23Criticisms of the Evolutionary Perspective
In a study where individuals posing as strangers offered compliments and proposed casual sex to students, the responses differed significantly based on gender. Not a single woman accepted the proposal, while 70% of the men agreed. This outcome provides a useful scenario to explore through the lens of evolutionary psychology and social learning theory, highlighting the diverse perspectives on human sexual behaviors.
Evolutionary psychology provides one explanation for these findings, suggesting...
Evolutionary psychology provides one explanation for these findings, suggesting...
02:27Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s 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...
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...
01:20Evolutionary Psychology
Evolutionary psychology explores the origins of human behavior and mental processes by framing them within the context of natural selection, a theory famously propounded by Charles Darwin. This field asserts that many behaviors common across human societies — ranging from instinctive fear reactions to complex social interactions — arose as evolutionary adaptations. These adaptations enhanced the survival and reproductive success of our ancestors, thereby becoming embedded in the human psyche...