Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Worms triple sperm transfer when paternity is at risk

08.05.2008
Scientists used to think that hermaphrodites, due to their low position in the evolutionary scale, did not have sufficiently developed sensory systems to assess the “quality” of their mates. A new work has shown, however, that earthworms are able to detect the competition by fertilising the eggs that is going to find its sperm, tripling its volume when there is rivalry. This ability is even more refined as they are able to transfer more sperm to more fertile partners.

Hermaphrodites, organisms that have both female and male reproductive organs, such as earthworms, are denied the right to choose their partner. However, a study by researchers at the University of Vigo has shown that worms are capable of telling whether another worm is a virgin or not, and triple the volume of sperm transferred during copulation if they detect a fertilisation competition risk.

According to the study, which appears in the latest edition of the magazine Proceedings of Royal Society B-Biological Sciences, the partner’s assessment ability, which has often been considered incompatible with invertebrates, is a firm characteristic of worms when their sperm is competing for fertilisation. Authors of the study explained to SINC that “in high sperm competition situations, partner assessment is subject to strong selection in hermaphrodites, making these organisms very selective when choosing to whom and how much sperm to transfer”.

In total, scientists analysed 42 mature and virgin worms, allowing researchers to reach their conclusions. When worms detect a risk of their sperm competing with their rivals, these invertebrates are able to determine whether their partners have copulated previously, in which case they increase the volume of sperm donated. “This increase is even higher when worms mate with much larger partners, as they are more fertile”, explains Jorge Domínguez, one of the authors of the study.

Worms control their sperm volume

Thanks to the double mating experiment carried out by the scientists, the results show that worms have a refined control over the volume of sperm transferred during copulation according to the sex of the partner they are mating with. The advantage of donating such amounts of sperm is due to the highly competitive environment in which these hermaphrodites live.

Multiple mating is common amongst worms and the reason why they have developed specific strategies to deal with strong sperm competition in fertilisation. Researchers suggest that “sperm competition in fertilisation is an evolutionary force which has affected worm mating behaviour”.

Worm courting can last up to an hour during which time the organisms secrete large amounts of mucus and press against each other with short, repetitive rubbing actions for subsequent exchange of sperm. If there is no fertilisation competition, worms are prudent in how much sperm they release, even waiting to mate with high-quality partners. “Worms can control copulation time or, alternatively, can have mechanisms which prevent all their sperm being released in a single mating event”, stress the authors.

The results of the study conclude that the volume of sperm donated to worms that are not virgins has been more variable than that transferred to virgin partners. In this respect, researchers estimated that the volume transferred to larger size partners which had previously copulated was five times greater than that transferred to virgin worms.

SINC Team | alfa
Further information:
http://www.plataformasinc.es

Further reports about: Competition fertilisation mating sperm transferred volume

More articles from Life Sciences:

nachricht Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University

nachricht Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017
25.04.2017 | Laser Zentrum Hannover e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>