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 Toward a 'smart' patch that automatically delivers insulin when needed
18.01.2017 | American Chemical Society

nachricht 127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>