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
Velcro for human cells
16.01.2019 | Albert-Ludwigs-Universität Freiburg im Breisgau
More efficient solar cells imitate photosynthesis
16.01.2019 | Friedrich-Alexander-Universität Erlangen-Nürnberg
Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.
In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...
Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.
It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:
The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.
One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...
Just in time for Christmas, a Mars-analogue mission in Morocco, coordinated by the Robotics Innovation Center of the German Research Center for Artificial Intelligence (DFKI) as part of the SRC project FACILITATORS, has been successfully completed. SRC, the Strategic Research Cluster on Space Robotics Technologies, is a program of the European Union to support research and development in space technologies. From mid-November to mid-December 2018, a team of more than 30 scientists from 11 countries tested technologies for future exploration of Mars and Moon in the desert of the Maghreb state.
Close to the border with Algeria, the Erfoud region in Morocco – known to tourists for its impressive sand dunes – offered ideal conditions for the four-week...
Research opens doors in photonic quantum information processing, optical signal processing and microwave photonics
Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new integrated photonics platform that can...
16.01.2019 | Event News
14.01.2019 | Event News
12.12.2018 | Event News
16.01.2019 | Life Sciences
16.01.2019 | Physics and Astronomy
16.01.2019 | Earth Sciences