Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Meaningless sex? Male mounting reduces the sexual promiscuity of hens

18.07.2005


Why does a male copulate without delivering semen? In a study that sheds new light on the evolution of sexual behaviour, researchers have utilised a novel technique to reveal that in feral chickens, the simple stimulus generated by male mounting reduces the sexual promiscuity of a hen, indicating that even copulations that do not result in semen transfer, a puzzling male behaviour frequently observed in the chicken and many other species, may be crucial to defend the paternity of a male.



Females of many species often copulate with multiple males, leading to the competition between the ejaculates of different males over fertilisation (sperm competition). Males are therefore selected to avoid sperm competition by preventing females from mating with other males. In a number of species, mostly insects, female promiscuity is temporarily reduced following copulation and this has been associated with highly specialised male insemination products. However, these paternity defence mechanisms typically require costly male investment in a female, and are at odds with the fact that males often copulate without delivering semen. Importantly, previous studies have not considered that female promiscuity may be inhibited by stimuli generated by the simple act of male mounting.

In a new study, a team of researchers from Stockholm University (Sweden), University of Sheffield and University of Oxford (UK) tested this idea in the sexually promiscuous chicken, using a novel technique that separates the effect of insemination products from that of mounting alone. The researchers detected the response of hens to the mounting of a rooster, by fitting some hens with a light plastic harness covering their cloaca, thus preventing insemination. The use of this technique demonstrated that mounting alone (independently of insemination) not only drastically inhibits the propensity of a hen to mate with a new rooster, but also reduces the number of sperm that she obtains from a new rooster in the 2-4 days following mounting. Therefore, roosters can defend their paternity by reducing the promiscuity of the hens that they have inseminated, by exploiting the hen’s response to the simple stimulus of mounting. Consistent with this idea, roosters often mount hens that they previously inseminated without delivering additional semen. Therefore, this study demonstrates that even though the ultimate function of sex is fertilisation, copulations resulting in the delivery of little or no sperm are not necessarily functionally meaningless but may have an important evolutionary significance.

Hanne Lovlie | alfa
Further information:
http://www.su.se

More articles from Life Sciences:

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

nachricht CWRU researchers find a chemical solution to shrink digital data storage
22.06.2017 | Case Western Reserve University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>