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.
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.
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
Lukas Schärer, University of Basel, Zoological Institute, Tel. +41 61 267 03 66, email: firstname.lastname@example.org
Steven A. Ramm, Evolutionary Biology, Bielefeld University, Tel. +49 521 106 2719, email: email@example.com
Olivia Poisson | Universität Basel
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy