Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

The Ratio of X Chromosome to Autosomes

The Ratio of X Chromosome to Autosomes

In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...

Dosage Compensation

Dosage Compensation

In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one Y chromosome, whereas C.elegans with one X chromosome is a male, and the one with two X chromosomes is a hermaphrodite.
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...

Background and Environment Affect Phenotype

Background 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...

Mate Choice

Mate 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.

Understanding Species and Reproductive Barriers

Understanding Species and Reproductive Barriers

A species is a group of organisms that interbreed and produce fertile offspring. Typically, individuals of the same species appear similar and share common characteristics due to their highly similar genomes. However, not all organisms that look alike are members of the same species. Various mechanisms keep most species discrete. While some mechanisms prevent reproductive behavior and fertilization (pre-zygotic isolation), others prevent the production of fertile offspring after mating has...

Formation of Species

Formation of Species

Speciation describes the formation of one or more new species from one or sometimes multiple original species. The resulting species are discrete from the parent species, and barriers to reproduction will typically exist. There are two primary mechanisms, speciation with and without geographic isolation—allopatric and sympatric speciation, respectively.Allopatric SpeciationIn allopatric speciation, gene flow between two populations of the same species is prevented by a geographic barrier, like...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Meta-analysis-derived estimates of stressor-response associations for riverine organism groups.

Nature ecology & evolution·2025

Same author

Macrophytes and their sedimentary phosphorus niche in lowland rivers.

PloS one·2025

Same author

Factors Driving Background Choice in Scorpionfish.

Ecology and evolution·2025

Same author

Evolution and co-evolution of the suck behaviour, a postcopulatory female resistance trait that manipulates received ejaculate.

BMC biology·2025

Same author

Integrative phylogenomics sheds light on the diversity and evolution of fluorescence in coral-dwelling gall crabs.

Proceedings. Biological sciences·2025

Same author

Differential associations of five riverine organism groups with multiple stressors.

The Science of the total environment·2024

Search research articles

Related Experiment Video

Updated: Jul 17, 2026

Measuring Sperm Guidance and Motility within the Caenorhabditis elegans Hermaphrodite Reproductive Tract

Measuring Sperm Guidance and Motility within the Caenorhabditis elegans Hermaphrodite Reproductive Tract

Published on: June 6, 2019

Phenotypically flexible sex allocation in a simultaneous hermaphrodite.

Verena S Brauer¹, Lukas Schärer, Nico K Michiels

¹Department of Evolutionary Biology, University of Muenster, Huefferstrasse 1, 48149 Muenster, Germany. v.s.brauer@rug.nl

Evolution; International Journal of Organic Evolution

|February 16, 2007

Summary

Simultaneous hermaphrodites, like the flatworm Macrostomum lignano, can adjust their sex allocation after maturation. This phenotypic flexibility allows them to opportunistically shift resources between male and female functions based on social environment.

More Related Videos

Effect of Male Accessory Gland Products on Egg Laying in Gastropod Molluscs

Effect of Male Accessory Gland Products on Egg Laying in Gastropod Molluscs

Published on: June 22, 2014

Manipulation of Ploidy in Caenorhabditis elegans

Manipulation of Ploidy in Caenorhabditis elegans

Published on: March 15, 2018

Related Experiment Videos

Last Updated: Jul 17, 2026

Measuring Sperm Guidance and Motility within the Caenorhabditis elegans Hermaphrodite Reproductive Tract

Measuring Sperm Guidance and Motility within the Caenorhabditis elegans Hermaphrodite Reproductive Tract

Published on: June 6, 2019

Effect of Male Accessory Gland Products on Egg Laying in Gastropod Molluscs

Effect of Male Accessory Gland Products on Egg Laying in Gastropod Molluscs

Published on: June 22, 2014

Manipulation of Ploidy in Caenorhabditis elegans

Manipulation of Ploidy in Caenorhabditis elegans

Published on: March 15, 2018

Area of Science:

Evolutionary Biology
Reproductive Biology
Animal Behavior

Background:

Simultaneous hermaphrodites possess both male and female reproductive organs.
Previous research focused on evolutionary or developmental optimization of sex allocation, neglecting lifetime variation.
The capacity for facultative sex allocation in hermaphrodites remains largely unexplored.

Purpose of the Study:

To investigate facultative sex allocation in simultaneous hermaphrodites.
To determine if phenotypic flexibility in resource allocation to reproduction occurs within an individual's lifetime.
To assess the influence of social environment on sex allocation strategies.

Main Methods:

Utilized the simultaneously hermaphroditic flatworm Macrostomum lignano.
Manipulated group sizes (pairs vs. octets) to alter local mate competition.
Compared sex allocation patterns in response to changing social environments.

Main Results:

Flatworms demonstrated facultative sex allocation in response to altered group sizes.
Increased group size led to a more male-biased sex allocation.
Decreased group size resulted in a more female-biased sex allocation.

Conclusions:

Sex allocation in M. lignano is not fixed post-maturation but remains phenotypically flexible.
Facultative sex allocation allows hermaphrodites to opportunistically adjust reproductive investment.
This flexibility may be crucial for understanding the evolution and ecology of hermaphroditism.