Related Experiment Video
Updated: May 31, 2026
04:10
Visually Sexing Loggerhead Shrike (Lanius Ludovicianus) Using Plumage Coloration and Pattern
Published on: March 8, 2020
A macroevolutionary perspective on multiple sexual traits in the phasianidae (galliformes).
Rebecca T Kimball1, Colette M St Mary, Edward L Braun
1Department of Biology, University of Florida, P.O. Box 118525, Gainesville, FL 32611, USA.
International Journal of Evolutionary Biology
|July 1, 2011
Summary
Many animal species have multiple sexual signals, but their evolution is complex. This study found that sexual signals in pheasants and partridges are lost more often than gained, suggesting diverse evolutionary pressures.
Area of Science:
- Evolutionary Biology
- Animal Behavior
- Sexual Selection
Background:
- Sexual signaling traits are widespread in animals, with many species displaying multiple signals.
- The evolution of multiple sexual signals is debated, with microevolutionary hypotheses focusing on signaling costs and receiver limitations.
- Understanding the macroevolutionary patterns of sexual dimorphism is crucial for explaining signal evolution.
Purpose of the Study:
- To extend microevolutionary hypotheses of multiple sexual signal evolution to a macroevolutionary scale.
- To compare evolutionary predictions with observed patterns of sexual dimorphism gains and losses in pheasants and partridges.
- To investigate the selective processes driving the evolution of sexual signals in phasianids.
Main Methods:
- Comparative analysis of sexual dimorphism patterns across pheasants and partridges.
- Examination of gains and losses of nine dimorphic characters, including intersexual signals and competitive ability indicators.
- Macroevolutionary modeling to test predictions of different evolutionary hypotheses.
Main Results:
- All nine dimorphic characters studied exhibited both gains and losses of dimorphism within the pheasant and partridge group.
- Intersexual signals showed higher rates of loss than gain, contrary to expectations from intersexual selection theories.
- Competitive traits displayed a slight bias towards gains, while models failed to provide unique predictions for distinguishing between hypotheses.
Conclusions:
- The evolution of sexual dimorphism in pheasants and partridges is characterized by heterogeneous patterns of gains and losses.
- Loss rates exceeding gain rates for intersexual signals suggest complex selective pressures beyond simple elaboration.
- Multiple, varied selective processes have likely contributed to the evolution of sexual signals in this avian group.
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.
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...
01:23Criticisms 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...
01:24Evolution of New Traits in Microbes
Microorganisms evolve rapidly due to their large population sizes and short generation times, often exhibiting measurable changes within days under laboratory conditions. Natural selection acts on standing genetic variation, enabling the retention and amplification of beneficial traits that confer fitness advantages in changing environments.Adaptive Pigment Regulation in RhodobacterIn Rhodobacter, a genus of purple non-sulfur bacteria, light-harvesting pigments such as bacteriochlorophyll and...
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...
02:16Genetics of Speciation
Speciation is the evolutionary process resulting in the formation of new, distinct species—groups of reproductively isolated populations.