Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The Bizarre Mating Habits of Flatworms

01.07.2015

Failing to find a mating partner is a dent to the reproductive prospects of any animal, but in the flatworm species Macrostomum hystrix it might involve a real headache.

Zoologists from the Universities of Basel and Bielefeld have discovered the extraordinary lengths to which this animal is willing to go in order to reproduce – including apparently injecting sperm directly into their own heads. The academic journal Proceedings of the Royal Society B has published their findings.


MicrMacrostomum hystrix showing the anterior eyes (1) in the head, followed by the paired testes (2), paired ovaries (3), developing eggs (4), the female genitalia containing three ma

(Image: Lukas Schärer)

The absence of a mate usually spells disaster for sexually reproducing animals. However, some simultaneous hermaphrodites – animals who have both male and female sex organs at the same time – have developed an escape route for this scenario: self-fertilization. It is an imperfect solution, as any offspring produced by so-called “selfing” are bound to be inbred, but still better than not reproducing at all.

In previous studies, it had been established that the flatworm species Macrostomum hystrix is capable of switching to just such selfing behavior when isolated from mating partners, a behavior found in many but not all simultaneous hermaphrodites. In their new study, Dr. Lukas Schärer from the University of Basel and his team now show the bizarre, yet remarkable mechanisms Macrostomum hystrix has developed that make this possible.

A shot to the head

The studied flatworms are highly transparent and their insides can therefore be easily observed under the microscope. By doing so, the zoologists discovered that under selfing conditions, when hermaphroditic individuals had to use their own sperm to fertilize their own eggs, the worms had very few sperm in their tail region.

This is in stark contrast to worms kept in a group, which contained most sperm in their tails, close to where fertilization actually occurs. Instead, isolated worms had more sperm in their head region.

This implies a rather strange insemination route: by using its needle-like male copulatory organ, an isolated worm can self-inject sperm into its own anterior body, from where the sperm then moves through the body towards the eggs.

“As far as we know, this is the first described example of hypodermic self-injection of sperm into the head. To us this sounds traumatic, but to these flatworms it may be their best bet if they cannot find a mate but still want to reproduce” explains Dr. Steven Ramm, first-author of the study.

Such a convoluted route is likely needed because, although hermaphrodites, there are no internal connections between the worm’s male and female reproductive systems.

Original source

Ramm SA, Schlatter A, Poirier M, Schärer L (2015)
Hypodermic Self-Insemination as a Reproductive Assurance Strategy
Proceedings of the Royal Society B | doi:10.1098/rspb.2015.0660

Further information

Lukas Schärer, University of Basel, Zoological Institute, Tel. +41 61 267 03 66, email: lukas.scharer@unibas.ch

Steven A. Ramm, Evolutionary Biology, Bielefeld University, Tel. +49 521 106 2719, email: steven.ramm@uni-bielefeld.de

Weitere Informationen:

https://www.unibas.ch/en/News-Events/News/Uni-Research/The-Bizarre-Mating-Habits...

Olivia Poisson | Universität Basel

Further reports about: Biology Evolutionary Macrostomum animals eggs flatworm mechanisms offspring species

More articles from Life Sciences:

nachricht Individual Receptors Caught at Work
19.10.2017 | Julius-Maximilians-Universität Würzburg

nachricht Rapid environmental change makes species more vulnerable to extinction
19.10.2017 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Electrode materials from the microwave oven

19.10.2017 | Materials Sciences

New material for digital memories of the future

19.10.2017 | Materials Sciences

Physics boosts artificial intelligence methods

19.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>